A Cistern or Tank used for potable water storage within England and Wales requires compliance with the requirements of Schedule 2, Section 16 of the Water Supply (Water Fittings) Regulations 1999. Similar Regulations also apply in Scotland and Northern Ireland.
The new BS EN 14622 and 14623 Standards explained.
Advised below are methods of determining the relative Air Gap values for multiple inlets feeding cisterns and tanks compliant with UK Water Regulations.
For the example advised above the required Air Gap (A) is determined by the formula depicted below.
Tank supplied with 2 F/V Inlets, 50mm and 25mm respectively. The appropriate Type ‘AF /’AG’ Air Gap is advised.
Tank with 3 Inlets, say, 100mm and 2 x 50mm respectively. The appropriate Type ‘AF’/ ‘AG’ Air Gap is advised.
The above information is offered for guidance only. For specific information related to Water Regulation Air Gap protection please refer to the BS EN 14622 and 14623 Standards.