Pipeline Safety: High Consequence Area Identification Methods for Gas Transmission Pipelines, 90062-90064 [2016-29880]

Download as PDF 90062 Federal Register / Vol. 81, No. 239 / Tuesday, December 13, 2016 / Notices SUPPLEMENTARY INFORMATION: Public Action Requested PHMSA advises offerors of DOT–39 cylinders having an internal volume exceeding 75 cubic inches (in3) (1.23 L) that such cylinders should not be filled with liquefied flammable compressed gas. PHMSA further advises the public not to use any DOT–39 cylinder with an internal volume greater than 75 in3 (1.23 L) containing a liquefied flammable compressed gas. pmangrum on DSK3GDR082PROD with NOTICES Safety Concern The release of a liquefied flammable compressed gas from or rupture of such a cylinder having an internal volume exceeding 75 in3 (1.23 L) is a safety concern that could result in extensive property damage, serious personal injury, or even death. A liquefied flammable compressed gas has a stored energy that is several times greater than that of a non-liquefied compressed gas. Further, a DOT–39 cylinder can have a volume of up to 1,526 in3 (25 L) at a service pressure of 500 psig or less and, as such, can have up to 22 times the stored energy of a DOT–39 cylinder limited to 75 in3 (1.23 L). Additionally, because of the design specifications that allow for thinner walls when used at lower pressure, the cylinders may be at greater risk from corrosion or puncture. Given the known risks associated with cylinders that are filled with liquefied flammable compressed gases, PHMSA is issuing this safety advisory notice to inform offerors and users of DOT–39 cylinders that cylinders with an internal volume of 75 in3 (1.23 L) or more should not be filled with liquefied flammable compressed gas. Background This safety advisory notice is being issued in part because of concern over confusion about the regulatory requirements when using DOT–39 cylinders for liquefied compressed gases. Historically, the Hazardous Materials Regulations (HMR; 49 CFR parts 171–180) limited the internal volume of a DOT–39 specification cylinder to 75 in3 (1.23 L) when used for certain liquefied flammable compressed gases. This size limitation applied when DOT–39 cylinders were used for gases that were subject to Note 9 following the table at § 173.304(a)(2) or liquefied petroleum gas as addressed in § 173.304(d)(3) (The table is currently located at § 173.304a). In an October 30, 1998 notice of proposed rulemaking (NPRM), the Research and Special Programs Administration (RSPA)—the predecessor agency to PHMSA— VerDate Sep<11>2014 15:08 Dec 12, 2016 Jkt 241001 proposed to extend the 75 in3 (1.23 L) volume limitation of DOT–39 cylinders to all liquefied flammable compressed gases by revising § 173.304 to delete Note 9 from the table at § 173.304(a)(2) and adding §§ 173.304a and 173.304b.1 RSPA received several comments in opposition to extending the limit to all liquefied flammable compressed gases which would have been codified in § 173.304a(a)(3). RSPA published a final rule on August 8, 2002 and, based on the opposing comments, decided not to extend the 75 in3 (1.23 L) limitation to all liquefied flammable compressed gases in a DOT–39 cylinder at that time. However, in the process of publishing the final rule, the agency inadvertently omitted the 75 in3 (1.23 L) limitation for liquefied flammable compressed gas and liquefied petroleum gas.2 On November 13, 2014, PHMSA accepted a petition for rulemaking (P– 1622) from Worthington Cylinders to address this error in a rulemaking. On July 26, 2016, PHMSA published in the Federal Register an NPRM titled, ‘‘Hazardous Materials: Miscellaneous Amendments Pertaining to DOT Specification Cylinders (RRR),’’ [81 FR 48977; Docket No. PHMSA–2011–0140 (HM–234) 3] that again proposes to extend the limit on the internal volume of DOT–39 cylinders to use with all liquefied flammable compressed gases, thus correcting the inadvertently omitted size limitation and expanding the applicability to capture those liquefied flammable compressed gases (e.g., difluoromethane (Refrigerant gas R 32)) either not reflected in the § 173.304a(a)(2) table or not considered a liquefied petroleum gas. Issued in Washington, DC on December 5, 2016. William S. Schoonover, Acting Associate Administrator for Hazardous Materials Safety, Pipeline and Hazardous Materials Safety Administration. DEPARTMENT OF TRANSPORTATION Pipeline and Hazardous Materials Safety Administration [Docket No. PHMSA–2016–0065] Pipeline Safety: High Consequence Area Identification Methods for Gas Transmission Pipelines Pipeline and Hazardous Materials Safety Administration (PHMSA); DOT. ACTION: Notice; Issuance of Advisory Bulletin. AGENCY: PHMSA is issuing this advisory bulletin to remind gas transmission pipeline operators of certain previously issued guidance and provide operators with additional guidance for the identification of High Consequence Areas (HCAs) along pipeline right-of-ways. This advisory bulletin provides suggestions for accurately mapping and integrating HCA data, documenting how mapping systems are used, periodically verifying and updating their mapping systems, utilizing buffer zones (tolerances) to provide additional protection around the calculated potential impact radius (PIR) along their pipelines, and ensuring the accuracy of class locations. The bulletin emphasizes that HCA identification relies on pipeline-specific information regarding the location, size, and operating characteristics of the