Section 1


Introduction to provisions

1.1 _ This Approved Document shows two main ways of complying with the requirement by:

a. _ following the provisions set out in paragraphs 1.2 to 1.8; or

b. _ alternative approaches set out in paragraph 1.9.

_ The performance will be achieved if the following provisions are made in accordance with Table 1:

a. _ for rapid ventilation, one or more ventilation opening with some part of the ventilation opening at high level (typically 1 .75m above the floor level), eg an opening window; and

b. _ for background ventilation, a ventilation opening (or openings), eg trickle ventilators, air bricks with a “hit and miss” ventilator, or where appropriate, suitably designed opening windows (see Diagram 1). The ventilation opening(s) should

be reasonably secure, adjustable and located (typically 1 .75m above the floor level) so as to avoid discomfort due to cold draughts and to prevent rain ingress; and

c. _ for extract ventilation, either by:

_ _i.mechanical extract ventilation operated
_ _manually and/or automatically by sensor or
_ _controller; or

_ _ii. passive stack ventilation operated manually
_ _and/or automatically by sensor or controller
_ _(see note 2 to Table 1); or

_ _iii. an appropriate open-flued heating appliance
_ _(see note 3 to Table 1).

For extract ventilation with open-flued appliances the guidance in paragraph 1.8 should be followed.

1.3 _ For kitchens, utility rooms, bathrooms and sanitary accommodation not containing openable windows see paragraph 1.5.

1.4 _ If the ventilation of a habitable room is through another room or space, see paragraphs 1.6 and 1.7

Table 1
Ventilation of rooms containing openable windows ( ie located on an external wall )
Room (6)  

Rapid ventilation
(eg opening windows)

Background ventilation (1)
(see Diagram 1)  
Extract ventilation fan rates
or passive stack (PSV)(2X3)
Habitable room 1/20th of floor area 8000 mm2
Kitchen     opening window
(no minimum size)
4000 mm
30 litres/second adjacent to
a hob or 6O litres/second
elsewhere (4) or PSV
Utility room (5)  opening window
(no minimum size)
4000 mm 30 litres/second or PSV
(with or without WC)
opening window
(no minimum size)
4000 mm 15 litres/second or PSV
Sanitary accommodation
(separate from bathroom)
1/20th of floor area or mechanical
extract at 6 litres/second
4000 mm -

1. _ As an alternative approach to the provisions listed in Table 1, the overall provision for background ventilation for the dwelling should be equivalent to an average of 6000mm2 per room for the rooms listed in Table 1, with a minimum provision of 4000mm2 in each room.

2. _ Passive stack ventilation provided in accordance with BRE Information Paper 13/94 or with appropriate third party certification, such as a BBA certificate, would be satisfactory.

3. _ Open-flued appliances take their combustion air from the room or space in which they are installed and so contribute to the extract ventilation when in operation.

They can also be arranged to provide adequate extract ventilation when not firing. For instance no additional extract ventilation would be necessary to satisfy the requirement if:
_ a. the solid fuel open-flued appliance is a primary source of heating, cooking or hot water production; or
_ b. the open-flued appliance has a flue with a free area at least equivalent to a 125mm diameter duct and the


appliance’s combustion air inlet and dilution air inlet are permanently open, ie there is a path with no control dampers which could block the flow or the ventilation path can be left open when the appliance is not in use (see also paragraph 1.8).

4. _ Mechanical extract ventilation should be rated:
_ a. not less than 30 litres/second, (i) when incorporated within a cooker hood or (ii) when located near the ceiling within 300mm of the centreline of the space for the hob and under humidistat control; or
_ b. rated not less than 60 litres/second when located elsewhere.

5. _ For the purpose of the Building Regulations, provision for ventilation need not be made for a utility room which is accessible only from outside the building.

6. _ Where rooms serve a combined function as defined in Table 1, such as a kitchen-diner, the individual provisions for rapid, background and extract ventilation need not be duplicated provided that the greatest provision for the individual functions is made from Table 1.

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