Interpretation Response #PI-18-0002
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Mr. Karl H. Baker
Public Utilities Supervisor of Technical Analysis
Connecticut Public Utilities
10 Franklin Square
New Britain, CT 06051
Dear Mr. Baker:
In a January 12, 2018, letter to the Pipeline and Hazardous Materials Safety Administration (PHMSA), you requested an interpretation of 49 CFR Part 192. Specifically, you requested an interpretation of the odorization requirement for combustible gas in a distribution line under § 192.625.
You stated that you need clarification on the odorant testing requirements for operators of liquefied petroleum gas pipeline distribution systems (LPGPDS). You stated that PHMSA's recent interpretation of § 192.625(f) states operators must conduct periodic sampling of combustible gases using an instrument, but you noted neither § 192.625 nor the interpretation letter define where the testing must take place. Therefore, you asked the following questions:
Question 1: Is it permissible for an operator of a LPGPDS to only perform the required periodic instrumented sampling at the bulk plant, as defined in NFPA 58 — 2004 edition, Section 3.3.10, that supplies the LPGPDS or must the sampling occur at each specific LPGPDS?
Question 2: If it is permissible to only sample at the bulk plant, is there a LPGPDS size at which this is no longer permissible? For example, would this only apply to a small LPG Operator as defined by 49 CFR 192.1001?
PHMSA's responses to your questions are as follows:
Response 1: For safe transportation of gas by pipeline on distribution and some transmission lines, odorization is required under § 192.625. The odorant must be of a concentration that the gas, at one-fifth of the lower explosive limit, is readily detectable by a person with a normal sense of smell. To assure the proper concentration of odorant in the gas pipeline, under § 192.625(f), each operator must conduct periodic sampling of combustible gases using an instrument capable of determining the percentage of gas in air at which the odor becomes readily detectable. Therefore, the required periodic instrumental sampling, in this case, cannot be limited to testing at the bulk plant, but must be performed in the pipeline system to ensure the entire pipeline system has the required odorant levels.
Response 2: Based on PHMSA's response to question 1, the response to this question is moot, since the bulk plant is not a pipeline facility and is not regulated under the Federal pipeline safety regulations. Therefore, the required periodic instrumental sampling, in this case, is not limited to testing at the bulk plant, but must also be performed in the pipeline system to insure gas odorant is present up to the consumption of the gas.
If we can be of further assistance, please contact Tewabe Asebe at 202-366-5523.
John A. Gale
Director, Office of Standards
|Odorization of gas