BCA Volume 2 - Energy Efficiency Measures
for Residential Buildings - Class 1

Part 3.12 - Energy Efficiency
Part 3.12.1 - Building Fabric

Part 3.12.2 - External Glazing
Part 3.12.3 - Building Sealing
Part 3.12.4 - Air Movement
Part 3.12.5 - Services

Part 3.12 - Energy Efficiency

Appropriate Performance Requirements:
Where an alternative energy efficiency design is proposed as an Alternative Solution to that described in Part 3.12, that proposal must comply with-
(a) Performance Requirement P2.6.1; and
(b) Performance Requirement P2.6.2; and
(c) the relevant Performance Requirements determined in accordance with 1.0.10.

STATE AND TERRITORY VARIATIONS
1. In New South Wales, Part 3.12 does not apply. Note: The New South Wales Additions contain energy efficiency measures that apply in New South Wales to support and complement BASIX.
2. In the Northern Territory, Part 3.12 is replaced with BCA 2009 Part 3.12.
3. In Tasmania, Part 3.12 is replaced with BCA 2009 Part 3.12.


PART 2.6 ENERGY EFFICIENCY

P2.6.1 Building
P2.6.2 Services
V2.6 Definitions
V2.6.1 Application of this Part
V2.6.2 * * * * *
V2.6.2.1 * * * * *
V2.6.2.2 Verification using a reference building
V2.6.3 Verification for a heaterin a hot water supply system

P2.6.1 Building

A building must have, to the degree necessary, a level of thermal performance to facilitate the efficient use of energy for artificial heating and cooling appropriate to—
  • (a) the function and use of the building; and
    (b) the internal environment; and
    (c) the geographic location of the building; and
    (d) the effects of nearby permanent features such as topography, structures
    and buildings; and
    (e) solar radiation being—
    (i) utilised for heating; and
    (ii) controlled to minimise energy for cooling; and
    (f) the sealing of the building envelope against air leakage; and
    (g) the utilisation of air movement to assist cooling.

    P2.6.2 Services

    A building’s domestic services, including any associated distribution system and components must to the degree necessary—

    (a) have features that facilitate the efficient use of energy appropriate to—
    (i) the domestic service and its usage; and
    (ii) the geographic location of the building; and
    (iii) the location of the domestic service; and
    (iv) the energy source; and
    (b) obtain heating energy from—
    (i) a source that h  as a greenhouse gas intensity that does not exceed 100 g CO2-e/MJ of thermal energy load; or
    (ii) a source that is renewable on-site such as solar, geothermal or wind; or
    (iii) another process as reclaimed energy.

    V2.6 Definitions

    The following definitions are used in this Part:

    Cooling loadmeans the calculated amount of energy removed from the cooled spaces of the building annually by artificial means to maintain the desired temperatures in those spaces.
    Heating loadmeans the calculated amount of energy delivered to the heated spaces of the building annually by artificial means to maintain the desired temperatures in those spaces.
    Reference buildingmeans a hypothetical building that is used to determine the maximum allowable heating load and cooling load for the proposed building.

    V2.6.1 Application of this Part

    The Verification Methods in this Part only apply to—
    (a) a Class 1 building; and
    (b) an enclosed Class 10a building attached to a Class 1 building.

    V2.6.2 * * * * *

    This clause has deliberately been left blank.

    V2.6.2.1 * * * * *

    This clause has deliberately been left blank.

    V2.6.2.2 Verification using a reference building

    (a) Compliance with P2.6.1 is verified when a proposed building, compared with a reference building, has in all climate zones appropriate cooling & heating loads equal or less than that of the reference building

    (b) The heating load and cooling load for the proposed building and the reference building must be determined using the same methods and conditions

    (c) The calculation method used must be capable of assessing the heating load and cooling load by modelling the building fabric; glazing & shading; and air infiltration & ventilation; the function and use of the building etc.

    (d) Climatic data employed in the calculation method must be based on hourly recorded values and be representative of a typical year for the proposed location.

