NCC 2022 Volume One - Building Code of Australia Class 2 to 9 buildings

J1

Part J1 Energy efficiency performance requirements

Part J1 Energy efficiency performance requirements

Introduction to this Part

This Part sets the thermal performance properties of building fabric, the energy efficiency of key energy using equipment and the features a building must have to facilitate the future installation of distributed energy resources.

Notes

From 1 May 2023 to 30 September 2023 Section J of NCC 2019 Volume One Amendment 1 may apply instead of Section J of NCC 2022 Volume One. From 1 October 2023 Section J of NCC 2022 Volume One applies.

Notes: Tasmania Section J Energy Efficiency

In Tasmania, for a Class 2 building and Class 4 part of a building, Section J is replaced with Section J of BCA 2019 Amendment 1.

Objectives

The Objective of this Section is to—

  1. reduce energy consumption and energy peak demand; and
  2. reduce greenhouse gas emissions; and
  3. improve occupant health and amenity.

Basis of Objective

This Objective reflects the Council Of Australian Governments (COAG) decision in 2009 that a building is to be capable of reducing its greenhouse gas emissions.  J1O1 aims to achieve sustainable building design with the dual intent of promoting environmental stewardship and enhancing occupant well-being. It focuses on reducing both the operational and embodied energy consumption of buildings, minimising peak energy demand to ensure grid stability, and curbing greenhouse gas emissions. In addition to these environmental goals, J1O1 also emphasises the importance of improving the health, comfort, and overall amenity for building occupants.

National Commitment

In November 1998, all jurisdictions demonstrated their commitment to an effective national greenhouse response by endorsing the National Greenhouse Strategy, a part of which recognised the importance of energy efficiency standards for housing and commercial buildings. An option outlined in the National Greenhouse Strategy was to introduce measures in the BCA to reduce greenhouse gas emissions by efficiently using energy.

On 19 July 2000, the Commonwealth Government announced that agreement had been reached between it and the State and Territory Governments to examine and develop suitable national energy efficiency provisions for domestic and commercial buildings. After taking account of the views of industry, the Commonwealth Government also announced its intention to pursue a strategy that included two elements: firstly, the encouragement of voluntary measures by industry, and secondly, the introduction of minimum mandatory requirements in the BCA.

As a result of the Commonwealth Government’s initiative, the Australian Greenhouse Office (AGO) and the Australian Building Codes Board (ABCB) entered into an agreement on 5 January 2001 to develop energy efficiency measures for inclusion in the BCA. Industry was supportive of the need to eliminate worst practice and accepted a minimum mandatory approach because it provides a level playing field. Further, industry took the view that any building-related regulations should be consolidated in the BCA wherever possible.

In 2003, energy efficiency provisions were introduced into the BCA for housing. In 2005, energy efficiency provisions were introduced for other residential buildings. In 2006, the provisions were expanded to include all other building classifications, as well as enhancing the stringency for houses to a target of 5 stars. In 2010, all measures were further strengthened for both commercial and residential buildings as part of the National Strategy on Energy Efficiency. For houses and apartments the stringency was increased to the equivalent of 6 stars.

In 2016, the COAG Energy Council requested a review of the provisions as part of the National Energy Productivity Plan. For commercial buildings this was to involve an economically feasible stringency increase in NCC 2019. For residential buildings this was to involve strengthening the intent and interpretation of the current provisions in preparation for future stringency increase, possibly in NCC 2022.

Goal

The underlying goal of the energy efficiency provisions is to reduce greenhouse gas emissions. Initially this was achieved by efficiently using energy. In BCA 2010, this was broadened to include consideration of the greenhouse intensity of the energy used for the building’s services.

It should also be noted that the goal is not focused on occupant comfort. The measures are based on achieving an internal environment in which the conditions are sufficiently tolerable for occupants to minimise their use of services including artificial heating, cooling or lighting.

