Gas information sheet 26: Flue clearances
This information sheet has been prepared to assist gasfitters in providing the correct flue clearances for gas appliances. The location of the flue terminal of a balanced flue appliance, room-sealed appliance, a fan-assisted appliance or an appliance designed for outdoor installation shall comply with the figure below.
For further information contact the Gas Safety Technical Information Line on 1800 652 563.
|Ref.||Item||Minimum clearances mm|
|Natural draft||Fan assisted|
|a||Below eaves, balconies and other projections:|
|Appliances up to 50 MJ/h input||300||200|
|Appliances over 50 MJ/h input||500||300|
|b||From the ground, above a balcony or other surface *||300||300|
|c||From a return wall or external corner *||500||300|
From a gas meter (M) (see Note 5)
(see Clause 18.104.22.168 for vent terminal location of regulator)
|1 000||1 000|
|e||From an electricity meter or fuse box (P)† (see Note 5)||500||500|
|f||From a drain pipe or soil pipe||150||75|
|g||Horizontally from any building structure * or obstruction facing a terminal||500||500|
|h||From any other flue terminal, cowl, or combustion air intake *||500||300|
|j||Horizontally from an openable window, door, non-mechanical air inlet, or any other opening into a building with the exception of sub-floor ventilation:|
|Appliances up to 150 MJ/h input*||500||300|
|Appliances over 150 MJ/h input up to 200 MJ/h input*||1 500||300|
|Appliances over 200 MJ/h input up to 250 MJ/h input*||1 500||500|
|Appliances over 250 MJ/h input*||1 500||1 500|
|All fan-assisted flue appliances, in the direction of discharge||—||1 500|
|k||From a mechanical air inlet, including a spa blower||1 500||1 000|
|n||Vertically below an openable window, non-mechanical air inlet, or any other opening into a building with the exception of sub-floor ventilation:|
|Space heaters up to 50 MJ/h input||150||150|
|Other appliances up to 50 MJ/h input||500||500|
|Appliances over 50 MJ/h input and up to 150 MJ/h input||1 000||1 000|
|Appliances over 150 MJ/h input||1 500||1 500|
* Unless appliance is certified for closer installation.
† Prohibited area below electricity meter or fuse box extends to ground level.
- Where dimensions c, j or k cannot be achieved an equivalent horizontal distance measured diagonally from the nearest discharge point of the terminal to the opening may be deemed by the Technical Regulator to comply.
- See Clause 6.9.4 for restrictions on a flue terminal under a covered area.
- See Figure J3 for clearances required from a flue terminal to an LP Gas cylinder. A flue terminal is considered to be a source of ignition.
- For appliances not addressed above acceptance should be obtained from the Technical Regulator.
- Minimum clearances d and e also apply to any combustion air intake openings of appliances.