    (e) The reference building must be modelled using the Deemed-to-Satisfy Provisions of Part 3.12.

    V2.6.3 Verification for a heater in a hot water supply system

    (a) Compliance with P2.6.2 for a heater in a hot water supply system is verified when the annual greenhouse gas intensity of the water heater does not exceed 100 g CO2-e/MJ of thermal energy load determined in accordance with AS/NZS 4234.
    (b) The annual greenhouse gas intensity of the water heater in (a) is the sum of the annual greenhouse gas emissions from each energy source in g CO2-e divided by the annual thermal energy load of the water heater.
    (c) The annual greenhouse gas emission from each energy source in (b) is the product of
    — (i) the annual amount of energy consumed from that energy source; and
    — (ii) the emission factor of— electricity, iquefied petroleum gas, natural gas, wood or biomass.

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    Part 3.12.1 Building Fabric

    3.12.1 Application
    3.12.1.1 Building fabric insulation
    3.12.1.2 Roofs
    3.12.1.3 Roof lights
    3.12.1.4 External walls
    3.12.1.5 Floors
    3.12.1.6 Attached Class 10a buildings

    The Energy Provisions reflects the ABCB objective of delivering minimum cost-effective measures.

    Building fabric or building envelope is a term used to describe the roof, walls, windows, floors and internal walls of a home. The envelope controls heat gain in summer and heat loss in winter.
    Building fabric separating heated or cooled interior spaces from the exterior of the building or unconditioned spaces i.e. spaces that:

  • Are habitable rooms
  • Are conditioned
  • Can be conditioned

    The envelope may comprise internal or external elements. Building regulations deal with design standards for fabric heat loss, and have set minimum insulation levels in terms of elemental U values. Each element of the building envelope (roof, wall, floor, window, door) is assigned a maximum heat loss rate. The unit of measurement, Watts per square metre Kelvin (W/m²K), is an expression of how quickly energy passes through a square metre of the element for a given temperature drop
    between inside and out (the Kelvin scale is quoted , but the temperature difference is practically measured in degrees Celsius). The aim is to slow down the rate of heat loss, which means a lower U value.

    Building fabric requirements apply to a Class 1 building, and a Class 10a building with a conditioned space.

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    PART 3.12.2 EXTERNAL GLAZING

    3.12.2 Application
    3.12.2.1 External glazing
    3.12.2.2 Shading

    3.12.2 Application

    This Part applies to—
    (a) a Class 1 building; and
    (b) a Class 10a building with a conditioned space.

    3.12.2.1 External glazing

    (a) The aggregate conductance of the glazing in each storey, including any mezzanine, of a building must—
    (i) not exceed the allowances resulting from—
    (A) in climate zone 1, multiplying the area of the storey, including any mezzanine, measured within the enclosing walls, by the constant CU obtained from Table 3.12.2.1; and
    (B) in climate zones 2 to 8, using the constant CU obtained from Table 3.12.2.1.
    (ii) be calculated in accordance with the following calculation—
    (A) in climate zone 1—

    (A1 x U1) + (A2 x U2) + (A3 x U3) + ..............

    where—
    A1, 2, etc = the area of each glazing element; and
    U1, 2, etc = the Total U-Value of each glazing element; and
    (B) in climate zones 2 to 8—

    [(A1 x U1) + (A2 x U2) + .......] / [(A1 x SHGC1 x EW1) + (A2 x SHGC2 x EW2) + ........ ]

    where—
    A1, 2, etc = the area of each glazing element; and
    U1, 2, etc = the Total U-Value of each glazing element; and
    SHGC1, 2, etc = the SHGC for each glazing element; and
    EW1, W2 etc = the winter exposure factor for each glazing element obtained from Table 3.12.2.2a.
    (b) The aggregate solar heat gain of the glazing in each storey, including any mezzanine, of a building must—
    (i) not exceed the allowances resulting from multiplying the area of the storey, including any mezzanine, measured within the enclosing walls, by the constant CSHGC obtained from Table 3.12.2.1; and
    (ii) be calculated in accordance with the following calculation—

    (A1 x SHGC1 x ES1) + (A2 x SHGC2 + ES2) + .........

    where—
    A1, 2, etc = the area of each glazing element; and
    SHGC1, 2, etc = the SHGC for each glazing element; and
    ES1, S2, etc = the summer exposure factor for each glazing element obtained from Table 3.12.2.2b.

