Document ID: PHMSA-2020-0115-0001
Agency: phmsa
Document Type: Notice
Title: Pipeline Safety: Inside Meters and Regulators
Posted Date: 2020-09-29T04:00Z

[Federal Register Volume 85, Number 189 (Tuesday, September 29, 2020)]
[Notices]
[Pages 61101-61104]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-21507]

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DEPARTMENT OF TRANSPORTATION

Pipeline and Hazardous Materials Safety Administration

[Docket No. PHMSA-2020-0115]

Pipeline Safety: Inside Meters and Regulators

AGENCY: Pipeline and Hazardous Materials Safety Administration (PHMSA); 
DOT.

ACTION: Notice; issuance of advisory bulletin.

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SUMMARY: PHMSA is issuing this advisory bulletin to alert owners and 
operators of natural gas distribution pipelines to the consequences of 
failures of inside meters and regulators. PHMSA is also reminding 
operators of existing Federal regulations covering the installation and 
maintenance of inside meter and regulators, including the integrity 
management regulations for distribution systems to reduce the risks 
associated with failures of inside meter and regulator installations.

ADDRESSES: PHMSA guidance, including this advisory bulletin, can be 
found on PHMSA's website at https://www.phmsa.dot.gov/guidance. You may 
also view this advisory bulletin and related documents at http://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: 
    Technical Questions: Michael Thompson, Transportation Specialist, 
by phone at 503-883-3495.

[[Page 61102]]

    General Questions: Ashlin Bollacker, Technical Writer, by phone at 
202-366-4203.

SUPPLEMENTARY INFORMATION:

Background

    On August 10, 2016, a natural gas-fueled explosion and fire caused 
the partial collapse of a 14-unit apartment building located at 8701 
Arliss Street (Building 8701) in the Flower Branch Apartment Complex of 
Silver Spring, Maryland. The explosion and fire also heavily damaged an 
adjacent apartment building, which shared a common wall with Building 
8701. As a result of this accident, 7 residents died, 65 residents were 
transported to the hospital, and 3 firefighters were treated and 
released from the hospital. The property damage from the accident 
exceeded $1 million.
    National Transportation Safety Board (NTSB) determined that the 
probable cause of the explosion was the failure of an indoor mercury 
service regulator with an unconnected vent line. The unconnected vent 
line allowed natural gas to flow into the meter room, where the gas 
accumulated and ignited from an unknown ignition source. A contributing 
factor to the accident was the mercury service regulator being located 
in a space where leak detection by odor was not readily available.
    A ``service regulator'' is defined in Sec.  192.3 as a ``device on 
a service line that controls the pressure of gas delivered from a 
higher pressure to the pressure provided to the customer. A service 
regulator may serve one customer or multiple customers through a meter 
header or manifold.'' Service regulators are installed to a meter inlet 
to control the gas pressure into a building. They reduce the high 
pressure used to transport natural gas through the delivery systems to 
the lower pressures used in homes and businesses. Service regulators 
include a relief valve that opens if the pressure of the regulated gas 
exceeds a specified pressure to allow the excess gas to vent to the 
outside atmosphere. Mercury service regulators present an increased 
risk of failure due to their age.\1\
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    \1\ The design of mercury service regulators includes materials 
such as leather diaphragms and rubber valve seats that are subject 
to age-related deterioration.
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    Building 8701 received natural gas from a distribution system owned 
and operated by Washington Gas Light Company (WGL). WGL delivers 
natural gas to more than one million residential, commercial, and 
industrial customers throughout Washington, DC, and the surrounding 
regions in Maryland and Virginia. According to WGL, the mercury service 
regulators installed in Building 8701 were also installed in all 26 
buildings of the Flower Branch apartment complex between 1955 and 1956. 
Since the accident, all of the mercury service regulators in the Flower 
Branch apartment complex have been removed and replaced.

NTSB Accident Investigation Findings and Recommendations to PHMSA

    On April 24, 2019, NTSB adopted its report, ``Building Explosion 
and Fire, Silver Spring, Maryland, August 10, 2016,'' \2\ determined 
the probable cause of the explosion, and issued safety recommendations. 
In its report, NTSB stated that several residents of Buildings 8701 and 
8703 reported to investigators that they smelled gas in the weeks and 
months leading up to the explosion. On July 25\,\ 2016, before the 
accident, several residents called the building manager, 9-1-1, and 
local fire personnel about gas odor. However, there was no evidence 
that residents, building management, or any emergency personnel 
notified the operator, WGL, of the gas odor. The investigation revealed 
that, had anyone notified WGL of a gas odor call made two weeks 
earlier, the accident may have been prevented. Notifying WGL would have 
allowed a service technician to enter the meter room of the building, 
identify the unconnected vent line, and remedy the situation. NTSB 
noted, however, that the use of gas odorants alone does not 
sufficiently mitigate the risk of death and injuries caused by gas 
system leaks, such as the leak that occurred in this accident.
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    \2\ NTSB/PAR-19/01. The details of this accident investigation 
and the resulting safety recommendations may be accessed at https://ntsb.gov/investigations/AccidentReports/Reports/PAR1901.pdf.
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    As discussed above, NTSB determined that the probable cause of the 
explosion was the failure of an indoor mercury service regulator with 
an unconnected vent line. The unconnected vent line allowed natural gas 
to flow into the meter room, where the gas accumulated and ignited from 
an unknown ignition source. NTSB issued Safety Recommendations P-19-001 
and P-19-002 to PHMSA based on the finding in the Silver Spring 
investigation that, had service regulators been located outside 
Building 8701, the explosion would have been avoided because gas would 
have vented to the atmosphere and dissipated. In light of these 
recommendations, PHMSA believes that operators should ensure compliance 
with the applicable pipeline safety regulations and should evaluate 
each service installation to determine the appropriate location of the 
service regulators. If access is an issue to check and maintain inside 
regulators properly, operators should do what is necessary to have the 
customer provide access for the operator to check the regulator and 
conduct the leakage and atmospheric corrosion surveys.

