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Minimizing Hot Water Burn Risk as a Legal Requirement: Here’s How to Do It

— August 21, 2020

While most people are generally aware of burn risks in the home, many of those without a plumbing background are unaware of what can be (and needs to be) done to manage these risks through the building’s plumbing system.

The tempering valve is a critical cog in any hot water system. Data shows that nearly half of all hospitalized burn cases are a result of contact with heat and hot substances, including hot tap water, and that it’s particularly dangerous to children, with nearly a third of all such hospitalizations occurring in children of the ages of 0-4.

What’s more, these injuries can happen fast. At 70C (158F) a scald will occur in less than one second after exposure. If the temperature is just ten degrees cooler — 60C (140F) — it takes five times as long for the same effect, and at twenty degrees cooler, it takes a full five minutes for the scald to occur. Clearly, there are some very good reasons to control the temperature of hot water.

Why temperature controls matter

Regulation (AS/NZS 3500.4) requires that landlords, real estate agents and homeowners alike have a duty of care responsibility that people on the property have a near-zero percent chance of gaining 3rd-degree burns when using hot water.

What this means is that all new heated water installations should have a temperature that doesn’t exceed 50C (122F) (43.5C or 110.3F in facilities that young children or the elderly principally use — e.g. child care, schools, and nursing homes).

One of the most effective and cost-efficient ways to do this is through the use of a tempering valve that complies with AS 4032.2 and adjusted to an outlet temperature not exceeding 50C (122F). With a reliable tempering valve such as this, you will be able to control the maximum temperature of the hot water that is pushed through the taps.

Are tempering valves all equal?

Hot water tap; image by Kirsten Marie Ebbesen, via
Hot water tap; image by Kirsten Marie Ebbesen, via

Not all tempering valves are of an equivalent standard, and in order to remain compliant with the law (let alone protect those who are on your property), it is important that plumbers use valves that have obtained the WaterMark Certificate.

The WaterMark Certification Scheme is managed by a government body — the Australian Building Codes Board (ABCB) — and this body has a remit covering all plumbing and drainage products. Only products that have been certified can print the trademark on them, and all products that have been certified must print the trademark onto them.

This Scheme is well-known for being rigorous, requiring annual audits, and an extensive testing process on top of a six-step process to obtain the certification in the first place. The tests determine the quality of the plumbing or drainage product, its resilience, its safety, and the conditions under which it can operate (or potentially will fail), and anything certified with the WaterMark Certificate can be relied on to meet the regulatory standards required of tempering valves.

In addition, there are two common types of tempering valve that have different applications in the market:

  • High performance or solar rated. These have a yellow or orange cap and are designed for solar hot water units or commercial boiler systems – essentially, those high-pressure environments where the water temperature can otherwise soar.
  • Standard performance. These have a blue, green, or black cap and are designed for standard systems, gas and electric storage units, and heat pumps.

Do tempering valves last forever?

Even those valves that meet the most stringent requirements can wear out – it will take many years of use, but over time you may notice some changes in your hot water system, such as:

  • Reduced hot water pressure
  • Lukewarm or cold water coming from the hot tap
  • A visible leak from the valve attached to the hot water system

Any of these are indications that it’s time to replace the tempering valve. It’s unlikely that a failing valve will go the other way and the tap will become dangerous to operate (initially), but if it fails completely it can cause more dangerous conditions. You should, of course, have a plumber replace a tempering valve. Never do it yourself.

Summing up

For plumbers and other professionals, it’s important to explain the tempering valve to the client, so that they understand what their legal responsibilities are, the function and role of the tempering valve, and the signs to look out for that there’s an issue with it, or the need to replace it. 

It’s also important to make it clear that you’re using WaterMark Certified valves, and should the valve need to be replaced, the replacement will likewise be WaterMark Certified. While most people are generally aware of burn risks in the home, many of those without a plumbing background are unaware of what can be (and needs to be) done to manage these risks through the building’s plumbing system.

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