Regulatory Compliance (Transportation)

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The Regulatory Compliance (Transportation) Technical Community of Interest is a group of people (both AMPP members and nonmembers) who have come together for the purpose of furthering a common cause by sharing wisdom, knowledge, information, and/or data for promoting information used by regulators within the construction industry. This community includes information related to OSHA, EPA, and etc.

  • 1.  H2S Limits in CFR 192.475 (US Standard)

    Posted 05-28-2025 11:43 AM

    All -

    I'm curious if anyone knows the actual logic behind limiting gas content to 4 ppm H2S in the US standard CFR 192.475.  I have copied the relevant section below. In my head, 4 ppm H2S is not a corrosion limit, but more likely a personnel safety limit. I'd welcome any thoughts / references / history that people can share.

    Krista Heidersbach

    192.475 Internal corrosion control: General.

    (a) Corrosive gas may not be transported by pipeline, unless the corrosive effect of the gas on the pipeline has been investigated and steps have been taken to minimize internal corrosion.

    (b) Whenever any pipe is removed from a pipeline for any reason, the internal surface must be inspected for evidence of corrosion. If internal corrosion is found-

    (1) The adjacent pipe must be investigated to determine the extent of internal corrosion;

    (2) Replacement must be made to the extent required by the applicable paragraphs of §§ 192.485, 192.487, or 192.489; and

    (3) Steps must be taken to minimize the internal corrosion.

    (c) Gas containing more than 0.25 grain of hydrogen sulfide per 100 cubic feet (5.8 milligrams/m.3) at standard conditions (4 parts per million) may not be stored in pipe-type or bottle-type holders.



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    Krista Heidersbach
    Brown Corrosion Services Inc
    Houston TX
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  • 2.  RE: H2S Limits in CFR 192.475 (US Standard)

    Posted 05-29-2025 02:32 PM

    The 4ppm is a safety standard used to protect personnel and infrastructure.  The EGR (Emergency Response Guidebook) from 2011 developed by the Department of Transportation is the first reference but newer version was published in 2024.  It was developed to provide guidance to First Responders during the initial phase of transportation incidents involving hazardous material.  The EGR Memo references a Dow Chemical Brochure from 1998 as the basis of the 4ppm level.  The reasoning for the 4ppm level was based on the corrosiveness and toxicity of H2S according the Dow Chemical Brochure and EGR.  



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    Kipp Keenan
    Martin Specialty Coatings, Inc.
    Shreveport LA
    +13185502685
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    Original Message


  • 3.  RE: H2S Limits in CFR 192.475 (US Standard)

    Posted 06-02-2025 01:45 PM

    Thank you Kipp.  I got a similar response in the SC15 Pipelines & Tank thread. I'll check out the information in the Dow reference, if I can find a copy.

    Krista



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    Krista Heidersbach
    Brown Corrosion Services Inc
    Houston TX
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    Original Message