The energy used over the life of a building has an operational energy component and an embodied energy component. Operational energy, and the related greenhouse gas emissions, is the focus of the NCC at this time; broader environmental sustainability measures may be considered in the future

Functional Statements

A building must—

  1. reduce the energy consumption and energy peak demand of key energy using equipment; and
  2. reduce the greenhouse gas emissions that occur as a result of a building’s energy consumption and energy source; and
  3. for a sole-occupancy unit of a Class 2 building or a Class 4 part of a building, improve occupant health and amenity by mitigating the impact of extreme hot and cold weather events and energy blackouts; and
  4. for other than in a sole-occupancy unit of a Class 2 building or a Class 4 part of a building, protect occupant health and amenity by ensuring the building envelope assists in the maintenance of acceptable internal conditions while the building is occupied; and
  5. be able to accommodate the future installation of distributed energy resources.

J1F1 refines the intention of J1O1.

The Functional Statement has five parts.

J1F1 mandates that buildings reduce energy consumption and peak demand, particularly regarding the operation of primary energy-using systems. This is critical not just for efficiency but also for reducing greenhouse gas emissions that result from the building's energy use and its sources. J1F1 also stresses the importance of occupant health and comfort, specifically within sole-occupancy units of Class 2 buildings or Class 4 parts of buildings, by ensuring these spaces can mitigate the effects of severe temperature fluctuations and power outages. For other spaces, the building's envelope must help maintain suitable internal conditions when occupied. Furthermore, J1F1 anticipates the integration of distributed energy resources, such as on-site renewable energy systems, by requiring the building to be adaptable to future installations.

Performance Requirements

A building, other than a sole-occupancy unit of a Class 2 building or a Class 4 part of a building, including its services, must have features that facilitate the efficient use of energy appropriate to—

  1. the function and use of the building; and
  2. the level of human comfort required for the building use; and
  3. solar radiation being—
    1. utilised for heating; and
    2. controlled to minimise energy for cooling; and
  4. the energy source of the services; and
  5. the sealing of the building envelope against air leakage; and
  6. for a conditioned space, achieving an hourly regulated energy consumption, averaged over the annual hours of operation, of not more than—
    1. for a Class 6 building, 80 kJ/m².hr; and
    2. for a Class 5, 7b, 8 or 9a building other than a ward area, or a Class 9b school, 43 kJ/m².hr; and
    3. for all other building classifications, 15 kJ/m².hr.

Efficient use of energy

J1P1 refines the intention of J1O1. A building, and its services, is required to use energy efficiently so that the greenhouse gas emissions associated with its operation are minimised. This is subject to the intended use of the building and the necessary level of occupant comfort. For buildings that are air-conditioned, the amount of energy has also been quantified.

Regulated energy consumption

The term “regulated energy consumption” has been defined to clarify the portion of a building’s energy use that is required to be less than the quantified value. This includes the energy used for air-conditioning, heated water, artificial lighting and lifts, minus the amount of renewable energy generated and used on site.

NCC Title
Thermal performance of a sole-occupancy unit of a Class 2 building or a Class 4 part of a building
NCC State
NSW
NCC Variation Type
Deletion
NCC SPTC Current
Thermal performance of a sole-occupancy unit of a Class 2 building or a Class 4 part of a building
NCC Notice
J1P2 does not apply in NSW as thermal performance of a sole-occupancy unit of a Class 2 building or a Class 4 part of a building is regulated by BASIX.

(1) The total heating load of the habitable rooms and conditioned spaces in a sole-occupancy unit of a Class 2 building or a Class 4 part of a building must not exceed the heating load limit in Specification 44.

(2) The total cooling load of the habitable rooms and conditioned spaces in a sole-occupancy unit of a Class 2 building or a Class 4 part of a building must not exceed the cooling load limit in Specification 44.

(3) The total thermal energy load of the habitable rooms and conditioned spaces in a sole-occupancy unit of a Class 2 building or a Class 4 part of a building must not exceed the thermal energy load limit in Specification 44.

