By Admin on Fri 10 February 2017 in WRAS/Certifications
格鲁竞技In this article we hope to help explain WRAS approval.
WRAS Solenoid Valve Approval.What Is WRAS Approval? Any water fitting, which when installed, will carry or receive water from the public mains water supply in the UK, must comply with the Water Supply (Water Fittings) Regulations or Scottish by-laws. These require that a water fitting should not cause waste, misuse, undue consumption or contamination of the water supply and must be ‘of an appropriate quality and standard’.
WRAS Approval is the easiest way to demonstrate compliance as it is granted directly by representatives of the water suppliers and is therefore accepted by every water supplier in the UK.
WRAS Product Approval: Whole products such as valves, boilers & showers undergo mechanical and water quality testing. This type of approval demonstrates full compliance with requirements of the regulations and by-laws, provided the fitting is installed according to any conditions given with the approval.
WRAS Material Approval: Non-metallic materials & components, such as rubber sheet material & ‘O’ rings, undergo testing only for their effects on water quality. This type of approval demonstrates that the non-metallic material/component does not itself contaminate the water and therefore satisfies this particular requirement of regulations and by-laws.
WRAS approved solenoid valves for mains water applications are available in most sizes from 3/8" - 1 1/4" BSP thread for 2/2 latching, 2/2 way normally closed and 2 way normally open. WRAS solenoid valve Certification and Approvals are only available to water solenoid valves that fully conform to the water regulations, although interestingly enough this only really applies to the non metallic parts of any solenoid valve such as the elastomer diaphragms, O ring seals, gaskets and other seals that come into contact with the water passing through the solenoid valve and typically must comply to BS6920 (test for water quality).
In the past NBR (Nitrile Buna Rubber) was the accepted standard seal material however EPDM (Ethylene Propylene Diene Monomer) and silicone rubber have now surpassed NBR seals for drinking water as they have a reduced effect on the taste of the water passing through the solenoid valve. Silicone being derived from silicon rather than oil is becoming more popular as a material for use with potable water. The other materials of construction of the solenoid valve such as brass and various grades of stainless steel are of no real concern so long as there are no harmful chemicals present or high content of potentially harmful substances such as lead and are of course totally free from potential internal or external leaks and fit for purpose.
The WRAS approval authority have confirmed that WRAS are seriously concerned about the flood of very cheap imports to the market that in some instances are dangerous/hazardous and are considered a real health and safety concern.
The cheap labour argument is redundant as quality manufacturers, such as RPE and ACL, use semi automated manufacturing processes, R&D cost savings are also irrelevant as these costs have already been met. This means that the cost savings are therefore solely based on cost of material and quality of construction alone.
格鲁竞技 The use of cheap imports will come to an inevitable end in the future when WRAS ban the use of these products within the UK water industry and engineers are made aware of the dangers of using this "cheap" imported equipment. If you are in any doubt you can