Technical Booklet P Sanitary Appliances Unvented Hot Water Storage and Scalding·Page 9·Regulation 88
Unvented hot water storage systems
Unvented hot water storage systems with a capacity greater than 15 litres must be installed by a suitably qualified person and equipped with safety devices to limit temperature to 100°C maximum, control working pressure, and safely convey any relief discharge.
Regulation 88 Unvented hot water storage systems
0.2 Any hot water storage system with no vent pipe to the atmosphere (other than a system or part of a system used solely for space heating or an industrial process) with a capacity greater than 15 litres must –
(a) be installed by a suitably qualified person;
(b) have safety devices that –
(i) prevent the temperature of the stored water at any time to exceed 100 ºC; and
(ii) control the working pressure and relieve excessive pressure; and
(c) allow any discharge for the purposes of temperature and pressure relief (see paragraph 0.2(b)) to be conveyed safely to where it can be readily seen without causing danger to people in or about the building.
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