20230103IPC to Staff 19-31.pdf

LISA D. NORDSTROM
Lead Counsel
[e-mail]
January 3, 2023
VIA ELECTRONIC FILING
Jan Noriyuki, Secretary
Idaho Public Utilities Commission 11331 West Chinden Blvd., Building 8 Suite 201-A Boise, Idaho 83714
Re: Case No. IPC-E-22-27 In the Matter of Idaho Power Company’s Application for Review of the Company’s Current Wildfire Mitigation Plan and Authorization to Defer Newly Identified Incremental Wildfire Mitigation Costs
Dear Ms. Noriyuki:
Attached for electronic filing is Idaho Power Company’s Response to the Second Production Request of the Commission Staff in the above-entitled matter.
The confidential attachment will be provided to the parties that execute the Protective Agreement in this matter.
If you have any questions about the attached documents, please do not hesitate to contact me.
Very truly yours,
Lisa D. Nordstrom LDN:sg Attachments
RECEIVED
Tuesday, January 3, 2023 3:18:46 PM
IDAHO PUBLIC
UTILITIES COMMISSION

CERTIFICATE OF ATTORNEY

ASSERTION THAT INFORMATION CONTAINED IN AN IDAHO PUBLIC UTILITIES
COMMISSION FILING IS PROTECTED FROM PUBLIC INSPECTION
Case No. IPC-E-22-27
Idaho Power Company’s Application for Review of the Company’s Current
Wildfire Mitigation Plan and Authorization to Defer Newly Identified Incremental
Wildfire Mitigation Costs

The undersigned attorney, in accordance with Commission Rules of Procedure 67 and 233, believes that the Attachment 1 in response to Request No. 28 to Idaho Power Company’s Response to the Second Production Request of the Commission
Staff dated January 3, 2023, may contain information that Idaho Power Company or a third party claims is confidential as described in Idaho Code § 74-101, et seq., and § 48-801, et seq., and as such is exempt from public inspection, examination, or copying.
DATED this 3rd day of January 2023.

LISA D. NORDSTROM Attorney for Idaho Power Company

IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 1
LISA D. NORDSTROM (ISB No. 5733) MEGAN GOICOECHEA ALLEN (ISB No. 7623) Idaho Power Company
1221 West Idaho Street (83702) P.O. Box 70 Boise, Idaho 83707 Telephone: [phone] Facsimile: [phone]
[e-mail]
[e-mail] Attorneys for Idaho Power Company
BEFORE THE IDAHO PUBLIC UTILITIES COMMISSION
IN THE MATTER OF THE APPLICATION
OF IDAHO POWER COMPANY FOR REVIEW OF THE COMPANY’S CURRENT WILDFIRE MITIGATION PLAN AND AUTHORIZATION TO DEFER
NEWLY IDENTIFIED INCREMENTAL
WILDFIRE MITIGATION COSTS
)
) ) ) )
)
) )

CASE NO. IPC-E-22-27 IDAHO POWER COMPANY’S RESPONSE TO THE SECOND
PRODUCTION REQUEST OF THE
COMMISSION STAFF TO IDAHO POWER COMPANY
COMES NOW, Idaho Power Company (“Idaho Power” or “Company”), and in
response to the Second Production Request of the Commission Staff (“Commission” or
“Staff”) dated December 13, 2022, herewith submits the following information:
IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 2
REQUEST FOR PRODUCTION NO. 19: Please describe alternative methods to
the proposed vegetation-focused satellite and aerial patrols that the Company evaluated.
Application at 21. Please provide the analysis the Company completed to determine the
use of vegetation-focused satellite and aerial patrols. Please include Excel spreadsheets
with cost comparisons between all alternative methods evaluated by the Company.
RESPONSE TO REQUEST FOR PRODUCTION NO. 19: In 2022, Idaho Power
evaluated a variety of new technologies and innovative practices that have potential to
reduce wildfire risk and associated impacts to customers and communities. Satellite
imagery was one such area the Company identified through benchmarking, as the
practice is being used by several western utilities, including Avista. Given the expense of
Idaho Power’s vegetation management program, the Company considers it prudent to
explore the potential of aerial and satellite imagery in a pilot setting.
With targeted satellite imagery, the process of tasking satellites, acquiring data,
and performing in-depth analysis to identify vegetation encroachment and hazard trees
takes only days to weeks to perform (significantly less time than the manual process of
vegetation management and inspection), providing a greater degree of situational
awareness prior to wildfire season. Such a tool would allow Idaho Power to focus
resources more effectively and mitigate hazards more quickly than relying solely on
traditional vegetation management and associated field inspections.
The Company also explored using aircraft to conduct similar inspections with Light
Detection and Ranging (“LiDAR”) technology. Both satellites and aircraft can scan large
areas in short amounts of time to detect vegetation encroachment.

IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 3
Idaho Power started a pilot in the fourth quarter of 2022 to begin collecting satellite
and aircraft imagery data and is working with vendors to gain insight into the value of
using satellite and aircraft imagery in the Company’s high risk wildfire areas. The goal of
the pilot is to confirm the accuracy of information received from vendors and to determine
where efficiencies can be made to decrease ignition potential.
Please refer to the attachment to this response for a table summarizing the line
miles associated with the pilot and cost comparison between satellite and aircraft imagery
used for vegetation encroachment and hazard tree detection. Idaho Power plans to
assess the costs and benefits of these three technologies in the first quarter of 2023.
Geiger LiDAR has the potential to survey larger areas at lower costs but does not
provide insight into vegetation health and hazard tree detection like satellite imagery can.
Additionally, satellite imagery can detect vegetation growth rate and individual tree
species, which the Company is planning on exploring further in future years as a way to
create efficiencies in traditional vegetation management. Through discussions with other
utilities, the Company has learned that more targeted enhanced vegetation management,
aided by satellite imagery and focused on tree species, has the potential to decrease
vegetation contact and ignition risk. The Company’s pilot effort will explore whether the
Company may be able to realize such efficiencies in its own vegetation management
program.
The response to this Request is sponsored by Jon Axtman, T&D Engineering
and Reliability Senior Manager, Idaho Power Company.
IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 4
REQUEST FOR PRODUCTION NO. 20: Please explain how the proposed
vegetation-focused satellite and aerial patrols described in the Application differ from
currently used satellite methods such as how satellites are used for the Fire Potential
Index (“FPI”) in the Wildfire Mitigation Plan (“WMP”). Wildfire Mitigation Plan at 34. Please
describe the additional capabilities or advantages expected.
RESPONSE TO REQUEST FOR PRODUCTION NO. 20: Idaho Power’s
Atmospheric Science department uses satellite data to forecast the Fire Potential Index
(“FPI”) used throughout fire season to gain situational awareness. Satellite imagery is
used as part of a data assimilation process to develop numerical weather models that are
used to forecast weather conditions in each region. Satellite data is also used to adjust
timing on forecasted weather conditions (e.g., when the models are behind or ahead of
actual conditions) and to determine the intensity of events (e.g., precipitation, wind,
thunderstorms). This satellite data allows calculation of the weather component of the
FPI. In addition, a satellite-derived product—the Normalized Difference Vegetation
Index—is used to determine the state of native grasses, the green-up component of the
FPI.
The key difference between how satellite data is used between atmospheric
science and vegetation management is in scale and context. The Atmospheric Science
department uses satellite data at the scale of 30 meters to 10 kilometers to look
at/collect parameters at a time scale of minutes to hours, whereas satellite imagery for
the purposes of vegetation management uses a finer scale (30-50 centimeters) to
determine proximity of vegetation to lines and facilities and generally is used at time
scales of weeks. The data sets are distinctively different and cannot be interchanged.
IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 5
The response to this Request is sponsored by Jon Axtman, T&D Engineering and
Reliability Senior Manager, and Mel Kunkel, Senior Atmospheric Scientist, Idaho Power
Company.
IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 6
REQUEST FOR PRODUCTION NO. 21: The Company states that “in 2024 and
beyond, it will utilize contract purchase services to aid in further refinement of the
ensemble weather forecast system and weather and climate data analysis.” Application
at 12. Please describe how the contract purchase services will be monitored following
implementation.
RESPONSE TO REQUEST FOR PRODUCTION NO. 21: Contract purchase
services will adhere to and be monitored based upon executed Professional Service
Agreements and Statements of Work that outline the scope of services, deliverables and
milestones, and compensation of those providing services related to refinement of the
ensemble weather forecast system and weather and climate data analysis in 2024 and
beyond.
The response to this Request is sponsored by Kresta Davis, Water Resources and
Policy Senior Manager, Idaho Power Company.
IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 7
REQUEST FOR PRODUCTION NO. 22: Please provide the analysis used by the
Company to determine that field observers will benefit from the deployment of mobile
weather kits. Application at 14.
a. How many field observers does the Company deploy?
b. How will the Company determine which field observers will be issued kits?
RESPONSE TO REQUEST FOR PRODUCTION NO. 22: In developing Idaho
Power’s Public Safety Power Shutoff (“PSPS”) program, the Company benchmarked with
other utilities to understand the benefit of deploying personnel to high wildfire risk and
PSPS areas to monitor real-time conditions. The Company found that most utilities use
Field Observers (“FOB”) in some capacity as part of their de-energization decision-
making process.
The Company currently has 24 trained Field Observers made up of Line
Operations Technicians, Distribution Designers, Patrolmen, and other technician roles.
There are between two and four FOBs for each major region within the Company’s
service area to ensure timely response to a PSPS event and to provide backup for long-
duration weather events. Each FOB is assigned weather instrumentation and carries it
on their vehicle during wildfire season to ensure a rapid response for PSPS can be
achieved.
The use of weather instruments (that is, mobile weather kits) is key to accurately
reporting real-time conditions, ensuring consistent observations, and helping
supplement information from fixed weather stations. The weather instruments include a
handheld wind meter, compass, and a notebook to record data.

IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 8
The response to this Request is sponsored by Jon Axtman, T&D Engineering and
Reliability Senior Manager, Idaho Power Company.
IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 9
REQUEST FOR PRODUCTION NO. 23: Please explain why the Company’s
Transition to/Maintain 3-yr Vegetation Management Cycle in Attachment 2 is
approximately $1.175 million higher in 2024 than planned spend for 2025. Please provide
supporting workpapers.
RESPONSE TO REQUEST FOR PRODUCTION NO. 23: Idaho Power estimated
that the transition to a three-year vegetation management cycle would be complete in the
latter half of 2025. Once the transition is complete, maintaining the system on a
sustainable three-year vegetation management cycle should require a levelized workload
that is lower than the workload required during the transition. During the transition in
2024, Idaho Power estimated almost 135,000 crew hours would be needed. Fewer crew
hours would be needed in 2025 after the transition is complete, bringing the estimated
crew hours down to approximately 124,000 in 2025. The reduced workload in 2025
results in a $1.175 million dollar reduction compared to 2024.
For documentation of vegetation management expenses, please see the
workpaper associated with the Company’s response to Staff’s production request 16.
The response to this Request is sponsored by Brent Van Patten, Engineering
Leader, Idaho Power Company.
IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 10
REQUEST FOR PRODUCTION NO. 24: Please describe what membership in the
Idaho Fire Board entails, provide how often the group meets, and supply copies of or links
to meeting information and minutes.
RESPONSE TO REQUEST FOR PRODUCTION NO. 24: Idaho Power has been
a member of the Idaho Fire Board (“Board”) since 2021. The Board holds meetings at
least quarterly. In response to this question, please see Attachments 1-4 to this request
which include the Fire Board charter (Attachment 1), the Board’s meeting agenda from
December 2022 (Attachment 2), the agenda from the October 2022 meeting (Attachment
3), and meeting notes from the October 2022 meeting (Attachment 4).
The response to this Request is sponsored by Jon Axtman, T&D Engineering
and Reliability Senior Manager, and Allison Murray, Environmental Manager, Idaho
Power Company.
IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 11
REQUEST FOR PRODUCTION NO. 25: Please describe the composition of the
Technology Strategy Initiative team and function of each member.
RESPONSE TO REQUEST FOR PRODUCTION NO. 25: In 2021, Idaho Power
established an initiative to explore new and innovative technologies that can be used to
decrease wildfire risk and associated impact on customers and communities. The
Wildfire Mitigation Technologies Project was established in support of the initiative and
includes five Idaho Power employees with diverse experience in transmission and
distribution operation, design, maintenance, reliability, protection, and analytics. The
Wildfire Mitigation Technologies Project is sponsored by Mitch Colburn, Idaho Power’s
Vice President of Planning, Engineering, and Construction. Project members and their
function are as follows:

 Jon Axtman, T&D Engineering and Reliability Senior Manager, project lead.
Focus areas include advanced materials and risk management.
 Steve Cozine, Senior Engineer, T&D Maintenance. Focus areas include wildfire
detection cameras, satellite imagery, and vegetation management.
 Brett Efaw, Senior Application Development Analyst. Focus area includes data
analytics and incorporating artificial intelligence (AI) and machine learning into
wildfire technology programs.
 Steve Moodry, Senior Engineer, Reliability Engineering. Focus areas include
advanced relay protection, decrease ignition potential under fault conditions, line
sensors, and fault locating.
IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 12
 Mike Spengler, Unmanned Aerial Systems (UAS) Program Manager. Focus area
includes asset inspection using drones and high-altitude aircraft, AI for defect
detection, and communication opportunities.
As part of this technology initiative, the team developed a six-year roadmap to begin
integrating new technologies and innovations into activities performed as part of the
Company’s Wildfire Mitigation Plan.
The response to this Request is sponsored by Jon Axtman, T&D Engineering and
Reliability Senior Manager, Idaho Power Company.
IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 13
REQUEST FOR PRODUCTION NO. 26: Please clarify if the Company’s fuel
reduction plan includes the regional fuel reduction program described on page 29 of the
2022 WMP. Additionally, please explain how costs are determined and allocated among
participants in the regional fuel plan. Please provide supporting workpapers.
RESPONSE TO REQUEST FOR PRODUCTION NO. 26: As an initial point of
clarification, Idaho Power conducts vegetation management, but does not consider this a
fuel reduction plan. Separately, the Company is taking part in a fuel reduction program,
as discussed on page 29 of the WMP and inquired about by Staff. The efforts undertaken
as part of the fuel reduction program are distinct from the activities performed as part of
the Company’s vegetation management work.
The fuel reduction program involves a partner-based strategy with the National
Forest Foundation (“NFF”) and other agencies to perform thinning of fuels in the Boise
Front Focal Area. Please see the Attachment 1 to this response for additional
information about the NFF Boise Front Focal Area. The partnership is designed to
enhance forest resilience, decrease hazardous fuel accumulations, increase powerline
resiliency while minimizing the risk of ignitions, and improve forest conditions in the
vicinity of Idaho Power infrastructure.
While Idaho Power has not yet established agreements with the NFF, the
Company expects that the NFF will act as an aggregator of funding for contracts
associated with work on the ground and oversee the work to ensure it is completed to
specification.
Idaho Power’s estimated costs were derived through verbal discussions about
costs incurred by Avista for a similar program with the Idaho Department of Lands.
IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 14
Additionally, the Company evaluated similar projects in Arizona and California, where
utilities contributed $100,000-$500,000/year.
The response to this Request is sponsored by Jon Axtman, T&D Engineering and
Reliability Senior Manager, Idaho Power Company.
IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 15
REQUEST FOR PRODUCTION NO. 27: Please provide an analysis that shows
how and why a 10-year cycle was selected for the detailed visual inspection and wood
pole ground line inspection programs. Please provide supporting workpapers.
RESPONSE TO REQUEST FOR PRODUCTION NO. 27: For clarity, Idaho Power
established a 10-year inspection and treatment cycle many years ago and has not
changed this cycle as a result of the Company’s WMP activities. That said, the Company
below provides some explanation of the function and purpose of the 10-year inspection
cycle across the Company’s service area.
Idaho Power aims to maximize the service life of wood poles, with service life
dependent on factors including pole classification, treatment, and conditions the pole is
exposed to at a given location. Idaho Power conducts inspections on a 10-year cycle to
detect decay and rot and to assess the remaining life. The inspection typically includes
application of a fumigant to provide an effective means to combat the spread of insect
damage and fungus decay in wood poles.
The Company is part of the Oregon State University Utility Pole Research
Cooperative (“UPRC”). The UPRC works to improve the performance of utility poles
through research on preservative treatments, biological decay, specifications,
maintenance, and disposal. As a member of the UPRC, the Company participates in
meetings and provides feedback for wood pole performance and practices in Idaho
Power’s service area. The UPRC and North American Wood Pole Council have
published that a 10-year inspection cycle is common for utilities.
In support of this response, please see Technical Bulletin on the Estimated
Service Life of Wood Poles and Wood Pole Maintenance Manual provided as
IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 16
Attachments 1 and 2, respectively, to this response. Based on work performed by the
UPRC and feedback from other utilities, Idaho Power considers a 10-year inspection
cycle accepted good practice for the industry.
The response to this Request is sponsored by Jon Axtman, T&D Engineering and
Reliability Senior Manager, Idaho Power Company.

IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 17
REQUEST FOR PRODUCTION NO. 28: Please provide a copy of the Company’s
Emergency Response Communication Plan.
RESPONSE TO REQUEST FOR PRODUCTION NO. 28: The Company has
attached to this request a confidential copy of its Outage Communication Playbook, a
document that was developed in 2022 and has taken the place of the Emergency
Response Communication Plan for the purposes of PSPS and load shed events. This
change is reflected in the 2023 WMP.
The response to this Request is sponsored by Naomi Shankel, Customer
Operations Support and Sustainability Senior Manager, Idaho Power Company.
IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 18
REQUEST FOR PRODUCTION NO. 29: Please quantify the updated overall cost
for the entire Wildfire Mitigation Plan for the years 2021 through 2025. Please include the
operating expenses specific to the wildfire mitigation plan, the increased vegetation
management expenses, Wildfire Mitigation Plan capital investments, the depreciation
expense associated with those capital expenditures, and the insurance cost. Please
break down the expenditures by project, by type of expense, and by year.
RESPONSE TO REQUEST FOR PRODUCTION NO. 29: Please see the
spreadsheet attached to this request.
The response to this Request is sponsored by Alison Williams, Regulatory Policy
and Strategy Leader, Idaho Power Company.
IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 19
REQUEST FOR PRODUCTION NO. 30: Please provide the supporting
documentation for the increase in insurance related to the Wildfire Mitigation Plan for
2021. Please provide any supporting documentation for the estimated increase to
insurance costs for 2022 and 2023.
RESPONSE TO REQUEST FOR PRODUCTION NO. 30: Idaho Power
experienced significant increases in the Company’s insurance premiums from 2020 to
2021. Based on the calendar year, total insurance costs were $12.1M in 2021 and are
expected to jump to $14.5M in 2022 and $15.6M in 2023. The Company’s 2022 costs are
based on an allocation of invoiced policy premiums from 2021 and 2022, and 2023 costs
are based on an allocation of invoiced policy costs for 2022 and an allocation of estimated
costs for 2023 policy renewals.
Please note that Idaho Power reported calendar year insurance costs in its
Application in this case. However, the Company’s actual insurance costs are based on
distinct policy years. For instance, the Company’s excess liability insurance renews each
July, meaning a portion of a policy year falls within two calendar years. To provide
reasonable cost comparisons across various insurance policies, Idaho Power converted
the cost of each insurance policy from policy year to calendar year. These two
breakdowns—policy year and calendar year—are provided in the attached spreadsheet
(Attachment 1 to this response).
Additionally, the Company has provided a 2021 memo from its third-party
insurance broker (Attachment 2 to this response), explaining the challenges of utilities
seeking to secure insurance in recent years based on wildfire risk.
The response to this Request is sponsored by Amy Shaw, Compliance, Risk &
IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 20
Security Director, Idaho Power Company.
IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 21
REQUEST FOR PRODUCTION NO. 31: Please provide the actual costs for 2021,
separated into the various components of the Wildfire Mitigation Plan. Please quantify
the incremental amounts that have been deferred by component.
RESPONSE TO REQUEST FOR PRODUCTION NO. 31: Please see the
spreadsheet attached to this request.
The response to this Request is sponsored by Alison Williams, Regulatory Policy
and Strategy Leader, Idaho Power Company.
IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 22
DATED at Boise, Idaho, this 3rd day of January 2023.

