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Part 2.6 Energy efficiency

Part 2.6 Energy efficiency

Note:

Note:

From 1 May 2019 to 30 April 2020 Part 2.6 of NCC 2016 Volume Two may apply instead of Part 2.6 of NCC 2019. From 1 May 2020 Part 2.6 of NCC 2019 applies.

State and Territory Variations

State and Territory Variations

  1. In New South Wales, Part 2.6 does not apply.

Note: The New South Wales Additions contain energy efficiency measures that apply in New South Wales to support and complement BASIX

In the Northern Territory, Part 2.6 is replaced with BCA 2009 Part 2.6

Explanatory information:

Explanatory information:

Objective

O2.6

The Objective is to reduce greenhouse gas emissions.

Functional Statements

F2.6

To reduce greenhouse gas emissions, to the degree necessary—

  1. a building, including its domestic services, is to be capable of efficiently using energy; and
  2. a building's domestic services for heating are to obtain their energy from—
    1. a low greenhouse gas intensity source; or
    2. an on-site renewable energy source; or
    3. another process as reclaimed energy.

Explanatory information:

Explanatory information:
  1. The greenhouse gas intensity of energy sources vary. For example, natural gas has a low greenhouse gas intensity compared with electricity generated from coal.
  2. For the purposes of F2.6, the renewable energy source must be on-site (so not Greenpower) and includes, but is not limited to, solar, wind, hydroelectric, wave action and geothermal.

Performance Requirements

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.

Explanatory information:

Explanatory information:

In P2.6.1(d) the term “permanent” is used to describe features that will have a long term impact on the building and includes natural features of the landscape, such as mountains and escarpments, while permanent man made features would be buildings likely to be in place for a long period of time.

State and Territory Variations

State and Territory Variations

P2.6.1 is replaced in Victoria as follows:

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 and a level of water use performance to facilitate the efficient use of water, appropriate to—

  1. the function and use of the building; and
  2. the internal environment; and
  3. the geographic location of the building; and
  4. the effects of nearby permanent features such as topography, structures and buildings; and
  5. solar radiation being—
    1. utilised for heating; and
    1. controlled to minimise energy for cooling; and
  6. the sealing of the building envelope against air leakage; and
  7. the utilisation of air movement to assist cooling; and
  8. water resources available; and
  9. pertinent water management measures of the responsible water authority.

P2.6.2 Services

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 has a greenhouse gas intensity that does not exceed 100 g CO2-e/MJ of thermal energy load; or

(ii)

an on-site renewable energy source; or

(iii)

another process such as reclaimed energy.

Explanatory information:

Explanatory information:
  1. For (a)(iv) the energy source can be a consideration if, for example, renewable energy such as electricity from a photovoltaic panel or a wind turbine was used to meet or supplement the lighting or cooling electricity load. For (b)(ii) similar sources could meet or supplement the heating load.
  2. The intent of P2.6.2(b) is to constrain the use of a high greenhouse gas intensity source of energy. It does not prevent the use of electricity because the greenhouse gas intensity is related to the thermal load rather than the energy consumption which is covered by P2.6.2(a). P2.6.2 also contains the qualification that it is to be applied "to the degree necessary", allowing electricity to be used, even by low efficiency plant when there are no reasonable alternatives.
  3. For the purposes of P2.6.2 the renewable energy source must be on-site (so not Greenpower) and includes, but is not limited to, solar, wind, hydroelectric, wave action and geothermal.

State and Territory Variations

State and Territory Variations

In Victoria, P2.6.2 does not apply to a hot water supply system.

Note: In Victoria, the design and installation of a hot water supply system is regulated under the Plumbing Regulations 2018.

Verification Methods

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.

Explanatory information:

Explanatory information:

The Verification Methods in this Part are intended to apply to whole Class 1 buildings and to whole Class 1 buildings that incorporate attached and enclosed Class 10a parts, such as attached garages. The Verification Methods are not intended to apply to detached garages or to open carports.

State and Territory Variations

State and Territory Variations

is replaced in Victoria as follows:

V2.6.1 Application of this Part

The Verification Methods in this Part only apply to—

  1. a new Class 1 building that has either a rainwater tank connected to all sanitary flushing systems, or a solar water heater system, installed in accordance with the Plumbing Regulations 2018; and
  2. a Class 1 building other than a new Class 1 building; and
  3. an enclosed Class 10a building attached to a Class 1 building.

V2.6.2 *  *  *  *  *

Explanatory information

This clause has deliberately been left blank.

V2.6.2.1 *  *  *  *  *

Explanatory information

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—

(i)

compared to a reference building, using a calculation method other than house energy rating software, has—

(A)

in climate zones 1 and 2, a cooling load equal to or less than that of the reference building; or

(B)

in climate zones 7 and 8, a heating load equal to or less than that of the reference building; or

(C)

in climate zones 3, 4, 5 and 6, a heating load and a cooling load equal to or less than that of the reference building.

