# Connecticut Public Utilities Regulatory Authority — Pipeline Safety Interpretation

- **operation:** document
- **citation:** PI-19-0008
- **title:** Connecticut Public Utilities Regulatory Authority — Pipeline Safety Interpretation
- **source type:** guidance
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** guidance
- **official:** true
- **published on:** 2019-10-22
- **effective on:** Not available
- **summary:** PI-19-0008 response to Connecticut Public Utilities Regulatory Authority concerning 192.201, 192.739.
- **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-interpretation-pi-19-0008.json
- **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-pi-19-0008.md
- **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-pi-19-0008
- **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/standards-rulemaking/pipeline/interpretations/72766/connecticut-pi-2019-0008-10-22-2019-part192.pdf
**body:**

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U.S. Department
ofTransportation
Pipeline and Hazardous Materials
Safety Administration
1200 New Jersey Avenue SE
Washington DC 20590
OCT 2 2 2019
Mr. Karl H. Baker
Public Utilities Supervisor of Technical Analysis
Connecticut Public Utilities Regulatory Authority
10 Franklin Square
New Britain, CT 06051
Dear Mr. Baker:
In a July 24, 2019, letter to the Pipeline and Hazardous Materials Safety Administration
(PHMSA), the Gas Pipeline Safety Unit (GPSU) of the State of Connecticut Public Utilities
Regulatory Authority requested an interpretation of the 49 CFR Part 192 requirements for
maximum allowable operating pressure (MAOP) for gas distribution pipelines during
maintenance operations.
You stated that PHMSA's interpretation letter dated April 21, 2015, sent to Mr. Christopher
LeBlanc of Northern Utilities, Inc., doing business as Unitil, discussed MAOP under normal and
emergency operations; however, it was not clear to you whether activities during maintenance
are included in this interpretation. Specifically, you asked that "since the maintenance
requirements contained in 49 CFR 192.739(a)(3) require operators to set overpressure protective
devices at pressures consistent with the pressure limits of 49 CFR 192.201(a), is it permissible
for an operator to exceed the MAOP when setting the overpressure protective device at a
pressure limiting station?"
The overpressure protective device, pressure limiting or regulator station that limits
overpressure beyond the MAOP must be isolated from the system prior to any testing of
buildup and set points. Operators can exceed the MAOP during maintenance of the isolated
overpressure protection equipment as specified under§ 192.739(a) consistent with the pressure
limits of§ 192.201(a), if the MAOP limits are met during a system maintenance and the pipeline
meets all Subpart D requirements of 49 CFR Part 192. The overpressure protective device
(pressure limiting or regulator station) that limits overpressure beyond the MAOP must be
isolated from the system prior to any testing.
The Pipeline and Hazardous Materials Safety Administration, Office of Pipeline Safety provides written clarifications of the Regulations (49 CFR
Parts 190-199) in the form of interpretation letters. These letters reflect the agency's current application of the regulations to the specific facts
presented by the person requesting the clarification. Interpretations do not create legally-enforceable rights or obligations and are provided to
help the public understand how to comply with the regulations.

<<<PAGE 2>>>

2
Maintenance operations that may result in overpressure conditions are only allowed for the time
interval required under§ 192.739(a) to activate the overpressure protection device and are not
meant for long term or frequently-occurring normal operating or maintenance conditions.
Ifwe can be of further assistance, please contact Tewabe Asebe at 202-366-5523.
Sincerely,
Jo . Gale
Oirector, Office of Standards
and Rulemaking
The Pipeline and Hazardous Materials Safety Administration, Office of Pipeline Safety provides written clarifications of the Regulations
(49 CPR Parts 190-199) in the form of interpretation letters. These letters reflect the agency's current application of the regulations to the
specific facts presented by the person requesting the clarification. Interpretations do not create legally-enforceable rights or obligations and
are provided to help the public understand how to comply with the regulations.

<<<PAGE 3>>>

STATE OF CONNECTICUT
PUBLIC UTILITIES REGULATORY AUTHORITY
July 24, 2019
Mr. John Gale
Director, Standards and Rulemaking Division
Office of Pipeline Safety (PHP-30)
Pipeline and Hazardous Materials Safety Administration
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC. 20590
Dear Mr. Gale,
The Gas Pipeline Safety Unit (GPSU) of the State of Connecticut Public Utilities
Regulatory Authority seeks clarification on exceeding the maximum allowable operating
pressure (MAOP) during maintenance operations. Your interpretation letter dated April
21, 2015, sent to Mr. Christopher LeBlanc of Unitil Corporation, clearly discusses MAOP
under normal and emergency operations; however, it is not clear whether maintenance
operations are included in this interpretation.
Therefore, the GPSU requests an answer to the following question:
Since the maintenance requirements contained in 49 CFR 192.739(a)(3) require
operators to set to overpressure protective devices at pressures consistent with
the pressure limits of 49 CFR 192.201(a), is it permissible for an operator to exceed
the MAOP when setting the overpressure protective device at a pressure limiting
station?
Thank you for your consideration in this matter. Please do not hesitate to contact
me at 860-827-2661 or by email at karl.baker@ct.gov if there are any questions or if you
require any additional information.
Sincerely,
Karl H. Baker
Public Utilities Supervisor of Technical Analysis
10 Franklin Square, New Britain, CT 06051
An Equal Opportunity Employer
www.ct.gov/pura
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