This British Standard specifies requirements for
two classes of wall ventilating units as follows:
class 1:airbricks for useinexternal walls;
class 2: wall ventilators or gratings for internal
use.
Some typicalexamples of designs are shown
in Figure 1,Figure 2 and Figure 3. Other patterns
may however be supplied, provided they conform to
the requirements of this standard.
Guidanceon the information to be supplied by the
purchaser when ordering is given in Annex A.
Thisstandard contains no requirements for the
following properties.
Durability (other t hanresistance t o colour change of thermoplastics materials). It is recommended that
where there is uncertainty about durability then
expert advice should be sought.
a) Fire properties s o tf hermoplastics materials. The general useof thermoplastics airbricks, wall
ventilators and gratings in isolation in masonry
is considered t ohave aninsignificant effect on t he
spreadoffire.However, special consideration
should begiven to the useof thermoplastics air
bricks where it is intended togroup a number of
them together, e.g. for boiler house ventilation.
b) Compressive strengthof thermoplastics air
bricks. The general useof theseinisolation is
considered tohave tohave aninsignificant effect on masonry strength. However, special consideration should begiven to their use where
it is intended t ogroup a number o ft hem t ogether,
e.g. for boiler house ventilation.