|
Section 2
|
|
|
2.1 _ This Approved
Document shows two main ways of complying with the requirement:
a. _ by following
the provisions set out in paragraphs 2.2 to 2.5 or by
following the alternative approaches set out in paragraph
2.6; and where relevant,
b. _ for specialist
activities by following the provisions set out in paragraph
2.7; and
c. _ for car parks
by following the provisions set out in paragraph 2.8
or the alternative approach set out in paragraph 2.9;
AND FOR MECHANICAL VENTILATION/AIR-CONDITIONING
PLANT
d. _ by following
the provisions set out in paragraphs 2.11 to 2.13 or
the alternative approaches set out in paragraph 2.14
for the design of mechanical ventilation/air-conditioning
plant and the provisions set out in paragraphs 2.15
and 2.16 for access for maintenance; and
e. _ where a mechanical
ventilation or air-conditioning system serving more
than 200m2 is installed by following the provision in
paragraph 2.17.
|
|
General
2.2 _ The requirement
will be satisfied if the
following provisions are made in accordance with
Table 2 for:
a. _ 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. _ background
ventilation. A ventilation opening (or openings),
eg trickle ventilators, air bricks with a "hit
and miss" ventilator, suitably designed opening
windows (see Diagram 4). The ventilation opening(s)
should be adjustable and located (typically 1 .75m above
floor level) so as to avoid discomfort due to cold draughts
and to prevent rain ingress; and
c. _ extract
ventilation. By mechanical extract ventilation operated
manually and/or automatically by sensor or controller.
|
|
Table 2
Ventilation of rooms containing openable windows ( ie
located on an external wall ) |
|
| Room |
Rapid ventilation
(eg opening windows)
|
Background ventilation
(1)
(see Diagram 3) |
Extract ventilation
fan rates (3,4)
|
|
| Occupiable room (1) |
1/20th of floor area |
for floor areas:up to 10m2 -
4000 mm2 greater than 10m2 - at
the rate of 400/m2 of floor area |
---
|
|
Kitchen (2)
(domestic type) |
opening window
(no minimum size) |
4000 mm2 |
30 litres/second adjacent to
a hob or 6O litres/second
elsewhere
|
|
|
Bathrooms
(including shower-rooms ) |
opening window
(no minimum size) |
4000 mm2 per bath/shower |
15 litres/second
per bath/shower |
|
Sanitary
(separate from bathroom)
|
1/20th of floor area, or (and/or washing
facilities) mechanical ventilation at
6 litres/second per WC or 3 air
changes per hour
|
4000 mm2 per WC |
- |
|
|
Notes:
1. For specific rooms designed for heavy smoking,
such as rest rooms where smoking is permitted, see an
alternative to a mechanical extract fan for domestic
paragraph 2.7(e).
2. A domestic type kitchen is one where the
appliances and usage is of a domestic nature. This provision
is not intended to cover commercial kitchens, see paragraph
2.7(f)
|
|
3. PSV as described in paragraph 1 .2(c)ii can be
used as an alternative to a mechanical extract fan for
domestic type facilities.
4. Where an open-flued appliance is provided
in a building with mechanical extract, the spillage
of flue gases could occur. The open-flued appliance
needs to be able to operate safely whether or not the
fan is running and guidance is provided in paragraph
1.8 and Approved Document J.
|
xx