J1P2 Thermal performance of a sole-occupancy unit of a Class 2 building or a Class 4 part of a building

J1P2 focuses on the thermal performance of sole-occupancy units within Class 2 and Class 4 buildings. It mandates that the total heating, cooling, and thermal energy load of habitable rooms and conditioned spaces within these units must not exceed the specified limits outlined in Specification 44.

NCC Title
Energy usage of a sole-occupancy unit of a Class 2 building or a Class 4 part of a building
NCC State
NSW
NCC Variation Type
Deletion
NCC SPTC Current
Energy usage of a sole-occupancy unit of a Class 2 building or a Class 4 part of a building
NCC Notice
J1P3 does not apply in NSW as the thermal performance of a sole-occupancy unit of a Class 2 building or a Class 4 part of a building is regulated by BASIX.

(1) The energy value of the domestic services of a sole-occupancy unit of a Class 2 building or Class 4 part of a building must not exceed the energy value with—

  1. a 3-star ducted heat pump, rated under the 2019 GEMS determination, heating all spaces that are provided with heating; and
  2. a 3-star ducted heat pump, rated under the 2019 GEMS determination, cooling all spaces that are provided with cooling; and
  3. a 5-star instantaneous gas water heater, rated under the 2017 GEMS determination, providing all domestic hot water; and
  4. a lighting power density of 4 W/m2 serving all internal spaces that are provided with artificial lighting.

(2) Domestic services, including any associated distribution system and components must, to the degree necessary, have features that facilitate the efficient use of energy appropriate to—

  1. the domestic service and its usage; and
  2. the geographic location of the building; and
  3. the location of the domestic service; and
  4. the energy source.

J1P3 Energy usage of a sole-occupancy unit of a Class 2 building or a Class 4 part of a building

J1P3 pertains to the energy usage of domestic services within sole-occupancy units of Class 2 and Class 4 buildings. It restricts the energy value of domestic services, including heating, cooling, hot water, and lighting power density, with specific requirements for each aspect.

A building must have features that facilitate the future installation of on-site renewable energy generation and storage and electric vehicle charging equipment.

J1P4 Renewable energy and electric vehicle charging

J1P4 requires buildings to incorporate features that enable the future installation of on-site renewable energy generation and storage, as well as electric vehicle charging equipment.

Verification Methods

‘Verification Method’ is an NCC defined term and means a test, inspection, calculation or other method that determines whether a Performance Solution complies with the relevant Performance Requirements.

To help ensure a Performance Solution provides the level of intended performance, clause A2G2(4) of the NCC mandates a process for developing Performance Solutions. This process must be followed regardless of whether the Performance Solution is simple or complex in nature.

Verification Methods

(1) For a Class 5 building, compliance with J1P1 is verified when—

  1. a minimum 5.5-star NABERS Energy base building Commitment Agreement is obtained; and
  2. the energy model required for (a) demonstrates—
    1. the base building’s greenhouse gas emissions are not more than 67% of the 5.5-star level when excluding—
      1. tenant supplementary heating and cooling systems; and
      2. external lighting; and
      3. carparkservices; and
    2. a thermal comfort level of between a Predicted Mean Vote of -1 to +1 is achieved across not less than 95% of the floor area of all occupied zones for not less than 98% of the annual hours of operation of the building; and
  3. the building complies with the additional requirements in Specification 33.

(2) For a Class 2 building, other than sole-occupancy units, compliance with J1P1 is verified when—

  1. a minimum 4-star NABERS Energy for Apartment Buildings Commitment Agreement is obtained; and
  2. air-conditioning, which operates not less than 18 hours per day, is provided to all enclosed common lift lobbies and corridors; and
  3. the energy model required for (a) demonstrates—
    1. the greenhouse gas emissions of the services are less than 90% of the 5-star level; and
    2. a thermal comfort level of between a Predicted Mean Vote of -1 to +1 is achieved across not less than 95% of the floor area of the air-conditioned common area occupied zones, excluding indoor swimming pool chambers, for not less than 98% of the annual hours of operation of the building; and
    3. the space temperature in any indoor swimming pool chamber is maintained at 2°C above the pool temperature during occupied hours of not less than 12 hours per day; and
  4. the building complies with the additional requirements in Specification 33.

