ENGLISH
SCOTLAND: STANDARD 3.14 VENTILATION,
TECHNICAL HANDBOOK - DOMESTIC -
ENVIRONMENT (2015)
The Building Standards technical handbooks provide
guidance on achieving the standards set in the Building
(Scotland) Regulations 2004.
1.
Calculate the volume of the heated envelope of the
dwelling in cubic metres and then calculate the air
volume at 0.5 Air Changes Per Hour (ACPH). This will
give the required rate in metres cubed per hour (m
3
/h).
To convert this value to litres per second (l/s) divide by
3.6.
m
3
of dwelling x 0.5 ACPH = low rate in m
3
/h
low rate in m
3
/h / 3.6 = low rate in l/s
This volumetric airflow needs to be split proportionately
by room size of the wet rooms within the dwelling.
Calculating the High Rate (boost)
The boost is calculated at a minimum of +25% of the
low rate and a maximum of +50% of the trickle rate.
low rate in m
3
/h + 25% = high rate (boost) in m
3
/h
or
low rate in l/s + 25% = high rate (boost) in l/s
This volumetric airflow needs to be split proportionately
by room size of the wet rooms within the dwelling.
Tab. 3 Example ventilation Solution 4: - Continously Operating Balced supply and Extract
(with or without Heat Recovery)
Apartment
Kitchen
Bathroom /
Shower
Toilet
Utility room
Openable
Ventilator
1/30th floor area
[1]
1/30th floor area
[1]
Trickle
Ventilator
N/A
N/A
N/A
N/A
N/A
Continously
Operating
Mechanical
Extract [2]
0.5 ACPH
minimum
0.5 ACPH
minimum
and 25 -50%
boost
0.5 ACPH
minimum
and 25 -50%
boost
0.5 ACPH
minimum
0.5 ACPH
minimum
Note:
[1] openable ventilators (generally windows)
provide summer cooling, rapid ventilation and for use
when mechanical system switched off.
[2] Based on whole house ventilation rate.
17
