Every year, over 300 children aged 0-4 years are admitted to hospitals in New South Wales, Australia, as a result of hot water burns. Most serious scalds are from hot tap water. Over 90% of these serious tap water scalds occur in the bathroom. NSW spends up to 13 million dollars every year treating hot water burns.

For this reason the NSW Code of Practice for Plumbing & Drainage Regulations is about to be amended to require the hot water delivery temperature to all sanitary fixtures, used primarily for ablution purposes, to be limited to 50°C (122° Fahrenheit) in all new buildings.

The current Australian Standard (AS3500.4, 1997) already requires this hot water temperature limit, but it also requires hot water to be stored at no less than 60°C (140° Fahrenheit) to prevent bacterial growth, such as legionella. This is a problem because water at 60°C (140° Fahrenheit) will cause a full thickness (third degree) burn to a child's skin in LESS THAN ONE SECOND.

The reason why AS3500.4 and the NSW Code have nominated 50°C (122° Fahrenheit) as the limit is because at that temperature, although still being hot enough for everyday household tasks, water will take five minutes to cause a full thickness burn to a child's skin - this gives you vital time to act and prevent any injury from occurring.

The only way to meet these requirements is either to install a Tempering Valve, Thermostatic Mixing Valve or a Continuous Flow Hot Water System (minimum storage temperature of 60°C (140° Fahrenheit)) with delivery temperature control.

How does this all affect you as the hydraulic engineer? Obviously, hydraulic engineers play a pivotal role in specifying the minimum design requirements on many large hot water installations, part of which should include a recommendation to limit the hot water delivery temperature at ablution (wash up area) fixtures to 50°C (122° Fahrenheit) to prevent serious scalds.

"What if we don't?" Technically, we are not responsible for other parents' children, but if we don't recommend it to our customers, or at least the builder, and someone is scalded down the track, there is a chance we may be held liable for not carrying out our "duty-of-care" under common law. As plumbers and consultants, our duty-of-care is to let our customers know of the dangers of hot tap water, and advise them of the solutions. By doing this, we protect ourselves from any liability, we give customers the power to make an informed decision about their own safety (or the safety of their customers) and it helps reduce the number of serious scald injuries that occur from hot tap (faucet) water. Do you know how hot your hot water is?

Written by:
Stephen Dennis - Licensed Plumber & Scald Prevention Coordinator, Kidsafe NSW