line, as well as the identification of structures, specified sites, and their intended usage along the pipeline rightof-way. FOR FURTHER INFORMATION CONTACT: Allan Beshore by phone at 405–834– 8344 or email at allan.beshore@dot.gov. All materials in this docket may be accessed electronically at https:// www.regulations.gov. Information about PHMSA may be found at https:// www.phmsa.dot.gov. SUMMARY: SUPPLEMENTARY INFORMATION: [FR Doc. 2016–29813 Filed 12–12–16; 8:45 am] I. Background BILLING CODE 4910–60–P A key component of PHMSA’s pipeline safety regulations is its integrity management (IM) program. For gas transmission pipelines, this program is outlined in Subpart O of 49 CFR part 192 and is based on the concept that pipeline operators need to identify those segments of their pipeline systems that pose the greatest risk to human life, property, and the environment, and to take extra precautions to ensure their safety. These higher-risk areas are known as ‘‘HCAs.’’ Each operator is required to survey its entire pipeline system to identify all pipeline segments 1 NPRM—Hazardous Materials: Requirements for DOT Specification Cylinders (HM–220D) [63 FR 58460]. 2 Final Rule—Hazardous Materials: Requirements for Maintenance, Requalification, Repair and Use of DOT Specification Cylinders (HM–220D) [67 FR 51625] 3 https://www.gpo.gov/fdsys/pkg/FR-2016-07-26/ pdf/2016-16689.pdf. PO 00000 Frm 00171 Fmt 4703 Sfmt 4703 E:\FR\FM\13DEN1.SGM 13DEN1 Federal Register / Vol. 81, No. 239 / Tuesday, December 13, 2016 / Notices pmangrum on DSK3GDR082PROD with NOTICES that could affect HCAs. Since the greatest risk posed by gas transmission pipelines is the risk of fire and explosion resulting from pipeline leaks and ruptures, gas HCAs consist of highly populated areas and ‘‘identified sites’’ where people regularly gather or live. An operator’s first step in developing a robust IM program is to properly identify and map all HCAs and perform periodic updates to the evaluation process to maintain accurate and current information. Subpart O of part 192 allows operators flexibility in making determinations to identify HCAs by defining two different identification methods, generally referred to as Method 1 or Method 2. Both methods require the operator to determine ‘‘identified sites’’ and calculate a PIR, using a formula to calculate the radius of a circle within which the potential failure of a pipeline could have significant impact on people or property. While Method 1 includes all pipe segments within Class 3 and Class 4 locations1 and ‘‘identified areas within a PIR in Class 1 and 2 locations,’’ Method 2 includes ‘‘identified sites’’ 2 within a PIR only, regardless of the class location, or the combination of ‘‘identified sites’’ with 20 or more buildings intended for human occupancy. A review of PHMSA and state data from ‘‘first-round’’ IM inspections indicates a large percentage of intrastate and small operators have been inconsistent in determining HCAs using ‘‘identified sites,’’ and operators that initially used Method 1 to identify HCAs have since transitioned to Method 2. On July 17, 2003, (68 FR 42458) PHMSA published an advisory bulletin titled ‘‘Identified Sites as Part of High Consequence Areas for Gas Integrity Management Programs’’ to provide 1 Under 49 CFR 192.5, all transmission pipelines fall into one of four ‘‘class locations.’’ Class 1 locations are offshore areas and all segments (‘‘class location units’’) one mile in length that contain 10 or fewer buildings intended for human occupancy Class 2 locations are units with more than 10, but fewer than 46, such buildings. Class 3 locations are units with 46 or more buildings or an area where the pipeline lies within 100 yards of either a building or a small, well-defined outside area (such as a playground or recreation area) that is occupied by 20 or more people on at least 5 days a week for 10 weeks in any 12-month period. Class 4 locations are units where buildings with 4 or more stories are prevalent. 2 ‘‘Identified sites’’ is a defined term under 49 CFR 192.903 in PHMSA’s IM regulations and refers generally to the type of specific areas included under the Class 3 location definition above, plus facilities occupied by persons who are confined, are of impaired mobility, or would be difficult to evacuate, including schools, prisons, nursing homes, etc. VerDate Sep<11>2014 15:08 Dec 12, 2016 Jkt 241001 guidance to gas transmission operators on the steps PHMSA expected them to take to determine ‘‘identified sites’’ along their pipelines. PHMSA intended the guidance in the advisory bulletin to support operators in identifying these sites for planning their IM programs and determined that certain measures, if properly applied, would satisfy the intent of the regulation. On December 15, 2003, (68 FR 69778) PHMSA published a final rule titled: ‘‘Pipeline Integrity Management in High Consequence Areas (Gas Transmission Pipelines)’’ that provided requirements for the identification of HCAs and further explanation of how best to conduct the identification process. In the preamble of the rule, PHMSA provided the basis for defining an identified site as follows: Define an identified site as any of the following within a Potential Impact Circle: 1. A facility housing persons of limited mobility that is known to public safety officials, emergency response officials, or local emergency planning committee, and which meets one of the following three criteria: (a) Is visibly marked, (b) is licensed or