________________________________ LISA D. NORDSTROM Attorney for Idaho Power Company

IDAHO POWER COMPANY’S RESPONSE TO THE SECOND PRODUCTION REQUEST OF THE COMMISSION STAFF TO IDAHO POWER COMPANY - 23
CERTIFICATE OF SERVICE
I HEREBY CERTIFY that on the 3rd day of January 2023, I served a true and
correct copy of Idaho Power Company’s Response to the Second Production Request of the Commission Staff to Idaho Power Company upon the following named parties by the method indicated below, and addressed to the following:
Commission Staff Riley Newton Deputy Attorney General
Idaho Public Utilities Commission
11331 W. Chinden Blvd., Bldg No. 8 Suite 201-A (83714) PO Box 83720 Boise, ID 83720-0074

Hand Delivered U.S. Mail Overnight Mail
FAX
FTP Site X Email [e-mail]

Stacy Gust, Regulatory Administrative Assistant

BEFORE THE

IDAHO PUBLIC UTILITIES COMMISSION

CASE NO. IPC-E-22-27

IDAHO POWER COMPANY

REQUEST NO. 19

ATTACHMENT No. 1

SEE ATTACHED SPREADSHEET 

BEFORE THE

IDAHO PUBLIC UTILITIES COMMISSION

CASE NO. IPC-E-22-27

IDAHO POWER COMPANY

REQUEST NO. 24

ATTACHMENT NO. 1

IDAHO FIRE BOARD CHARTER
Version August 3, 2022
PURPOSE: This agreement expresses the commitment of Idaho Wildfire Board members to
work together on issues and opportunities around wildland fire management in the state of
Idaho. This document does not commit funding or other responsibilities or authorities to the
group beyond that which individual members wield as a representative of their organization.
The Idaho Wildfire Board will not attempt to engage in fire response and resource
prioritization; that is the role of the respective interagency coordination and dispatch system.
Our intent is to create a forum to discuss and solve wildland fire management issues at the
statewide level that does not currently exist.

BACKGROUND: The state of Idaho is a fire prone environment. Land ownership patterns are
complex and fire management agencies and bureaus have a long history of working together
and helping one another out. We work together in every aspect of fire management, from
sending closest forces to initial attack new starts to determining fire restrictions and managing
smoke.
Wildland fire staffing and resource prioritization are well managed by two different
Geographic Areas, with Northern Rockies coordinating fires in the north part of the state and
Great Basin coordinating fires in the south. This duality creates unique challenges in the
state, and there are opportunities to take a whole state view of issues and opportunities that
are sometimes missed between the two geographic areas.

OBJECTIVES: Members of the Idaho Wildfire Board will solicit issues ripe for discussion and
create solutions. The goal is to create a forum for discussion and problem solving to benefit
citizens of the state of Idaho and help the various partners be more efficient and successful
in accomplishing their own missions. Examples of the kinds of issues for the Board to
address may include dealing with the significant unprotected lands issue or crafting
meaningful, consistent messaging and initiatives around Idaho’s wildfires.

MEMBERSHIP: Membership is voluntary and open to all parties who participate in or are
affected by wildfire management.
Members may choose to designate a second member from their organization to represent
their interests if they cannot attend.

MEETINGS and GOVERNANCE: This group will meet in person or virtually quarterly or more
frequently if deemed necessary.
The Board will elect leadership for a term of two years, each position voted in every other
year, to aid in consistency. The Chair will set the agenda and facilitate meetings. The Vice
Chair will track issues and tasks, schedule meetings, and share information to the Board (i.e.
notes, assignments, documents, etc.).
There is no budget for this board at this time; all participants will pay their own expenses for
travel and time spent on projects or issues.
Decisions will be made by consensus of the Board.
This charter is a living document. Review and revision will be conducted on an annual basis.

BEFORE THE

IDAHO PUBLIC UTILITIES COMMISSION

CASE NO. IPC-E-22-27

IDAHO POWER COMPANY

REQUEST NO. 24

ATTACHMENT NO. 2
From:McCormick, Kyle
To:Harris, Dana -FS; [e-mail]; Cleverley, Susan (External); Murray, Allison; [e-mail];[e-mail]; [e-mail]; [e-mail]; Rau, Ralph -FS;[e-mail]; [e-mail]; [e-mail]; Glazier, Craig -FS;[e-mail]; Dingman, Gina - FS; [e-mail]
Cc:Julia Sullens; [e-mail]
Subject:December Idaho Fire Board Meeting
Start:Wednesday, December 15, 2021 2:30:00 PM
End:Wednesday, December 15, 2021 3:30:00 PM
Location:https://fema.zoomgov.com/j/1608267220
Hello all-
Looking forward to catching up with you all next week at our December Fie Board Meeting. Below is the agenda along with the Zoom meetinginformation. Please reach out with any questions.

Agenda:
* Introductions
* Drought Update and Winter Forecast- Basil Newmerzhycky* Idaho’s Unprotected Lands- Dennis Strange

Join ZoomGov Meeting- Click Link Below
https://fema.zoomgov.com/j/1608267220
Meeting ID: 160 826 7220
Passcode: 930303

BEFORE THE

IDAHO PUBLIC UTILITIES COMMISSION

CASE NO. IPC-E-22-27

IDAHO POWER COMPANY

REQUEST NO. 24

ATTACHMENT NO. 3
IDAHO FIRE BOARD
Agenda: Tuesday October 11, 2022
12:30 to 1:30 PM Mountain Time
Join ZoomGov Meeting
• https://fema.zoomgov.com/j/1605963819
• Passcode: 456405

Welcome and Opening Remarks
- Introduction to new members
Identify Top Concerns & Challenges—Group Discussion
- Identify primary objectives/tasks to concentrate our efforts
Next steps
- Identify steps to take to address top challenges as well as a timeframe for
next quarterly meeting

BEFORE THE

IDAHO PUBLIC UTILITIES COMMISSION

CASE NO. IPC-E-22-27

IDAHO POWER COMPANY

REQUEST NO. 24

ATTACHMENT NO. 4
October Fire Board Notes
Ideas for topics to tackle as a group:
• Unprotected lands issues
o Master agreements- implementation of protection plan-
o Over protected areas--dual joint response issues – when multiple agencies respond
o Utility infrastructure protection in unprotected areas
o Overall question: What are the issues in areas not formally protected by fire agencies?
What can this group do to solve those issues?
• Identify opportunities for how to prioritize Federal funding opportunities for supporting fire
management and mitigation opportunities. Breakdown how federal funding from
infrastructure act can support priorities in Idaho
o Need to identify what funding may be available and what priorities are along with
partners needed to support those
o Analysis of grants programs and funding
o Overall Question: Identify how this group can help with connecting funding mechanisms
to State’s priorities
• Urban growth in high hazardous areas
o Mitigation challenges related to increasing building/land use code requirements and
challenges (local capacity) for obtaining federal funding for fuel reduction/defensible
space/home retrofits
o Infrastructure protection for utilities and challenges with permitting work on federal
land before fire occurs
o Need to differentiate what the ILRCC can support and what this group can support-
follow up with Susan Cleverley

Schedule next meeting for January – send out a when2meet poll

BEFORE THE

IDAHO PUBLIC UTILITIES COMMISSION

CASE NO. IPC-E-22-27

IDAHO POWER COMPANY

REQUEST NO. 26

ATTACHMENT NO. 1

The National Forest Foundation
To create healthier, more resilient forests, the National Forest Foundation (NFF) works to accelerate the pace and
scale of forest restoration through highly leveraged projects across the United States. Chartered by Congress, the
NFF is the only national nonprofit organization solely dedicated to enhancing the health of and promoting the
public enjoyment of America’s 193-million-acre National Forest System. We are a key nonprofit partner of the U.S.
Forest Service and work together with local government, conservation organizations, foundations, businesses,
and individuals to spearhead landscape-scale restoration on these public lands.

To secure the greatest return on investment, we focus our work in
locations where projects are collaboratively prioritized by public
and private stakeholders and in close partnership with the local
communities. Working at a landscape scale and across
jurisdictional boundaries, our approach is informed by the best
available science and management practices. Through this work,
we can reduce insect and disease issues across landscapes,
reduce the likelihood of large-scale high-intensity wildfire, and
reduce the risk of post-fire flooding and degradation of water
quality due to sedimentation and debris runoff. Our projects also
result in a net carbon benefit, as avoidance of severe fire equals
more carbon retained in the forest. On average, NFF leverages
every private dollar that is contributed by 5X for forest health and
fuels reduction projects.

Boise Front Focal Area
Over the past year, NFF has been working with the Boise National
Forest and other partners to develop an implementation strategy
for fuels reduction, forest health, and fire risk prevention in the
Boise Front Focal Area. The majority of the Boise Front Focal Area
is located in the Idaho City Fireshed and the National Fireshed
Registry ranks this fireshed as number 13 out of over 7500
firesheds in the country for wildfire risk to local communities. The
fireshed is ranked as the #1 priority in the State and Region for
addressing wildfire risk.

The purpose of the partner-based strategy is to increase the pace and
scale of on-the-ground work over the next 5-10 years in the Boise Front
by building capacity and unifying priority areas for implementation. To
achieve this, the intention is to utilize NFF as an aggregator of funding
sources that can be used to leverage additional federal funding to
complete priority fuels reduction and forest health work across
jurisdictional boundaries.

The National Forest Foundation’s Work with Utilities
In many of the areas where the NFF works, utilities are a key
investment and implementation partner that help shape
implementation priorities for fuels reduction and forest health work.
Below are some bullets on NFF’s existing utility partnerships:
Boise Front Focal Area
Existing Partners for Partner-Based
Implementation Strategy

• Liberty Utilities (CA) – This is the most involved partnership, which includes funding from the utility to NFF
and coordination of implementation activities, within and outside of the utility’s rights of way. The
partnership is designed to enhance forest resilience to wildfire, decrease hazardous fuel accumulations,
minimize the risk of powerline wildfire ignitions, and overall improve forest conditions in the vicinity of
Liberty infrastructure. Implementation priorities benefit wildfire resiliency of Liberty infrastructure in
order to best serve the needs of Liberty rate payers. Types of projects may include, but are not limited to:

o Mechanical Forest Thinning – Mechanically thin trees to reduce fuel loading, minimize the risk of
high severity wildfires, and improve wildfire resiliency adjacent to Liberty infrastructure.
o Mastication – Masticate trees and brush to reduce fuel loading, minimize the risk of high severity
wildfires, and improve wildfire resiliency adjacent to Liberty infrastructure.
o Hand Thinning and Hand Piling – Hand thin and hand pile trees to reduce fuel loading, minimize the
risk of high severity wildfires, and improve wildfire resiliency adjacent to Liberty infrastructure.

• Xcel Energy (CO) – Through the Upper Ark Forest Fund, we are coordinating our landscape-scale
treatments with Xcel energy’s wildfire mitigation efforts. Xcel’s transmission and distribution
infrastructure was also included as an asset in the area’s landscape-scale planning, in an effort to reduce
the risk of fire damage to infrastructure. Xcel is supporting NFF’s landscape-scale fuel reduction
treatments with annual contributions from its foundation.

• Salt River Project (AZ) – In 2015, the NFF partnered with SRP to develop the Northern AZ Forest Fund. This
program was designed to improve forest and watershed health in the Salt and Verde River watersheds,
that provide surface water to the Phoenix Metro Area. The program implements numerous fuel
reduction/forest resilience, wetland and stream restoration, and sediment reduction projects across
National Forests in the watersheds. Through the partnership, SRP contributed annually to the fund ($100-
$250K/year) and helped develop donor relationships between NFF and SRP’s large-scale corporate
customers.

• Southern CA Edison – SCE supports landscape-scale fuel reduction and forest resilience projects across
its service area through annual donations to the NFF. Each year, the NFF proposes 2-4 specific projects
that will reduce wildfire risk to SCE transmission and distribution infrastructure. SCE then provides a
grant $350-$500K per year to support those specific projects.

We welcome additional conversation with Idaho Power on potential partnership strategies and opportunities as it
relates to Idaho Power’s goals and objectives under the company’s Wildfire Mitigation Plan for the utility service
area.

Contacts

Dani Southard
Director, Northern Rockies
National Forest Foundation
208.720.0957
[e-mail]

Marcus Selig
Vice President, Field Programs
National Forest Foundation
720.437.0290
[e-mail]

BEFORE THE

IDAHO PUBLIC UTILITIES COMMISSION

CASE NO. IPC-E-22-27

IDAHO POWER COMPANY

REQUEST NO. 27

ATTACHMENT NO. 1
No. 16-U-101NORTH AMERICAN WOOD POLE COUNCIL
TECHNICAL
BULLETIN
Estimated
Service Life
of Wood Poles
Prepared by:
Jeffrey J. Morrell
Department of Wood Science & Engineering
Oregon State University
The North American Wood Pole Council (NAWPC) is a federation of three organizations representing the wood
preserving industry in the U.S. and Canada. These organizations provide a variety of services to support the use of
preservative-treated wood poles to carry power and communications to consumers.
The three organization are:
Western Wood Preservers Institute
With headquarters in Vancouver, Wash., WWPI is a non-profi t trade association founded in 1947. WWPI serves the
interests of the preserved wood industry in the 16 western states, Alberta, British Columbia and Mexico so that
renewable resources exposed to the elements can maintain favorable use in aquatic, building, commercial and utility
applications. WWPI works with federal, state and local agencies, as well as designers, contractors, utilities and other
users over the entire preserved wood life cycle, ensuring that these products are used in a safe, responsible and
environmentally friendly manner.
Southern Pressure Treaters’ Association
SPTA was chartered in New Orleans in 1954 and its members supply vital wood components for America’s
infrastructure. These include pressure treated wood poles and wood crossarms, and pressure treated timber piles, which
continue to be the mainstay of foundation systems for manufacturing plants, airports, commercial buildings, processing
facilities, homes, piers, wharfs, bulkheads or simple boat docks. The membership of SPTA is composed of producers of
industrial treated wood products, suppliers of AWPA-approved industrial preservatives and preservative components,
distributors, engineers, manufacturers, academia, inspection agencies and producers of untreated wood products.
Wood Preservation Canada
WPC is the industry association that represents the treated wood industry in Canada. WPC operates under Federal
Charter and serves as a forum for those concerned with all phases of the pressure treated wood industry, including
research, production, handling, use and the environment. WPC is dedicated to promoting and supporting a stronger
Canadian wood treating industry; informing the public on the benefi ts to be gained from the use of quality wood
products; and preserving the integrity of the environment through the promotion of responsible stewardship of our
resources.
About NAWPC
Estimated Service Life
of Wood Utility Poles
Prepared by
Jeffrey J. Morrell
Department of Wood Science & Engineering
Oregon State University
Introduction
Utilities are often faced with questions about how
long a pole lasts once it is placed in the ground. Why
does it matter? There are a number of important
reasons for paying attention to service life.
First, utilities want to maximize their capital dollars
and longer service life reduces the need for pole
replacements. More recently, utilities have begun to
examine their carbon footprint. Trees fi x or sequester
carbon from the atmosphere as they grow and this
carbon remains locked in the wood once the pole is
manufactured.
While thousands of tons of carbon are stored in
the utility wood pole plant, a relatively small portion
of a utility’s total carbon footprint is represented by
the electric transmission and distribution system.
Efforts to reduce this footprint can have important
public relations value. Wood poles offer an
opportunity for atmospheric carbon sequestration
not provided by other materials.
Assumptions About Service Life
An Electric Power Research Institute study
suggested that wood poles lasted 50 years. Most
utilities assume that their poles provide 30 to 40
years of service life. Which is really true or are they
both wrong? How would you fi nd out? How do you
compare these numbers with claims by producers
of competing materials that their poles will last 80 or
more years?
There are a variety of competing claims about
how long poles last. In some cases, such as for
wood, lattice steel and pedestal-mounted thick-
walled steel poles, the claims are based upon actual
performance data.
However, there is little or no long term data for
many more recently developed materials, or new
use patterns such as direct-burial of steel poles.
Instead, the producers of these products depend
upon accelerated testing or extrapolations from the
performance of similar materials to support claims.
The assumptions about the service life of a
treated wood utility pole represent a wide range in
terms of years. In 2000, an Oregon State University
survey of utilities across the U.S. revealed that a
majority of respondents believe that their poles last
between 31 and 40 years.
An updated survey of utilities was conducted by
OSU in 2013 and it determined the replacement
rate indicates pole service lives “are far in excess of
the 30 to 40 years estimated by many utilities.”
There is compelling evidence indicating that the
estimated 30-year pole service life originated from
curves developed to estimate economic service
rather than actual service life. The goal was to
determine when the investment had been returned,
rather than when the pole had actually failed.
Service Life Factors
Actual pole service life is a function of many
factors including the specifi cation, the quality
of treatment, the conditions to which the pole is
exposed, and how well the pole is maintained
during use. In a single utility, one can look at pole
records to estimate service life.
Many utilities record the date of pole installation
along with supplier, wood species and treatment
details. They may also record inspection dates
along with any supplemental treatments applied
and, fi nally, they record when the pole is changed
out.
Final information may not be directly tracked
because new pole information automatically
populates the data base replacing original data. But
if it is, the utility can directly calculate service life.
As you might expect, pole quality can have a
major effect on service life. All poles should be
Estimated Service Life of Wood Utility Poles Page 3
Estimated Service Life of Wood Utility Poles Page 4
specifi ed to the standards
of the American Wood
Protection Association
(AWPA). These consensus
standards provide minimum
levels of treatment for
all native pole species
currently listed within
the American National
Standards Institute (ANSI)
Standard O5.1.
Although there
will be differences
in characteristics of
poles treated with
various preservatives,
new formulations are
assessed by the technical
committees that set
AWPA Standards with
the assumption that they
should all provide similar
resistance to deterioration.
This leaves the user with a
suite of preservatives that
may produce poles that
are different colors, vary in
fi re resistance, or differ in
climbing characteristics.
However, these preservatives should provide similar
service with regard to resistance to fungal or insect
attack.
Utility enhancements to specifi cations can also
enhance performance. For example, most users of
Douglas Fir utility poles through-bore, radial drill,
deep-incise or kerf to improve treatment at the
groundline and these practices markedly reduce
internal decay and extend pole service life.
Environmental Factors
The environment to which a pole is exposed has
a major effect on service life. For the U.S., the AWPA
Standards divide the country into fi ve decay zones
(see Figure 1), with Zone 1 having the lowest risk of
decay and Zone 5 the highest.
Clearly, a pole treated to similar levels will
perform differently in different zones. However, the
AWPA standards address this issue by providing
several retentions that can be specifi ed for a given
preservative. The assumption is that poles exposed
to a higher decay hazard will be treated to higher
preservative loadings.
Remediation and Service Life
Maintenance is also a major factor in pole service
life. A 2012 Quanta Technology study on wood
pole service life calculated the average expected
lifetime of a wood utility pole with an inspection and
treatment program at 96 years.
Osmose Utilities Services reviewed data on
751,000 utility poles inspected across the U.S.
between 1988 and 1999. It determined a national
predicted service life for poles without remedial
treatment at 45 years, with ranges from 40 years in
the most demanding conditions and 56.8 years in
the low to moderate decay zones.
However, application of a pole inspection and
remediation program was determined to signifi cantly
add to the service life. Assuming no pole will last
longer than 71 years, remediation can increase the
service life of a pole by 33 percent, or 16 years. With
no cap on the potential length of service, remedial
treatment can extend the service life by 60 percent,
or some 28 years on average.
The National Electrical Safety Code mandates
that utilities maintain their wood poles so that they
Figure 1 - The U.S. has fi ve decay hazard zones, where 1 is a low hazard and 5 is a severe
decay hazard. In certain modifi ed environments such as banks along irrigation canals or irragated
residential or agricultural lands, a higher degree of protectio might be needed than would be
required in the local environment. Within individual regions, certain natural environments such as
river valleys or coastlines may present greater potential for wood deterioration. (Map courtesy of
American Wood Protection Assn.)
retain 2/3 of their original required design strength.
In order to meet this requirement, utilities must
establish some regular program of inspection and
maintenance. Most utilities inspect their poles on
a 10-year cycle, using intrusive procedures that
include boring into the pole at or below groundline
and, for some species, excavating around the pole
and examining the surface for external decay.
Estimating Service Life
So, how can we estimate pole service life across
the United States? Utilities can examine pole
purchasing records to infer replacement rates, but
this depends on how much new line construction is
occurring within the system.
This data must be viewed carefully because it
includes poles removed for all causes, not just those
no longer capable of supporting their original design
load. Poles may be removed for upgrades, road
widening, car/pole interactions, storm damage, or a
number of other reasons.
The 2013 OSU survey collected pole purchasing
data, with 86 utilities reporting they purchased
on average 5,845 poles a year. When compared
to the total pole population, the estimated pole
replacement rate would be 1.12 percent a year,
compared to 0.7 percent indicated in the 2000
survey. However, this rate must be viewed with
some caution since the purchases include poles for
new line construction.
Pole Removal Data
Pole removals provide a much better measure
of pole service life. Data collected in the 2013 OSU
survey indicated a replacement rate of 0.56 percent,
which suggests an average service life far beyond
the 30 to 40 years previously assumed.
A 2006 survey of utilities in the Pacifi c Northwest
found similar results and further segregated the
causes for replacement (see Figure 2). In this case,
the survey revealed a slightly higher replacement
rate (0.8 percent vs. 0.6 percent in the larger survey).
More than half of the poles removed from service
(56 percent) were decayed; however, poles removed
for road widening or upgrades represented 38.1
percent of poles removed from service.
While some of these poles might have had
reduced capacity, they had not deteriorated
to the point where their condition necessitated
replacement. This means that over a third of the
poles removed from service were candidates for
reuse and, if these poles could be reused, they
would further reduce the replacement rate.
Based on the 0.6 percent replacement rate, the
average pole service life would easily reach 80 years
in many areas of the country, far in excess of the
perceived 30 to 40 years. Thus, old wood does not
mean weaker wood.
While service life will vary among utilities, if we
look in most utility systems, we see enormous
quantities of lines installed in the 1950s where the
vast majority of the poles remain in service. In 2014,
the Los Angeles Department of Water and Power
reported that more than half of 320,000 poles in
service were 50 years or older, with some exceeding
90 years or longer.
Improving Quality
It is also important to remember that like most
materials used by utilities, wood pole quality
has improved. Throughout the last century
as the U.S. expanded the electrical grid, the
AWPA specifi cations have shifted from gauge to
results-type treatments, which means that actual
preservative content in the wood is assayed.
In addition, most utilities do regular inspections,
ensuring all poles installed in a system are
properly treated. Finally, development of effective
maintenance programs further extends the life of
poles. All of these actions have resulted in wood
poles that perform more reliably for longer than ever
before.
Estimated Service Life of Wood Utility Poles Page 5
Figure 2 - While decay was the chief reason for removing a
wood pole, the number of poles removed for road widening
and line upgrades comprised nearly 38 percent of removals
according to a survey of utilities. These poles could be
candidates for reuse, which should be factored in when
determining the overall service life. (Source: 2007 Utility Pole
Research Cooperative Annual Report)
Epilogue
Wood poles already have substantial advantages
over other materials because wood is renewable,
sustainable, generates less greenhouse gases during
manufacture and provides a long-term repository for
atmospheric carbon.
Internationally recognized life cycle assessments
confi rm the production and use of wood poles has
lower environmental impacts and less energy and
resource use compared to galvanized steel, concrete
and fi ber-reinforced composites.
Prolonging the useful life of a wood pole further
enhances the carbon footprint through requiring
less replacement activities, keeping thousands of
tons of carbon stored in the existing pole plant (i.e.
utility distribution and transmission system) and
allowing growing replacements to continue carbon
sequestration in the forest.
Thus, wood poles offer utilities some attractive
options as companies move to do their part with
regard to global climate change.
The next time you are asked how long a pole will
last, remember that the answer is as long as you
want it and far longer than you ever thought.
References
Oregon State University Utility Pole Research
Cooperative. 2007. 27th Annual Report. Pages 93-97
Morrell, J.J. 2012. Wood Pole Maintenance
Manual. Research Contribution 51, Forest Research
Laboratory, Oregon State University, Corvallis, OR.
46 pages
Oregon State University Utility Pole Research
Cooperative. 2013. 33rd Annual Report. Pages 50-57
Los Angeles Daily News. “DWP’s Aging Power
Poles” May 2, 2014
Bingel III, N. and Bonk, D. 2015. Wood Pole Life
Extension & The Case for Capitalization. Osmose
Utility Services. 6 pages
Estimated Service Life of Wood Utility Poles Page 6
Disclaimer - The North American Wood Pole Council and its member organizations believes the information contained in this
document to be based on up-to-date scientifi c and economic information and is intended for general informational purposes.
In furnishing this information, NAWPC makes no warranty or representation, either expressed or implied, as to the reliability or
accuracy of such information; nor does the Institute assume any liability resulting from use of or reliance upon the information
by any party. This document should not be construed as a specifi c endorsement or warranty, direct or implied, of treated wood
products or preservatives, in terms of performance, environmental impact or safety. The information contained herein should
not be construed as a recommendation to violate any federal, provincial, state or municipal law, rule or regulation, and any party
using or producing pressure treated wood products should review all such laws, rules or regulations prior to using or producing
preservative treated wood products.
North American Wood Pole Council
NAWPC 16-U-101
02-2016© 2016 North American Wood Pole Council

