Hot water safety
Contents |
[edit] Introduction
Hot water is considered an essential building service. The two components of a typical hot water system are:
- The central heating system which supplies hot water to radiators located around a building.
- Domestic hot water supplied to taps and sometimes to appliances.
The water and pipework used for these two systems are not mixed, although both share some of the same components.
[edit] Hot water safety under Section G3 of Approved Document G
Section G3 of Approved Document G defines ‘domestic hot water’ as water that has been heated for cooking, food preparation, personal washing or cleaning purposes. Under Approved Document G, the “suitable installation for the provision of heated wholesome water or heated softened wholesome water” is required.
Section G3 provides specific guidance regarding hot water safety for sanitaryware (including washbasins, sinks, baths, showers and bidets) and other water storage systems (including cisterns or other water supply vessels). Under Section G3, systems should incorporate precautions to:
- Prevent the temperature of the water stored in the vessel at any time exceeding 100C.
- Ensure that any discharge from safety devices is safely conveyed to where it is visible but will not cause a danger to persons in or about the building.
Furthermore, the hot water supply to any fixed bath must be so designed and installed as to incorporate measures to ensure that the temperature of the water that can be delivered to that bath does not exceed 48C.
Section G3 provides specific information on additional areas, including
Guidance:
- Performance
- General
- Provision of hot water supply
Design and installation of directly or indirectly heated hot water storage systems:
- General
- Vented hot water storage systems
- Unvented hot water storage systems – all systems
- Unvented hot water storage systems – systems up to 500 litres capacity and 45kW power input
- Unvented hot water storage systems – systems over 500 litres capacity or over 45kW power input
Safety devices:
- Non-self-resetting energy cut-outs
- Temperature and pressure relief devices
Discharge pipes from safety devices:
Prevention of excessive temperatures
Prevention of scalding
Commissioning of fixed building services
Notice of completion of commissioning
[edit] Further guidance
In addition to the information in Approved Document G, further guidance for hot water storage system design and installation can be found in three British Standards Institution (BSI) documents:
- BS EN 806-5:2012 Specifications for installations inside buildings conveying water for human consumption. Operation and maintenance.
- BS 8558:2015 Guide to the design, installation, testing and maintenance of services supplying water for domestic use within buildings and their curtilages.
- BS EN 12897:2006 Water supply.
[edit] Related articles on Designing Buildings
- A guide to installing thermostatic mixing valves: what, why and how.
- Approved Document G.
- Building services.
- Hot water.
- Hot water safety in health and social care settings.
- Plumbing.
- Stagnation point.
- Tap.
- Water heating.
[edit] External resources
- BSI, BS EN 806-5:2012 Specifications for installations inside buildings conveying water for human consumption. Operation and maintenance.
- BSI, BS 8558:2015 Guide to the design, installation, testing and maintenance of services supplying water for domestic use within buildings and their curtilages.
- BSI, BS EN 12897:2006 Water supply.
- Gov.uk, Approved Document G.
Featured articles and news
Designing sustainability and performance into buildings
Specifying and selecting sustainable resilient timber products.
Modifying wood to improve resistance to decay and movement.
A last minute, long look for built environment professionals.
The architecture of creative reuse. Book review.
Installing solar panels on listed structures.
Sustainable development global goals, history in progress?
"Unless we act now, the 2030 Agenda will become an epitaph for a world that might have been."
Mike Kagioglou FCIOB named CIOB President
'Sustainable Development Goals must be focus for construction'
BSRIA training; a look at what's on offer
From energy management to compliance training.
TESP video warns to beware of rogue trainers.
Highlighting the slippery tactics of non-approved providers.
New Building Safety Wiki launched
Boosting awareness and understanding of the new fire safety regime.
New playbook on AI in construction published by CIOB
How to get to grips with, and the best from AI.
Digital Construction Report NBS
BIM, cloud, off-site, immersive tech, AI, twins and sustainability.
ECA learning zone and industry focus video series
From updates and amendments to circular economy, emergency lighting and much more.