Open Fireplaces and Chimneys.

Original Article
February 10th, 2018


The number of chimneys/fireplaces affects the ventilation rate assumed in the SAP calculation and all open chimneys/fireplaces should be included in the open fireplace count . 

‘No of open fireplaces’ is a straight forward count of the open fireplaces in a property. The definition of an open fireplace/chimney is a vertical duct with a flue diameter of at least 200 mm or its equivalent. The following are not counted as open fireplaces:

·         Any open flue that is less than 200 mm diameter

·         A permanently blocked up fireplace, even if fitted with an airbrick

·         Any heating appliance with controlled flow of air supply i.e. appliance has closing doors

·         A flexible gas flue liner sealed into the chimney (because the diameter is less than 200 mm)

·         A chimney fitted with a damper enabling the flue to be mechanically closed when not in use

Above: The solid fuel stove fitted to the fireplace means that it is not open for RdSAP. The stove restricts air flow up the chimney.

Above: A damper which enables the air flow up the chimney to be closed off when fireplace is not in use. This is fitted at base of chimney.

Temporary means of blocking a flue, e.g. cardboard, newspaper bungs and similar, are not a permanent means of controlling ventilation and therefore the chimney is counted as an open fireplace.

Open fireplaces and heating

Other than open fireplaces in bedrooms, an open fireplace should be considered in the heating assessment if it is capable of supporting an open fire (that includes having a grate suitable for holding fuel), even if no fuel is present (Convention 5.02). The fuel to be specified is smokeless fuel in smoke control areas and dual fuel outside smoke control areas.

Open fires in bedrooms are disregarded when identifying the heating systems (main and secondary) and heated habitable room count. They are counted in the number of open chimneys (for ventilation), if appropriate.

Above: When recorded the heating present in a property, open fireplaces should be considered if they are capable of supporting an open fire.