Minimum Federal Safety Standards for Customer Meters, Service 
Regulators and Service Lines

    The Federal Pipeline Safety Regulations prescribe minimum safety 
standards for customer meters, service regulators, and service lines. 
They require operators to take into consideration the possibility of 
corrosion, overpressure events, and physical damage in the design, 
installation, and maintenance of these facilities. The Federal Pipeline 
Safety Regulations at 49 CFR 192.353 require that each meter and 
service regulator, whether inside or outside a building, must be 
installed in a readily accessible location and be protected from 
corrosion and other damage, including vehicular damage. For regulators 
located inside a building, each service regulator must be located as 
near as practical to the point of service line entrance. Each meter 
must be located in a ventilated place and not less than 3 feet from any 
source of ignition or any source of heat that might damage the meter. 
Section 192.355(b) states: ``[s]ervice regulator vents and relief vents 
must terminate outdoors, and the outdoor terminus must . . . [b]e 
located at a place where gas from the vent can escape freely into the 
atmosphere and away from any opening into the building.'' Section 
192.357(d) requires regulators that might release gas to be vented to 
the outside atmosphere.
    Federal Pipeline Safety Regulations include requirements that 
operators conduct leakage surveys of their systems, including meter and 
service regulators located inside buildings (Sec.  192.723). In 
scheduling such surveys, operators must consider the nature of their 
operations and the local conditions. At a minimum, operators must 
conduct surveys: (1) In business districts at intervals not exceeding 
15 months, but at least once each calendar year; and (2) outside 
business districts as frequently as necessary, but at least once every 
five calendar years at intervals not exceeding 63 months. The 
regulations also require that operators inspect each pipeline or 
portion of pipeline that is exposed to the atmosphere for evidence of 
atmospheric corrosion in accordance with Sec.  192.481. Further, if 
atmospheric corrosion is found during an inspection, the operator

[[Page 61103]]

must provide protection against the corrosion as required by Sec.  
192.479.
    PHMSA is reminding operators of these existing requirements for 
inside meters and regulators. This advisory bulletin notes that, if 
access is an issue to check and maintain inside regulators properly, 
operators should endeavor to have the customer provide access for the 
operator to check the regulator and conduct the leakage and atmospheric 
corrosion surveys.

Distribution Integrity Management Program (DIMP) Regulations

    In addition to these requirements for inside meters and regulators, 
PHMSA is also reminding operators of their obligation to continually 
assess risks to their systems and address those risks in accordance 
with DIMP regulations at Sec.  192.1007. A DIMP program requires that 
operators demonstrate knowledge of their system (Sec.  192.1007(a)). 
Additionally, a DIMP program requires that operators identify existing 
and potential threats (Sec.  192.1007(b)). Identification of the 
threats that affect, or could potentially affect, a distribution 
pipeline is key to assuring its integrity. Knowledge of applicable 
threats allows operators to evaluate the risks they pose and to rank 
those risks, allowing safety resources to be applied where they will be 
most effective. Section 192.1007(c) requires that an operator evaluate 
the identified threats to determine their relative importance and rank 
the risks associated with its pipeline. Operators must consider the 
likelihood of threats as well as the consequences of a failure that 
might result from each threat. The integrity management programs must 
include measures designed and implemented to reduce the risk of failure 
from identified threats (Sec.  192.1007(d)). Measuring performance 
periodically and conducting a complete program re-evaluation at least 
every five years allows operators to determine whether actions being 
taken to address threats are effective, or whether different or 
additional actions are needed (Sec.  192.1007(e)-(f)). An operator 
should conduct a program evaluation any time there are changes in 
factors that would affect the risk of failure.
    While the DIMP Regulations have been in place since 2009, some 
operators may not be sufficiently aware of their pipeline attributes, 
or may not be adequately or consistently assessing threats as part of 
their DIMP programs. For example, NTSB found that WGL's inadequate 
procedures led to the exclusion of the requirement that technicians 
verify the connection of vent lines for indoor service regulators 
during service and maintenance activities, and as such, vent lines 
could be inadvertently left disconnected following service work. NTSB 
concluded that WGL relied on unvalidated information to determine the 
location and condition of mercury service regulators. Therefore, the 
NTSB recommended that throughout the WGL network, WG implement an audit 
program to verify the data on the service forms used to determine the 
location and condition of mercury service regulators to ensure the 
accuracy of this safety-critical data.
    Because it is so essential that operators identify the conditions 
that can cause failures and address them before a failure can occur, 
PHMSA is reminding operators of their obligations to comply with DIMP 
regulations. This advisory bulletin serves as a reminder to operators 
to identify and evaluate the physical and operational characteristics 
of each pipeline system. Operators following these requirements should 
help to ensure the safety of customer meters and regulators.

