Cistern storage, warnings, float valve types, and overflow pipe sizing.
Under C&G Unit 204, a cold water storage cistern is used to feed domestic outlets and vented heating systems. Key requirements include:
- Float Valves: Part 1 float valves (standard) vs Part 2 float valves (diaphragm type, quieter and prevents backsiphonage).
- Warning/Overflow Pipe: Every cistern must have a warning pipe positioned below the cold feed outlet to warn occupants of a valve failure before water overflows the cistern. The warning pipe should terminate in a conspicuous position outside the building.
- Lid and Insulation: Cisterns must be fitted with a close-fitting lid to prevent contamination, and be insulated to protect against freezing and reduce heat gain.
*Original revision guidance; confirm against Approved Document G G1 guidelines.*