Cold Water Storage and Expansion Cisterns

Abstract

Storage cistern, Fig. 1 A storage cistern, in an indirect system of cold water supply, supplies cold water to the hot water tank or cylinder, and to the bath, basin and W.C. In a direct system the cistern supplies cold water to the hot water tank or cylinder only. The capacity of the cistern therefore is determined by the type of cold water system; for an indirect system a minimum capacity of 227. 3 litre is required, whilst a direct system needs a minimum capacity of 113. 652 litre, i.e. at least equal to the capacity of the hot water tank or cylinder. For larger buildings the capacity of the cistern is based upon the number and type of sanitary fittings, and the probable demand on them.