June 2010 - NHBC Home

Issue 47
June 2010
Regulations changes
A new requirement to Part F means
that where possible, fixed mechanical
ventilation systems require testing and
commissioning. In addition, for both
intermittent and continuous mechanical
ventilation installations, air flow should
be measured. This would include cooker
hoods for kitchens and extract fans to
bathrooms.
Details of this data must then be sent
to the Building Control Body within
five days of completion, adding another
procedure to follow at the completion
stage.
It is also a requirement to hand over
sufficient information to the building
owner in relation to the systems
installed in a new dwelling.
Main changes
As mentioned above the most
significant change is to dwellings
with air permeability of less than
5.0m 3 /(h.m 2 ).
By choosing a continuous mechanical
extract system, Part F 2010 now
removes the need for background
ventilation in dwellings designed with
air permeability rates above 5.0m 3 /
(h.m 2 ). There are also benefits in SAP
2009 for continuous systems, which
may lead designers to adopt whole
house mechanical extract ventilation
systems, possibly including heat
recovery as well, which would maximise
the SAP benefits.
If using passive stack ventilation,
internal pipes should now be sized at
125mm diameter serving all spaces,
an increase from the Part F 2006
requirements.
Published alongside the new
regulations is the Domestic Building
Services Compliance Guide, in which a
new requirement for specific fan power
of less than 0.5 watt/sec applies for
intermittent extract fans.
ACTION
Part J 2010 – Combustion
appliances and fuel storage
systems
Introduction
There are a number of changes in
the new Part J 2010 beyond those
relevant to the new requirements
of Part L 2010, the most significant
change is the requirement for carbon
monoxide alarms in dwellings with fixed
combustion appliances.
There is new guidance on protection to
oil tanks, external vertical flues, access
to concealed flues and additional
ventilation requirements for open
flued appliances in dwellings with air
permeability of less than 5.0m 3 /(h.m 2 ).
Main Changes
There is now a requirement to provide
a carbon monoxide alarm to dwellings
with a fixed combustion appliance,
although the Approved Document
guidance applies only to solid fuel and
biofuel appliances. An alarm should
be sited between 1m and 3m of an
appliance, and be provided with a
suitable long term power supply.
There is guidance on the provision of
access to concealed flues/chimneys.
Inspection hatches should be at least
300mm x 300mm, the number and
location must be sufficient to allow
visual inspection of the flue/chimney
system, and check that:
• The flue/chimney is continuous
throughout its length
• Joints are correctly assembled
and sealed
• The flue/chimney is adequately
supported throughout its length, and
• Any required gradient or drain
points for condensate are provided.
Flues should be designed not to pass
through other dwellings, and access
If you would like to find out more about the changes or would like to
talk about a new project please contact 0844 6331000 and ask for
‘Building Control’ / ‘Colin Blatchford-Brown’, or visit our website
www.nhbc.co.uk/bc
should not adversely affect fire,
thermal or acoustic provisions.
To link in with the requirements in
Part L 2010, for dwellings with air
permeability of less than 5.0m 3 /
(h.m 2 ), there are additional ventilation
requirements for open flued appliances.
For example an appliance with a
rated output up to 50kW should have
850mm 2 /kW of permanent ventilation
for this level of air permeability as
opposed to 550mm 2 /kW for more
leaky dwellings.
Another consideration within Part
J 2010, is the potential requirement
to provide additional containment
protection to oil tanks up to 3500
litres for new dwelling. If a new
dwelling is located within Zone 1 of
the Environment Agency Groundwater
Source Protection Zone (SPZ), then
secondary containment is required to
the oil tank. Further information on the
mapping can be found at
www.environment-agency.gov.uk/
research/library/maps.
And finally there is now clarification on
the recommended flue outlet position
for external vertical flues fixed to an
outside wall, essentially to comply as if
it were a normal chimney or flue above
a pitched roof.
…and building regulation changes
in Scotland
In April the Scottish Government
published the 2010 edition of
the Technical Handbooks. The
amendments to the Scottish
building regulations come into
force on 1 October 2010. The
handbooks can be downloaded
from the Scottish Government
website (http://www.scotland.gov.
uk/Topics/Built-Environment/
Building/Building-standards/
publications/pubtech).
Alternatively hard copies can be
purchased from The Stationery
Office (TSO).
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