NT Part 13.7 Services
NT 13.7.1 Application of Part 13.7New for 2022
This Part applies to—
- a Class 1 building; and
- a Class 10a building.
NT 13.7.2 Insulation of servicesNew for 2022
Thermal insulation for central heating water piping and heating and cooling ductwork must be—
- protected against the effects of weather and sunlight; and
- able to withstand the temperatures within the piping or ductwork.
The central heating water piping provisions apply to systems designed to heat the building via water, such as a hydronic heating system.
NT 13.7.3 Central heating water pipingNew for 2022
- flow and return piping that is—
- within an unventilated wall space; or
- within an internal floor between storeys; or
- between ceiling insulation and a ceiling; and
- heated water piping encased in a concrete floor slab (except that which is part of a floor heating system), must in all climate zones, have a minimum material R-Value of 0.4.
- The insulation levels in NT Explanatory Table 13.7.3 are typical examples of materials that can be used to insulate central heating water R-Value. Other methods are available for meeting the Total R-Values required.
Piping within a timber member, such as that passing through a wall stud, is considered to have sufficient insulation.Insert NT table (13.7.3 (explanatory)) 13.7.3 as follows:
NT Table 13.7.3 (explanatory): R-Value of the insulation used for smaller diameter piping Insulation R-Value 9 mm of closed cell polymer 0.4 13 mm of closed cell polymer 0.6 19 mm of closed cell polymer 0.9 25 mm of closed cell polymer 1.3 25 mm of glasswool 1.3
NT 13.7.4 Heating and cooling ductworkNew for 2022
- achieve the minimum Total R-Value in accordance with NT Table 13.7.4; and
- use thermal insulation material in accordance with AS/NZS 4859.1; and
- be sealed against air loss—
- by closing all openings in the surface, joints and seams of ductwork with adhesives, mastics, sealants or gaskets in accordance with AS 4254 for a Class C seal; or
- for flexible ductwork, with a draw band in conjunction with a sealant or adhesive tape.
- be protected by an outer sleeve of protective sheeting to prevent the insulation becoming damp; and
- have the outer protective sleeve sealed with adhesive tape not less than 48 mm wide creating an airtight and waterproof seal.
|Element||Minimum R-Value for ductwork and fittings|
|Evaporative cooling system||Heating-only system or refrigerated cooling-only system||Combined heat and refrigerated cooling system|
The minimum material R-Value required for ductwork may be reduced by 0.5 for combined heating and refrigerated cooling systems if the ducts are—
- under a suspended floor with an enclosed perimeter; or
- in a roof space that has an insulation of greater than or equal to R0.5 directly beneath the roofing.
- Insulation for refrigerated cooling ductwork should have a vapour barrier to prevent possible damage by condensation.
- The insulation levels in NT Explanatory Tables 13.7.4a, 13.7.4b and 13.7.4c are typical examples of materials that can be used to insulate ductwork and fittings and the R-Values they contribute.
- For fittings, 11mm polyurethane typically provides an R-Value of 0.4.
NT Explanatory Tables 13.7.4a, 13.7.4b and provides R-Values for typical ductwork insulation materials:Insert NT table (13.7.4a (explanatory)) 13.7.4 as follows:
NT Table 13.7.4a (explanatory): Flexible ductwork Insulating material and thickness R-Value 45 mm glasswool (11 kg/m3) 1.0 70 mm polyester (6.4 kg/m3) 1.0 63 mm glasswool (11 kg/m3) 1.5 90 mm polyester (8.9 kg/m3) 1.5 85 mm glasswool (11 kg/m3) 2.0Insert NT table (13.7.4b (explanatory)) 13.7.4 as follows: NT Table 13.7.4b (explanatory): Sheetwork ductwork – external insulation Insulating material and thickness R-Value 38 mm glasswool (22 kg/m3) 1.0 50 mm polyester (20 kg/m3) 1.1 50 mm glasswool (22 kg/m3) 1.5 75 mm polyester (20 kg/m3) 1.7Insert NT table (13.7.4c (explanatory)) 13.7.4 as follows: NT Table 13.7.4c (explanatory): Sheetmetal ductwork – internal insulation Insulting material and thickness R-Value 38 mm glasswool (32 kg/m3) 1.0 50 mm polyester (32 kg/m3) 1.3 50 mm glasswool (32 kg/m3) 1.5
NT 13.7.5 Water heater in a heated water supply systemNew for 2022
A water heater in a heated water supply system must be designed and installed in accordance with Part B2 of NCC Volume Three – Plumbing Code of Australia.