| Ventilation
Information
Ventilation
Rates
The
points which affect this are:
(a)
the size of the building or room
(b)
the purpose for which it is used
(c)
the number of occupants
(d)
the type of work they are doing
(e)
heat gains from other sources, e.g., electric motors and
equipment
(f)
the amount of steam, dust and odours from production processes
(g)
whether the customer has any particular temperature requirement
for the building
The
table of recommended ACH given in information leaflets,
and the more extensive and detailed list given for different
types of rooms and buildings is based on a combination of
practical experience and theory, and can safely be used
as a guide for all normal conditions in this country. The
figures should be doubled for work in hot climates or situations,
and increased by 50% if there is a possibility of much tobacco
smoke. How to calculate the number of Ventilation units
required for a room: =
Volume
of room in m³ × ACH required / Volume
of air moved by one unit in m³/h
e.g.
A workshop 25 × 10 × 4.5m requiring 8 ACH
Number
of 300mm impeller units:
25
× 10 × 4.5 × 8 / 1415 (medium speed)
=
6.4 (say 6)
This
would be increased to 7 if Roof Mounted fans were used due
to the lower output (1305 m³/h on medium speed).
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