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Ventilation Catalogue

Ventilation Introduction

Calculating Fan Performance

 
1. Litres/Second (l/s)
2. Cubic Metres/Hour (m3/hr)
     

 To convert from one to other types of
measurement:

If you know Litres/Second (l/s):

l/s x 3.6 = m3/hr.
(e.g. 25 l/s x 3.6 = 90m3/hr)

If you know Cubic Metres/Hour (m3/hr):

m3/hr ÷ 3.6 = l/s
(e.g. 200m3/hr ÷ 3.6 = 55.55 l/s

     
3. ACH (Air changes per hour  

The number of times the total room volume of air is changed each hour.

Refer to the table below for the recommended Air Changes per hour based on the room type.

 

Application Description

Air Changes Per Hour

Bathrooms 11 - 15
Kitchens - (private) 15 - 20
Laundries - (no drier) 6 - 10
Laundries - (with drier) 10 - 30
Toilets 6 - 10
Bedroom 2 - 5
Offices 6 - 10
Cafes 10 - 12
Canteens 8 - 12
Garages 6 - 8
Kitchens - (commercial) 20 - 30
Restaurants 8 - 12
Factories 8 - 10
Stores & Warehouses 3 - 6
Libraries 3 - 5
Classroom 5 - 7

What Effects Fan Performance?
Ventilation Selection Guide

4. Working out the right fan for the job

  1. Calculate the room volume in metres (L x W x H)

  2. Multiply the room volume by the recommended air changes per hour for that room. Always use the higher limit.

  3. The result is the total performance required in cubic metres per hour.

Select a fan with a higher performance
than this figure.

For Example:
What is the best fan for a bathroom that is 2.8m long by 2.8m wide with a ceiling height of 2.4m?

  1. Calculate the volume of the bathroom:
    2.8 x 2.8 x 2.4 = 18.8m3

  2. 11-15 air changes per hour are recommended for a bathroom. Multiply the room volume by 15:
    18.8m3 x 15 = 282m3/hr.

  3. The fan to choose for this bathroom would be a fan that performs at greater than 282m3/hr. A fan that has a performance level of 313m3/hr or higher (e.g. XP150, or SF150) would do this job.

5. Converting Measurements

Converting Measurements table