This British Standard specifies requirements for the selection,
installation, inspection, commissioning and maintenance of gas?fired
water-heating appliances, which have a rated heat input not
exceeding 70 kW, based on net calorific value.
It applies to water-heating appliances utilizing 1st, 2nd or 3rd family
gases designed to operate in the condensing or non?condensing
mode for the supply of hot water for domestic purposes in domestic
dwellings or domestic dwellings in commercial premises.
This standard does not apply to:
a) water-heating appliances with a rated input of over 70 kW;
b) hot water supply systems in multiple dwellings supplied from a
central source.
It does not cover the detailed design and installation of the whole hot
water distribution system, which was specified in BS 5449.
This standard applies to water-heating appliances which carry a
CE mark and also to previously used water-heating appliances which
do not carry the CE mark (see 5.3.1).