Residential UV Regulations
Residential applications do not simply indicate a private home, but can include a wide variety of different markets which can be deemed ‘residential’. These can include point-of-entry (POE) applications for multi-family apartments as well as other non-transient, non-community water systems with flow rates from 0.5 USGPM to 50 USGPM. Private homes do not typically fall under the drinking water regulations, depending on where the home is located, however any residential-type system that feeds water to the public does and therefore must comply. Ultra-violet equipment installed in such applications must have undergone third party testing in order to prove its performance and this testing must follow a specific procedure or validation protocol. The validation protocol required will depend on the application and the regulation that that specific application must comply with. The most recognized UV validation protocols for residential-type applications are NSF 55 Class A, ETV, WQA Gold Seal or the German protocol DVGW 294.
NSF 55 Class A:
NSF 55 is a UV disinfection validation protocol that is used to prove the performance of the UV equipment under specific conditions. This protocol is defined as a residential protocol and only tests up to a maximum flow rate of 50 USGPM.
NSF’s web link is www.nsf.org
The NSF 55 protocol requires the UV system to deliver a dose of 40 mJ/cm² at the system’s alarm set-point. The alarm set-point of a UV system is achieved during testing by lowering the UV transmittance (UVT) of the influent water to a minimum UVT level to a minimum of 70%. What NSF wants to ensure is that the dose being delivered by the system never falls below 40 mJ/cm². This protocol also includes detailed testing on the materials that make the equipment itself, ensuring that nothing is being leached into the water as well as pressure and hydraulic testing. This protocol is widely accepted across North America and some parts of Europe.
The ETV validation protocol is one that can be described as an independent validation of the claims made about the performance of the environmental benefits of an innovative technology. This program offers not a label of a specific validation but a statement of verification of the equipment for use in business-to-business relations. ETV can be used to prove compliance with any relevant legislation or it can be used to convince others of performance claims, like regulators or potential customers of a certain technology.
How ETV works is a four step process:
- STEP 1: Proposal phase - the technology is explained and any existing test data is examined at this time as well as the initial claims that have been made for this product
- STEP 2: Specific protocol preparation phase - the protocol that the manufacturer wishes to follow is determined
- STEP 3: Assessment and verification phase - the testing of the equipment and gathering of results is carried out
- STEP 4: Publication phase - the data is published and signed off on by the third party expert
WQA Gold Seal:
The WQA Gold Seal program was developed by the WQA (Water Quality Association) for testing of all products that come into contact with drinking water. This program certification complies with all requirements of the standards used throughout the drinking water industry (WQA, NSF, APAMO, ASME and ASTM). The products that display the Gold Seal mark provide assurance to consumers and regulatory agencies that products have been tested and meet the requirements of the standards. This is an accredited program. WQA’s web link is www.wqa.org
DVGW is a German standard for products that come into contact with drinking water. This standard is similar to the NSF 55 standard with some significant differences. Under the DVGW standard the equipment being tested must comply with the rigors of the protocol which include a specific dose delivery of 40 mJ/cm² as well as stringent design specifications of the system’s UV sensor.
CSA B483.1 is a Canadian standard that was created by the Canadian Standards Association (CSA) in order to develop additional requirements, outside the existing NSF/ANSI standards, to meet plumbing, mechanical, and electrical requirements for drinking water treatment components and complete systems. Products under this scope include POU and POE plumbed systems and POU non-plumbed systems.