    3.12.2.2 Shading

    Where shading is required to comply with 3.12.2.1, it must—
    (a) be provided by an external permanent projection, such as a verandah, balcony, fixed canopy, eaves, shading hood or carport, which—
    (i) extends horizontally on both sides of the glazing for a distance not less than the projection distance P in Figure 3.12.2.2; or
    (ii) provide the equivalent shading to (i) with a reveal or the like; or
    (b) be provided by an external shading device, such as a shutter, blind, vertical or horizontal building screen with blades, battens or slats, which—
    (i) is capable of restricting at least 80% of the summer solar radiation; and
    (ii) if adjustable, is readily operated either manually, mechanically or electronically by the building occupants.
    . Fig3.12.2.2.

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    PART 3.12.3 BUILDING SEALING

    3.12.3 Application
    3.12.3.1 Chimneys and flues
    3.12.3.2 Roof lights
    3.12.3.3 External windows and doors
    3.12.3.4 Exhaust fans
    3.12.3.5 Construction of roofs, walls and floors
    3.12.3.6 Evaporative coolers

    PART 3.12.3 BUILDING SEALING

    3.12.3 Application
    (a) This Part applies to—
    (i) a Class 1 building; and
    (ii) a Class 10a building with a conditioned space.
    (b) The provisions of (a) do not apply to the following:
    (i) A building in climate zones 1, 2, 3 and 5 where the only means of air-conditioning is by using an evaporative cooler.
    (ii) A permanent building ventilation opening that is necessary for the safe operation of a gas appliance.
    (iii) A Class 10a building used for the accommodation of vehicles.

    3.12.3.1 Chimneys and flues

    The chimney or flue of an open solid-fuel burning appliance must be provided with a damper or flap that can be closed to seal the chimney or flue.

    3.12.3.2 Roof lights

    (a) A roof light must be sealed, or capable of being sealed, when serving—
    (i) a conditioned space; or
    (ii) a habitable room in climate zones 4, 5, 6, 7 and 8.
    (b) A roof light required by (a) to be sealed, or capable of being sealed, must be constructed with—
    (i) an imperforate ceiling diffuser or the like installed at the ceiling or internal lining level; or
    (ii) a weatherproof seal; or
    (iii) a shutter system readily operated either manually, mechanically or electronically by the occupant.

    3.12.3.3 External windows and doors

    (a) A seal to restrict air infiltration must be fitted to each edge of an external door, openable window and other such opening—
    (i) when serving a conditioned space; or
    (ii) in climate zones 4, 5, 6, 7 and 8, when serving a habitable room.
    (b) A window complying with the maximum air infiltration rates specified in AS 2047 need not comply with (a).
    (c) A seal required by (a)—
    (i) for the bottom edge of an external swing door, must be a draft protection device; and
    (ii) for the other edges of an external swing door or the edges of an openable window or other such opening, may be a foam or rubber compressible strip, fibrous seal or the like.

    3.12.3.4 Exhaust fans

    An exhaust fan must be fitted with a sealing device such as a self-closing damper, filter or the like when serving—
    (a) a conditioned space; or
    (b) a habitable room in climate zones 4, 5, 6, 7 and 8.