BEFORE THE

IDAHO PUBLIC UTILITIES COMMISSION

CASE NO. IPC-E-22-27

IDAHO POWER COMPANY

REQUEST NO. 27

ATTACHMENT NO. 2
Wood Pole Maintenance
Manual: 2012 edition

Research Contribution 51
December 2012
Forest Research Laboratory
The Forest Research Laboratory of Oregon State University, established
by the Oregon Legislature, conducts research leading to sustainable
forest yields, innovative and efficient use of forest products, and
responsible stewardship of Oregon's resources. Its scientists conduct
this research in laboratories and forests administered by the University
and cooperating agencies and industries throughout Oregon. Research
results are made available to potential users through the University's
educational programs and through Laboratory publications such as this,
which are directed as appropriate to forest landowners and managers,
manufacturers and users of forest products, leaders of government and
industry, the scientific community, the conservation community, and
the general public.
the author
Jeffrey J. Morrell is Professor of Wood Preservation in the Department of
Wood Science and Engineering at Oregon State University.
acknoWledgMents
This report was completed with the support of the OSU Utility Pole
Research Cooperative.
disclaiMer
Mention of trade names and products does not constitute endorsement,
recommendation for use, or promotion of the products by the authors
or the organizations with which they are affiliated.
to order coPies
Forest Research Laboratory publications are available online or in print
at no charge. To view and order, visit www.forestry.oregonstate.edu/
forestry-communications-group
Forestry Communications Group
Oregon State University
202 Peavy Hall
Corvallis, OR 97331
Voice: [phone]
Email: [e-mail]
Editing, design, and layout by Caryn M. Davis, Forestry Communications Group, OSU College of Forestry, Corvallis.
Wood Pole Maintenance
Manual: 2012 edition

