Have you ever stepped in the bath and jumped back out because it was too hot? Hot water safety is a serious issue. Don’t believe us? Check out the stats below:

Did you know nearly 600 people suffer the effects from a severe scald injury in the UK each year? Three quarters of the victims are under the age of 5 and in 2007, 21 people died in the UK after contact with hot tap-water. In light of these accident figures, it was clear something needed to be done and an amendment to the Building Regulations was made in 2010.

Hot Water Supply

Section G3 of approved document G, covers ‘sanitation, hot water safety and water efficiency’, we take a closer look at some of the requirements for hot water safety.

The amendment meant that all new-build homes across England and Wales are required to have devices fitted to baths to limit the temperature of the water to 48 degrees. If intermittent use of the bath is anticipated, provisions should also be made for high temperature flushing to allow for pasteurisation of pipes and outlet fittings.

Section G3 also covers the safety of Unvented Hot Water Systems which in recent years have become very popular.

Factors to consider

Unvented hot water systems are a lot more complicated and have many more parts to them. It is imperative that all unvented hot water systems must:

  • Have a minimum of two independent safety devices
  • A thermostat is required to control the desired temperature of the stored water

It is important to consider whether  the safety devices have access to suitable external areas to allow them to vent outside. This is sometimes a problem in flats where the boiler or storage vessel is positioned internally within the accommodation.

Suitable approaches to this requirement include:

  • A non-self-resetting emergency cut out to disconnect the supply of heat.
  • A temperature and/or pressure relief valve to safely discharge water.
  • Temperature and pressure relief valves must discharge into a tundish which must be visible.
  • The discharge pipe from the tundish should be made of metal or another suitable material and vent externally where there is no risk to persons in the vicinity.
  • All unvented pressurised systems with hot water storage capacity must have some form of third party accreditation.
  • All unvented boiler and hot water storage systems must be installed and commissioned by a person registered with a competent person scheme.

There have been a number of warranty claims for temperature and pressure relief valves discharging into S&V pipes.

Check out Chapter 9 of our Technical Manual for detailed requirements or view approved document G.

By Frzana Ashraf