Schools and nursery schools should ensure children and staff cannot be scalded by hot water by fitting fail-safe thermostatic mixing valves (TMVs) on hot water outlets, says Honeywell, the leading manufacturer of water valves and heating controls. 

TMVs are fitted in the hot and cold supplies to baths, showers and hand basins, to ensure a constant safe temperature at the point of delivery. Regulations demand them on baths and showers, but they should also be fitted to hand basins, advises Honeywell. The scale-resistant Honeywell TM300 is designed for installation on both high and low pressure systems, and certified to the Buildcert TMV2 scheme. It is therefore acceptable in all schools and nurseries except those used by the severely disabled; these require a valve such as the Honeywell TM200VP, rated to the higher TMV3 standard.

The new Honeywell TM300 is one of very few TMV2 valves certified for use with the full range of bathroom appliances: bidets, showers, washbasins and bathtubs. It employs a highly sensitive wax element which controls the hot and cold water inlets to provide a safe uniform temperature between 38 and 46 degrees C, as set by the installer. In addition, it ensures safety by cutting off the hot water inlet automatically if the cold supply fails.

Honeywell explains that the BuildCert TMV scheme recommends the following maximum hot water temperatures for use in all premises: 46 degrees C for bath fill; 41 degrees for showers and washbasins; and 38 degrees C for bidets. 

However, while 46 degrees C is the maximum temperature for water from the bath hot tap, it takes into account the margin of error inherent in TMV valves and temperature loss in metal baths, especially in cold bathrooms. It is not a safe bathing temperature for adults or children. The British Burns Association recommends 37 to 37.5 degrees C as a comfortable bathing temperature for children. In premises covered by the Care Standards Act 2000, the maximum water outlet temperature is 43 degrees C.

For more advice on regulating maximum hot water temperatures, see Building Research Establishment (BRE) Building Bulletin 87 (2nd edition) and The School Premises Regulations/National Minimum Care Standards Section 25.8.