U.S. Code of Federal Regulations
Regulations most recently checked for updates: Feb 24, 2020
(a) Each valve shall be tested by air or gas before being put into service. The valve shall open and be vapor-tight at the pressure prescribed in § 179.301.
(b) Rupture disks of non-reclosing pressure relief devices must be tested and qualified as prescribed in appendix A, Paragraph 5, of the AAR Manual of Standards and Recommended Practices, Section C - Part III, AAR Specifications for Tank Cars (IBR, see § 171.7 of this subchapter).
(c) For pressure relief devices of the fusible plug type, a sample of the plug used shall function at the temperatures prescribed in § 179.300-15.
(d) The start-to-discharge and vapor-tight pressures shall not be affected by any auxiliary closure or other combination.