Viega Prevista WC suites now comply with the Regulation 4 of the Water Supply (Water Fittings) Regulations of 1999 and have achieved certifications with WRAS and KIWA (KUKreg4).

To address industry concerns about potential backflow from WC cisterns into the mains supply, WRAS and KIWA have updated their acceptance criteria for approval of WC suites. Evidence suggests that in some cases existing backflow protections could be compromised and are allowing ‘blue water’ stored in WC cisterns to enter into the mains supply via the filling valve. The revised requirements are that a Type AG filling valve be installed inside the cistern to allow for a physical “air gap” between the lowest point of the water outlet and the critical water level.

Viega’s Prevista Dry WC element in construction heights 1120, 980 and 820 mm, as well as Prevista Pure 3H and 3L cisterns, all include the required Type AG filling valves that provides a complete physical air break between water discharge and the water level of the cistern. This air gap must be at least 20mm, or twice the inlet internal diameter of the inlet pipe, whichever is the greater. This ensures compliance with the regulations regardless of the requirements of the bathroom or washroom design.

Commenting on Viega’s WRAS approved cisterns, Scott James, Managing Director at Viega said: “Viega has invested heavily into the research and development of this topic to ensure our products provide the highest levels of reliability, safety and water quality.”

“We believe it is important to ensure that all our pre-wall systems and WC cisterns have been designed and manufactured to exceed the regulations – and as well-respected testing and accreditation authorities both here in the UK and in the global market, we’re pleased that our products have been confirmed as meeting WRAS and KIWA’s high standards.”


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