registered by a Federal, state, or local agency, or (c) is listed on a map maintained by or available from a Federal, State, or local agency, or 2. An outdoor area where people congregate that is known to public safety officials, emergency response officials or local emergency planning committee and which is occupied by 20 or more people on at least 50 days per year, or 3. A building occupied by 20 or more people 5 days per week, 10 weeks in any 12-month period (the days and weeks need not be consecutive). To assist operators in meeting the requirements of the regulation, PHMSA introduced a ‘‘buffer zone’’ concept. This additional safety margin was intended to compensate for inaccuracies (e.g., incorrect pipeline center data or mapping errors) when implementing the regulation and determining the PIR. As defined in § 192.903, a PIR is the radius of the potential impact circle (PIC), measured in feet surrounding the point of failure, within which the potential failure of a pipeline could have significant impact on people or property. Part 192 provides the formula for determining a PIR that takes into account the Maximum Allowable Operating Pressure (MAOP) in the pipeline segment in pounds per square inch, the nominal diameter of the pipeline in inches, and a numeric factor, PO 00000 Frm 00172 Fmt 4703 Sfmt 4703 90063 which varies for other gases depending upon their heat of combustion.3 Following the publication of the regulations and advisory bulletin, PHMSA inspections have revealed that operators may need further guidance regarding the identification of HCAs, as operators have been inconsistent in determining HCAs using ‘‘identified sites.’’ Additionally, in CY 2015, the National Transportation Safety Board (NTSB) published SS–15–01, ‘‘Safety Study: Integrity Management of Gas Transmission Pipelines in High Consequence Areas.’’ The study was conducted in response to concerns about deficiencies in operators’ IM programs that had been identified by the NTSB in three gas transmission pipeline accidents from the previous 5 years. Recommendation P–15–06, issued as a part of the study, recommended that PHMSA ‘‘[a]ssess the limitations associated with the current process for identifying high consequence areas, and disseminate the results of [the] assessment to the pipeline industry, inspectors, and the public.’’ PHMSA has noted that proper identification of an HCA and periodic verification relies on two key types of information: (1) Pipeline-specific information that includes the accurate location of the centerline of the pipeline, the nominal diameter of the pipeline, and the pipeline segment’s MAOP; and (2) all the structures and their usage (including occupancy) located along the pipeline. PHMSA subject matter experts performed an assessment of the impact of these two issues on identifying HCAs using Methods 1 and 2 as defined in § 192.903, by reviewing failure investigations, inspector experiences, and Gas IM inspection results and has documented these insights in this advisory bulletin. PHMSA will be including these insights in updated inspection materials, as appropriate. PHMSA is publishing this advisory bulletin to meet NTSB Recommendation P–15–06 by providing operators with additional guidance on how to improve the accuracy of their class location identification process, which may also lead to operators improving HCA identification. 3 Operators transporting gas other than natural gas must use section 3.2 of ASME/ANSI B31.8S (incorporated by reference, see § 192.7) to calculate the impact radius formula. For flammable gases, additional information on factors may be found in TTO–13, Potential Impact Radius Formulae for Flammable Gases Other Than Natural Gas Subject to 49 CFR 192, June 2005, Table 7.1 which can be found in https://primis.phmsa.dot.gov/gasimp/docs/ TTO13_PotentialImpactRadius_FinalReport_ June2005.pdf). E:\FR\FM\13DEN1.SGM 13DEN1 90064 Federal Register / Vol. 81, No. 239 / Tuesday, December 13, 2016 / Notices pmangrum on DSK3GDR082PROD with NOTICES II. Advisory Bulletin (ADB–2016–07) To: Owners and Operators of Natural Gas Pipelines. Subject: High Consequence Area Identification Methods. Advisory: PHMSA is issuing this advisory bulletin to inform owners and operators of gas transmission pipelines that PHMSA has developed guidance on the identification and periodic verification of HCAs, including the application of a buffer zone to the PIR, and information regarding the accuracy of class locations. PHMSA is recommending that operators review and consistently monitor class location and PIR data on an annual basis as part of their IM program. PHMSA anticipates this annual review will improve the accuracy of operator HCA determinations. A review of early PHMSA inspections has shown that many operators (28%) did not have procedures to adequately describe how to identify HCAs, using Method 1 or Method 2. To effectively use Method 2, operators should have a detailed and documented process in place to monitor the conditions surrounding their pipelines, including the existence of ‘‘identified sites.’’ Therefore, PHMSA is reminding operators of the existing guidance for making those determinations and is providing additional recommendations on how to improve the accuracy of HCA identification. Specifically: • PHMSA expects that most large operators will use a geographic information system or similar mapping software for segment identification. Operators should be able to demonstrate the usability of their system and show a graphical overlay of HCAs with their pipeline system. • An operator not using geographic information system or similar mapping software should describe or demonstrate how it performed its HCA segment identifications. • For both geographic information system-based and non-geographic information system-based HCA identification processes, the operator should address how it will deal with tolerances (or buffers) on top of the calculated PIR regarding the accuracy of measured distances to structures and the location of the pipeline centerline. PHMSA recognizes that global positioning system measurements and maps have some limitations in their accuracy; however, the rule applies to pipelines—and distances from those pipelines—as they actually exist in the field. PHMSA also reminds operators of the need to continually improve the VerDate Sep<11>2014 15:08 Dec 12, 2016 Jkt 241001 accuracy of their pipeline data. As technology advances, pipeline operators have more access to tools that provide improved accuracy for determining class locations (including the determination of the centerline of the pipeline), the application of aerial photography, pipeline operating characteristics (diameter, grade, MAOP), population studies, and mapping software. It is important that operators continuously improve the accuracy of the data and conduct the required class location studies as required in § 192.609, along with the confirmation or revision of MAOP in § 192.611, as this affects the operation of their pipelines. Operators should include provisions in their continuing surveillance monitoring procedures (§ 192.613) to constantly monitor the surrounding conditions, report that information, and update their maps each calendar year. This is similar to the requirements for including newly identified areas for segments in HCAs (§ 192.905(c)) and for filing annual report information relating to the performance of IM plans (§ 191.17). Operators must use MAOP when calculating PIR, and accurate pipeline data is necessary to ensure that operators are correctly applying the MAOP value in the PIR calculation when determining whether areas qualify as HCAs. PHMSA also recommends that operators review their pipeline centerline and map data to account for any potential inaccuracies or data limitations and to add an appropriate buffer zone to the calculated PIR. This would establish a PIR that includes any areas that could potentially be excluded due to data limitations. A list of PHMSA-provided frequently asked questions on this subject can be found on the gas IM site at: https:// primis.phmsa.dot.gov/gasimp/ index.htm. Gas IM Frequently Asked Question Number 174 reminds operators that they should consider the uncertainties in the distances they measure or infer when evaluating PICs and consider geographic information system accuracy in locating HCAs: ‘‘. . . Operators may use a combination of techniques in order to account for these inaccuracies. For instance, aerial photography may be used as an initial screen. Field measurements (such as pipeline locators along with chainage measurements or survey quality range finders) may be used to verify if structures near the edge of the PIC (i.e., within the range of mapping/geographic information system inaccuracies) are actually inside or outside the PIC. PHMSA will inspect each operator’s approach to assure that PO 00000 Frm 00173 Fmt 4703 Sfmt 4703 the operator’s process is adequate to identify all covered segments.’’ PHMSA recommends operators frequently and consistently review their data—including class location data—for potential inaccuracies or limitations, and add a buffer zone to the calculated PIR to help ensure proper HCA identification. The purpose and usage of buildings, open structures, and outside areas can shift over time, changing the number of ‘‘identified sites’’ in a PIR, and therefore, whether an area is an HCA. PHMSA believes that if operators review class location and PIR data on an annual basis as a part of their IM programs, the accuracy of HCA determinations will be greatly improved. Issued in Washington, DC, on December 8, 2016, under authority delegated in 49 CFR 1.97. Alan K. Mayberry, Acting Associate Administrator for Pipeline Safety. [FR Doc. 2016–29880 Filed 12–12–16; 8:45 am] BILLING CODE 4910–60–P DEPARTMENT OF TRANSPORTATION Office of the Secretary of Transportation Notice of Funding Availability for the Small Business Transportation Resource Center Program Office of Small and Disadvantaged Business Utilization (OSDBU), Office of the Secretary of Transportation (OST), Department of Transportation (DOT). ACTION: Notice of funding availability for the Northwest Region SBTRC. AGENCY: The Department of Transportation (DOT), Office of the Secretary (OST), Office of Small and Disadvantaged Business Utilization (OSDBU) announces the opportunity for business centered community-based organizations, transportation-related trade associations, colleges and universities, community colleges, or chambers of commerce, registered with the Internal Revenue Service as 501 C(6) or 501 C(3) tax-exempt organizations, to compete for participation in OSDBU’s Small Business Transportation Resource Center (SBTRC) program in the Northwest Region (Alaska, Idaho, Oregon, and Washington). DATES: Complete Proposals must be received on or February 3, 2017, 6:00 p.m. Eastern Standard Time (EST). Proposals received after the deadline will be considered non-responsive and will not be reviewed. SUMMARY: E:\FR\FM\13DEN1.SGM 13DEN1

