Legal
Don’t get into hot water
Changes to Building Regulations Part G, covering water supply
in buildings, come into force next month. Hywel Davies looks
at some key new provisions that come into effect on October 1
M
any in the industry are busy thinking of the Building Regulations. The calculator uses
about proposed changes to the capacity or flow-rate details of the toilets, baths and
requirements of Parts L and F of the showers, sinks and washbasins, appliances and
Building Regulations. But Part G, on water softeners, and calculates the daily usage per
water supply to buildings, has recently undergone person. New homes must not exceed 125 litres per
major revision, with several new requirements person per day, although the Code for Sustainable
introduced. The previous three requirements are Homes requires lower consumption (120 litres at
replaced by six requirements, which come into levels 1 or 2, down to 80 litres at levels 5 or 6). The
force from 1 October 2009. Regulation specifically addresses “consumption of
The six relate to: cold water supply (G1); water wholesome water”, so it can be anticipated that this
efficiency (G2); hot water supply and systems (G3); will begin to drive wider use of recycled water in
sanitary conveniences and washing facilities (G4); new developments.
bathrooms (G5); and kitchens/food preparation A further new Regulation, 20E, requires that the
areas (G6). calculation is submitted to building control, along
The main changes are a new limit of 125 litres with the carbon emissions calculations introduced
per person per day on provision of “wholesome” under Regulation 20D.
water in new homes, or those created by a G3 is the most detailed requirement, and also has
“material change of use”. New rules cover use of the most comprehensive guidance to accompany it.
“non-wholesome” water to flush toilets, safety It now addresses all hot water supply in buildings,
KEY DOCUMENTS
of hot water systems and measures to prevent whether from vented or unvented systems, and
CIBSE Commissioning Code M:
bathwater from exceeding 48 deg C. A new whether from conventional water heating sources,
Commissioning
requirement is for sinks in food preparation areas. or from solar heating sources. There is explicit Management – this is the
G1 requires provision of “wholesome” water for guidance on the use of additional heat sources
approved methodology
drinking, washing and food preparation. However, to ensure that water heated by solar systems is
for management of the
commissioning process for
it also introduces a provision, which is optional, to treated to restrict microbial growth. There is
fixed building services.
use “non-wholesome” water – recycled greywater also a reference to the CIBSE Domestic Building
or water from industrial processes, harvested Services Guide to solar water heating, as a source of
CIBSE Domestic Building
Services Panel:
rainwater or water from springs and boreholes – authoritative guidance on solar thermal systems.
Solar Heating Design and
for toilet flushing or irrigation. There is guidance G3 also introduces a requirement for hot water
Installation Guide. Covers
on assessing the feasibility and risk of using such systems to be commissioned, and brings in limits predominant types of systems
supplies, as well as on the installation, marking, on water temperatures when water leaves storage
and notes their advantages
maintenance and operation of such systems. tanks and when it is discharged into baths. Where
and disadvantages. The broad
range of systems covered
G2 covers “reasonable provision” for the water in a domestic hot water store is capable of
will assist those engaged in
installation of water-efficient fixtures and fittings. exceeding 80C in normal operation, then the store
repair and maintenance work
From October, not only will new dwellings need must be so designed that it does not allow water to understand the principles
a SAP calculation for carbon emissions, but into the distribution at temperatures exceeding
of operation of existing
also a new calculation of the potential water 60 deg C.
equipment, as well as guide
the design and installation of
consumption, using the government’s “Water Engineers need to be aware of these imminent
new systems.
Efficiency Calculator for New Dwellings”. This changes, as they will have an impact on services
The water efficiency calculator
describes the approach that must be used when provision in both homes and non-domestic
can be downloaded from
calculating the potential consumption per person, buildings. l
www.planningportal.gov.uk/
in order to demonstrate that the dwelling meets
uploads/.../water_efficiency_
the new requirement set out in Regulation 17K
Hywel Davies is technical director of CIBSE.
calculator.pdf
22 CIBSE Journal September 2009 www.cibsejournal.com
CIBSEsep09 pp22 legal.indd 22 20/8/09 19:08:06
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