Section 179.300-17 - Tests of pressure relief devices(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.29 FR 18995, 12/29/1964. Redesignated at 32 FR 5606, 4/5/1967, and amended by Amdt. 179-10, 36 FR 21355, 11/6/1971; 66 FR 45390, 8/28/2001; 68 FR 48572, 8/14/2003; 68 FR 75763, 12/31/2003