Research Contribution 51
December 2012
Forest Research Laboratory
abstract
Morrell, Jeffrey J. 2012. Wood Pole Maintenance Manual: 2012 Edition. Research
Contribution 51, Forest Research Laboratory, Oregon State University, Corvallis.
The specification, inspection, and remedial treatment of utility poles are
addressed. Included are discussions of enhancing specifications for improved
performance, techniques for detecting decay and other defects, and chemical
treatments available for arresting decay of poles in service.
contents
AbstrAct .........................................................................................ii
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decAy-detecting driLLs ..................................................................29
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list of figures
Figure 1. Cross sections of Douglas-fir ................................................................2
Figure 2. Enlarged view of fibers in Douglas-fir .....................................................3
Figure 3. Air seasoning of poles. .........................................................................4
Figure 4. Decay at the bolt hole and pole failure caused by decay ...........................5
Figure 6. Deep incising, radial drilling, through-boring, and kerfing .........................6
Figure 5. Cross section of deep-incised and through-bored poles. ...........................6
Figure 7. Kerfing can be used to control checking of poles .....................................7
Figure 8. Checks have exposed heartwood to decay fungi. .....................................7
Figure 9. Relative risk of decay in poles in the United States. .................................9
Figure 10. Typical vacuum pressure cycles for treatment processes. .....................10
Figure 11. Bleeding from a creosote-treated pole. ...............................................11
Figure 12. Commercially applied pole barrier ......................................................12
Figure 13. Non-capped pole top with decay; available pole caps. ..........................12
Figure 15. Requirements for decay. ...................................................................13
Figure 16. The conk of a decay fungus produces microscopic spores .....................13
Figure 14. Weathering of a cedar pole turns the surface grey. ..............................13
Figure 17. Decay fungus growing over malt agar. ................................................14
Figure 18. Brown, white, and soft rot. ...............................................................14
Figure 19. Termite colony in a pole and reproductives. ........................................15
Figure 20. Termite damage to wood ..................................................................16
Figure 21. Carpenter ants (Camponotus sp.) ......................................................16
Figure 22. Carpenter ant damage in poles. ........................................................17
Figure 23. Golden buprestid beetle (Buprestis aurulenta). ....................................17
Figure 24. Woodpecker hole on pole surface and nest void. ..................................18
Figure 25. Section with old woodpecker nest attached to new pole .......................18
Figure 26. Gribbles and shipworms are marine borers ........................................19
Figure 27. Crossarms with and without end-plates that limit checking. . .................20
Figure 28. Polyurea-coated crossarms ..............................................................20
Figure 29. USA Climate-index map with decay potential for wood. .........................22
Figure 30. Decay hazard map, as reported by the REA ........................................22
Figure 31. Internal decay. ................................................................................23
Figure 32. Both external (a) and internal decay (b)..............................................24
Figure 33. Steel trusses used to reinforce deteriorated poles. ..............................24
Figure 34. “Pick test” to detect rot ....................................................................25
Figure 35. Cores extracted with an increment borer ............................................27
Figure 36. Shell-thickness indicator ..................................................................28
Figure 37. Shigometer™ measures electrical resistance .......................................28
Figure 38. Resistance-type meter for detecting MC levels ....................................28
Figure 39. Resistograph drill for detecting voids or softer wood ............................29
Figure 40. Strong and weak acoustic signals ......................................................29
Figure 41. Pole test with an acoustic inspection device. .......................................30
Figure 42. X-ray of wood. ................................................................................30
Figure 43. Hyphae of a decay fungus in a wood section. ......................................31
Figure 44. Theoretical strength vs. residual shell thickness of a pole. ....................33
Figure 45. Applying groundline treatment. .........................................................34
Figure 46. Ability of selected fumigants for eliminating decay fungi .......................35
Figure 47. Fumigant application. .......................................................................37
Figure 48. Example of field inspection form. .......................................................39
1
Wood poles have been used for over a century to support telephone and electric lines
throughout North America. In the beginning, poles of selected species such as American
chestnut (Castanea dentata) and western redcedar (Thuja plicata) were used untreated.
Those naturally durable woods provided reasonable service life, but, as utilities rapidly
expanded their systems, increased demand for poles forced a switch to alternative species.
The alternative species had good mechanical properties, but generally lacked natural
durability; thus, they required supplemental treatment.
Wood species differ widely in the degree to which they accept treatment. Those
differences result in variations in performance that affect decisions on how to maintain
poles for maximum service life. Maintaining wood poles to maximize service life involves
the development of good specifications for treatment, inspection after treatment to assure
conformance to the standard, a well-developed inspection program to detect poles that are
decaying in service, and a program to supplementally protect decaying poles. This manual
describes the properties of wood used for poles, methods of treatment, and the process of
inspection and remedial treatment. Although these guidelines were specifically developed for
Douglas-fir (Pseudotsuga menziesii), western redcedar, and southern pine (Pinus spp.), they
can be applied to poles of virtually all coniferous species.
2
When you cross-cut almost any Douglas-fir,
southern pine, or western redcedar log, you will
see that the tree is divided into distinct zones
(Figure 1). The outer and inner bark, which can
be peeled away, protect the tree from fungi
and insects, and from drying. Bark is normally
removed from poles during processing because
it attracts many types of wood-boring insects,
retards drying, and prevents preservative treat-
ment. Inside the bark layer is the sapwood, a
normally white-to-cream-colored band of wood
in which fluids move up and down the living tree.
Inside that zone is the heartwood, which consists
of older, dead sapwood. Heartwood of many spe-
cies is red or brown and may be more durable
than the sapwood.
Sapwood depth varies widely within and among
wood species, depending on the health of the
tree. Sapwood of western redcedar is thin, rarely
exceeding 3/4 inches; sapwood of Douglas-fir is
somewhat thicker, ranging from 1 to 3 inches. The
thickness of Douglas-fir sapwood may be increas-
ing as timber is more intensively managed to
encourage growth. Sapwood of southern pine and
ponderosa pine (Pinus ponderosa) is extremely
thick, ranging from 3 to 5 inches. Sapwood can
often be distinguished from heartwood through
the use of chemical indicators that are based
upon differences in pH between sapwood and
heartwood (AWPA 2008).
Sapwood of the three primary pole species
has little natural durability and is susceptible to
fungal and insect attack as long as it remains
wet. As the sapwood ages in a live tree, it begins
to die, and, in some species, the dying cells
convert their contents into a diverse array of
compounds called extractives. Some extractives
are toxic to insects and decay fungi and can pro-
tect the heartwood for many years. One of the
best examples of this is western redcedar, which
has highly durable heartwood.
Heartwood of Douglas-fir and southern pine
is classified as moderately durable. Some species
produce no detectable heartwood, but those spe-
cies are not typically used for poles. Poles from
species with durable heartwood have long ser-
vice lives, especially when the sapwood receives
some supplemental preservative treatment. Users
should be aware, however, that the durability of
heartwood does vary among trees of the same
species.
Figure 1. Cross sections of Douglas-fir showing typical sapwood (left) and deep sapwood (right).
Pith
Heartwood
Sapwood
Inner
bark
Outer bark
3
In addition to sapwood and heartwood, there
are differences in annual growth that produce
distinct rings in most temperate woods species.
Cells produced early in the season have large
cell lumens and thin cells walls and are termed
earlywood. Cells produced later in the season are
thicker walled with smaller cell lumens and are
termed latewood.
Ninety percent of coniferous wood is made up
of minute, hollow fibers (called tracheids) oriented
lengthwise along the tree stem, which transport
water and nutrients from the roots up through
the sapwood to the leaves (Figure 2). The length
of these fibers is 100 times longer than the width.
The remaining 10% of the wood is composed of
short, hollow, brick-shaped ray cells oriented from
the bark toward the center of the tree as ribbons
of unequal height and length. These rays (a mix-
ture of tracheids and parenchyma cells) distribute
food, manufactured in the leaves and transported
down the inner bark, to the growing tissues
between the bark and wood.
density
Density is a measure of weight per unit volume.
Because of its low density, wood of cedar is light
when dry, but may be very heavy when wet.
Low-density wood contains more voids than does
high-density wood and, therefore, more space
for water. One cubic foot of water-free (ovendry)
western redcedar weighs about 19 lb, about 9 lb
less than Douglas-fir, which is more dense.
Because density reflects the thickness of the
fiber walls, it indicates the strength of the wood.
The higher the density of wood at a specified
moisture content (MC), the greater its strength.
Therefore, a cedar pole must be larger in diam-
eter than a Douglas-fir pole to support the same
load.
Density has little or no relationship to durabil-
ity. Dense woods can have little durability, while
light woods, such as western redcedar, can be
quite durable.
groWth rate
The American National Standards Committee
Standard ASC 05.1 specifies maximum growth
rates in the outer 2 to 3 inches of a pole
Figure 2. In this greatly enlarged view of fibers in Douglas-fir, large, open ends of thin-walled springwood fibers change abruptly to thick-walled summerwood fibers. Horizontal ribbons of short ray fibers are interspersed among long vertical fibers that make up about 90% of the wood. Photo provided courtesy of the N.C. Brown Center for Ultrastructure Studies, College of Environmental Science and Forestry, SUNY, Syracuse.
(depending on pole size). This requirement
reflects a tendency for faster grown wood to be
less dense and therefore weaker. This standard
also allows for use of poles with slightly faster
growth, provided that the percentage of denser
latewood is high.
Moisture content
Sapwood, which conducts nutrients in water from
the roots to the leaves, is nearly saturated with
water in a standing tree. Wood density tends to
be lower at the top, enabling a tree to store large
quantities of water where it will be readily avail-
able to the leaves. Heartwood usually contains
much less water than sapwood. Because of its low
density, cedar can hold much more water than
4
Douglas-fir can. In freshly cut cedar trees, the
MC of sapwood and heartwood approaches 250%
and 60% respectively, calculated on a water-free
wood basis. Ponderosa and southern pine both
contain high percentages of sapwood, which holds
more water than does heartwood.
Moisture content is expressed as a percent-
age of the dry weight of the wood. To determine
the amount of water in wood, weigh pieces of the
wood, then dry them in an oven at 220°F until
their weights remain constant (wood 1 inch thick
or less usually dries within 24 h). Do not use wood
that contains resin or pitch for MC determina-
tions, because it evaporates with the water.
be driven into the wood so that the meter is
read every 1/2 inch. The uncoated pins read MC
only at the tip. Before driving the probes into
the wood, be sure that they are parallel to each
other and are aligned with the long fibers of the
wood; that way, the probes will not break off
and the data will be more accurate. The meter is
useful for a MC range of 7% to 25%, but accuracy
decreases rapidly outside this range (Graham et
al. 1969). Creosote and oil-based preservatives
have little effect on meter readings, but inorganic
water-based preservatives may cause large errors
(James 1976).
seasoning
Wood poles that are treated with preservatives
must be dried either before or during preserva-
tive treatment. The simplest moisture removal
method is air seasoning, in which poles are
stacked in well-ventilated piles for 1 to 12 mo
(Figure 3). Air seasoning is inexpensive because
it requires little equipment and minimal han-
dling of the wood. This method does necessitate
a large storage area for poles, and it includes
the cost of carrying a large white, or untreated,
wood stock in anticipation of orders. It also per-
mits the entry of fungi and insects into the wet
wood. Despite these drawbacks, air seasoning
remains a common method for drying Douglas-
fir and western redcedar poles before treatment.
Air seasoning is less frequently used for southern
pine because pine is much more susceptible to
decay. Poles to be air seasoned should be placed
Figure 3. Air seasoning poles.
Then, MC can be calculated as:
MC = (initial weight/oven dry weight) - 1 x 100
OR
MC = [(initial weight - oven dry weight)/oven
dry weight] x 100
For example, if 1.0 ft3 of Douglas-fir sapwood weighs 60.2 lb and its oven dry weight is 28.0 lb,
the calculations would be:
MC = (initial weight/oven dry weight) - 1 x 100
MC = (60.2/28.0) - 1 x 100
MC = 115% MC
OR
MC = [(initial weight - oven dry weight] x 100
MC = [(60.2 - 28.0)/28.0] x 100
MC = 115% MC
Moisture content also can be determined
with a moisture meter that measures the electri-
cal resistance between two probes driven into
the wood with a sliding hammer (Salamon 1971,
James 1975). Because a moisture gradient indi-
cates moisture distribution in a pole much better
than does a single reading at a specified depth,
the 3-inch-long probes with uncoated tips should
5
in well-aerated stacks with stickers (spacers)
between rows to allow airflow. These poles should
be kept at least 1 ft above the ground on well-
drained sites that are free of vegetation.
The need to produce poles quickly (without
the long drying times required for air seasoning)
has encouraged the development of alternative
seasoning processes, which include Boulton sea-
soning, steam conditioning, and kiln drying. These
processes reduce wood moisture near the sur-
face of the pole and, if carried out for a sufficient
period, can heat-sterilize the wood, eliminating
fungi or insects that became established between
felling and treatment.
Boulton seasoning was first developed in
1878. It involves placing the wood in a treat-
ment cylinder, adding treatment solution, and
applying a vacuum while raising the temperature
to between 190 and 210°F. The vacuum lowers
the boiling point of water, permitting vaporiza-
tion of water in the wood in a process that may
last 6 to 48 h. Boulton seasoning is a relatively
mild method for removing water from wood and
causes little or no strength loss; it is most com-
monly used to dry Douglas-fir poles.
Kiln drying is increasingly used for southern
pine and Douglas-fir poles. In this process, the
poles are placed on carts with stickers between
the poles to permit air flow. The poles are then
placed into a kiln, where they are subjected to
combinations of elevated temperatures and rapid
air flow. The rate of drying is controlled by the
velocity of air passed through the kiln, as well
as by temperature and relative humidity (RH).
Kiln schedules that dry
the poles too rapidly can
result in excessive check-
ing or in case-hardening
of the wood, a process
that makes subsequent
preservative treatment
more difficult. Careful
control of temperature,
RH, and air velocity can
produce dry, high-quality
poles over a period of 3 to
5 d.
Steam conditioning
can be used to treat
southern pine poles while
the moisture levels remain elevated (~40%
MC). Partially seasoned poles are steamed for
up to 20 h at 240°F in a process that results
in the drying of the wood near the surface and
the redistribution of moisture deeper within the
pole. As a result, the wood can be treated at
higher overall MC, reducing energy costs. Steam
conditioning is typically used to treat southern
pine poles with oil-based preservatives; it is not
permitted for Douglas-fir, western redcedar, or
ponderosa pine because of concerns about the
potential for temperature-induced strength loss in
these species. Southern pine is less susceptible to
this damage. This process is less commonly used
and has largely been replaced by kiln drying.
PretreatMent Processing
In addition to seasoning, there are a number of
steps a utility can take to improve pole perfor-
mance and reduce long-term maintenance costs.
These include pre-boring, incising, deep incising,
radial drilling, through-boring, and kerfing.
Pre-boring all holes used for attachments
such as guy wires or cross-arms helps to protect
the preservative-treated shell from damage. Field
drilling exposes untreated wood, creating the
potential for aboveground decay (Figure 4).
Incising can be used in the treatment of spe-
cies in which the thin bands of sapwood pose a
major challenge. Incising involves using sharp-
ened metal teeth to punch a series of small holes
into the wood, improving the uniformity of treat-
ment to the depth of the incisions. Wood treats
Figure 4. (a) Decay at the bolt hole and (b) pole failure caused by decay in a field-drilled hole.
ba
6
more easily along the grain, and incising exposes
more longitudinal flow paths, thereby improving
treatment (Figure 5). Incising is recommended
for western redcedar poles; utilities also incise
Douglas-fir, lodgepole pine (Pinus contorta), and
western larch (Larix occidentalis), particularly in
the groundline zone.
Deep incising and radial drilling improve on
conventional incising, the effect of which is gener-
ally limited to the outer 3/4 inch of the wood. In
deep incising, a series of 3-inch-long knives are
driven into the wood around the groundline area
(Figures 5 and 6). Similarly, radial drilling involves
drilling a series of holes to depths ranging from
3 to 5 inches in a diamond-shaped pattern in the
groundline zone. Both of these processes allow
preservative treatment to the depth of the knife
or drill, which increases the zone of protected
wood.
Through-boring takes radial drilling further
in that holes are drilled at a slightly downward-
sloping angle completely through the pole in
the critical groundline zone. Through-boring can
produce nearly total treatment of the groundline
zone (Figure 6).
Although incising, radial drilling, and
through-boring improve the depth of preserva-
tive treatment, none control in-service checking,
which results in exposure of untreated wood.
These processes all protect the zone to which
they are applied, but do not markedly affect the
risk of decay above or below that zone.
Kerfing involves making a saw cut to the pith
of the pole prior to treatment (Figures 6 and 7).
Once treated, the kerf acts to relieve subsequent
drying stress, preventing the development of
checks that penetrate beyond the treated shell. It
is important to note that decay can occur above
the kerfed zone; however, kerfing markedly
reduces the incidence of internal decay in thin
sapwood species around the groundline.
Radial drilling, deep incising, through-boring,
and kerfing are all typically used on species with
thin sapwood and low to moderately durable
heartwood. They are primarily used on Douglas-
fir, but would also find application on western
larch and lodgepole pine. Engineers have long
expressed concerns about the effects of holes
or cuts on pole flexural properties. Extensive
full-scale tests indicate that these processes do
produce slight reductions in properties; however,
the losses are more than offset by the improve-
ment in treatment that limits subsequent decay
development in the critical groundline zone.
A B C D
Figure 6. (A) Deep incising, (B) radial drilling, (C) through-
boring, and (D) kerfing can improve treatment of the affected
zone.
Figure 5. Incising and through-boring can markedly improve preservative penetration. (a) Cross section of a deep-incised pole and (b) a copper naphthenate through-bored pole.ba
7
As poles dry or season, they lose water from
the surface, but they shrink only when MC drops
below 30%. This is the fiber saturation point,
the point when the wood fibers contain a maxi-
mum amount of water, but there is no “free or
liquid water” in the cell lumens. Wood shrinks
more along than across the growth rings. As a
result, many small, V-shaped seasoning checks
form in the surface of poles. As drying continues
deeper into the wood, the number of small checks
decreases; however, a few checks drive deep
into the wood. Deep checks to the center indi-
cate a well-seasoned pole and do not adversely
affect strength. Numerous small checks do not
always reliably indicate the extent of seasoning
because some poles check very little as they dry.
However, most softwood poles eventually develop
deep checks (1/8 to 1/2 inch wide). Pretreatment
seasoning removes moisture from the wood and
encourages check development before treatment.
Even under the most favorable drying conditions,
however, large poles require a long time for the
heartwood to completely dry to in-service equi-
librium MC. Consequently, most poles are treated
with preservatives and put in service while they
still have high internal MC. As checks on these
poles continue to deepen, they expose untreated
wood to attack by wood-destroying organisms,
which results in the development of internal
decay (Figure 8). The development of checks
before treatment results in well-treated checks
that help to reduce the risk of internal decay.
Many utilities incorporate a pre- or post-treat-
ment MC requirement into their specifications to
ensure that the wood is dry before treatment or
that it will not check excessively once in service.
A typical pretreatment MC might be 20% to 25%
at 2 inches from the surface, although this will
sometimes vary seasonally to reflect both the dif-
ficulty of seasoning during wet periods and the
inability of in-cylinder treatment processes to
remove some of this moisture.
Most utilities also limit the maximum width
and length of checks to avoid creating a hazard
to linemen climbing the poles. This is particularly
true in drier climates where the poles are likely
to dry to much lower in-service moisture levels.
These requirements must be applied cautiously,
however; unreasonable check limitations will
force treatment at higher MC when the poles have
not yet developed a normal checking pattern.
These poles will then continue to dry after treat-
ment and may develop even deeper checks that
penetrate beyond the treated zone.
The degree of drying required before treat-
ment will vary by species and by ultimate
exposure site. For example, southern pine can
be treated at higher MC through the use of pre-
steaming, although care must be taken to ensure
uniform treatment gradients. Douglas-fir and
western redcedar poles are normally treated
when dry (approximately 25% MC). Ultimate
exposure conditions may also affect the degree
Figure 7. Kerfing (arrow) can be used to control checking of
poles, thereby reducing internal decay in service.
Figure 8. Narrow checks that widened and deepened after
treatment have exposed the untreated heartwood of this
Douglas-fir pole to decay fungi.
8
of drying required. Poles that are exposed in dry
regions (precipitation <20 inches annual precipi-
tation) should be drier before installation because
they are more likely to develop deep checks.
Users should carefully consider the impacts of
drying and check requirements on initial pole
costs and ultimate service life.
Preservatives
Wood poles can be treated with various pre-
servatives specified under the standards of
the American Wood Protection Association.
These systems are either oil- or water-based.
Preservatives listed under the AWPA Standards
have been reviewed by technical committees for
their effectiveness under a variety of regimes.
Chemicals that meet these standards are
expected to produce equivalent biological perfor-
mance, although they may have other attributes
such as color or “climbability” that make them
attractive in a given utility.
oil-based Preservatives
Oil-based systems include creosote, penta-
chlorophenol (penta), and copper naphthenate.
Creosote and penta are both restricted-use pesti-
cides; those seeking to use these liquid chemicals
must be licensed by an appropriate state agency.
Although wood treated with these chemicals is
not restricted, users should carefully read and
follow all product information with regard to
application.
Creosote is the oldest preservative in gen-
eral use for wood protection; it was patented in
1838 by John Bethell. Creosote is a mixture of
polynuclear aromatic hydrocarbons produced by
the destructive distillation of coal. Creosote is
an oil substance that is typically used undiluted
for wood-pole treatments. It is highly effective
against many decay organisms and provides
long service life. One hazard is that contact with
this chemical can sensitize the skin to sunlight.
Creosote can be used either as a stand-alone
preservative or diluted with a heavy petroleum
solvent
Pentachlorophenol (penta) was developed
in the 1930s as an easily synthesized substitute
for creosote. Penta is normally used in a heavy
hydrocarbon solvent (P-9 Type A) for treatment
of wood poles. Penta is broadly toxic to fungi
and insects. The one major concern with penta
is the presence of dioxins; however, manufactur-
ing processes have sharply reduced the amount
of dioxin. Despite its potential drawbacks, penta
remains the preservative of choice for many utili-
ties because of its excellent field performance.
The solvent system used with penta has a marked
influence on performance, as evidenced by the
diminished performance of poles treated with
penta in liquefied petroleum gas (Arsenault 1973).
The use of heavy aromatic oils tends to produce
the best performance with this chemical. These
oils are typically specified in AWPA Standard P9
Type A.
Copper naphthenate was developed in the
early 1900s. It is produced by combining copper
with naphthenic acids derived from the oil-refining
process. Copper naphthenate has been available
for wood-pole treatments for many years, but its
slightly higher cost, combined with a general sat-
isfaction with penta, have limited its use. Unlike
creosote and penta, copper naphthenate is not a
restricted-use pesticide, and it is commonly used
to field-treat cuts or holes made in poles after ini-
tial preservative treatment.
In addition to the previously described sys-
tems, a variety of newer oil-based chemicals are
being evaluated for wood poles. These include
chlorothalonil and isothiazolone. The development
of new systems for protecting wood poles is gen-
erally slow because of both the need for highly
reliable protection and a general reluctance on
the part of utilities to accept new treatments rap-
idly without first performing limited tests within
their systems. It is likely, however, that we will
see a gradual evolution to a new generation of
less broadly toxic preservatives for wood poles.
Water-based Preservatives
Water-based preservatives for wood poles include
chromated copper arsenate (CCA), ammonia-
cal copper zinc arsenate (ACZA), copper azole
(CA), and ammoniacal copper quaternary (ACQ).
Although CCA and ACZA are restricted-use pes-
ticides, wood treated with these systems is not.
Wood treated with ACQ is not restricted, and ACQ
itself is not a restricted-use pesticide.
9
Water-based systems produce clean, resi-
due-free surfaces. Many utilities object to the
hardness of poles treated with these systems,
however, as well as a tendency for the wood to be
more conductive when wet. Another concern with
water-based preservative treatment is that the
processes require lower temperatures. Treatment
with ACZA does sterilize the wood, as does kiln
drying before treatment with CCA, but an alter-
native sterilization process must be used when
air-seasoned poles are treated with CCA.
CCA was first developed in the 1930s in
India. It is an acid system containing copper
oxide, arsenic pentoxide, and chromium trioxide.
The system uses chromium reactions with the
wood to fix the copper and arsenic. The process
takes several days to many weeks, depending
on the wood temperature. CCA is increasingly
used to treat poles of southern pine; however, it
is difficult to impregnate Douglas-fir with CCA.
Thus, this chemical/species combination is not
recommended unless material is selected by pre-
treatment permeability trials.
ACZA, originally formulated without zinc as
ammoniacal copper arsenate (ACA), was first
developed in the 1930s in California. ACA and
ACZA use ammonia to solubilize the metals. Once
applied to the wood, the ammonia evaporates and
the metals precipitate. The presence of ammonia
and the use of heated preservative solutions gen-
erally result in deeper preservative penetration
than is found with CCA. For this reason, ACZA is
typically used to treat refractory woods such as
Douglas-fir.
ACQ is among the most recently standardized
preservatives for wood poles. This formulation
uses ammonia or ethanol amine to solubilize
copper and it adds a quaternary ammonium
compound to limit the potential for damage by
copper-tolerant fungi. This preservative is not yet
widely used for wood poles, but comparative field
tests suggest that its performance will be similar
to that of other alkaline copper systems.
Copper Azole Type B (CA-B) is also a
recently standardized system that uses copper as
the primary biocide, with a small amount of a tri-
azole compound to protect against fungi that are
tolerant of copper. Like ACQ, this system is not
widely used for poles.
3
1
2
3
3
4
5
2 4
Figure 9. Relative risk of decay in poles (1 = low risk, 5 = high risk) exposed in various sites in the United States.
Preservative treatMents
Preservative treatment involves forcing oil- or
water-based preservatives into wood to a desired
depth of penetration at a level or retention
that confers biological protection. The depth of
penetration varies with wood species; western
redcedar requires the shallowest penetration and
southern pine the deepest. Penetration require-
ments are generally based upon the amount of
sapwood present and the ease with which it can
be treated. Retention is expressed as the weight
of preservative per volume of wood (lb/ft3 or kg/
m3); this varies with wood species and applica-
tion. For example, wood poles used in warmer,
wetter climates are exposed to a higher risk of
decay and are usually treated to a higher reten-
tion than are those exposed to drier, cooler
conditions. The AWPA Use Category standards
provide a map showing relative risk of decay
across the United States (Figure 9).
Three general treatment processes are used
to impregnate wood poles. In the thermal pro-
cess, dry poles are placed in either a large tank
or a closed cylinder. Oil-based preservative is
added to cover the wood and is heated over a
6- to 18-h period. The oil is pumped out of the
vessel, then pumped back in a process that cools
the oil slightly. As the cooler oil touches the
hotter wood, a partial vacuum is created, which
draws additional preservative into the wood. The
thermal process is used primarily to treat west-
ern redcedar, although it is occasionally used to
treat lodgepole pine, western larch, or Douglas-fir
10
poles for drier or cooler climates, where the decay
hazard is lower. The other two treatment meth-
ods use elevated pressure in a treatment vessel
or retort to force chemical into the wood to the
required depth (Figure 10).
The full-cell process was developed in 1836
by John Bethell. It begins with an initial vacuum
to remove as much air as possible from the wood.
The preservative solution is then added to the
treatment vessel and the pressure is raised (100
to 150 psi). Gauges on the treatment vessel allow
the treater to determine how much solution has
been absorbed by the wood; this information,
in combination with the amount of wood in the
