top of page

Chimney Requirements

Pre-Installation Guidelines

Before installation of a fireplace, which is to be used for solid fuel or gas,
a flue should be swept, smoke tested and integrity tested to –

  • BS5871 part 3 (for gas) by a registered chimney sweep.

  • BS5440 Part 1

  • BS6461

(Please see our list of recommended chimney sweeps)

This will ascertain the maximum working size for your fireplace opening and will pick up any problems with the flue itself. If the chimney fails an integrity test then it will have to be lined or a fan system will have to be used(please see our fan and flue liner section).

As flues and fireplaces now come under building control you will have to notify your local authority concerning works that are to be carried out. As we are Hetas registered we are qualified to carry out work on chimneys and issue certificates which are passed onto building control so that you do not need to worry about contacting them.


All of our work is done to current building regulations. If you are having a decorative fuel effect fire (DFE) then you may need ventilation in the room of the fire.

Normal appliances covered by –

  • BS5440 Part 1

  • BS6461


We will require a minimum of 100cm Square of purpose ventilation. If the fire is under 7kw input then it may not be necessary to have an air vent installed (see manufacturers guidelines).


If two appliances are installed in the same room the ventilation increases to 235cm Square unless the manufacturer advises differently. The manufacturers we use recommend any fire over 7Kw requires 100cm2 free air and two in the same room would require 5cm2 per Kw over 7Kw. e.g two 9Kw burner in the same room = 18Kw – 7Kw (this allowance is for adventitous air) =11Kw x 5cm2 = 55cm2 free air.

Please note it is illegal for a gas fire to be connected until the ventilation has been installed.

bottom of page