Regulation guide library

Regulation Guides

A complete, cross-linked set of water-system references for backflow protection — organised by risk, device and sector.

Double Check Valves

ED devices for Fluid Category 3 and the cases where they are no longer sufficient.

Pipework System Designs

Sizing, materials and isolation strategy for protected wholesome supplies.

RPZ Valves

Reduced pressure zone valves — installation, AIM, annual testing and Fluid Category 4 protection.

Filling Systems

Closed heating and chilled-water filling loops, Category 4 protection and RPZ vs break-tank choices.

Air Gaps

Type A and Type B air gap dimensions and where a mechanical device cannot replace an air gap.

HU Taps

Backflow protection requirements for all wholesome-water fitting connection points under Water Supply (Water Fittings) Regulations 1999, Schedule 2, Regulation 15.