Agencies

[Federal Register Volume 81, Number 239 (Tuesday, December 13, 2016)]
[Notices]
[Pages 90062-90064]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-29880]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Pipeline and Hazardous Materials Safety Administration

[Docket No. PHMSA-2016-0065]


Pipeline Safety: High Consequence Area Identification Methods for 
Gas Transmission Pipelines

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

ACTION: Notice; Issuance of Advisory Bulletin.

-----------------------------------------------------------------------

SUMMARY: PHMSA is issuing this advisory bulletin to remind gas 
transmission pipeline operators of certain previously issued guidance 
and provide operators with additional guidance for the identification 
of High Consequence Areas (HCAs) along pipeline right-of-ways. This 
advisory bulletin provides suggestions for accurately mapping and 
integrating HCA data, documenting how mapping systems are used, 
periodically verifying and updating their mapping systems, utilizing 
buffer zones (tolerances) to provide additional protection around the 
calculated potential impact radius (PIR) along their pipelines, and 
ensuring the accuracy of class locations. The bulletin emphasizes that 
HCA identification relies on pipeline-specific information regarding 
the location, size, and operating characteristics of the line, as well 
as the identification of structures, specified sites, and their 
intended usage along the pipeline right-of-way.

FOR FURTHER INFORMATION CONTACT: Allan Beshore by phone at 405-834-8344 
or email at allan.beshore@dot.gov. All materials in this docket may be 
accessed electronically at https://www.regulations.gov. Information 
about PHMSA may be found at https://www.phmsa.dot.gov.

