A202301 NOPV Response

2406 N. Dollar Road
Spokane Valley, WA 99212
Submitted to Jeff Brooks via electronic mail at [e-mail].
July 17,2023
Mr. Jeff Brooks
Pipeline Safety Program Manager
Idaho Public Utilities Commission
11331 Chinden Blvd., Building 8, Suite 201-A
Boise, ID 83714
Re: IPUC Coeur d'Alene District Field Audit Probable Violation Letter—Avista Response
Dear Mr. Brooks:
In your letter of June 14, 2023,you listed two Probable Violations discovered during the 2023
Coeur d'Alene District Field Audit that was conducted June 6-7, 2023. In this letter we have
provided a restatement of the probable violations as noted in your letter, and Avista's response.
Notice of Probable Violation (NOPV) References:
49 CFR §192.739(a)(4)and 49 CFR §192.605(a)(4)
Description of NOPVs
49 CFR §I92.739(a)(4)—Pressure limiting and regulating stations: Inspection and Testing
(a) Each pressure limiting station, relief device (except rupture discs), and pressure regulating
station and its equipment must be subjected at intervals not exceeding 15 months, but at least
once each calendar year, to inspections and tests to determine that it is—
(4) Properly installed and protected from dirt, liquids, or other conditions that might
prevent proper operation.
49 CFR §192.605(a)—Procedural manual for operations, maintenance, and emergencies.
(a)General. Each operator shall prepare and follow for each pipeline, a manual of written
procedures for conducting operations and maintenance activities and for emergency response.

Avista Standard 5.12—Regulator&Relief Inspection (Annual Regulator Station Maintenance—
Maintenance of Overpressure Protection Devices)
Overpressure protection devices(including relief valves, monitor regulators, and safety shutoff
valves) shall be inspected and tested once each calendar year.
Overpressure protection devices shall be inspected to ensure the following:
• They are in good mechanical condition
• They are as specified by Gas Engineering. 1n some cases,the relief set point may be less
than the MAOP due to operating conditions.
• They are properly installed and protected from dirt, liquids, and other conditions that
might affect proper operation.
• Sensing lines,control lines, filters, restrictors, etc. on relief valves have been inspected
and repaired as necessary.
Findinds)•
Regulator Station 2029 failed to lock up on the worker regulator due to fouling on the pilot stem.
Regulator Station 4246 failed to lock up on the worker and the monitor due to fouling on the
pilot stem and diaphragm. This regulator station additionally failed during the 2022 Coeur
d'Alene field audit.
Regulator 604 failed to lock up on the worker and monitor. Avista personnel observed a small
indentation on the rubber portion of the pilot stem.
The above station failures were corrected on-site during the audit.
Avista Response to NOPVs:
Avista continues to diligently work to address the operational issues resulting from dithiazine
fouling at company gate stations and regulator stations. In addition,the company has a robust
Dithiazine Monitoring and Surveillance Program (as detailed in a previous response to the IPUC
in 2022) and addresses the topic of dithiazine in the company's DIMP Plan Document.
Although Avista concurs that dithiazine is an ongoing operations challenge,we respectfully
disagree that the dithiazine issues observed at Regulator Station 2029 and 4246 and the pilot
stem manufacturing defects at Regulator Station 604 rise to the level of being Probable
Violations of federal code or Avista Gas Standards.
At Regulator Station 4246 neither the monitor regulator nor the worker regulator achieved
"bubble tight" lock up. The way this station operates,there is constant flow and no safety or
operational requirement for the worker or monitor regulator to lock up bubble tight. This being

the case, there would not be an instance where "proper operation" is affected to the point of a
safety or operations issue from current operations.
At Regulator Station 2029,dithiazine fouling was found on the pilot stem and a replacement of
that device remedied the issue. Once again,the way this station operates,there is constant flow
and no safety or operational condition for the worker or monitor regulator to lock up bubble
tight. As with Regulator Station 4246,there would not be an instance where "proper operation"
is affected to the point of a safety or operations issue from current operations.
At Regulator Station 604, bubble tight lock up of both the worker and monitor regulator failed to
occur due to a manufacturing anomaly on the pilot stems. Avista submits that a shortcoming such
as a manufacturing defect does not rise to level of a violation of federal code or Avista's Gas
Standards.
As a manner of improved operations,the Pressure Controlman for Coeur d'Alene District is
planning to interchange the function of the worker and monitor regulator at Regulator Station
4246. He believes having the worker regulator downstream of the monitor regulator will
decrease the chances of main body dithiazine fouling of the monitor regulator since it will be
upstream of the pressure cut. Additionally, he is planning to add a dithiazine pilot filter to
Regulator Station 2029 by the end of the year to minimize the future possibility of dithiazine
accumulation on the pilot stem.
Avista is optimistic these efforts will serve to advance the reliability and public safety of our
natural gas system in the years to come.
Respectf ly Submitted,
d r C+:t fp —
Ali is Gibbs
Director,Natural Gas
AG/rkb
Cc: Brian Schultz, Manager, Gas Compliance, and Integrity
Jeff Webb, Manager, Gas Design, Measurement and Planning
Michelle Heskett, Manager, Coeur d'Alene Gas Operations