NSF International manages the TMV2 and TMV3 certification schemes that verify thermostatic mixing valves (TMVs) for domestic and healthcare use. These certifications satisfy the robust performance requirements detailed in the standards BS EN 1111 and BS EN 1287 (domestic) and in the UK Department of Health and Social Care performance specification D 08 (healthcare). NSF International delivers TMV2 testing and certification against the 2017 version of these performance standards.

TMVs can be classified as safety devices and as such they must be initially type tested, installed appropriately, site tested and maintained on-site in accordance with the manufacturer’s instructions.

The NSF TMV2 and TMV3 certification schemes also require certified valves to be performance audit tested within the five-year certification period, and valves requiring continuing certification must be fully re-tested every five years. This re-test ensures that the quality and safety of the valves produced by the manufacturers continue to meet the requirements over time.

At NSF we believe that safety devices put on the market to prevent scalding must be able to demonstrate continuing compliance by undergoing audit testing to ensure they can perform to deliver water at appropriate temperatures. Regular testing can also shed light on unaddressed risk and liability for manufacturers of certified TMVs and avoid unwanted surprises. Manufacturers can use this information to improve the quality of the TMVs they produce and offer the highest safety to their customers.

For the past two decades, the Department of Health (DH) has recognized that NSF testing and auditing requirements meet the strong listed requirements of DH performance specification D 08:

  • Type 3 approval is issued for five years, after which a full re-test is required.
  • Approved Type 3 valves must be performance-audited twice within the five-year approval period with failures reported to DH and systems established to eliminate risks to users.

This commitment is in line with NSF’s global mission to protect human health and safety, that are reflected in other certification testing and auditing requirements.