Ventilation Systems
Fitting extraction fans and ventilation systems has long formed part of the work carried out by electrical contractors. It is commonplace to install extraction fans in walls, cooker hoods, or even complex whole-house systems on a new build property.
Since the introduction of Part P building regulations in 2005, the technical performance of extraction equipment and also the areas in which it is to be installed needs consideration to ensure Part P compliance.
Changes were made to the HM Government Approved Document F – Means of ventilation, which came into effect on the 1st October 2010. Although the fundamental requirements for domestic ventilation remained unchanged additional focus concerning the need to commission and test certain systems was published.
Why test a ventilation system?
The performance of a ventilation system will vary depending on the manner in which it has been installed, but also on the manufacturer’s specification of the equipment installed.
The specifications set by the fan manufacturer boast performance figures recorded with the equipment running in a perfect scenario, more often than not in a controlled laboratory environment. Obviously the published figures will vary somewhat by the time the equipment is installed into a property and connected to a duct system. ‘Real life’ variables such as weather and environmental changes can also have an effect on the extraction rates of the fan.
Having taken the above into consideration and with new buildings needing to be more and more air tight in order to increase energy efficiency, a ventilation system will need testing within a new build property.
How to test a ventilation system?
A hand held anemometer or airflow meter can be used at either the inlet or extraction point in order to measure the flow rate of a ventilation system in order to see if the system meets the published Part F requirements.
What are the Requirements?
The basic performance figures that Approved Document F requires are as follows:
The test results obtained from the anemometer or airflow meter may reveal some interesting findings. It could possibly be that the ventilation system does not meet the requirements as per above.
This being said, it needs to be understood that the ventilation performance can be greatly influenced by many factors, including:
- The specification of the fan unit;
- The specification, route length, size and installation conditions of ducting;
- Recirculated air that is able to get into the extraction environment;
- Recirculated air that is able to get into the building in general.