treatment cylinder and the retention required,
dictates the length of the treatment cycle.
Once the desired amount of solution has been
absorbed, the pressure is released. The release of
pressure forces some preservative from the wood
in a process called kickback. After the pressure
period, a series of vacuums are drawn to recover
excessive preservative and minimize bleeding.
In addition, poles of some species are steamed
to clean the surface and enhance fixation reac-
tions. The full-cell process is normally used to
treat wood poles with water-based preservatives
whose concentration can be changed to achieve
the desired retention.
Empty-cell processes were developed in the
early 1900s. In these treatments, the process
begins when preservatives are introduced into
the treatment cylinder at atmospheric pressure
without a vacuum. In the absence of a vacuum,
air trapped in the wood at the start of the pres-
sure cycle is compressed; at the end of the
pressure period it expands and carries additional
preservative or kickback from the wood, reducing
retention. Kickback can be further increased by
introducing a slight pressure prior to the addition
of preservative, thereby increasing the amount
of trapped, compressed air and the subsequent
kickback. Empty-cell processes are normally
used to treat poles with oil-based preservatives
and are used to reduce the amount of preserva-
tive injected into the wood, thereby producing a
cleaner, drier pole.
In addition to the initial vacuums and pressure
processes, most treatment processes also incor-
porate practices that relieve internal pressure,
recover solution from the wood, or encourage
fixation reactions. Expansion baths at the end
of oil-borne processes heat the wood to relieve
internal pressure. Removing this pressure reduces
the risk of bleeding in service. Similarly, steam-
ing heats the wood surface to force chemical from
the wood, cleans the surface, and can accelerate
fixation reactions with water-based systems. All
of these processes produce a cleaner pole. Many
of these processes are incorporated in a series of
specifications termed Best Management Practices
that are used to produce treated wood for use in
or near aquatic environments.
Figure 10. Typical vacuum pressure cycles used to impregnate wood poles with preservative. (A) Full-cell, (B) Rueping, and (C) Lowry processes.
105
0
26
A
105
0
26
B
105
0
26
C
0 1 2 3 4 5 6 7 8
Pr
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s
s
u
r
e
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e
s
s
u
r
e
(p
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i
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H
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Time (h)
11
Treatment of wood poles is specified under
the AWPA Use Category Standards, which set
minimum levels for penetration and retention
of preservatives for wood poles and define pro-
cess limitations for each species. The standards
are results-oriented, in that they specify chemi-
cal levels but do not require a specific treatment
method for achieving the goal. Successful treat-
ment is confirmed by post-treatment sampling.
The standards should be considered minimum
specifications. Utilities that desire greater treat-
ment, however, should carefully consider the
costs and benefits of additional requirements.
For example, higher loadings of chemical may
not always increase service life and they can
sometimes lead to higher loss rates into the sur-
rounding environment.
Pole treatments are specified under the Use
Category System under Standards U1 and T1. U1
lists the various chemicals that can be used for
various commodities, while T1 lists the various
process requirements. Utility poles are specified
under Use Categories 4 A, 4B or 4C where 4A
is the lowest risk of decay and 4C is the high-
est for land-based poles. Utilities can use either
prior experience or a risk map in the Standard to
determine the appropriate level for their system.
fire Protection
Poles in some areas are also subjected to fire
risk. This becomes a special concern in rural
areas, particularly when poles are treated with
either CCA or ACZA. There are a number of field
applied fire retardant barriers. These systems
have been shown to limit the risk of fire damage
for at least 5 years. There are also temporary fire
retardants that can be applied shortly before a
fire. In addition, some utilities have used barriers,
such as aluminum or steel sheets to protect the
wood. While these systems can be effective, care
must be taken since the sheets trap water and
can sometimes accelerate decay.
other treatMent requireMents
In addition to preservative loading, utilities may
incorporate other requirements into their speci-
fications. Among the most common are surface
color and cleanliness. Some utilities require that
poles be treated to a uniform color, particularly
with penta, and this is accomplished by using the
proper solvent and avoiding the accumulation of
debris in the treatment solution. Pole bleeding
can be minimized by varying process conditions
to avoid over-treatment and relieve excess pres-
sure remaining inside the pole (Figure 11). This
pressure can eventually force preservative to
the pole surface. The most comprehensive pro-
cedures for reducing bleeding are described by
the Western Wood Preservers’ Institute Best
Management Practices (WWPInstitute.org).
Preservative Migration
froM Poles
All preservatives used for wood poles have some
degree of water solubility and will migrate from
the wood into the surrounding soil over time. This
ability to migrate is essential for their function
since the chemical must be able to move into a
fungus or insect to be effective. Numerous field
surveys indicate that this chemical migration is
limited to a zone 6 to 12 inches around the pole.
As a result, the risk of environmental contami-
nation from a properly treated pole is minimal.
There are specially designed pole barriers for use
in especially sensitive environments where utili-
ties feel extra protection is warranted.
barriers
A variety of barrier products have recently
emerged that are applied to the area below the
Figure 11. Example of bleeding from a creosote-treated pole.
12
groundline (Figure 12). These systems do not
contain any biocides and are designed to limit
preservative migration from the pole and to limit
soil contact. These two activities should improve
pole performance. Barrier systems include
sock–like materials that are applied prior to pole
installation and polyurea coatings that are applied
at the treating plant. These systems have the
greatest potential use where poles are used in
sensitive environments or where poles might be
Figure 13. (a) example of an older, non-capped pole top with extensive decay, (b and c) commercially available pole caps.
installed in concrete, making future inspection
extremely difficult. Barrier systems that use hard
coatings may have an impact on an inspector’s
ability to perform future inspections.
Pole toPs
Pole top decay can become a problem on older
poles and, if allowed to progress, can eventually
necessitate pole replacement. A number of sys-
tems are available for capping poles (Figure 13).
Caps can be simple plastic discs that have spaces
underneath to allow for air-exchange or they
can be plastic wraps that exclude all moisture.
Field tests indicate that these systems mark-
edly reduce the risk of pole wetting which in turn
reduces the risk of internal decay.
a b
c
Figure 12. Example of a commercially applied pole barrier used to protect the belowground portion of a pole.
13
Wood can be degraded by a variety of living and
non-living agents. The most important non-living
agent is ultraviolet light, which degrades the
wood surface (Figure 14). This damage occurs
very slowly and is normally not an issue for poles.
fungi
The structural integrity of wood may be destroyed
by decay fungi that feed on wood. Wood also
contains a wide variety of so-called non-decay
fungi that usually do not weaken wood. Insects,
woodpeckers, and marine boring animals also
can extensively damage wood structures in some
areas.
Decay fungi are, by far, the most destructive
of the organisms that inhabit wood. Fungi require
water, air, a favorable temperature, and food
(Figure 15). Wood with MC below 20% (oven-dry
basis) usually is safe from fungi. Lack of air limits
fungal growth only when wood is submerged in
water or buried deep in the ground. Freezing
temperatures stop fungal growth but seldom
kill fungi. Above 32°F, fungal activity increases,
peaking between 60 and 80°F and decreasing
as temperatures approach 100°F. Most fungi are
killed at temperatures exceeding 150°F.
decay fungi
Mushrooms and “conks” are typical fruiting bodies
of decay fungi; they produce billions of micro-
scopic seed-like structures called spores (Figure
16). However, not all fungi produce large, visible
fruiting bodies; they may produce microscopic
structures that also produce large numbers of
spores. In favorable conditions, these spores
germinate and produce hyphae, minute thread-
like strands that penetrate throughout wood. The
hyphae secrete enzymes that dissolve the cel-
lulose and lignin of wood into simpler chemicals
that fungi can use as food.
“Decay” describes wood in all stages of fungal
attack, from the initial penetration of hyphae into
the cell wall to the complete destruction of the
wood. Early fungal attack on wood usually can be
detected only by microscopic examination or by
incubating wood on nutrient agar for outgrowth
of decay fungi (Figure 17). If decay fungi can be
Figure 15. Requirements for decay.
Figure 16. The conk (fruit body) of a decay fungus produces microscopic spores that, finding suitable conditions for growth, infect other wood products. Fungal threads spread decay through moist wood.
Food
Spores
Mycelia
Heat Air
Food
Moisture
Fungus
fruiting
body
Figure 14. Weathering of a cedar pole turns the surface grey, but the wood underneath is unaffected.
cultured from wood
that appears visu-
ally sound, the solid
wood is in the incipi-
ent stage of decay.
During the early
stages of decay, some
fungi may discolor or
substantially weaken
the wood, especially
its toughness.
As decay contin-
ues, wood becomes
brash (breaks
abruptly across the
grain), loses luster
and strength, and
14
noticeably changes in color; eventually, it may
be completely destroyed. Wood that is visibly
decayed, greatly weakened, and conspicuously
brash or soft is in the advanced stage of decay
called rot. Three groups of fungi, brown rot, white
rot, and soft rot, cause wood degradation; each
affects the wood in a different manner (Figure 18).
Brown rot is a brown, advanced decay that
crumbles when dry and is common in most
softwoods. Although it is called “dry rot,” this
nomenclature is misleading because at one time
the wood must have been wet enough to sup-
port fungal growth. At very early stages of decay,
brown rot fungi preferentially remove cellulose
from the wood, producing extensive strength
loss and significantly damaging the wood’s utility.
Brown rot fungi are important because they cause
very substantial strength losses at the early
stages of decay.
White rot fungi are more prevalent on hard-
woods, although they are also present in many
conifer species. In the advanced stage of decay,
white-rot fungi bleach or whiten wood or they
form small degraded white pockets in the wood.
Brown and white rot fungi tend to be inside
the pole where moisture conditions are more
stable. They are often associated with deep
checks that penetrated past the original treat-
ment zone. While their damage is important, they
can generally be controlled by the application of
volatile or water diffusible treatments. The end
result of internal decay is a shell of treatment
surrounding a hollow core. The thickness of that
Figure 18. (a) Brown, (b) white, and (c) soft rot.
cb
a
Figure 17. A decay fungus growing over malt agar from a sound-appearing increment core is a positive sign of decay, even though the pole may contain no visible rot.
15
original treatment can determine whether an
internally decayed pole is salvageable.
Soft rot fungi attack the surfaces of both
hardwoods and conifers, particularly where pre-
servative levels have declined below their initial
treatment levels through leaching. Soft-rot fungi
slowly cause external softening of treated wood,
resulting in extensive damage below ground.
Soft rot fungi are most prevalent on southern
pine poles, although they are also common on
poles of Douglas-fir that have been treated with
pentachlorophenol in either methylene chloride
or liquefied petroleum gas. Although neither of
these treatments is currently used, many poles
treated with these systems remain in service.
Soft rot fungi are especially important because
they reduce the effective pole circumference,
producing very sharp declines in flexural prop-
erties. Many of these fungi are also tolerant of
preservatives, allowing them to attack wood that
may have lost some, but not all of its original
treatment.
non-decay fungi
Numerous non-decay fungi also inhabit wood;
they feed on cell contents, certain components of
cell walls, and the products of decay. Frequently,
only non-decay fungi can be isolated from rotten
wood because the decay fungi, having run out
of food, have died. Sapwood-staining fungi may
reduce the toughness of severely discolored
wood; other non-decay fungi gradually detoxify
preservatives, preparing the way for decay fungi.
Some rapidly growing non-decay fungi may inter-
fere with efforts to culture the slower growing
decay fungi from wood. The interaction of fungi,
both decay and non-decay types, and their roles
in the decay process are still to be defined.
insects
Wood in or above ground may be attacked by ter-
mites, carpenter ants, or beetles. Termites work
within and use wood as a food source; there is
virtually no external evidence of their presence
until winged adults emerge and swarm in late
summer and early fall. These social insects have
a well organized colony structure with a queen,
workers and soldiers. Workers feed nearly con-
tinuously and a large colony can approach one
Figure 19. A termite colony includes many workers that burrow in wood for food and shelter, soldiers that protect the colony from other insects, and one egg-laying queen. (a) These reproductives later will fly from the nest to initiate new colonies (photo credit: Scott Bauer, USDA Agricultural Research Service, Bugwood.org). (b) Usually poles show no sign of termites until the reproductives emerge, discard their wings, and mate to start new colonies (photo credit: Gerald J. Lenhard, Louisiana State University, Bugwood.org).
million workers. Collections of wings outside the
nest in checks or other collection areas, discarded
by reproductives (alates) as they mate to start
new colonies, may be the first indicator of termite
presence. Some species also produce mud tubes
up the pole surface or inside checks that indicate
the presence of an infestation. Although their
lengths vary from 1/4 inch or less (subterranean
and drywood) to 3/4 inch (dampwood), termites
have bodies of fairly uniform width; the reproduc-
tives have wings of equal length (Figure 19).
Subterranean termites are wide-spread and
cause extensive damage, especially in southern
states but they are also present in drier parts
of the country. Sure signs of their presence are
the mud tunnels that the termite workers build
from their nests in the ground up across treated
wood or concrete to non-treated wood above.
Subterranean termites are distributed between
50° N and 50° S latitude although there may be
b
a
16
isolated occurrences north of this zone. Global
changes in climate are likely to extend this range.
In warmer portions of the country, wood
may also be subject to very aggressive attack
by an introduced species, the Formosan termite
(Coptotermes formosanus). This subterranean
termite has large colonies with as many as 6 to 7
million workers. Fortunately, this species is cur-
rently only found in Hawaii, along the Gulf Coast
and in extreme southern California. The presence
of this termite in Hawaii, however, has resulted
in a requirement that all wood used in houses be
preservative protected.
Dampwood termites (Zootermopsis augus-
ticollis) inhabit moist wood in, on, or above the
ground along the Pacific Coast. The workers of
this species are very large and easily identified,
while the soldiers have extremely large pincers.
This species can be a problem in poles, but it
is most often associated with very deep wide
checks or prior woodpecker attack. In both cases,
the openings allow moisture to enter, creating
ideal conditions for attack. Dampwood termites
appear to be very susceptible to preservative
treatments.
Drywood termites feed on dry wood, primar-
ily in the southern United States and the Pacific
Southwest. These species can live in wood at 12%
MC, and the only evidence of their presence is the
frass or insect droppings that they periodically
expel from their colonies. (Figure 20). Drywood
termites can invade poles and crossarms, where
their presence is difficult and expensive to detect.
The best preventative method is a well-treated
preservative shell.
The initial treatments currently used for poles
are all capable of preventing termite attack, but
checks or other damage to the wood can create
non-treated zones where termites can invade.
Termites are best controlled by producing a well-
treated pole without deep checks that penetrate
beyond the treated shell.
Carpenter ants are also social insects with
a queen and major or minor workers (Figure
21). The ants have a restricted waist, and the
reproductives have wings of unequal length. The
dark-colored ants grow as long as 3/4 inch. Unlike
termites, which eat wood, ants hollow out wood
only for shelter, forming piles of “sawdust” at the
base of poles, which attest to their presence in
the wood Figure 22). Ants must leave the nest
to find food and are frequently seen scurrying
around poles particularly at night (they are noc-
turnal). They are difficult to control because they
do not eat the wood. They also tend to have a
main nest along with satellite nests. This makes it
Figure 21. In contrast to termites, carpenter ants (Camponotus sp.) have restricted waists and reproductives have shorter wings of unequal length (photo credit: Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org).
Figure 20. Example of termite damage to wood. Note the debris and termite excrement on the wood.
17
difficult to treat the pole and expect to eliminate
the infestation. A well-treated pole without checks
penetrating beyond the treated shell is the best
method for preventing carpenter ant attack.
Beetles that attack poles typically invade the
wood while the bark is still on the freshly fallen
tree. The adult lays eggs that hatch into larvae
that tunnel beneath the bark. If the bark is not
removed in a timely manner, the larvae will then
move into the wood. An effective sterilization
treatment will kill the larvae; however, inadequate
treatment can allow the beetle to survive, con-
tinue its life cycle and emerge once the pole has
been placed in service.
The most common beetles in poles are
buprestids, also called flat-headed or metallic
wood borers (Figure 23). The golden buprestid is
the most common of these beetles in the Pacific
Northwest. This beetle has a life cycle that can
range from 2 to 40 y. The 3/4-inch-long, metallic
golden or green adult makes an elliptical hole as
it emerges from the pole to mate. Trained pole-
maintenance personnel recognize these elliptical
holes as indicators of internal rot often associated
with beetle attack. Numerous emergence holes
may indicate an unsafe pole.
Beetles in other wood species may be indica-
tors of prior insect attack. For example, western
redcedar heartwood may have been attacked by
another species of buprestid beetle as a stand-
ing tree. This species attacks only living trees,
and the damage does not spread in the finished
product. Similarly, some buprestid species attack
wounds in standing southern pine. Those beetles
do not cause further damage in the finished
products.
Beetle damage, while not always a long-term
problem, can be an indicator of poor handling. As
a result, the ANSI specifications reject poles with
beetle holes.
Figure 23. Golden buprestid beetle (Buprestis aurulenta). As an indication of internal rot in the aboveground portion of poles, look for the oval holes (0.5 in. long), that the buprestid beetle leaves as it emerges from wood. Many holes could mean an unsafe pole.
Figure 22. Carpenter ant damage in poles. Carpenter ants also live in colonies, hollowing out nests in poles for shelter. A pile of sawdust at the base of the pole is a sure sign of their presence.
18
Woodpeckers sometimes nest in poles, drum on
poles as part of their mating rituals, use poles as
a source of insects, store acorns in small holes
as a future food source, and make holes for other
unknown reasons (Figure 24). Woodpecker holes
also open the pole interior to moisture intrusion,
creating an ideal environment for fungal and
insect attack. Dampwood termite colonies have
been found 30 to 40 ft above ground in aban-
doned woodpecker nests.
Woodpeckers will tend to be more prevalent in
forested areas; however, there are very few areas
in a rural or suburban setting that would not be
suitable for woodpecker habitat. Woodpeckers
also appear to choose poles because they offer
a clear unobstructed view of the area, allowing
them to avoid predators. Woodpeckers are feder-
ally protected and it is illegal to disturb nesting
birds.
Chemical repellents, plastic wraps that deny
the birds a toehold and stuffed owls have been
tried as woodpecker deterrents. When poles with
woodpecker damage have been replaced, the
pole section containing the nest cavity has even
been retained and attached to the new pole at its
original height (Figure 25). These methods, how-
ever, usually do not prevent woodpecker damage.
Heavy galvanized hardware cloth applied tightly
over much of the pole has been the most suc-
cessful preventative measure, but can cause
problems when poles must be climbed. The use
of ACZA-treated poles has been reported to
reduce, but not completely prevent woodpecker
damage. Damage is most often repaired by treat-
ing the wood with preservative and filling holes
with an epoxy resin or foam. These actions, how-
ever, do not prevent renewed attack. It is critical
that woodpecker holes be repaired as soon as
possible so that they do not provide entry points
for other agents of decay.
Marine borers
Utility poles are rarely used in salt water contact,
but where they are, utilities must be concerned
about marine borers. Non-treated wood piles
and poles in saline coastal waters are attacked
rapidly by marine borers. Shipworms (Bankia or Figure 24. (a) Example of a woodpecker hole on the pole surface and (b) the extent of void associated with a nest.
Figure 25. A section of old pole containing a woodpecker nest attached to a new pole in hopes of discouraging new attack.
b
a
19
Teredo spp.) riddle interior wood with long holes,
and Limnoria (gribbles) burrow small tunnels near
wood surfaces (Figure 26).
Shipworms are bivalves (mollusks) with a pair
of small shells at their heads. As small larvae,
they burrow into wood and continue to tunnel
away from the hole. Their tunnels may be up to
3/4 inch in diameter and 2 ft in length (Figure
26).
Gribbles, small crustaceans about 1/10 inch
long, tunnel in large numbers just below the
surface of wood. Waves then break off these
weakened surface layers, which gradually reduces
the effective diameter of the wood.
Marine borers are very destructive in southern
latitudes, where wood needs special preservative
treatments (south of San Francisco, CA or New
York Harbor, NY). In northern latitudes, they do
little damage to wood that has been pressure-
treated with marine-grade creosote or wood
with high retentions of certain water-based salts,
unless cracks, bolt holes, or cuts expose non-
treated wood. Pentachlorophenol-treated wood
should not be used in marine waters. Non-treated
wood such as bracing should not be fastened
to treated wood below the tidal zone, because
borers can become established in the non-treated
wood and penetrate the treated wood. Where
damage occurs, plastic wraps or concrete barriers
have proven useful for arresting attack by cutting
off oxygen to the organism.
insPection of neW Poles
The treater is responsible for ensuring adher-
ence to specifications and plants routinely test
the quality of their treated poles prior to ship-
ping. Utilities may find it helpful to have in-house
or third-party inspection of all incoming poles to
ensure compliance. In-house inspection is usu-
ally most practical for large utilities with specially
trained quality control staff. Third-party inspec-
tion is more appropriate for smaller utilities that
buy fewer poles. New pole inspection combines
a final check on wood quality with an assess-
ment of treatment quality. The inspector checks
the pole for knots that exceed the specification,
the presence of excessive spiral grain, checks or
splits, and other wood defects limited in the ASC
05.1 Standard (ANSI 2008). The inspector then
removes increment cores from the designated
sampling zone and assesses preservative pen-
etration. The cores are then collected, combined
and ground to a fine powder so that they can be
analyzed for chemical content. This is most often
done using an x-ray fluorescence analyzer. The
treatment quality inspection follows the standards
Figure 26. Marine borers attack wood in coastal waters where salinity and oxygen supply are favorable. Gribbles (a) make smaller tunnels near the surface (photo courtesy Wikimedia Commons). Shipworms (b) are marine borers that make long tunnels (c,d).
c
a
d
b
20
of the American Wood Protection Association or
the Rural Utility Services.
This practice provides a final check on pole
quality and helps to identify potential problems
before costly construction time is wasted install-
ing an inferior pole. Inspection can occur in the
plant or at the final destination. The small cost
associated with inspection is easily offset by
avoiding placing an inadequately treated pole in
service.
insPection of in-service
Poles
For many years, utilities installed poles with
little thought to the necessity of regular mainte-
nance. The need to minimize potential liabilities
while maximizing the investment in wood poles
has encouraged many utilities to institute regu-
lar programs of inspection and retreatment.
Inspection programs and the tools they use vary
widely depending on the wood species, chemical
treatments, and climate to which the poles are
exposed.
crossarMs
Crossarms are a critical, but often overlooked
element in a utility structure. Crossarms are
exposed to less severe decay risk than the pole
itself, but eventually, decay will develop in these
elements. Tests of arms removed from service
suggest that they are often removed while still
retaining sufficient capacity. This often occurs
because excessive weathering makes the arm
appear weak. In other cases, checks developing
on the upper surface of the arm trap moisture
and allow fungi to grow. At least one crossarm
manufacturer produces arms coated with a
polyurea polymer that may provide long term
protection against checking and ultra-violet light
damage.
The other types of damage incurred by cross-
arms are splits or deep checks. These splits can
widen to the point that insulator bolts fall out of
the arm. Field trials indicate that end-plates can
markedly reduce this checking (Figure 27). Arm
damage can also be limited by the application of
polyurea coatings (Figure 28).
Figure 28. Polyurea-coated arms designed to reduce the risk of checks developing on the upper surface. Figure 27. Crossarms (a) with and (b) without end-plates that limit end-checking. Note the large checks on non-plated ends.
b
a
21
The timing and extent of a pole inspection pro-
gram varies greatly depending on the climate,
geography, wood species, initial preservative, and
age of the system (Table 1). The risk of decay
above the ground can be estimated using average
monthly temperatures and days with precipitation
to produce a climate index (Scheffer 1971). The
risk of decay in soil contact also varies and maps
have been developed to guide utilities. For exam-
ple, wood exposed in cool, dry regions, such as
those in the Upper Great Basin, can be inspected
less frequently than wood in sub-tropical south-
ern Florida (Figures 29 and 30). In wetter regions,
internal decay typically starts at or slightly below
the groundline, whereas in drier regions it often
extends more deeply below the ground. Similarly,
internal decay in wetter regions can extend many
feet up from the ground. Some aboveground
internal inspection should be considered for older
poles in these regions or for poles in coastal
regions. It can be difficult to predict the rate of
decay in ground contact because soil conditions
can have such a major impact on biological activ-
ity. As a result, inspection programs are best
determined using local data on pole performance.
In addition, the Rural Utility Service has devel-
oped maps of decay risk and these are cited in
the AWPA Standards.
Wood species and the initial treatment chemi-
cal can strongly influence both the type and
frequency of inspection due to the rates and
types of decay. Most decay in well-treated south-
ern pine poles occurs below the groundline on
the wood surface. As a result, inspections that
include digging, combined with an inspection and
probing of the wood surface below groundline,
Table 1. Recommended pole inspection schedules, from RUS 1730B-121 (1996).
Decay zone Years before initial inspection Years before subsequent re-inspection Percent total poles inspected each year
1 12–15 12 8.3
2 & 3 10–12 10 10.0
4 & 5 8–10 8 12.5
are essential for detecting damage in this spe-
cies. Most pole strength is in the outer 2-3 inches,
so external surface decay can have a significant
impact on the strength of the pole. Douglas-fir,
western larch, western redcedar, and lodgepole
pine are more prone to internal decay at and/
or below the groundline (although older cedar
may also have some external decay), which
makes internal inspection critical for early decay
detection.
The initial treatment chemical can also influ-
ence inspection. For example, poles treated with
pentachlorophenol in liquefied petroleum gas by
either the Dow® or the Cellon® process tend
to have surface decay below the ground level,
regardless of the wood species. As a result, dig-
ging inspections are required for poles treated
by these processes, regardless of species.
Conversely, CCA- or ACZA-treated poles tend to
have much slower rates of surface decay, and
excavation is probably advisable after approxi-
mately 30 y of service (although some partial
excavation prior to that is advisable to make sure
that poles are performing as expected in your
system). Finally, inspection in the through-bored
region is not necessary because the wood is thor-
oughly treated in that zone. The wood above that
level should be inspected.
Most utilities in North America physically
inspect poles on a cycle of 8-15 y. This inspection
comes in addition to annual drive-by inspections
used by some utilities to detect obvious physical
defects such as cracked insulators, split pole tops
or other damage that can be seen from either
the ground or air. An examination of national field
inspection data suggests that a cycle of 8-12 y
is best; rejection rates increase markedly when
a longer cycle is employed for utilities in areas
with moderate decay risks (Figure 30). Shorter
Note: see Figure 9 (p. 9), AWPA Use Category Standards.
22
cycles may be advisable in areas with extreme
decay risk, such as those along the Gulf Coast
of the United States. Utilities in extremely dry
areas may extend their cycle because the risk
is so low, but they should use their own data to
decide whether this extension is advisable. Even
within these areas; however, there may be loca-
tions where the decay risk is high, such as in
70
70
70
100
70
80
90100
110120
6050
40
30
2010
0
30
405060
70
40
Less than 35
35 to 70
More than 70
Climate Index
20
3020
130
Figure 29. This climate-index map of the United States provides an estimate of potential for decay of wood above ground (Scheffer 1971).
Low
LowMedium
Medium
High
Severe
Figure 30. Decay hazard map, as reported by the Rural Electrification Administration (REA), is derived from the decay hazard to which the wood is exposed.
zones where the soil is irrigated. A good inspec-
tion process incorporates local knowledge in order
to tailor the program to the system. Obviously, it
is not possible to treat each pole as an individual,
but it is possible to identify problem areas within
a system where climate, wood species, or initial
treatment type may require some different steps
in order to ensure long service life.
the initial insPection
When first evaluating a line
or system, it is helpful to
thoroughly inspect a smaller
population of representative
poles through an excavation
18-20 inches deep and 360°
around the pole. These poles
can provide useful informa-
tion on wood species, original
treatment, seasoning checks,
insect attack, internal or
external decay, and any other
defects. The pre-inspection
can also identify populations of
poles that should receive extra
attention.
The number of poles sam-
pled in the initial inspection
will depend on prior mainte-
nance practices, as well as the
exposure hazard (Figure 30).
Where personnel continually
check poles above and below