II. Advisory Bulletin (ADB-2020-01)

    To: Owners and Operators of Gas Distribution Systems.
    Subject: Requirements for Inside Meters and Regulators.
    Advisory: To further enhance PHMSA's safety efforts and implement 
NTSB's April 24, 2019, Recommendations P-19-001 and P-19-002, PHMSA is 
issuing this advisory bulletin to remind operators of the requirements 
for inside meters and regulators. PHMSA is also reminding operators of 
existing Federal DIMP regulations to reduce the possibility of the 
failure of inside meter and regulator installations. Further, PHMSA 
advises operators to review NTSB's report concerning the August 10, 
2016, accident as it may serve as prudent guidance regarding potential 
safety problems that operators may need to act on if it addresses a 
relevant factor on their system. This advisory bulletin is intended to 
clarify and describe the existing pipeline safety standards for 
operators and the public. The contents of this advisory bulletin do not 
have the force and effect of law and are not meant to bind the public 
in any way. However, pipeline operators must comply with the underlying 
pipeline safety standards at 49 CFR part 192.
    PHMSA is reminding operators of Sec. Sec.  192.353, 192.355, and 
192.357, which provide requirements regarding the location and safety 
of customer meters and regulators. While the regulations allow service 
regulators to be located inside or outside structures, the requirements 
for indoor regulators are more stringent than those located outdoors. 
Section 192.353(a) requires that each meter and service regulator, 
whether inside or outside of a building, be installed in a readily 
accessible location and be protected from corrosion and other damage, 
including vehicular damage. Section 192.353(b) requires each service 
regulator installed within a building to be located as near as 
practical to the point of service line entrance, and Sec.  192.353(c) 
requires that each meter installed within a building must be located in 
a ventilated place and not less than 3 feet from any source of ignition 
or any source of heat that might damage the meter. In addition, Sec.  
192.355(b) requires that the service regulator vents and relief vents 
must terminate outdoors, and the outdoor terminus must be located at a 
place where gas from the vent can escape freely into the atmosphere and 
away from any opening into the building. Section 192.357(d) requires 
regulators that might release gas to be vented to the outside 
atmosphere.
    The Federal Pipeline Safety Regulations include requirements that 
operators conduct leakage and atmospheric corrosion surveys of their 
systems, including service regulators located inside or outside a 
building (Sec. Sec.  192.723 and 192.481). If access is an issue to 
check and maintain inside meter and regulators properly, operators 
should endeavor to have the customer provide access for the operator to 
check these facilities and conduct the leakage and atmospheric 
corrosion surveys.
    PHMSA is also reminding operators of their obligation to 
continually assess risks to their systems and address those risks as 
required by the DIMP regulations (Sec.  192.1007). PHMSA reminds 
pipeline operators of their responsibilities to continuously improve 
their knowledge of their pipeline systems, identify integrity threats, 
evaluate and rank risks, and identify, evaluate, and implement 
preventative and mitigative measures as required by the Federal 
Pipeline Safety Regulations. PHMSA recommends that operators thoroughly 
review their current DIMP for the threat of the failure of inside meter 
and regulator installations and make any changes necessary to become 
compliant with the Federal Pipeline Safety Regulations. For example, 
based on the requirements in Sec.  192.1007(a) for operators to know 
their systems, PHMSA would expect operators to know the location 
(inside or outside) of all meters and regulators installed on their 
distribution system. Operators must evaluate the risks associated with 
these facilities, determine the relative importance of each threat, and 
rank the

[[Page 61104]]

risks posed to their pipeline (Sec.  192.1007(c)). PHMSA urges 
operators to consider the points-of-failure identified in NTSB's 
accident investigation report as they relate to operators' inside meter 
and regulator installations and to adjust their DIMP accordingly. These 
measures must include an effective leak management program unless all 
leaks are repaired when found (Sec.  192.1007(d)). As part of their 
leak management program, operators must consider all risks, including 
the risk of failure or damage to inside meter and regulator 
installations. If risks are identified, risk reduction measures must be 
put in place to address them, or if additional actions have not been 
taken to reduce risks, justification must be documented.

    Issued in Washington, DC, on September 24, 2020, under authority 
delegated in 49 CFR 1.97.
Alan K. Mayberry,
Associate Administrator for Pipeline Safety.
[FR Doc. 2020-21507 Filed 9-28-20; 8:45 am]
BILLING CODE 4910-60-P