SUPPLEMENTARY INFORMATION: 

I. Background

    A key component of PHMSA's pipeline safety regulations is its 
integrity management (IM) program. For gas transmission pipelines, this 
program is outlined in Subpart O of 49 CFR part 192 and is based on the 
concept that pipeline operators need to identify those segments of 
their pipeline systems that pose the greatest risk to human life, 
property, and the environment, and to take extra precautions to ensure 
their safety. These higher-risk areas are known as ``HCAs.'' Each 
operator is required to survey its entire pipeline system to identify 
all pipeline segments

[[Page 90063]]

that could affect HCAs. Since the greatest risk posed by gas 
transmission pipelines is the risk of fire and explosion resulting from 
pipeline leaks and ruptures, gas HCAs consist of highly populated areas 
and ``identified sites'' where people regularly gather or live.
    An operator's first step in developing a robust IM program is to 
properly identify and map all HCAs and perform periodic updates to the 
evaluation process to maintain accurate and current information. 
Subpart O of part 192 allows operators flexibility in making 
determinations to identify HCAs by defining two different 
identification methods, generally referred to as Method 1 or Method 2.
    Both methods require the operator to determine ``identified sites'' 
and calculate a PIR, using a formula to calculate the radius of a 
circle within which the potential failure of a pipeline could have 
significant impact on people or property. While Method 1 includes all 
pipe segments within Class 3 and Class 4 locations\1\ and ``identified 
areas within a PIR in Class 1 and 2 locations,'' Method 2 includes 
``identified sites'' \2\ within a PIR only, regardless of the class 
location, or the combination of ``identified sites'' with 20 or more 
buildings intended for human occupancy.
---------------------------------------------------------------------------

    \1\ Under 49 CFR 192.5, all transmission pipelines fall into one 
of four ``class locations.'' Class 1 locations are offshore areas 
and all segments (``class location units'') one mile in length that 
contain 10 or fewer buildings intended for human occupancy Class 2 
locations are units with more than 10, but fewer than 46, such 
buildings. Class 3 locations are units with 46 or more buildings or 
an area where the pipeline lies within 100 yards of either a 
building or a small, well-defined outside area (such as a playground 
or recreation area) that is occupied by 20 or more people on at 
least 5 days a week for 10 weeks in any 12-month period. Class 4 
locations are units where buildings with 4 or more stories are 
prevalent.
    \2\ ``Identified sites'' is a defined term under 49 CFR 192.903 
in PHMSA's IM regulations and refers generally to the type of 
specific areas included under the Class 3 location definition above, 
plus facilities occupied by persons who are confined, are of 
impaired mobility, or would be difficult to evacuate, including 
schools, prisons, nursing homes, etc.
---------------------------------------------------------------------------

    A review of PHMSA and state data from ``first-round'' IM 
inspections indicates a large percentage of intrastate and small 
operators have been inconsistent in determining HCAs using ``identified 
sites,'' and operators that initially used Method 1 to identify HCAs 
have since transitioned to Method 2.
    On July 17, 2003, (68 FR 42458) PHMSA published an advisory 
bulletin titled ``Identified Sites as Part of High Consequence Areas 
for Gas Integrity Management Programs'' to provide guidance to gas 
transmission operators on the steps PHMSA expected them to take to 
determine ``identified sites'' along their pipelines. PHMSA intended 
the guidance in the advisory bulletin to support operators in 
identifying these sites for planning their IM programs and determined 
that certain measures, if properly applied, would satisfy the intent of 
the regulation.
    On December 15, 2003, (68 FR 69778) PHMSA published a final rule 
titled: ``Pipeline Integrity Management in High Consequence Areas (Gas 
Transmission Pipelines)'' that provided requirements for the 
identification of HCAs and further explanation of how best to conduct 
the identification process.
    In the preamble of the rule, PHMSA provided the basis for defining 
an identified site as follows:
    Define an identified site as any of the following within a 
Potential Impact Circle:
    1. A facility housing persons of limited mobility that is known to 
public safety officials, emergency response officials, or local 
emergency planning committee, and which meets one of the following 
three criteria: (a) Is visibly marked, (b) is licensed or registered by 
a Federal, state, or local agency, or (c) is listed on a map maintained 
by or available from a Federal, State, or local agency, or
    2. An outdoor area where people congregate that is known to public 
safety officials, emergency response officials or local emergency 
planning committee and which is occupied by 20 or more people on at 
least 50 days per year, or
    3. A building occupied by 20 or more people 5 days per week, 10 
weeks in any 12-month period (the days and weeks need not be 
consecutive).
    To assist operators in meeting the requirements of the regulation, 
PHMSA introduced a ``buffer zone'' concept. This additional safety 
margin was intended to compensate for inaccuracies (e.g., incorrect 
pipeline center data or mapping errors) when implementing the 
regulation and determining the PIR. As defined in Sec.  192.903, a PIR 
is the radius of the potential impact circle (PIC), measured in feet 
surrounding the point of failure, within which the potential failure of 
a pipeline could have significant impact on people or property. Part 
192 provides the formula for determining a PIR that takes into account 
the Maximum Allowable Operating Pressure (MAOP) in the pipeline segment 
in pounds per square inch, the nominal diameter of the pipeline in 
inches, and a numeric factor, which varies for other gases depending 
upon their heat of combustion.\3\
---------------------------------------------------------------------------

