BS 6283-4:1991 Safety and control devices for use in hot water systems - Specification for drop-tight pressure reducing valves of nominal size up to and including DN 50 for supply pressures up to and including 12 bar
Design, construction and testing of drop tight pressure reducing valves, sometimes known as pressure limiting valves. Does not give recommendations on application or installation of the valves.
BS 6283-4:1991 history
2000BS EN 1567:1999 Building valves - Water pressure reducing valves and combination water reducing valves - Requirements and tests
1991BS 6283-4:1991 Safety and control devices for use in hot water systems - Specification for drop-tight pressure reducing valves of nominal size up to and including DN 50 for supply pressures up to and including 12 bar