Recommended Air Changes

Recommended Air Changes

Calculating the right fanCalculating the right fan

In order to provide sufficient ventilation it is essential that the correct fan is selected for the application.

1. Firstly calculate the volume of the room (length x width x height)

2. Multiply this by the recommended number of air changes per hour, the total will give the fan performance required, expressed in m3/hr

3. Find the fan that matches the performance and application

Recommended Air Changes per HourRecommended air changes

Assembly plants4-8
Auditoriums6-8
Bakeries20-30
Banks4-8
Bathrooms5-10
Battery rooms*5-10
Bedrooms2-4
Billiard rooms6-8
Boiler rooms15-30
Cafes10-12
Canteens8-12
Car parks5-8
Celalrs3-10
Changing rooms6-8
Churches1-3
Cinemas and theatres8-12
Classrooms5-7
Cloakrooms4-6
Club rooms12-15
Compressor rooms10-12
Conference rooms6-12
Dairies8-12
Dance halls12-15
Dark rooms10-15
Dye rooms*15-30
Electrplating shops10-12
Engine rooms15-30
Entrance halls3-5
Factories8-10
Foundries10-20
Garages6-8
Glass houses25-60
Gymnasiums6-10
Hairdressers10-15
Hospitals (Sterilising)15-25
Hospital wards6-8
Kitchens (Domestic)15-25
Kitches (Commercial)20-30
Laboratories*6-15
Launderettes10-15
Lecture theatres5-8
Libraries4-5
Living rooms3-6
Meeting rooms5-10
Mushroom houses6-10
Offices6-10
Paint rooms*10-20
Plant rooms10-40
Pubs15-25
Recording studios10-12
Restaurants8-12
Retail shops4-8
School rooms5-7
Sheet metal shops8-12
Shower rooms15-25
Supermarkets8-15
Spray booths*25-50
Stores and warehouses3-6
Squash courts4-8
Swimming pools10-15
Tanneries*5-15
Toilets (Domestic)6-10
Toilets (Public)8-15
Utility rooms15-20
Waiting rooms4-6
Welding shops20-30
Workshops6-10
  
* These rooms may require an explosion proof, flame proof or anticorrosive fans. Please ask for our technical team on 08456 44 6001 to discuss your specific requirements

Alternatively, if your working with Litres per second then here is a simple example:

Imagine a room measuring 3 metres in all directions, with a single extractor fan for ventilation.

The volume of your room is 3m x 3m x 3m = 27m³. There are 1000 litres in a cubic metre, so another way to state the volume of your room is 27,000 Litres.

If this room requires one air change per hour, the fan will have to move 7.5 Litres of air a second. (27,000 / 60 / 60, or 27,000 Litres divided by 60 minutes in an hour, divided by 60 seconds in a minute)

If the room needed two air changes per hour, we’d need 15 Litres per second to pass through the fan. (27,000 x 2 / 60 / 60)

So when thinking of replacing or installing ventilation, you’ll need your tape measure and a calculator handy. Remember if you’re not shifting enough air, you’re not going to solve that mould, smell or moisture problem.

The above information is offered as guidance only. Discuss your specific requirements with our technical team on 08456 44 6001.

 

 

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