Requirements for units and packages heated directly by gas or electricity, or indirectly heated. The cylinders have a capacity between 15 and 500 L, having a minimum opening pressure of 1.0 bar and a minimum working pressure of either 3 or 6 bar, fitted with safety devices to prevent water temperature from exceeding 100C.
BS 7206:1990 history
2016BS EN 12897:2016 Water supply. Specification for indirectly heated unvented (closed) storage water heaters
2007BS EN 12897:2006 Water supply - Specification for indirectly heated unvented (closed) storage water heaters
1990BS 7206:1990 Specification for unvented hot water storage units and packages