|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 × 81415 (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).|