Domestic water often ‘hotter than necessary’

Press, 20 August 1986, Page 34

Domestic water often ‘hotter than necessary’

PA Wellington Scalding hot tap water in homes puts more than 100 pre-school children in hospital every year with burns, according to the Building Research Association. Surveys in Wellington have found the average domestic hot water temperature is about 74deg., said the latest edition of the association newsletter, “Build.” This was far hotter than necessary for cleaning and hygiene, and extremely dangerous for children and old people, it said.

One second’s exposure at 70deg. caused a fullthickness skin bum on the average adult. Water from a hot tap should be about 55deg., hot enough for all normal household uses and still too hot to put the hands in for any length of time without adding cold water, “Build” said. Most people bath in water about 38deg. and find 40deg. too hot, and water at 50deg. in the kitchen sink is hot enough

for greasy pots and pans. Makers of automatic washing machines and dish washers recommend using water in the 55deg. to 60deg. range for best performance and long life. But the association says turning down the thermostat on gas and electric water heaters to 55deg. is not the answer, and solidfuel wet-back;,; systems cannot i be thermostatically controlled. When families use water in big quantities for repeated showers or baths, setting the thermostat at 55deg. can lead to the water getting too cool as cold water replaces the hot water drawn off. To overcome this problem big families in particular often have thermostats set at about 72deg., and add more cold water at the tap, "Build" says, • ■

It says a safe way to keep the .advantages of a higher-stored water temperature in the cylinder is to use a tempering or mixing valve in. the hot water supply system. These valves automatic-

ally mix in cold water to bring the water temperature down to 55deg., even if the hot water is at boiling point, from a wetback system. “Build” says the Health Department believes the valves .are good safeguards. They not only prevent scalding but; also allow water to be stored at temperatures hot enough to kill any possible Legionnaire’s /.disease, or other hot water bacteria.