(ii)

complies with—

(A)

for building fabric thermal insulation, 3.12.1.1; and

(B)

for thermal break, 3.12.1.2(c) and 3.12.1.4(d); and

(C)

for compensating for a loss of ceiling insulation, 3.12.1.2(e); and

(D)

for floor edge insulation, 3.12.1.5(c) and 3.12.1.5(d); and

(E)

for building sealing, Part 3.12.3 or V2.6.2.3.

(b)

The heating loads and cooling loads in (a) must be calculated for the reference building using—

(i)

internal heat gains from appliances and equipment of 5 W/m2 averaged for 24 hours per day, 7 days per week; and

(ii)

an infiltration value of 0.6 air changes per hour; and

(iii)

the modelling criteria in Table V2.6.2.2.

Table V2.6.2.2 Reference building requirements

Item

Description

Criteria to be modelled

1

Roof

Pitched roof (23 degrees) with solar absorptance of 0.6

2

Ceiling

2.4 m high horizontal, 10 mm plasterboard ceiling

3

Roof and ceiling insulation

In accordance with Tables 3.12.1.1a to 3.12.1.1g

4

Roof lights

No roof light, unless required by Part 3.8.4

5

External walls

Masonry veneer with 110 mm thick masonry with a solar absorptance of 0.6

6

Wall insulation

The minimum Total R-Value specified in 3.12.1.4(b)

7

Internal walls

70 mm timber frame with 10 mm internal plaster lining

8

Ground floor

Concrete slab-on-ground, insulated in accordance with 3.12.1.5(c)

9

Glazing

In accordance with Part 3.12.2

10

Air movement

In accordance with Part 3.12.4

11

Artificial lighting

In accordance with the maximum illumination power density allowed by 3.12.5.5 without any increase for a control device illumination power density adjustment factor
(c)

The heating load and cooling load for the proposed building and the reference building must be determined using the same—

(i)

calculation method; and

(ii)

location specific data, including that of climate and topography appropriate to the location where the proposed building is to be constructed if the data is available, or the nearest location with similar climatic conditions in the same climate zone for which the data is available; and

(iii)

impact of adjoining structures and features; and

(iv)

soil conditions; and

(v)

orientation; and

(vi)

floor plan, including the location and size of glazing; and

(vii)

number of storeys; and

(viii)

roof cladding and roof lights; and

(ix)

separating walls; and

(x)

external non-glazed doors; and

(xi)

intermediate floors; and

(xii)

floor coverings; and

(xiii)

internal heat gains from equipment and appliances; and

(xiv)

air infiltration and ventilation; and

(xv)

function and use of the building and spaces, including zoning, hours of occupation, hours of heating and cooling availability; and

(xvi)

space temperature settings within the ranges of 20°C to 21°C for heating and 25°C to 28°C for cooling; and

(xvii)

the profiles for occupancy and air-conditioning.

(d)

The calculation method used must comply with ANSI/ASHRAE Standard 140 and be capable of assessing the heating load and cooling load by modelling—

(i)

the building fabric; and

(ii)

glazing and shading; and

(iii)

air infiltration and ventilation; and

(iv)

the function and use of the building including zoning, hours of occupation, hours of heating and cooling availability and internal heat gains; and

(v)

relevant built-environment and topographical features; and

(vi)

the sensible heat component of the cooling load and heating load.

(e)

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.

Explanatory information:

Explanatory information:
  1. The items listed in (c) must be the same for both the proposed building and reference building. This means that those factors applicable to the proposed building must be applied to the reference building. For example, if the proposed building is subject to overshadowing by an existing adjoining building, in accordance with (c)(iii) the same overshadowing must be applied to the reference building.
  2. In (d)(iv), the number of hours per day for which heating and cooling is available would be expected to lie between 8 and 17, with values outside this range unlikely in other than exceptional circumstances.
  3. To comply with (c)(xv) all internal zones need to be modelled for each internal area. For example, zones for conditioned spaces, unconditioned spaces, day time, night time and the like appropriate to their intended usage. It is expected that each room including significant hallways will be modelled as a separate thermal zone.
  4. Suitable climatic data including dry-bulb temperature, direct and diffuse solar radiation, wind speed, wind direction and cloud cover can be obtained from the Australian national climate database.

V2.6.2.3 Verification of building envelope sealing

Compliance with P2.6.1(f) is verified when a building envelope is sealed at an air permeability of not more than 10 m3/hr.m2 at 50 Pa reference pressure when tested in accordance with AS/NZS ISO 9972 Method 1.

Explanatory information

Explanatory information

The intent is that 10 m3/hr.m2 at 50 Pa is broadly equivalent to 10 air changes per hour at 50 Pa when applied to homes.

It should be noted that V2.6.2.3 is only one way of achieving compliance with P2.6.1(f). Other ways of complying include the following:

  1. The relevant provisions of Part 3.12.3.
  2. A Performance Solution that uses one of the other NCC Assessment Methods which verifies that compliance with P2.6.1(f) will be achieved.

V2.6.3 *  *  *  *  *

Blank clause

This clause has deliberately been left blank.

Explanatory information:

Explanatory information:

The content of V2.6.3, which existed in BCA 2013, has been moved to Part B2 of NCC Volume Three — Plumbing Code of Australia.