ground and detect developing
problems, the initial sampling
inspection may be limited to
relatively few poles in certain
lines or in certain areas. If little
is known about a pole system,
the inspection could involve a
statistical sampling of poles
in each line throughout the
system. Some utilities sample a
set number of poles (e.g., 300)
of a similar age, species, and
treatment that were produced
by the same manufacturer.
RUS 170B-121 generally
23
recommends inspecting a “1,000 pole sample
made up of continuous pole line groupings of 50
or 100 poles in several areas of the system” (RUS
1996). The percentage of poles deteriorating and
rejected then becomes a basis for decisions on
the scope and nature of the pole maintenance
program. The 1000-pole sample is arbitrary.
Utilities should use some judgment based upon
more intimate knowledge of their pole plant to
determine appropriate initial samples.
to dig or not to dig?
Initial pole inspection should include digging,
because poles can be sound above the ground-
line, but badly decayed below. As poles age and
as poles of new species or with new preservative
treatments are installed, do not hesitate to make
early digging inspections to find out how the poles
are performing. As you become better acquainted
with the condition of poles in your system, you
can vary the frequency and extent of digging
to suit the local conditions. Some utilities use
what is called a partial excavation, where they
dig only one-third of the pole’s circumference in
the groundline area. These “partial excavations”
can vary in depth from 6-20 inches or deeper. If
nothing is found, the exposed surface is treated
with a supplemental paste and a wrap or a pre-
made bandage, and the hole is filed in. If decay
is evident, then the rest of the pole should be
excavated.
Digging 18 inches deep will reveal surface
decay in most areas, but you may have to dig
deeper in dry areas where poles can decay
below the incised zone (about 1 ft above to 3
ft below the groundline). One utility found that
cedar poles set in gravel decayed “from the butt
up.” To get the facts, inspect and cut up poles
removed from service. Although surface rot is
uncommon in pressure-treated Douglas-fir poles,
it does occasionally occur, so some initial dig-
ging is still necessary to ensure that it is absent
in your locality. Most southern pine poles should
be excavated. The exception would be younger
CCA-treated poles (<30 y old). Older CCA-treated
poles should receive at least a partial excava-
tion. Internal decay pockets can also occur well
below or above the groundline, depending on local
conditions.
to culture or not to
culture?
Early decay in the pole interior is difficult to
detect visually. It can be helpful during the ini-
tial sampling of poles in a system to culture the
wood for decay fungi. Culturing involves remov-
ing increment cores from the poles and placing
the core on nutrient media (called agar) in petri
dishes. Any fungi in the wood can then grow onto
the media surface where they can be identified.
Most decay fungi have distinctive characteristics
that make them easy to distinguish; however, the
process requires trained personnel, such as plant
pathologists, who use microscopes to distinguish
between decay and non-decay fungi. Although
numerous cores can be cultured simultaneously,
this process is not feasible for large-scale inspec-
tion. It is most useful for determining the risk
of decay in a line. Culturing can also indicate
whether it is advisable to remedially treat poles
that might not have visible decay.
For example, inspection of Douglas-fir trans-
mission poles installed 10 y earlier revealed only
a few poles with internal rot; yet 30% of the poles
contained decay fungi, warranting a program of
internal treatment (Zabel et al. 1980). In western
Oregon, for each Douglas-fir pole that contained
rot, we found one or two poles that contained
decay fungi. These decay fungi represent a future
risk of damage that can be easily controlled by
active remedial treatments.
Decay can be internal (Figure 31), external, or
a combination of both on the same pole (Figure
32). Appearances can be deceiving, however.
Figure 31. Internal decay.
24
Poles that look weathered or checked are often
rejected because of their appearance, but further
inspection often reveals that the damage is shal-
low. Checks have little or no effect on strength. A
careful internal inspection by boring and probing
is always warranted before arbitrarily rejecting
Figure 33. Examples of steel trusses used to reinforce deteriorated poles.
Figure 32. Both external (a) and internal decay (b).
a pole. External decay is typically found in older
southern pine poles below the groundline. This
damage develops slowly, but eventually reduces
the effective circumference and strength of the
pole, forcing replacement or reinforcement.
(Figure 33).
ba
25
Pole inspectors in areas with low hazards of decay
or termites should not be complacent. Warm, dry
climates are conducive to pole checking. Both
surface and internal decay of poles can occur
below ground in dry climates in areas along rivers
or in irrigated land. It is important to inspect
poles in these areas to a depth of 3 ft below the
groundline. Termites can attack wet wood any-
where and they can be surprisingly abundant in
desert areas. Metal wraps around butt-treated
cedar as well as around older, full-length treated
poles to protect against fire can encourage decay
and termite attack of unprotected sapwood
beneath the wrap. The same can apply to fire
retardant coatings that do not breathe, such as
polyurea coatings.
Linemen sometimes cut longer poles to length
during installation. This practice is costly, since it
wastes wood, but it also exposes untreated wood
at the top. Internal decay can begin in untreated
pole tops within 1 y and reach the visible
advanced stage called rot within 2 to 4 y under
ideal conditions. Any cuts or borings made in the
field should be treated. Pole tops should have
a cap to protect against decay. The cap sheds
water, creating conditions that are less suitable
for fungal attack.
inciPient decay
Before it is visible, decay can produce dramatic
reductions in wood strength (Wilcox 1978).
Termed “incipient decay,” this damage can extend
4 ft or more above internal rotten areas in the
groundline zone of Douglas-fir poles. Because
incipient decay is invisible to the unaided eye,
it cannot be reliably detected in the field.
Microscopic examination and the culturing of
wood remain the only ways to detect decay fungi
at the earliest stages of attack; however, these
are clearly not feasible for regular pole inspection.
As a result, inspectors must be fairly conserva-
tive when estimating remaining pole flexural
properties.
sound or rotten?
Eventually, decaying wood becomes discolored
or the physical properties of its fibrous structure
change sufficiently to be recognized as rot. Sound
wood has a fibrous structure and splinters when
broken across the grain, whereas rotten wood
is brash and breaks abruptly across the grain
or crumbles into small particles. Decaying wood
also may have an abnormal moldy or pungent
odor. Wet, sound wood, which is much softer than
dry sound wood, is frequently confused with rot
on the surface of poles below the groundline. If
in doubt, use the “pick test” (Figure 34). Lift a
small sliver of wood with a pick or pocket knife
and notice whether it splinters (sound) or breaks
Figure 34. Use the “pick test” to detect rot. When a sliver of wood is lifted, abrupt failure (a) usually indicates rot, whereas a splintering failure (b) indicates sound wood. Photo courtesy of the U.S. Forest Products Laboratory, Madison, WI.
b
a
26
abruptly (rotten). Sound wood has a solid feel
when scraped or probed. Surface rot feels soft
and usually has minute fractures like charred
wood. Remember—”sound” and “solid” wood
cannot be reliably distinguished in the field!
As discussed earlier, rot in cedar heartwood
may occur as voids or as well-defined pockets
of rotten wood that abruptly changes to the
adjacent sound heartwood. In Douglas-fir and
southern pine, the change from rotten to sound
wood is much less distinct because incipient
decay usually extends a considerable distance
from the rot.
Drilling and probing with a metal gauge with
a hook may reveal natural voids that can be con-
fused with decay, or wet wood may drill easily like
decayed wood. Ring shake, a natural separation
along a growth ring, usually creates a short radial
void with wood on both sides that feels solid.
Internal radial checks create long narrow voids
that may or may not be coated with preservative.
In cedar poles, decay pockets caused by fungi in
living trees can be misleading. While ANSI speci-
fications allow the presence of visible decay in the
butts of cedar poles, they limit the distance from
the butt that decay pockets can extend in cedar.
This decay is allowed because the smaller pock-
ets do not affect strength in this location and the
fungi that caused the damage do not survive the
seasoning and treatment process.
Surface rot can be detected by scraping,
probing with a dull tool, or visually examining the
wood. Internal decay is detected by sounding,
drilling, coring, measuring electrical resistance,
or feeling within a drilled hole with a metal gauge
with a hook as it is pulled across the growth
rings. Poles with extensive rot are easy to detect,
but detection becomes more difficult as the
extent of the rot decreases. The sooner decay
can be detected, the earlier remedial treatments
can be applied to arrest the attack and retain the
structural integrity and strength of poles. Field
personnel should practice scraping, probing, lift-
ing slivers, drilling, and coring both sound and
decaying poles to develop and improve their abil-
ity to detect rot. Use pole sections removed from
service to verify predictions by boring, then cut-
ting, the cross section to see the actual damage.
Select the equipment that best meets your needs.
Some sources of equipment are listed in the
Equipment Appendix.
insPection tools and techniques
scraPing devices
A shovel, scraper with triangular blade, wire
brush, or dull probe can be used to detect below-
ground rot on the pole surface and internally, in
some cases. Cutting the blade of a shovel back
several inches facilitates the removal of earth
around poles and from the surface of poles. The
pole is excavated to a depth of 18 to 24 inches;
the scraper is then rubbed along the surface. If
scraping exposes untreated or decayed wood,
treat that area with a preservative paste or a
groundline bandage. Be careful not to confuse
softer, wet wood with decay. A scraper or wire
brush can often be useful in identifying inter-
nal decay, particularly when the decay occurs
at or near the bottom of the excavation where a
hammer is difficult to use effectively (see below).
With a thin shell, an experienced inspector can
pick-up an audible difference between solid wood
and internal decay when the brush or scraper is
rubbed along the surface.
haMMer
In the hands of an experienced inspector, a
hammer is a simple, rapid, and effective tool
for sounding poles to detect internal rot. Use a
lightweight (16-24 oz) hammer that is comfort-
able to swing and strong enough to withstand
27
repeated solid blows to the pole. Start hammer-
ing as high as you can reach, and work down the
pole. Experienced inspectors can tell much about
a pole by the “feel” of the hammer during sound-
ing. A sharp ring indicates sound wood, whereas a
hollow sound or dull “thud” indicates rot. Because
seasoning checks, internal checks, and knots
can affect the sound, suspicious areas should be
drilled or cored with an increment borer. A leather
punch 1/4 inch in diameter can be welded to the
back of the hammer to make a starter hole for an
increment borer bit.
drills
Drilling into the wood at a steep angle produces
a hole through which the pole interior can be fur-
ther investigated. Some utilities use a 3/8-inch
diameter bit for this purpose, but larger diameter
bits are used where the hole will also be used
to apply remedial treatments. A careful inspec-
tor will listen to the drill as it enters the wood.
Sudden speeding up of the drill indicates softer
wood that merits further investigation. Drills used
for this purpose can be gas or battery powered.
Chips from sound wood tend to be bright and
larger than those from decayed wood. In addi-
tion, shavings from weak wood will be darker and
more easily broken than those from sound wood.
For southern pine poles, inspectors typically use
3/8-inch diameter bits; for Douglas-fir or western
redcedar, inspectors often use 13/16-inch or 7/8-
inch diameter bits. The latter bits create an ideal
hole or “reservoir” for subsequent application of
remedial treatments for arresting internal decay.
increMent borer
Increment borers were originally used to measure
tree growth and consist of a hollow, fine-steel bit
that is twisted into the pole along with an extrac-
tor for removing the wood core from inside the
tube (Figure 35). The cores can be examined for
visible decay and measured for shell thickness
and depth of preservative treatment. Starter
holes created with a metal punch welded on one
face of an inspection hammer can speed coring
and reduce breakage of the expensive bits. Gas
or battery-powered drills can also be used, but
must be used carefully to avoid damaging the
bits. To speed drilling, special chucks can be
Figure 35. Cores extracted with an increment borer permit detection of rot, as well as measurement of shell thickness and depth of preservative penetration. Cores can be retained and cultured for fungi.
fabricated to fit into a variable-speed power drill.
This arrangement works well, but be careful not
to damage the bit by drilling too fast. If boring
resistance increases, back out and remove the
core before boring deeper. Unusual or abrupt
force can snap the bit or can pack wood in so
tightly that the bit must be cleared of compacted
wood by drilling with a smaller diameter bit.
Rubbing increment borers with a moistened bar of
soap or wax eases drilling.
Increment corers work best when the cores
are taken at a 90° angle to the pole in order to
cut across growth rings. It is also important to
regularly sharpen the bits with a fine hone, espe-
cially when cores become twisted and difficult to
remove. Cores taken with a dull borer may appear
decayed or damaged. Some suppliers of incre-
ment borers also sharpen bits. Keep the bits free
of rust or pitch. To avoid corrosion, keep a small
can of machine oil on hand to coat the outside of
the bit during use and to coat the inside after use,
especially during wet weather. A rifle cleaning kit
is handy for cleaning increment borers.
shell-thickness indicator
An important part of the inspection process is
determining how much residual shell remains
in a pole along with the extent of any internal
decay. The inspection hole, either drilled or from
an increment borer, provides a convenient mea-
surement location. The shell-depth indicator is
a calibrated metal rod with a hook on the end
28
(Figure 36). The indicator is inserted into the hole
and pulled back out so that the hook rides along
the wood. The hook at the end should catch on
the edge of the rot pocket. When pushing a tight-
fitting shell-thickness indicator into a hole, you
can feel the tip of the hook pass from one growth
ring to another in solid wood, but not in rotten
wood. Inscribe marks on the sides of the rod to
indicate the shell thickness at different drilling
angles, usually 45° and 90°. The rod will occa-
sionally overestimate the residual shell, but it is a
useful tool for identifying dangerous poles. Some
inspectors automatically subtract 1/2 inch from
the measurements to account for the decayed
wood. The rods can be home-made or purchased
from pole-inspection agencies.
shigoMeter®
The Shigometer® (Figure 37) was developed
for detecting decay in living trees by measur-
ing electrical resistance (Shigo et al. 1977). It
should be used in wood with MC at or above 27%,
which is typical of decaying wood at the ground-
line of poles. A probe with two twisted, insulated
wires with the insulation removed near the tip is
inserted to various depths into a hole 3/32 inch
in diameter. A marked change in electrical resis-
tance as the probe goes deeper indicates rot or a
defect. The device effectively detects rot, but it
also can yield “bad” readings on apparently sound
poles. For example, free water in the wood may
affect resistance. As a precaution, drill or core all
poles to determine the nature of the defect. The
Shigometer® should be used by trained person-
nel and calibrated frequently (Zabel et al. 1982).
Moisture Meter
Resistance-type meters can be used to detect
wood with MC exceeding 20%, the safe limit to
prevent decay (Figure 38). They are also useful
for assessing post-treatment MC specifications.
Long electrodes can measure moisture to a depth
of about 2-1/2 inches. Because the high MC of
decaying wood (usually greater than 30%) causes
steeper-than-normal moisture gradients in poles
decaying internally, the meter becomes a useful
tool for determining the extent of decay in poles
and other timbers. For example, meter read-
ings above 20% and steep moisture gradients
Figure 37. The Shigometer™ measures electrical resistance to detect rot in poles. Use an increment borer to determine the nature of the defect.
Figure 36. A shell-thickness indicator detects rot in poles by “feeling” growth rings in sound, but not rotten, wood when inserted or removed from snug-fitting holes.
Figure 38. A resistance-type meter can be useful for detecting MC levels that are high enough (over 20%) for decay. As a sliding hammer drives two electrodes into the wood, a ruler emerging from the top of the hammer measures their depth. Shanks of the electrodes are coated so moisture readings are made between the uninsulated points.
29
can indicate the height of decaying wood in
Douglas-fir poles with rot below, but not above,
the groundline. Similar readings in poles without
rot should be suspect. Moisture readings below
20% indicate the absence of conditions for fungal
growth to the depth of the electrodes.
Check the batteries regularly, and calibrate
the meter frequently. Make sure the coating
on the shank of the electrodes is intact. When
necessary, correct meter readings for ambient
temperature and wood species. Moisture meters
should be considered secondary tools for inspec-
tion because they are limited in the zone they can
inspect and are not able to detect decay; instead,
they can only detect the conditions where it might
occur.
decay-detecting drills
Although conventional drills create a large hole
in the pole, decay-detecting drills use a small,
1/8-inch diameter bit to bore into the pole (Figure
39). As the bit enters the wood, the bit rotation
is recorded (either on paper or electronically),
providing a viewable graph of the pole’s internal
condition. These graphs can be saved for record
keeping purposes. Bits require fewer rotations
to penetrate weaker, decayed wood than sound
material. These devices were originally developed
for detecting decay pockets in living trees, where
the tree could later grow over the inspection
hole. Poles cannot “grow over” the hole; there-
fore, some caution must be exercised to ensure
that the poles are flooded with a supplemental
Sound wood
Decayed wood
Figure 40. Strong and weak acoustic signals showing sound
and weak wood, respectively.
Figure 39. The resistograph drill uses a very fine bit to detect voids or softer wood that may be decayed.
preservative to avoid creating avenues of entry
for decay fungi. These devices are especially
useful where there may be concerns about drill-
ing too many holes or where unsightly holes
might be objectionable. They are also useful for
above-ground inspection near attachments or on
crossarms.
acoustic insPection
The desire for nondestructive inspection tech-
niques that do not cause wood damage has
stimulated the development of acoustic inspec-
tion devices. In principle, a sound wave moving
across a wood pole is affected by all character-
istics of the material, including growth rings,
moisture, checks, decay pockets, knots, and a
myriad of other wood properties (Figure 40).
These characteristics affect both the speed at
which the wave moves across the pole (time-of-
flight) and the shape of the wave that exits the
wood (attenuation of the wave). Large voids,
30
Figure 42. X-ray of wood.
Figure 41. Pole test with an acoustic inspection device.
checks, ring shakes, or internal burst increase the
time required for a sound wave to traverse a pole
cross section.
Early acoustic inspection devices used time-
of-flight to detect voids, but the effectiveness
of those devices was limited by the presence of
natural defects that affected time-of-flight in a
similar manner. Later devices used time-of-flight,
but also recorded the changes in wave-form,
or modulation of the sound wave as it passed
through the pole, which provided more reliable
estimates of pole condition (Figure 41). The devel-
opers of acoustic devices then tested poles both
sonically and in bending to failure and used sta-
tistical techniques to relate sonic parameters to
residual strength. Data from this population was
then used to produce estimates of residual modu-
lus of rupture of poles in service.
These devices do not detect decay; instead,
they use acoustic parameters to estimate residual
strength based upon the relationship between
modulus of elasticity and modulus of rupture.
Thus, a strong pole with significant decay may
produce a reading similar to a weaker pole with-
out decay. In this case, the device might infer
that no action was required on either pole; how-
ever, the initially strong pole would continue to
decay between inspections and could fail.
There is considerable debate concerning the
merits of the currently available systems. They
are best used as supplemental tools to the con-
ventional inspection methods and should never
be the sole inspection method used (Wright and
Smith 1992). One especially useful application is
for re-inspection of poles that have been rejected
by prior physical inspection. The acoustic device
can be used to help assess pole properties to
determine whether the pole can be restored or
needs to be replaced. This process must take
place in conjunction with a remedial treatment
program in order to arrest any existing decay,
otherwise pole condition can continue to decline.
X-ray toMograPhy
Like the bones in our bodies, wood varies widely
in density, and those variations can be detected
with x-rays (Figure 42). X-rays were used in
the 1960s and early 1970s for in situ inspec-
tion of wood poles, but the process was slow,
the equipment was bulky, and interpretation of
31
Figure 43. Hyphae of a decay fungus in a wood section.
the resulting x-rays was difficult. As a result, the
technique was abandoned.
The use of x-ray tomography, similar to that
used in the medical field, has been explored
for this purpose but the cost and speed make
it largely impractical for field use. Continued
improvements in computing power may someday
make this technology feasible. Even with these
improvements, however, considerable research
will be needed to fully understand the result-
ing variations that may occur in the field. For
example, variations in moisture can affect x-ray
attenuation, producing the image of a decay
pocket. Methods are needed for rapidly separat-
ing natural wood characteristics from defects that
threaten a pole. This technique could provide a
powerful new inspection tool when methods for
segregating defects from natural wood character-
istics are developed.
ground Penetrating radar
Ground penetrating radar has recently been
commercialized for assessing the internal condi-
tion of both poles and crossarms. The process
produces three dimensional maps of internal con-
dition (density) using a system mounted on either
a truck or a helicopter. At present, the system
does not appear to be practical for rapid inspec-
tion of every structure, but it can be useful for
detailed analysis of critical structures. In addition,
the system does not detect decay, so it must be
used in conjunction with some other inspection
process.
Mechanical Pole tester (MPt)
The MPT essentially deflects the pole a short dis-
tance at the groundline and then uses the
resulting load/deflection data to calculate a modu-
lus of elasticity (MOE) of the pole. This value is, in
turn, used to estimate modulus of rupture (MOR).
This device has been used in Australia for many
years and is just beginning to see application in
the United States. The advantages include the
ability to directly test flexure instead of relying on
acoustic tests to derive MOE; however, the device
cannot distinguish between a strong, decaying
pole and a non-decaying, but weaker pole. As a
result, the device is best used in conjunction with
other devices or methods that can detect decay.
MicroscoPic decay detection
Most inspection techniques detect decay in its
intermediate to advanced stages, when the
damage is clearly visible. Ideally, an inspector
would detect damage at an earlier stage when
treatment chemicals are more effective. At pres-
ent, the most reliable technique for detecting the
early stages of decay is microscopic examination
of either wood fibers or thin sections cut from
the wood (Figure 43). Microscopic analysis is
tedious and time consuming, and is not suitable
for routine evaluations. It is, however, useful for
delineating the cause of failure in specific cases.
The observer looks for bore holes, cell-wall thin-
ning, and other evidence of fungal attack. One
shortcoming of this technique is that it cannot
determine whether the attack was actively occur-
ring at the time of failure. Culturing wood from
the same zone can help determine whether
viable fungi remain in the wood. This is more of a
research technique and would not be feasible for
decay detection on a larger scale.
infrared assessMent
Infrared technologies are used in a variety of
industries to measure minor changes in tempera-
ture. Temperature differences can be useful in
inspecting wood because the temperature of wet
or decaying wood will change at different rates
from that of sound wood. Infrared devices detect
these differences and thus can be used to image
or map decay pockets. These devices are not cur-
rently used for pole inspection but have some
potential applications.
32
shell thickness and depth of preservative treat-
ment. Poles that sound “good” should be drilled or
cored at the groundline or, better yet, 1 ft below
the groundline, near or below the widest check.
Generally, all poles in service for more than
15 y should be inspected by drilling. In some
cases, depending upon pole species, original
treatment and geographical location, poles should
be bored earlier.
• If the wood is solid, rate the pole as
good.
• If rot is present, drill or core the pole at
additional points around the circumference
and above or below the defect until there
is no sign of decay.
Measure shell thickness in each hole, depth
of preservative treatment (if using an increment
borer), and pole circumference. From minimum
circumference tables such as those used by RUS
1730B-121 (1996), but modified for your system,
determine if the pole should be replaced, rein-
forced, left in service and remedially treated
to stop or prevent the decay, or scheduled for
re-inspection.
Poles that sound suspicious should be drilled
or cored in those areas and near the widest check
at or below the groundline.
• If the shell is inadequate (i.e., fails
National Electric Safety Code minimum for
bending strength), schedule the pole for
reinforcement or replacement.
• If the shell is adequate, remove cores
at additional points; depending on shell
thickness, schedule the pole for replace-
ment, stubbing, supplemental treatment,
or re-inspection.
digging insPection
To check for surface rot, dig around the
pole to a depth of 18 inches in wet climates and
deeper, if necessary, in dry climates. Some utili-
ties initially limit digging to one side of the pole
and only completely excavate if surface decay is
found in the smaller zone. This reduces inspec-
tion costs, but may miss some decay in the
non-excavated zone. Brush the pole free of dirt
Procedure for insPecting
Poles froM the ground
This general procedure for inspecting poles
from the ground should be modified to meet the
requirements of your pole system.
condition of Pole above ground
Note the general condition of the pole,
unusual damage to the pole or attachments, and
the size and location of seasoning checks. In
general, the wider the checks, the deeper they
penetrate and the more likely they are to expose
untreated heartwood; however, some narrow
checks can be very deep.
Look for the following:
• elliptical holes made by buprestid beetles
• mounds of sawdust and the carpenter ants
that make them
• mud tubes in checks made by termites
• woodpecker holes
Examine cedar poles for surface rot and
shell rot that are typical of non-treated sapwood
above the treated butt. Surface rot below the
groundline of pressure-treated Douglas-fir poles
can occur with Cellon® or Dow® process poles.
Inspect the top of the pole for evidence of splits,
cracked insulators, and other defects.
sounding
Sound the pole from as high as you can
reach to the groundline and around the circumfer-
ence. Excavated poles should be sounded below
ground. “Bad” poles usually are easy to detect
and, as you gain experience, you will become
more proficient in detecting isolated suspicious
areas that should be cored or drilled. Sounding
alone is a poor inspection procedure that locates
only the worst poles.
drilling or coring
After sounding, drill holes downward into
the pole at an angle of about 45° beginning at the
groundline or slightly above in wetter areas and
farther down the pole in drier climates. Determine
33
and examine its surface for rot. Probe suspicious
areas for soft wood that may be indicative of
decay. Scrape the surface with a dull tool, shovel,
or chipper to remove all rotten wood. If in doubt,
use the “pick test” to check for rot.
To detect internal rot, drill or core the
pole below the largest check. If rot is present,
determine shell thickness and preservative pen-
etration. Measure the pole circumference after
the rot has been removed from the surface. Using
the minimum circumference tables, determine if
the pole should be scheduled for reinforcement,
replacement, given a supplemental treatment, or
scheduled for re-inspection.
holes Made during insPection
Unless the hole is to be used for the application
of internal remedial treatment, some utilities
treat all openings made during inspection with
a preservative solution or paste (for example,
2% copper naphthenate as Cu) prior to plugging
all holes with tight-fitting preservative-treated
dowels or plastic plugs. Wear protective goggles
when this is done, because preservative may
squirt out of the hole when the dowel is driven.
treating eXcavated Poles
Preservatives may bleed, migrate, or leach from
poles into the surrounding soil, and, in some
cases, creosote or pentachlorophenol in heavy
petroleum solutions may build up a protective
barrier around the pole. Removal of this treated
soil during excavation often is considered reason
enough for applying an external supplemental
treatment to poles with no evidence of surface
decay.
Many pole managers consider the added cost
of such treatment as good insurance that the
outer shell of the poles will be protected until the
next inspection 8 or more years later. A policy
of treating all excavated poles at the ground-
line, especially those in lines of mixed-age poles,
removes a difficult decision from the inspec-
tor’s shoulders and can be a good habit. On the
other hand, if the external shell of a pole is free
of rot and still well protected by the original pre-
servative, the additional cost of the groundline
treatment may be an unnecessary maintenance
expense. Experience, good records, and random
follow-up inspections can be useful for develop-
ing criteria for each component of an inspection.
Since conditions for preservative users vary with
climate, wood species, and chemical treatment,
utilities should consider some analysis of residual
preservative content in the surface of excavated
poles before applying supplemental external
preservatives. One utility performing such an
analysis on Douglas-fir poles treated with penta
in heavy oil found that residual chemical levels
were far in excess of those needed and eliminated
excavation and external treatment for these poles.
treatMent of in-service Poles
Once a pole has been found to be visibly decay-
ing, the inspector must make one of three
decisions based on the amount of sound wood
remaining and the configuration of the pole. The
poles can be accepted with remedial treatment,
accepted with remedial treatment and reinforce-
ment, or rejected. These decisions are often
based upon prior experience within the system.
To comply with NESC requirements, poles must
be replaced or rehabilitated when they have 67%
or less of the original required strength. In most
cases, utilities require a minimum of 2 inches of
remaining sound wood in the outer shell of poles
with internal decay, although thickness require-
ments can vary with pole load, configuration, or
climatic conditions. These requirements reflect
the fact that most of the bending strength of a
pole lies in the outer shell (Figure 44).
Figure 44. Theoretical strength vs. residual shell thickness of a pole.
10 2 43
100
90
80
70
60
50
40
30
20
10
Residual Shell (inches)
Re
s
i
d
u
a
l

