Pressure Vessel Quality : Metallic material whose integrity is such that it can be used to safely contain pressure without risk of leakage or rupture. (Spec 6A, Spec 16A)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}