    3.12.3.5 Construction of roofs, walls and floors

    (a) Roofs, external walls, external floors and any opening such as a window frame, door frame, roof light frame or the like must be constructed to minimise air leakage in accordance with (b) when forming part of the external fabric of—
    (i) a conditioned space; or
    (ii) a habitable room in climate zones 4, 5, 6, 7 and 8.
    (b) Construction required by (a) must be—
    (i) enclosed by internal lining systems that are close fitting at ceiling, wall and floor junctions; or
    (ii) sealed by caulking, skirting, architraves, cornices or the like.

    3.12.3.6 Evaporative coolers

    An evaporative cooler must be fitted with a self-closing damper or the like when serving—
    (a) a heated space; or
    (b) a habitable room in climate zones 4, 5, 6, 7 or 8.

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    PART 3.12.4 AIR MOVEMENT

    3.12.4 Application
    3.12.4.1 Air movement
    3.12.4.2 Ventilation openings 3.12.4.3 Ceiling fans and evaporative coolers

    3.12.4 Application

    This Part applies to a habitable room in a Class 1 building.

    3.12.4.1 Air movement

    (a) Air movement must be provided to habitable rooms in accordance with Table 3.12.4.1.
    (b) Air movement required by (a) may be provided through an opening from an adjoining room (including an enclosed verandah) if—
    (i) the adjoining room is not a sanitary compartment; and
    (ii) the opening between the adjoining room and the habitable room complies with Table 3.12.4.1 as if it were a ventilation opening to the habitable room or a proportion thereof if some ventilation is provided from another source; and
    (iii) the ventilation opening to the adjoining room complies with Table 3.12.4.1 for the floor area of the adjoining room and the proportion of the habitable room that is ventilated from the adjoining room.
    (c) The requirements of (a) do not apply to buildings in Region D severe tropical cyclone areas (see Figure 3.10.1.4) provided the external walls are shaded with a verandah, balcony, eaves, carport or the like that projects at a minimum angle of 15 degrees in accordance with Figure 3.12.1.2.

    3.12.4.2 Ventilation openings

    (a) In climate zones 1, 2, 3, 4 and 5, the total ventilation opening area required by Table 3.12.4.1 to a habitable room must—
    (i) be connected by a breeze path complying with (b) to another ventilation opening in another room or space; or
    (ii) be provided by a minimum of two ventilation openings located within the same habitable room, with each ventilation opening having an area of not less than 25% of the area required by Table 3.12.4.1.
    A breeze path required by (a)(i) must—
    (i) pass through not more than two openings in the internal walls with each opening having an area of not less than 1.5 m2; and
    (ii) have a distance along the breeze path between ventilation openings of not more than 20 m.

    3.12.4.3 Ceiling fans and evaporative coolers

    Ceiling fans or evaporative coolers required to comply with 3.12.0.1, Table 3.12.2.1 or Table 3.12.4.1 must—
    (a) be permanently installed; and
    (b) have a speed controller; and
    (c) for ceiling fans, serve the whole room, with the floor area that a single fan serves not exceeding—
    (i) 15 m2 if it has a blade rotation diameter of not less than 900 mm; and
    (ii) 25 m2 if it has a blade rotation diameter of not less than 1200 mm.

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    PART 3.12.5 SERVICES

    3.12.5 Application
    3.12.5.0 Acceptable construction manual
    3.12.5.1 Insulation of services
    3.12.5.2 Central heating water piping
    3.12.5.3 Heating and cooling ductwork

    Application

    This Part applies to—
    (a) a Class 1 building; and
    (b) a Class 10a building; and
    (c) a Class 10b swimming pool.

    A. Acceptable construction manuals

    3.12.5.0
    (a) A hot water supply system must be designed and installed in accordance with Section 8 of AS/NZS 3500.4 or clause 3.38 of AS/NZS 3500.5.
    (b) A solar hot water supply system in climate zones 1, 2 and 3 is not required to comply with (a).
    Explanatory information:
    See Part 2.6 for the relevant Performance Requirement that is satisfied by compliance with 3.12.5.0.
    STATE AND TERRITORY VARIATIONS
    1. In Victoria, delete 3.12.5.0
    2. In South Australia, 3.12.5.0 is replaced with the following:SA 3.12.5.0
    A heated water service must be designed and installed in accordance with the Waterworks Act 1932 and the Waterworks Regulations 1996.