S
t
r
e
n
g
t
h

(
%
)
34
redcedar should be aware that sapwood decay will
eventually occur, and that damage will reduce the
effective cross-sectional area and may prevent
climbing. Thus, butt treatments should not be
used in wetter climates. The lower cost of butt-
treated poles should therefore be weighed against
the costs of performing future maintenance from
bucket trucks.
beloWground
Decay below the groundline is normally controlled
by the application of external preservatives,
either in thickened pastes or deposited on self-
contained wraps. For many years, external
preservatives included mixtures of various oil and
water soluble preservatives. The water-soluble
components were presumed to diffuse for rela-
tively short distances (1/2 inch for Douglas-fir,
2 to 3 inches in southern pine) into the wood to
control the existing fungal attack, whereas the
oil-based components were presumed to stay
near the wood surface, where they acted as bar-
riers against renewed attack. Concerns about
the safety of many components in older systems
have resulted in a shift to formulations contain-
ing copper naphthenate, sodium fluoride, or
boron. Recent studies suggest that these systems
perform similarly to older systems. More recent
formulations also include copper, permethrin,
bifenthrin, and tebuconazole.
Wraps or bandages are typically applied at
the groundline, then extended downward for
18-24 inches (Figure 45). Preservative pastes are
Deciding on the fate of poles with external
decay requires a different approach. The inspec-
tor measures the residual circumference after
all of the decayed wood has been removed and
makes adjustments for any internal decay or
exposed decay pockets, then consults a chart
showing the amount of circumference permitted
for a pole of that class. Poles that retain adequate
shell thickness, percent remaining strength, or
circumference are then remedially treated. There
are strength calculating programs available that
calculate the percent of remaining strength and/
or residual circumference, taking into account the
orientation of defects relative to the line of lead.
The inspector simply inputs in the field the mea-
surements associated with the decay or defect
conditions and the program outputs percent
remaining strength and/or residual circumference.
For a utility, the economic benefits of a main-
tenance program, compared with no maintenance
program at all, can be exceptional. The exten-
sion of average pole service life by a maintenance
program results in the deferral of capital replace-
ment costs and reduced disposal costs. New York
State Electric & Gas Corp., a mid-sized utility that
has a wood pole plant with a pole replacement
cost of $1.3 billion, estimated annual savings of
$53 million resulting from pole maintenance in
1983 dollars. Regular inspection coupled with
aggressive remedial treatment markedly extends
pole service life.
eXternal treatMents
aboveground
External decay above the ground can occur in
western redcedar poles that were initially treated
only in the butt zone. Sapwood above this zone
decays and separates from the more durable
heartwood. These separations create a hazard for
personnel climbing the pole. Until recently, this
damage was controlled by spraying the surface
of the pole with a 2% solution of copper naph-
thenate in diesel oil. Spraying was performed
at 10-15 y intervals and was a highly effective
method for protecting this wood. Concerns about
the potential effects of chemicals that drifted
from the poles during the spray operation, how-
ever, have largely curtailed this practice. Utilities
that continue to specify butt-treated western Figure 45. Applying groundline treatment.
35
identification of fumigants and water diffusible
chemicals as internal treatments provided a new
technology for controlling decay.
Fumigants
Fumigants are either liquid or solid at room tem-
perature, but have high vapor pressures. As a
result, fumigants rapidly become gases and are
able to move throughout the wood.
Four fumigants, metham sodium (32.7%
sodium n-methyldithiocarbamate in water),
chloropicrin (97% trichloro-nitromethane), methy-
lisothiocyanate or MITC (97% active in aluminum
vials), and dazomet (Tetrahydro-3,5-dimethyl-
-2H- 1,3,5-thiodiazine-2-thione) are registered
for wood use (Figure 46). All are restricted-use
pesticides in the United States. Applicators must
pass a state test on pesticide handling and safety
before using these chemicals.
Metham sodium is a caustic, yellowish
liquid with a strong sulfur odor like rotten eggs.
This fumigant must decompose into methyliso-
thiocyanate to become active. Previous trials
suggest that metham sodium provides protection
to Douglas-fir poles for 7-10 y and to southern
pine poles for 3-6 y. These differences appear to
reflect the higher permeability of southern pine,
which enhances chemical diffusion through the
wood.
Chloropicrin is among the most effective
wood fumigants and has been detected in wood
up to 20 y after application. This highly volatile,
100
80
60
40
20
0 5 10 15 20
ControlMetham sodiumVorlexChloropicrin
Years in Test
%
C
o
r
e
s

I
n
f
e
s
t
e
d
Figure 46. Ability of selected fumigant treatments to eliminate decay fungi in Douglas-fir poles.
applied at the specified label thickness, then cov-
ered with polyethylene backed paper; the soil is
then backfilled against the barrier. Some external
systems are also supplied in self-contained wraps
that require no chemical application to the wood
surface. These treatments are generally designed
to protect the wood for about 10 y.
internal treatMents
internal void treatMents
Poles that contain large voids caused by insects
or fungal attack are often treated with internal
void chemicals. These treatments are injected
under low pressure into a hole drilled directly into
the void, and are presumed to coat the surface
of the void to prevent further expansion. They
may also kill any insects in the galleries where
the chemicals penetrate. Void treatments gener-
ally consist of a water-based preservative, but
they may also contain insecticides. Sodium fluo-
ride, boron, and copper naphthenate have been
used for internal void treatments. Although these
chemicals will kill insects on direct contact, their
ability to penetrate the wood is a more important
component of their use. Boron and fluoride can
diffuse with moisture.
The value of internal void treatments in a
regular maintenance program is the subject of
some debate; utilities should carefully examine
their use. These chemicals are most effective
in wood poles that have well-defined rot pock-
ets and an abrupt transition between sound and
decayed wood. In addition, many voids are check
associated and therefore have a connection to the
surrounding soil. Pumping chemicals under pres-
sure can permit them to escape from the pole
into the surrounding soil. When considering the
use of void treatments, utilities may want to set
up treated and non-treated test poles to assess
the chemicals’ ability to arrest expansion of voids,
and to evaluate other effects of treatments.
internal diffusible treatMents
Until the late 1960s, internal remedial treatments
were largely restricted to oil- or water-based
chemicals. These chemicals were unable to
move through the heartwood and were largely
ineffective for controlling internal decay. The
36
difficult-to-handle chemical must be applied by
applicators wearing respirators and there are
strict requirements for signage on vehicles car-
rying this chemical. As a result, its use is largely
confined to poles that are away from inhabited
areas.
MITC is a solid at room temperature, but sub-
limes directly to a gas. Pure MITC is caustic and
causes skin burns, but this problem is overcome
by placing the chemical into sealed aluminum
vials prior to application (MITC-Fume). The entire
ampule is added to the pole. Field trials indicate
that this chemical is more effective than metham
sodium, and is much safer and easier to apply.
Dazomet is a caustic, crystalline powder that
decomposes in the presence of water to produce
MITC along with an array of other compounds.
Although it initially produces less MITC than either
metham sodium or solid MITC, it tends to produce
protective levels in the wood for longer time peri-
ods than either of these systems. The slow initial
MITC production may be a concern when treat-
ing poles with active decay. The initial breakdown
rate can be accelerated by the addition of copper
naphthenate at the time of application. Field trials
are underway to determine the rate of MITC pro-
duction in drier climates.
Water-diffusible chemicals
Although fumigants are highly effective, their
volatility and toxicity have led some utilities to
consider alternative treatment systems that are
based on water-soluble fungicides, such as boron
and fluoride. These chemicals are usually applied
in a concentrated rod form and move through
the wood with any moisture present to eliminate
fungal infestations.
Borate rods have been widely used in Europe
and Australia, where the chemical is reported to
move well through most wood species. In gen-
eral, it takes 2-3 y to reach protective levels with
boron rods; however, these levels remain effec-
tive for up to 15 y in poles. Thus, the slow release
rate is offset by the long protective period. The
negative aspect of the slow release rate is the
fact that active fungal decay can continue to
occur until the boron levels reach the threshold
for fungal protection.
In North America, boron rods are produced by
heating material to a molten state and then pour-
ing this liquid into a mold. The cooled rods are
glass-like and release boron as they are wetted.
Two systems are available, a boron rod and a
boron/copper rod. Both work equally well.
Fluoride and fluoride/boron rods are more
chalk like and less dense than boron or boron/
copper rods. As a result, they contain less active
ingredient. Fluoride has been used for decades
for fungal control and is used in Australia in a
fluoride/boron rod. Fluoride tends to remain in
the wood for longer periods and moves at least as
well as boron.
At present, the primary advantage of fluoride
and boron over fumigants is applicator safety; the
drawbacks include little ability to move upward
from the point of application, a slower release
rate, and a dependency on moisture for move-
ment. The slower release rate can permit fungal
infestations to cause more damage before they
are finally controlled. Moisture levels vary widely
in poles, both positionally and seasonally. Rods
placed in drier zones of the wood will be unable to
diffuse to the wetter sites. Once they do diffuse
into place, however, the field data indicate that
they remain at effective levels for up to 15 y after
installation.
drilling treatMent holes
Drill a reasonable number of holes to obtain good
distribution of the fumigant or the water-diffus-
ible chemical in rod form, but stagger the holes
so they do not weaken the pole. Table 2 speci-
fies the number of holes of different diameters
and lengths needed to place various amounts of
liquid fumigant in poles. Note that the hole length
allows for the insertion of a 3-inch treated plug.
Shorter plastic plugs may allow for the use of
shorter holes. One utility recommends that the
number of holes meets the limits of knot sizes in
Table 2 of American National Standard 05.1 (ANSI
2008).
Because water-soluble rods vary in diameter
and length, consult the product label to determine
the number of rods needed to treat a particular
diameter pole. Plug treatment holes as described
above.
37
Figure 47. Fumigant application includes drilling holes at
a steep angle (a), adding chemical (b), then plugging the
holes. In (b), copper accelerant is being added to a dazomet
treatment. Note the plastic plugs, which are used to plug
inspection and treatment holes.
Starting at the groundline, drill a hole directly
toward the center of the pole at a steep down-
ward angle that will not go through the pole
or through seasoning checks where much of
the fumigant could be lost (Figure 47). If the
hole intersects a check, plug that hole and drill
another. Space the remaining holes equally
around the pole upward in a spiral pattern with a
vertical distance of 6-12 inches between holes. If
more than two treating holes intersect an internal
void or rot pocket, re-drill the holes farther up the
pole into relatively solid wood where the fumigant
will gradually volatilize and move through the
wood. Much of the fumigant placed in rot pockets
will be lost if the void connects to a seasoning
check. Where a rot pocket is above the ground-
line, drill holes in solid wood below and above the
pocket.
aPPlying internal treatMents
Pour powdered dazomet or liquid fumigants from
polyethylene bottles directly into holes drilled into
the pole. Care should be taken to avoid overfilling
the holes. MITC-Fume tubes are uncapped and
inserted into the treatment hole. Water-diffusible
chemicals in concentrated rod form should be
inserted into the treatment holes.
Drive tight-fitting, preservative-treated
wooden dowels or plastic plugs into the holes to
minimize chemical loss. Threaded plastic plugs
are driven in with a hammer, but can be removed
for reapplication of fumigant. Some users have
b
a
Table 2. Number of holes required in poles of different sizes to hold varying amounts of liquid fumigant.
Hole dimensions in inches Pints of fumigant Pole circumference* in inches
Diameter Total length per inch of hole < 32 (3/4 pint)32–45 (1 pint)> 45 (2 pints)
5/8 15 0.010 6 ––
18 0.010 5 ––
3/4 15 0.015 4 6 –
18 0.015 –5 –
21 0.015 4 ––
24 0.015 –3 6
7/8 21 0.024 –3 5
24 0.024 ––4
* Total dosages per pole are in parentheses.
38
noted that these plugs deform to an oval shape in
some poles, but the effect of the deformation on
treatment is not known. Wood dowels generally
must be drilled out whenever poles are retreated.
This process can enlarge the treatment hole,
making it difficult to seal tightly. The use of an
oversized plug can overcome this problem.
retreatMent
The timing of retreatment schedules varies with
the wood species and climate. Poles under severe
conditions may be inspected as often as every
5 y. Those in drier climates may be inspected at
15-y intervals; most utilities, however, use a 10-y
retreatment cycle. Metham sodium, chloropicrin,
MITC and dazomet all appear to be effective for
10 y in Douglas-fir, and limited studies suggest
that the results should be similar in western red-
cedar. Retreatment cycles with fumigants will
tend to be shorter in southern pine because the
chemicals dissipate and wood degrading organ-
isms invade the wood more rapidly.
Most utilities add more chemical to the origi-
nal treatment holes. Questions remain about what
to do when retreating with dazomet, since some
residual chemical is often present in the holes.
Some utilities now add small amounts of addi-
tional dazomet plus more copper naphthenate
accelerant. Retreatment cycles for boron and
fluoride remain poorly defined because the rate
of initial movement is limited. Utilities using these
chemicals should consider limited, mid-cycle
inspections to confirm that the chemicals are per-
forming as expected. Unless there is a compelling
reason to do otherwise, re-inspection should
use the original inspection holes for assessing
decay and chemical application. This minimizes
the potential effects of repeated drilling on pole
properties.
aboveground decay control
Although decay at the groundline remains the
most prevalent in-service wood problem, decay
above ground can also cause severe problems
wherever adequate moisture from wind-driven
rain occurs. This decay can either be associated
with deep checks that form after the pole has
been placed in service or from damage to the
treated shell during field drilling.
Controlling aboveground decay can be both
expensive and challenging. Metham sodium, MITC
and dazomet are registered for aboveground use
and should effectively control decay. Diffusible
rods or pastes can also be used for this applica-
tion, but both require moisture for movement.
Therefore, the treatment holes must be close
enough to the decay zone to ensure that moisture
is present for diffusion.
Field-damaged wood on the surface can be
remedially treated with an oil-based preserva-
tive, such as copper naphthenate, applied as soon
as possible after the damage occurs. This treat-
ment does not penetrate far into the wood, but
provides a surface barrier against fungal attack.
Studies also show that applying a concentrated
borate paste to the exposed wood in a protected
site, such as a bolt hole, can provide excellent
protection against fungal attack.
record keePing and data ManageMent
No inspection and maintenance program is com-
plete without a thorough record-keeping system.
At their simplest, accurate records can help iden-
tify dangerous poles so they can be removed or
repaired as soon as possible. Good records can
also be used to track the performance of par-
ticular treatments, wood species, suppliers, or
specifications. In larger systems, they can be
used to monitor performance under different
environmental conditions. All of these factors can
be used to more carefully allocate scarce main-
tenance dollars to those poles most in need of
attention.
A good initial record should include pole sup-
plier, wood species, chemical treatment, retention,
height/class, and year installed (Figure 48). Later
entries should include the results of inspections,
including preservative penetration, presence of
internal decay (with shell thickness), presence of
external decay (with loss of circumference), pres-
ence of above ground defects such as woodpecker
holes and split or decayed tops and the types of
internal and external treatments applied for each
year. This information can then be used to iden-
tify poles that are in need of immediate remedial
attention.
39
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26

