CFR / 
Title 46
 / Part 153
 / 
Sec. 153.370 Minimum relief valve setting for ambient
The relief valve setting for a containment system that carries a cargo at ambient temperature must at least equal the cargo's vapor pressure at 46 [deg]C (approx. 115 [deg]F).
[CGD 81-078, 50 FR 21173, May 22, 1985]