    B. Acceptable construction practice

    3.12.5.1 Insulation of services

    Thermal insulation for central heating water piping and heating and cooling ductwork must—
    (a) be protected against the effects of weather and sunlight; and
    (b) be able to withstand the temperatures within the piping or ductwork; and
    (c) use thermal insulation material in accordance with AS/NZS 4859.1.
    Explanatory information:
    The Acceptable Construction Manuals described in 3.12.5.0 is for use with hot water systems that provide hot water for general domestic use in areas such as bathrooms, kitchens, laundries and the like.
    The central heating water piping provisions apply to hot water systems designed to heat the building.

    3.12.5.2 Central heating water piping

    Central heating water piping that is not within a conditioned space must be thermally insulated to achieve the minimum material R-Value in accordance with Table 3.12.5.1.
    Table 3.12.5.1 CENTRAL HEATING WATER PIPING—MINIMUM MATERIAL R-VALUE
    This table shows 'Piping to be insulated Minimum material R-Valuefor each climate zone 1, 2, 3 and 5 / 4, 6 and 7 / 8 range from 0.2 to 0.6 depending on the climate zone'.

    3.12.5.3 Heating and cooling ductwork

    (a) Heating and cooling ductwork and fittings must—
    (i) achieve the material R-Value in Table 3.12.5.2; and
    (ii) be sealed against air loss—
    (A) 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
    (B) for flexible ductwork, with a draw band in conjunction with a sealant or adhesive tape.
    (b) Duct insulation must—
    (i) abut adjoining duct insulation to form a continuous barrier; and
    (ii) be installed so that it maintains its position and thickness, other than at flanges and supports; and
    (iii) where located outside the building, under a suspended floor, in an attached Class 10a building or in a roof space—
    (A) be protected by an outer sleeve of protective sheeting to prevent the insulation becoming damp; and
    (B) have the outer protective sleeve sealed with adhesive tape not less than 48 mm wide creating an airtight and waterproof seal.
    (c) The requirements of (a) do not apply to heating and cooling ductwork and fittings located within the insulated building envelope including a service riser within the conditioned space, internal floors between storeys and the like.
    Explanatory information:
    Ductwork within a fully insulated building may still benefit from insulation particularly when the system is only operating for short periods.

    Table 3.12.5.2 HEATING AND COOLING DUCTWORK AND FITTINGS—MINIMUM MATERIAL R-VALUE
    Ductwork element Minimum material R-Values in climate zones 'range from 1.0 to 1.5 for Heating-only system or cooling-only system including an evaporative cooling system & Combined heating and refrigerated cooling system'.

    3.12.5.4 Electric resistance space heating

    An electric resistance space heating system that serves more than one room must have—
    (a) separate isolating switches for each room; and
    (b) a separate temperature controller and time switch for each group of rooms with common heating needs; and
    (c) power loads of not more than 110 W/m2 for living areas, and 150 W/m2 for bathrooms.

    3.12.5.5 Artificial lighting

    (a) The lamp power density or illumination power density of artificial lighting, excluding heaters that emit light, must not exceed—
    (i) in a Class 1 building, 5 W/m2; and
    (ii) on a verandah or balcony attached to a Class 1 building, 4 W/m2; and
    (iii) in a Class 10 building, 3 W/m2, and where illumination power density is used, it may be increased by dividing it by the illumination power density adjustment factor in Table 3.12.5.3 where applicable.

    Table 3.12.5.3 ILLUMINATION POWER DENSITY ADJUSTMENT FACTOR FOR A CONTROL DEVICE
    Item Description Illumination power density adjustment factor
    Lighting timer For corridor lighting 0.7
    This Table list Illumination power density adjustment factor

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    Karl Boeing