Backflow arising from connections between potable (drinking) water and non-potable water can constitute a serious public health hazard.
The Water Supply (Water Fittings) Regulations 1999 for England & Wales and the Water Byelaws 2000 (Scotland) detail the rules & requirements for the installing & use of RPZ Valves as backflow prevention devices.
RPZ Valves (sometimes referred to as type BA devices) can protect against backflow at the point of use from a possible contamination of fluid up to Category 4. RPZ valves should not be used in Category 5 situations, such as mortuary or embalming, commercial agricultural insecticide or fertiliser applications and reclaimed water systems.
Specific instructions relating to the INSTALLATION OF RPZ VALVES should be followed, basically:
- The Installation and use of RPZ valves must be notified in advance
- All RPZ valves reduce the water pressure available ( this varies according to the Make / Model used )
- Only UK approved RPZ valves can be legally fitted
- RPZ valves should only be tested & certified by an Accredited UK RPZ VALVE TESTER
- The RPZ valve should not be fitted in areas that are liable to flooding
- RPZ valves should not be fitted above Electrical Equipment
- RPZ valves must not be in a concealed compartment
- They should not be exposed to frost or freezing conditions ( unless protected from freezing )
- In the UK only Horizontal fitting of RPZ valves is appropriate.