8
Fig. 3.5.1
3.6 Reducing Clearances
The clearances to combustible specified in section 2.0 of this manual, can be safely reduced by following
guidelines specified in AS/NZS 2918:2001 table 3.1 & 3.2.
- Heat shield should be made of non-combustible material like metal or masonry.
- Installed between burner and the combustible wall
- With an air gap behind it and vented top and bottom
- The shield should extend a minimum of 450mm beyond the top of the appliance and extend width-wise so
that unshielded rear clearance is maintained
Clearance factors for heat shield which is within 45 degrees of the vertical
Heat Shield Construction Minimum Air Gap Dimension Clearance Factor
Single layer of continuous material 12mm 0.4
Single layer of continuous material 25mm 0.3
Two spaced layers of continuous material 12mm+12mm 0.2
Clearance factors for heat shield which is more than 45 degrees off the vertical
Heat Shield Construction Minimum Air Gap Dimension Clearance Facto
Single layer of continuous material 12mm 0.8
Single layer of continuous material 25mm 0.6