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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.
Reproduced with permission from SAI Global Ltd under Licence 1502-c091.
For all references to clauses, figures and appendices in the table opposite refer to AS/NZS 5601.1:2013 Gas installations.
| 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 |
| d |
From a gas meter (M) (see Note 5) (see Clause 5.11.5.9 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.
Notes:
- 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.