But I need to try and make a point as clearly as possible on this; These PRVs (in fact all Henry PRVs) are the back-pressure dependant type as specified in EN 13136. This means that the valves must be discharged to atmospheric pressure. The outlet-body joint is not designed to seal against pressure as the outlet line should be piped to atmosphere. The only time this section of the valve – downstream of the seat – should be exposed to any pressure is actually during a discharge, which may only last for a few seconds. During that time, the gas in the downstream line will take the path of least resistance, which should be out of the downstream line and to atmosphere. The outlet-body joint is not intended and is not considered by the design codes to be a pressure-retaining joint. I cannot state clearly enough that there should be no pressure acting on this joint from the inside other than a very minimal amount and then only for a few seconds during a discharge.