Ventilation Introduction

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.

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.

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