This standard is now limited to the manufacture of metal flue boxes. It gives requirements for the dimensions, material and performance of metal flue boxes that enable gas fire flues to be installed within a dwelling against or within a wall, which does not have a fireplace or flue. The performance of the flue boxes are tested through a strength test and a temperature test. The flue boxes specified are intended to be used with metal flue pipes conforming BS EN 1856-1 and BS EN 1856-2.Cross References:BS 1251:1987BS 1449-1BS 7977-1:2002BS EN 509:2000BS EN 1559-1BS EN 1559-2BS EN 1856-1BS EN 1856-2BS EN 10088-1BS EN 10327BS 6332-4:1983BS EN 573-3