October 25, 2016

Simplifying Ventilation Regulations

3 Key Points

Sufficient and efficient ventilation is a key safety feature of any combustion appliance but interpreting Building Regulations Part J and HETAS Guidelines can be confusing.  Here we’ve drawn on our experience as the only HETAS Approved ventilation manufacturer to simplify three points we are often asked to clarify.


1:  In a modern airtight property (determined as one built in or after 2008) all solid fuel and gas installations require ventilation calculated from 1kW.  Also, if an older property has had extensive measures to improve air-tightness a dedicated air supply is required from 1kW.


2:  It is a requirement to use a ventilator that has an equivalent area, not free area, calculation.

Here’s a recap of the difference between equivalent area and free area: Equivalent area is calculated by independent testing to BS EN 13141-1:2004, and gives an accurate result of actual air flow through a vent.  Free area is achieved by simply adding the measurements of the smallest venting gaps together to determine an air space.

Regulations changed in favour of equivalent area in 2010, when free area was deemed not give an reliable result of how air flows through cowls, baffles and the changes in shape that most ventilators have.


3:  Tempted to make your own vent?  A home-made vent will not comply to Standards as an equivalent area cannot be determined accurately (see 2).


Should you have any queries regarding these points, or wish to discuss any ventilation issues, please do not hesitate to contact our technical sales team on 01536 511874.

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