1884 M. N. Forney (ed. 2) 133/1 Pressure-retaining valve... A valve for use on long and steep gradients,..which keeps the train under control.
1971 B. Scharf xii. 177 Pressure-retaining valves which maintain the pressure on the upstream side.
2003 (Nexis) 1 June 75 All pressure-retaining components of the system are manufactured from ASME SA-designated materials.