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40
A good database can be a powerful tool for
tracking the performance of various treatments
and specifications, for prioritizing maintenance,
and for identifying other system issues. For
example, Bonneville Power Administration work-
ers carefully followed the performance of the
Douglas-fir poles in their system before and after
they implemented through-boring of new poles
and fumigant treatments of existing poles. In
both cases, the results were dramatic—pole fail-
ures declined to levels that approached those
found with western redcedar and fully justified
the use of both through-boring before treatment
and maintenance after treatment.
Record keeping used to be a labor intensive
process, but the development of handheld data
loggers eliminates the need for paper and permits
the field inspector to enter all pertinent inspec-
tion data directly. These systems can store data
for later transfer directly to a personal computer
or can even be transferred directly from the
field. The risk of error can be further reduced
through the use of bar codes on poles or GPS
coordinates. These systems can be integrated so
that a line crew can access data on how to best
get to a structure and prior pole treatments, as
well as prepare work orders for items identified
in the inspection. Whatever system is employed,
all software and hardware should be thoroughly
compatible and should be usable without exten-
sive training. Databases that require extensive
training to access will be under-utilized. Examples
of several handheld data entry systems are listed
in the Equipment Appendix.
41
ANSI. 1992. American National Standard for Wood Poles - specifications and dimensions, 05.1-1992. American National Standards Institute, New York.Arsenault, R.D. 1973. Factors influencing the
effectiveness of preservative systems. P. 121-278 in Wood Deterioration and its Prevention by Preservative Treatments. Volume II. D.D. Nicholas, ed. Syracuse University Press, Syracuse, New York.
AWPA. 2011. Book of Standards, America Wood Protection Association, Birmingham, Alabama.Graham, R.D., D.J. Miller, and R.H. Kunesh. 1969. Pressure treatment and strength of deeply perforated Pacific Coast Douglas-fir poles.
Proceedings, American Wood-Preservers’ Association 62:155-158.James, W.L. 1976. Effects of wood preservatives on electric moisture-meter readings. USDA Forest Service, Forest Products Laboratory, Madison,
Wisconsin. Research Note FPL-0106.RUS (Rural Utilities Service). 1996. Pole Inspection and Maintenance. USDA Bulletin 1730B-121. US Department of Agriculture, Washington, DC.Salamon, M. 1971. Portable electric moisture meters
for quality control. Western Forest Products Laboratory, Department of the Environment, Vancouver, B.C. Information Report VP-X-80. 36 p.Scheffer, T.C. 1971. A climate index for estimating
potential for decay in wood structures above ground. Forest Products Journal 21(10):25-31.Shigo, A.L., W.C. Shortle, and J. Ochrymowych. 1977. Detection of active decay at groundline in utility poles. USDA Forest Service, Northeastern
Forest Experiment Station, Upper Darby, Pennsylvania General Technical Report NE-35. 26 p.Wilcox, W.W. 1978. Review of literature on effects of early stages of decay on wood strength. Wood
and Fiber 9:252-257.Wright, M.E. and W.B. Smith. 1995. Performance of utility pole strength prediction techniques. Proceedings, America Wood Preservers’ Association 91:34-54.
Zabel, R.A., F.F. Lombard, and A.M. Kenderes. 1980. Fungi associated with decay in treated Douglas-fir transmission poles in the northeastern United States. Forest Products Journal 30(4):51-56.Zabel, R.A., C.J.K. Wang, and F.C. Terracina. 1982.
The fungal associates, detection, and fumigant control of decay in treated southern pine poles. Electrical Power Research Institute, Palo Alto, California. EPRI EL-2768, Project 1471-1, Final Report.
related literature
Arsenault, R.D., J. Ochrymowych, and J.N. Kressbach. 1984. Solvent and solution proper-ties affecting pentachlorophenol performance as a wood preservative. Proceedings, American Wood Preservers’ Association 80:140-170.
ASTM. 1993. Standard D1036-83. Standard meth-ods of static tests of wood poles. Volume 04.09. American Society for Testing and Materials, Philadelphia, Pennsylvania.ASTM. 1993. Annual book of ASTM standards.
Volume 04.09 - Wood. American Society for Testing and Materials, Philadelphia, Pennsylvania.ASTM. 1989. Standard G53-89. Annual book of standards. American Society for Testing and
Materials, Philadelphia, Pennsylvania.Baker, W.L. 1972. Eastern Forest Insects. USDA Forest Service, Washington, D.C. Miscellaneous Publication 1175. 642 p.Barbera, P., and M.R. Wagner. 1988. Introduction to
Forest and Shade Tree Insects. Academic Press, San Diego, California. 639 p.Barnes, H.M. 1985. Trends in the wood-treating industry: state-of-the-art report. Forest Products Journal 35(1):13-22.
Barton, G.M. 1973. Chemical color tests for Canadian woods. Western Forest Products Laboratory, Department of the Environment, Vancouver, B.C. 5 p.Bodig, J., and J.R. Goodman. 1986. Wood pole prop-
erties. Volume 3: Western red cedar data and size effect. Electric Power Research Institute, Palo Alto, California. EPRI EL 4109.Brown, D.L., and D.F. Davidson. 1961. Field tests of relative strength of incised poles. Unpublished
report. Portland General Electric Co., Portland, Oregon.Furniss, R.L., and V.M. Carolin. 1977. Western Forest Insects. USDA Forest Service, Washington, D.C. Miscellaneous Publication 1339. 654 p.
Gjovik, L.R., and R.H. Baechler. 1977. Selection, production, procurement and use of preser-vative treated wood; supplementing Federal Specification TT-W-571. USDA Forest Service, Forest Products Laboratory, Madison, Wisconsin.
General Technical Report FPL-15. 37 p.Goodell, B.S., and R.D. Graham. 1983. A survey of methods used to detect and control fungal decay of wood poles in service. International Journal of Wood Preservation 3(2):61-63.
Graham, R.D. 1973. Preventing and stopping inter-nal decay of Douglas-fir poles. Holzforschung 27:168-173.Graham, R.D. 1983. Improving the perfor-mance of wood poles. Proceedings, American
42
Wood-Preservers’ Association 79:222-228.
Graham, R.D., and M.E. Corden. 1977. Controlling
biological deterioration of wood with volatile chemicals. Electric Power Research Institute, Palo Alto, California. EPRI EL-366, Project 212-1, Interior Report 1. 61 p.
Graham, R.D., and M.E. Corden. 1980. Controlling
biological deterioration of wood with volatile chemicals. Electric Power Research Institute, Palo Alto, California. EPRI EL-1480, Project 212-1, Final Report. var. p.
Graham, R.D., and R.J. Womack. 1972. Kiln and
Boulton-drying Douglas-fir pole sections at 220° to 290°F. Forest Products Journal 22(10):50-55.Grassel, E. 1969. Bonneville Power Administration Mechanical Laboratory report on bending tests
of through-bored poles. Unpublished report.
Bonneville Power Administration, Vancouver, Washington.Haygreen, J.G., and J.L. Bowyer. 1989. Forest Products and Wood Science. Second edition.
Iowa State University Press, Ames, Iowa. 500 p.
Helsing, G., and R.D. Graham. 1976. Saw kerfs reduce checking and prevent internal decay in pressure-treated Douglas-fir poles. Holzforschung 30:184-186.
Helsing, G.G., J.J. Morrell, and R.D. Graham. 1984.
Evaluations of fumigants for control of internal decay in pressure-treated Douglas-fir poles and piles. Holzforschung 38:277-280.Inwards, R.D., and R.D. Graham. 1980. Comparing
methods for inspecting Douglas-fir poles in ser-
vice. Proceedings, American Wood-Preservers’ Association 76:283-286.James, W.L. 1975. Electric moisture meters for wood. USDA Forest Service, Forest Products
Laboratory, Madison, Wisconsin. General
Technical Report FPLGTR-6. 27 p.Lassen, L.E., and E.A. Okkonen. 1969. Sapwood thickness of Douglas-fir and five other west-ern softwoods. USDA Forest Service, Forest
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Research Paper 124. 16 p.MacLean, J.D. 1946. Temperatures obtained in tim-bers when the surface temperature is changed after various periods of heating. Proceedings,
American Wood-Preservers’ Association
42:87-139.Merz, G.K. 1959. Merz method for heartwood treat-ment of ground line area of poles. Unpublished report. Portland General Electric Co., Portland,
Oregon.
Meyer, R.W., R.A. Zabel, C.J.K. Wang, and F.C. Terracina. 1988. Wood pole decay character-ization: Volume 2. Soft rot characteristics and identification manual for the decay fungi in
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Energy Research Corp., New York, Research
Report EP84-5.
Miller, D.J., and R.D. Graham. 1963. Treatability of Douglas-fir from the western United States. Proceedings, American Wood-Preservers’ Association 59:218-222.
Morrell, J.J. 1989. The fumigants used for controlling
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wood deterioration with fumigants: a review.
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southern yellow pine poles during air-season-
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New York.
Przybylowicz, P.R., B.R. Kropp, M.E. Corden, and R.D. Graham. 1987. Colonization of Douglas-fir by decay fungi during air-seasoning. Forest Products Journal 37(4):17-23.
REA. 1974. Pole inspection and maintenance. USDA,
Rural Electrification Administration, Washington, D.C. Bulletin 161-164.Richardson, B.A. 1993. Wood Preservation. Second edition. E. and F.N. Spon, London. 226 p.
Ruddick, J.N.R. 1981. The effect of kerfing on check
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and M.A. Newbill. 1992. Modeling internal
43
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Zabel, R.A., and J.J. Morrell. 1992. Wood
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Manual for Fungi from Utility Poles in the eastern United States. American Type Culture Collection,
44
EDM International
4001 Automation WayFort Collins, CO 80525(Pole Test)www.edminternational.com
MetriguardP.O. Box 399Pullman, WA 99163www.metriguard.com
PoleScanPO Box 342 Orewa, AucklandNew Zealandwww.polescan.com
b. drills (resistograPh)
IML, Inc1275 Shiloh road, Suite 2780Kennesaw, GA 30144
800-815-2389www. Imlusa.com
c. Moisture Meter
Delmhorst Instrument Co.51 Indian Lane EastTowaco, NJ 07082www.delmhorst.com
Wagner Electronic Products326 Pine Grove RoadRogue River, OR 97537www.wagnermeters.com
Lignomat USA Ltd.P.O. Box 30145Portland, OR 97230www.lignomatusa.com
d. insPectors
Osmose Utilities Services, Inc.215 Greencastle Road Tyrone, GA 30290www.osmoseutilities.com
National Wood TreatingP.O. Box 1946Corvallis, OR 97330
Davey Tree Co.
P.O. Box 351
Livermore, CA 94551
www.davey.com
McCutchan InspectionPO Box 397Banks, OR 97106
Intec Services, Inc.
4001 Automation Way
Fort Collins, CO 80255
Ph 970-482-6550
www.intecservicesinc.com
Independent Inspection Co.P.O. Box 1776Havre, MT 59501http://www.iic-us.com/
Utility Pole Technologies
708 Blair Mill Rd.
Willow Grove, PA 19090
www.utiliconltd.com/utiliconpolemaintenance.htm
Estrada Consultants LLCPO Box 1239
Redmond, OR 97756
[e-mail]
Southeast Woodland Services431 Caines Landing Road
Conway, SC 29526
www.southeastwoodland.com
e. increMent borers
The Ben Meadows Co.3589 Broad StreetAtlanta, GA 30341www.benmeadows.com
Forestry Suppliers, Inc.
P.O. Box 8397
Jackson, MS 39284-8397
www.forestry-suppliers.com
f. reMedial treatMents
1. Wraps/Bandages
ISK Biocides, Inc.
416 East Brooks Road
Memphis, TN 38109
www.woodguard.com
45
Osmose Utilities Services, Inc.
215 Greencastle Road
Tyrone, GA 30290www.osmoseutilities.com
Copper Care Wood Preservatives, Inc.
P.O. Box 707
Columbus, NE 68602-0707www.coppercarewoodpreservatives.com
Genics Inc.
561 Acheson Rd., 53016 Hwy 60
Acheson, AB T7X 5A7 CANADAwww.genicsinc.com
Poles, Inc.
336 Clarksley Road
Manitou Springs, CO 80829www.poles.com
Preschem Ltd
147-149 Herald Street
Cheltenham, Victoria 3192Australia www.preschem.com
2. Internal Treatments
a. Fumigants
Osmose Utilities Services, Inc. 215 Greencastle Road
Tyrone, GA 30290
www.osmoseutilities.com(Metham sodium, chloropicrin, MITC-Fume)
ISK Biocides, Inc.
416 East Brooks Road
Memphis, TN 38109
www.woodguard.com
(Metham sodium)
Great Lakes Chemical Co.P.O. Box 2200
West Lafayette, IN 47906
(Chloropicrin)
Copper Care Wood Preservatives, Inc.P.O. Box 707
Columbus, NE 68602-0707
www.coppercarewoodpreservatives.com(dazomet)
Poles, Inc.
336 Clarksley Road
Manitou Springs, CO 80829www.poles.com(metham sodium, dazomet)
b. Diffusible Rods
Genics, Inc.561 Acheson Rd., 53016 Hwy 60
Acheson, AB T7X 5A7 CANADA
www.genicsinc.com(copper boron rods)
Intec Services, Inc.
4001 Automation Way
Fort Collins, CO 80525Phone [phone]www.intecservicesinc.com(boron rods)
Poles, Inc.336 Clarksley RoadManitou Springs, CO 80829www.poles.com
(boron rods)
Wood Care SystemsPO Box 2160Kirkland, WA 98083
www.ewoodcare.com
(boron rods)
Osmose Utilities Services, Inc.215 Greencastle Road
Tyrone, GA 30290
www.osmoseutilities.com(sodium fluoride rods)
g. bolt hole and surface Preservative treatMents
Copper Care Wood Preservatives, Inc.P.O. Box 707
Columbus, NE 68602-0707
www.coppercarewoodpreservatives.com
Poles, Inc.336 Clarksley Road
Manitou Springs, CO 80829
www.poles.com
Nisus Corporation100 Nisus Drive
Rockford, TN 37853
www.nisuscorp.com
Osmose Utilities Services, Inc.
215 Greencastle Road Tyrone, GA 30290www.osmoseutilities.com
46
Osmose Utilities Services, Inc.215 Greencastle Road Tyrone, GA 30290www.osmose utilities.com
(plastic and wood plugs)
Materials Procurement L.L.C. 7885 Guemes Island Road. Suite 40. Anacortes. WA. 98221
www.replugs.com
(plastic plugs)
Morgan Lumber Co.625 West Indian Creek Road
Collinwood, TN 38450
(wood plugs)
Poles, Inc.336 Clarksley Road
Manitou Springs, CO 80829
www.poles.com(plastic and wood plugs)
i. handheld data loggers and data ManageMent
EDM International2301 Research Blvd, #110
Fort Collins, CO 80526-1825
(Husky FS2/Micropalm data logger)
Corvallis Microtechnology, Inc.413 SW Jefferson Avenue
Corvallis, OR 97331
SPIDA Software560 Officecenter PlaceGahanna, OH 43230
www.spidasoftware.com
VarassetAccent Business Services Inc. 7710 Northeast Greenwood Drive, Suite 170
Vancouver, WA 98662
www.varasset .com
J. drills
Forestry Suppliers, Inc.
P.O. Box 8397Jackson, MS 39284-8397www.forestry-suppliers.com
The Ben Meadows Co.
3589 Broad Street
Atlanta, GA 30341www.benmeadows.com
k. other devices
MPTDeuar Pty Ltd92 Hawthorn RoadMorayfield, Queensland
Australia 4056
www.deuar.com
1. Pole Setting Foams
Chemque
6101 Guion Road, Indianapolis, IN 46254www.chemque.com
GRA Services
5000 East 2nd Street Edmond, OK 73034-7545www.graservices.com
Intec Services, Inc.
4001 Automation WayFt. Collins, CO 80525www.intecservicesinc.com/
Rainbow Technology Corporation
261 Cahaba Valley Pkwy Pelham, AL 35124www.rainbowtech.net
2. Pole Reinforcements
GRA Services5000 East 2nd Street Edmond, OK 73034-7545
www.graservices.com
(Fiberglass and steel reinforcements)
Laminated Wood SystemsPO Box 386
Seward, NE 68434
www.lwsinc.com(Phase riser, steel reinforcements)
Osmose Utilities Services, Inc.
215 Greencastle Road
Tyrone, GA 30290www.osmoseutilities.com(steel reinforcements and ET Truss )
BEFORE THE
IDAHO PUBLIC UTILITIES COMMISSION
CASE NO. IPC-E-22-27
IDAHO POWER COMPANY
REQUEST NO. 28
ATTACHMENT NO. 1
CONFIDENTIAL

BEFORE THE

IDAHO PUBLIC UTILITIES COMMISSION

CASE NO. IPC-E-22-27

IDAHO POWER COMPANY

REQUEST NO. 29

ATTACHMENT NO. 1
SEE ATTACHED SPREADSHEET 

BEFORE THE

IDAHO PUBLIC UTILITIES COMMISSION

CASE NO. IPC-E-22-27

IDAHO POWER COMPANY

REQUEST NO. 30

ATTACHMENT NO. 1
SEE ATTACHED SPREADSHEET 

BEFORE THE

IDAHO PUBLIC UTILITIES COMMISSION

CASE NO. IPC-E-22-27

IDAHO POWER COMPANY

REQUEST NO. 30

ATTACHMENT NO. 2
Greg Miller
Marsh USA Inc. 1301 Fifth Avenue Suite 1900 Seattle, WA 98101 [phone] [e-mail] www.marsh.com

August 10th, 2021 Jeff Pleimann Insurance & Risk Administrator Idaho Power 1221 West Idaho St. Boise, ID 83702

Subject: Excess Liability Insurance Challenges
Dear Jeff, This letter describes challenges Idacorp is facing in buying Excess Liability Insurance Limits. In summary, there is reduced appetite amongst liability underwriters to offer coverage to all electric utilities in wildfire-prone regions of the US, including Idacorp, due to the perceived risk; in addition, the challenge is compounded by the fact that there has been a significant reduction in the supply of liability insurance available in the market in general. Liability insurance covers claims of property damage and bodily injury to third parties for which the policyholder is legally liable. In the event a wildfire is caused by electric distribution equipment, the utility may be held liable for ensuing losses. California utilities have been held liable for several catastrophic wildfires over the past several years, resulting in billions of dollars of losses to utilities and their insurers. As catastrophic wildfires have become more common over the past few years in several western states outside of California, insurers have become increasingly concerned about such losses. Concerns about climate change, in addition to increasing development in wildfire-prone areas, suggest this trend will continue for the foreseeable future. As a result, insurers’ appetite to write coverage for such risks at reasonable pricing has greatly reduced. This perception has coincided with a general “hardening” of the broader commercial liability insurance market, meaning all buyers of commercial liability insurance are experiencing a reduction in capacity (capital available to write insurance) and significant price increases. Commercial liability insurers are experiencing rapidly increasing loss costs due to several factors including runaway jury verdicts, at the same time investment returns have reduced due to the prolonged low interest environment. As a result, capital providers in the insurance industry have pulled back. This means underwriters are being more selective about the types of risks they will write, resulting in less capacity available for higher risk buyers such as electric utilities in the western US. For this year, Idacorp was able to secure substantial capacity from the two utility industry mutual insurers. As mutuals, these insurers are obligated to provide coverage as they were created and

continue to exist to serve the needs of the electric utilities that own them. The mutuals are providing
$135m, except this is reduced to $110m in Oregon and Nevada. General concerns in these two
states resulted in the mutuals providing less capacity than in Idaho, despite the fact that Idacorp’s
exposures in these states are relatively small compared to Idaho. For additional capacity, Idacorp is
reliant on the commercial insurers that make up the rest of the global market. We were able to fill the
25m gap in Oregon and Nevada using commercial insurers. However, after canvasing the global
market, Idacorp’s brokers have found very little appetite to provide additional capacity except at
pricing this is unreasonable. Therefore, Idacorp is exploring alternative methods for financing this
risk, including the use of a captive.

I trust this is helps communicate to others the situation. Please let me know if you have questions or
would like additional information.

Sincerely,

Greg Miller
Managing Director

BEFORE THE

IDAHO PUBLIC UTILITIES COMMISSION

CASE NO. IPC-E-22-27

IDAHO POWER COMPANY

REQUEST NO. 31

ATTACHMENT NO. 1
SEE ATTACHED SPREADSHEET