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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Interpretation Response #PI-17-0008

Below is the interpretation response detail and a list of regulations sections applicable to this response.

Interpretation Response Details

Response Publish Date:

Company Name: AmeriGas Propane, LP

Individual Name: Mr. David Hedrick

Location State: MI Country: US

View the Interpretation Document

Response text:

December 4, 2017

Mr. David Hedrick
National Pipeline Safety Manager
AmeriGas Propane, LP
1173 Parkland
Lake Orion, MI 48360

Dear Mr. Hedrick:

In a May 9, 2017 letter to the Pipeline and Hazardous Materials Safety Administration (PHMSA), you requested an interpretation of 49 CFR Part 192. Specifically, you requested an interpretation on the odorization requirements of § 192.625(f) as it relates to liquefied petroleum gas.

You asked whether a verification of the concentration level in air of odorant in a combustible gas in a pipeline using an instrument is required for petroleum gas. You stated that the 2004 Edition of the National Fire Protection Association (NFPA) 58 requirement for liquefied petroleum allows odorant determined by sniff testing. Also, you mentioned that 49 CFR Part 173.315(b)(1) specifies the minimum addition ratio of odorants to liquefied petroleum gas.

You asked "Since both codes, National Fire Protection Association Pamphlet 58, Liquefied Petroleum Gas Code, and Title 49 Code of Federal Regulations specify the minimum addition ratios of certain odorants to LP Gases (propane in particular) for the gas to be readily detectible in air at a concentration of not over one-fifth the lower explosion level, if the amount of odorant used per LP Gas gallon meets the Code requirements and that amount is documented, and if sniff testing is an allowable measure to determine the presence of odorant, should operators of LP Gas pipeline distribution systems be exempted from the requirements of 192.625 (f) to use test instruments to determine the concentration level of odorant in the gas?"

49 CFR Part 173 governs the transportation of hazardous materials "shipment by air, highway, rail, or water, or any combination thereof." It does not include regulations regarding the transportation of liquefied petroleum gas through a pipeline. Therefore, 49 CFR Part 173.315(b)(1) does not apply to an operator's obligations for transporting liquefied petroleum gas through a pipeline distribution system. Liquefied petroleum gas pipeline distribution systems are regulated under 49 CFR Part 192, the pipeline safety regulations governing the transportation of natural and other gas by pipeline.

PHMSA regulates petroleum gas pipeline systems under 49 CFR § 192.11. Section 192.11 requires that each plant that supplies petroleum gas by pipeline to a natural gas distribution system must meet the requirements of Part 192 and NFPA 58 and 59 (2004) (192.11(a)). It also states that each pipeline system subject to Part 192 that transports only petroleum gas or petroleum gas/air mixtures must meet the requirements of Part 192 and of NFPA 58 and 59 (192.11(b)). Finally, the regulation lays out a primacy provision stating that in the event of a conflict between the regulation and the standard, NFPA 58 and 59 prevail (§ 192.11(c)). However, this primacy provision does not excuse operators from following the Part 192 requirements. For instance, when NFPA 58 or 59 (2004) does not address a specific subject, then no conflict has occurred and the operator must follow the Part 192 requirements.

Gas odorization is governed by 49 CFR 192.625, which states that "combustible gas in a distribution line must contain a natural odorant or be odorized so that at a concentration in air of one-fifth of the lower explosive limit, the gas is readily detectable by a person with a normal sense of smell." 49 CFR § 192.625(a). Under § 192.625(f) all operators must conduct periodic sampling of combustible gases using an instrument capable of determining the percentage of gas in the air at which the odor becomes readily detectable, except for master meter system operators.

Operators of liquefied petroleum gas pipeline distribution systems must comply with the requirements of Part 192, including its gas odorization regulations unless there is a conflict between Part 192 and NFPA 58 and NFPA 59. In this case, there is no conflict between Part 192 and NFPA 58 and NFPA 59. Therefore, under § 192.625(f), such operators must use test instruments to determine the concentration level of odorant in the gas. If we can be of further assistance, please contact Tewabe Asebe at 202-366-5523.


John A. Gale
Director, Office of Standards
and Rulemaking

Regulation Sections

Section Subject
192.625 Odorization of gas