49 CFR 178.347-4 - Pressure relief.

§ 178.347-4 Pressure relief.

(a) Each cargo tank must be equipped with a pressure and vacuum relief system in accordance with § 178.345-10 and this section.

(b)Type and construction. Vacuum relief devices are not required for cargo tank motor vehicles that are designed to be loaded by vacuum in accordance with § 178.347-1(c) or built to withstand full vacuum in accordance with § 178.347-1(d).

(c)Pressure settings of relief valves. The setting of pressure relief valves must be in accordance with § 178.345-10(d).

(d)Venting capacities.

(1) The vacuum relief system must limit the vacuum to less than 80 percent of the design vacuum capability of the cargo tank.

(2) If pressure loading or unloading devices are provided, the relief system must have adequate vapor and liquid capacity to limit the tank pressure to the cargo tank test pressure at maximum loading or unloading rate. The maximum loading or unloading rate must be included on the metal specification plate.

[Amdt. 178-89, 54 FR 25030, June 12, 1989, as amended at 55 FR 37064, Sept. 7, 1990. Redesignated by Amdt. 178-112, 61 FR 18934, Apr. 29, 1996; 76 FR 43532, July 20, 2011]

This is a list of United States Code sections, Statutes at Large, Public Laws, and Presidential Documents, which provide rulemaking authority for this CFR Part.

This list is taken from the Parallel Table of Authorities and Rules provided by GPO [Government Printing Office].

It is not guaranteed to be accurate or up-to-date, though we do refresh the database weekly. More limitations on accuracy are described at the GPO site.


United States Code

Title 49 published on 09-May-2017 04:41

The following are ALL rules, proposed rules, and notices (chronologically) published in the Federal Register relating to 49 CFR Part 178 after this date.

  • 2017-03-30; vol. 82 # 60 - Thursday, March 30, 2017
    1. 82 FR 15796 - Hazardous Materials: Harmonization With International Standards (RRR)
      GPO FDSys XML | Text
      DEPARTMENT OF TRANSPORTATION, Pipeline and Hazardous Materials Safety Administration
      Final rule.
      Effective date: This rule is effective March 30, 2017, except for instruction 22, which is effective January 2, 2019. Voluntary compliance date: January 1, 2017. Delayed compliance date: Unless otherwise specified, compliance with the amendments adopted in this final rule is required beginning January 1, 2018. Incorporation by reference date: The incorporation by reference of certain publications listed in this rule is approved by the Director of the Federal Register as of March 30, 2017.
      49 CFR Parts 107, 171, 172, 173, 175, 176, 178, and 180
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