Some mixer taps are fitted with a thermostatic device which blends the incoming hot and cold water to maintain a constant set temperature. The device can be set to a maximum temperature to prevent scalding. Sometimes the thermostatic blending device is separate from the tap bodies, not built in.

British Standards Institution
Always check for the most up-to-date version of the standard

BS 6700
Specification for design, installation, testing, and maintenance of services supplying water for domestic use within buildings and their cartilages.

BS 7942
Thermostatic mixing valves for use in care establishments. Requirements and test methods

BS EN 1111
Sanitary tapware. Thermostatic mixing valves (PN10). General technical specification.

BS EN 1112
Sanitary tapware. Shower outlets. Shower outlets for sanitary tapware for water supply systems type 1 and type 2. General technical specification.

BS EN 1113
Sanitary tapware. Shower hoses for sanitary tapware for water supply systems type 1 and type 2. General technical specification.

BS EN 1287
Sanitary tapware. Low pressure Thermostatic mixing valves. General technical specification

NHS Model Engineering Specification D 08
Specifies the performance, material requirements and test methods for thermostatic mixing valves for use in care establishments.Is referenced in many other NHS documents.Forms the basis for BuildCert TMV3 approval.


BuildCert
Independent third party approval body responsible for the running of the TMV2 and TMV3 approval schemes. It accepts results from various test houses accredited to BS EN ISO / IEC 17025. 

Water Regulations Advisory Scheme (WRAS)
Approval body responsible for the running of the WRAS approval scheme that certifies product complying to the Water Regulations. It accepts results from various test houses accredited to toBS EN ISO / IEC 17025.

Kiwa UK
Third party independent test house and approval body that undertakes testing to toBS EN ISO / IEC 17025 for fittings for Kiwa UK approval (compliance to Water Regulations), WRAS approval and BuildCert Approval.

WRc-NSF
Third party independent test house that undertakes testing to toBS EN ISO / IEC 17025for fittings for WRAS approval and BuildCert Approval.

BS EN ISO/IEC 17025
General requirements for the competence of testing and calibration laboratories.


BRE IP 14/03
This document provides guidance on the best practice and the suitability of thermostatic mixing valves for the intended application and includes details of legal requirements of particular types of installations.