    \3\ Operators transporting gas other than natural gas must use 
section 3.2 of ASME/ANSI B31.8S (incorporated by reference, see 
Sec.  192.7) to calculate the impact radius formula. For flammable 
gases, additional information on factors may be found in TTO-13, 
Potential Impact Radius Formulae for Flammable Gases Other Than 
Natural Gas Subject to 49 CFR 192, June 2005, Table 7.1 which can be 
found in https://primis.phmsa.dot.gov/gasimp/docs/TTO13_PotentialImpactRadius_FinalReport_June2005.pdf).
---------------------------------------------------------------------------

    Following the publication of the regulations and advisory bulletin, 
PHMSA inspections have revealed that operators may need further 
guidance regarding the identification of HCAs, as operators have been 
inconsistent in determining HCAs using ``identified sites.''
    Additionally, in CY 2015, the National Transportation Safety Board 
(NTSB) published SS-15-01, ``Safety Study: Integrity Management of Gas 
Transmission Pipelines in High Consequence Areas.'' The study was 
conducted in response to concerns about deficiencies in operators' IM 
programs that had been identified by the NTSB in three gas transmission 
pipeline accidents from the previous 5 years. Recommendation P-15-06, 
issued as a part of the study, recommended that PHMSA ``[a]ssess the 
limitations associated with the current process for identifying high 
consequence areas, and disseminate the results of [the] assessment to 
the pipeline industry, inspectors, and the public.'' PHMSA has noted 
that proper identification of an HCA and periodic verification relies 
on two key types of information: (1) Pipeline-specific information that 
includes the accurate location of the centerline of the pipeline, the 
nominal diameter of the pipeline, and the pipeline segment's MAOP; and 
(2) all the structures and their usage (including occupancy) located 
along the pipeline. PHMSA subject matter experts performed an 
assessment of the impact of these two issues on identifying HCAs using 
Methods 1 and 2 as defined in Sec.  192.903, by reviewing failure 
investigations, inspector experiences, and Gas IM inspection results 
and has documented these insights in this advisory bulletin. PHMSA will 
be including these insights in updated inspection materials, as 
appropriate.
    PHMSA is publishing this advisory bulletin to meet NTSB 
Recommendation P-15-06 by providing operators with additional guidance 
on how to improve the accuracy of their class location identification 
process, which may also lead to operators improving HCA identification.

[[Page 90064]]

II. Advisory Bulletin (ADB-2016-07)

    To: Owners and Operators of Natural Gas Pipelines.
    Subject: High Consequence Area Identification Methods.
    Advisory: PHMSA is issuing this advisory bulletin to inform owners 
and operators of gas transmission pipelines that PHMSA has developed 
guidance on the identification and periodic verification of HCAs, 
including the application of a buffer zone to the PIR, and information 
regarding the accuracy of class locations. PHMSA is recommending that 
operators review and consistently monitor class location and PIR data 
on an annual basis as part of their IM program. PHMSA anticipates this 
annual review will improve the accuracy of operator HCA determinations.
    A review of early PHMSA inspections has shown that many operators 
(28%) did not have procedures to adequately describe how to identify 
HCAs, using Method 1 or Method 2. To effectively use Method 2, 
operators should have a detailed and documented process in place to 
monitor the conditions surrounding their pipelines, including the 
existence of ``identified sites.'' Therefore, PHMSA is reminding 
operators of the existing guidance for making those determinations and 
is providing additional recommendations on how to improve the accuracy 
of HCA identification. Specifically:
     PHMSA expects that most large operators will use a 
geographic information system or similar mapping software for segment 
identification. Operators should be able to demonstrate the usability 
of their system and show a graphical overlay of HCAs with their 
pipeline system.
     An operator not using geographic information system or 
similar mapping software should describe or demonstrate how it 
performed its HCA segment identifications.
     For both geographic information system-based and non-
geographic information system-based HCA identification processes, the 
operator should address how it will deal with tolerances (or buffers) 
on top of the calculated PIR regarding the accuracy of measured 
distances to structures and the location of the pipeline centerline. 
PHMSA recognizes that global positioning system measurements and maps 
have some limitations in their accuracy; however, the rule applies to 
pipelines--and distances from those pipelines--as they actually exist 
in the field.
    PHMSA also reminds operators of the need to continually improve the 
accuracy of their pipeline data. As technology advances, pipeline 
operators have more access to tools that provide improved accuracy for 
determining class locations (including the determination of the 
centerline of the pipeline), the application of aerial photography, 
pipeline operating characteristics (diameter, grade, MAOP), population 
studies, and mapping software. It is important that operators 
continuously improve the accuracy of the data and conduct the required 
class location studies as required in Sec.  192.609, along with the 
confirmation or revision of MAOP in Sec.  192.611, as this affects the 
operation of their pipelines. Operators should include provisions in 
their continuing surveillance monitoring procedures (Sec.  192.613) to 
constantly monitor the surrounding conditions, report that information, 
and update their maps each calendar year. This is similar to the 
requirements for including newly identified areas for segments in HCAs 
(Sec.  192.905(c)) and for filing annual report information relating to 
the performance of IM plans (Sec.  191.17).
    Operators must use MAOP when calculating PIR, and accurate pipeline 
data is necessary to ensure that operators are correctly applying the 
MAOP value in the PIR calculation when determining whether areas 
qualify as HCAs. PHMSA also recommends that operators review their 
pipeline centerline and map data to account for any potential 
inaccuracies or data limitations and to add an appropriate buffer zone 
to the calculated PIR. This would establish a PIR that includes any 
areas that could potentially be excluded due to data limitations.
    A list of PHMSA-provided frequently asked questions on this subject 
can be found on the gas IM site at: https://primis.phmsa.dot.gov/gasimp/index.htm. Gas IM Frequently Asked Question Number 174 reminds 
operators that they should consider the uncertainties in the distances 
they measure or infer when evaluating PICs and consider geographic 
information system accuracy in locating HCAs:
    ``. . . Operators may use a combination of techniques in order to 
account for these inaccuracies. For instance, aerial photography may be 
used as an initial screen. Field measurements (such as pipeline 
locators along with chainage measurements or survey quality range 
finders) may be used to verify if structures near the edge of the PIC 
(i.e., within the range of mapping/geographic information system 
inaccuracies) are actually inside or outside the PIC. PHMSA will 
inspect each operator's approach to assure that the operator's process 
is adequate to identify all covered segments.''
    PHMSA recommends operators frequently and consistently review their 
data--including class location data--for potential inaccuracies or 
limitations, and add a buffer zone to the calculated PIR to help ensure 
proper HCA identification. The purpose and usage of buildings, open 
structures, and outside areas can shift over time, changing the number 
of ``identified sites'' in a PIR, and therefore, whether an area is an 
HCA. PHMSA believes that if operators review class location and PIR 
data on an annual basis as a part of their IM programs, the accuracy of 
HCA determinations will be greatly improved.

    Issued in Washington, DC, on December 8, 2016, under authority 
delegated in 49 CFR 1.97.
Alan K. Mayberry,
Acting Associate Administrator for Pipeline Safety.
[FR Doc. 2016-29880 Filed 12-12-16; 8:45 am]
 BILLING CODE 4910-60-P
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.