(3) For a Class 3 building, compliance with J1P1 is verified when—

  1. a minimum 4-star NABERS Energy for Hotels Commitment Agreement is obtained; and
  2. the operating hours of the services are not less than 12 hours per day in bedrooms, dining rooms and conference facilities, 24 hours per day in corridors and foyers and 18 hours per day in back-of-house areas; and
  3. the energy model required for (a) demonstrates that—
    1. the greenhouse gas emissions of the services are less than 70% of the 5-star level; and
    2. a thermal comfort level of between a Predicted Mean Vote of -1 to +1 is achieved across not less than 95% of the floor area of occupied zones, excluding indoor swimming pool chambers, for not less than 98% of the annual hours of operation of the building; and
    3. the space temperature in any indoor swimming pool chamber is maintained at 2°C above the pool temperature during occupied hours of not less than 12 hours per day; and
  4. the building complies with the additional requirements in Specification 33.

(4) For a Class 6 shopping centre, compliance with J1P1 is verified when—

  1. a minimum 4.5-stars NABERS Energy for Shopping Centres Commitment Agreement is obtained; and
  2. the building has:
    1. an air-conditioned common area of not less than 20% of the gross lettable area; and
    2. a gross lettable area greater than 15 000 m2; and
  3. the energy model required for (a) demonstrates—
    1. the greenhouse gas emissions of the services covered within the scope of NABERS Energy for Shopping Centres ratings are less than 80% of the 4.5-star level; and
    2. a thermal comfort level of between a Predicted Mean Vote of -1 to +1 is achieved across not less than 95% of the floor area of air-conditioned spaces within the scope of the rating for not less than 98% of the annual hours of operation the building; and
  4. the building complies with the additional requirements in Specification 33.

(5) The calculation method for (1), (2), (3) and (4) must comply with ANSI/ASHRAE Standard 140.

J1V1 NABERS Energy

This Verification Method allows the use of the modelling protocols and schedules of the National Building Environment Rating System for energy efficiency (known as NABERS Energy) to demonstrate compliance with J1P1 for Class 5, Class 2, and Class 3 buildings, and Class 6 shopping centres. NABERS Energy has a well-established energy modelling framework, which is used primarily to benchmark a building’s energy use against a 6-star scale based on its actual energy consumption over a 12-month period. However: 

For a Class 5 building: under J1V1 compliance is shown when an energy model of the building design predicts the energy consumption to be less than 67% of 5.5 stars on the NABERS Energy for Offices base-building scale. 67% of 5.5 stars is roughly equivalent to a 6-star NABERS Energy rating.

For Class 2 buildings (other Than sole-occupancy units): under J1V1 compliance is shown when an energy model of the building design predicts the energy consumption to be less than 90% of 5 stars on the NABERS Energy for Offices base-building scale. 90% of 5 stars is roughly equivalent to a 6-star NABERS energy rating.

For Class 3 buildings: under J1V1 compliance is shown when an energy model of the building design predicts the energy consumption to be less than 70% of 5 stars on the NABERS Energy for Offices base-building scale. 70% of 5 stars is roughly equivalent to a 6-star NABERS energy rating.

For Class 6 shopping centres: under J1V1 compliance is shown when an energy model of the building design predicts the energy consumption to be less than 80% of 4.5 stars on the NABERS Energy for Offices base-building scale. 80% of 4.5 stars is roughly equivalent to a 6-star NABERS Energy rating.

All the above buildings must also comply with any additional requirements specified in Specification 33 and the calculation methods must adhere to ANSI/ASHRAE Standard 140.

Commitment Agreement

In addition to the energy model, the Verification Method requires a NABERS Energy for Offices base-building Commitment Agreement to be obtained. This ensures that the necessary rating has been verified through the NABERS Energy process, committing to the design being followed through to the building’s operation.

The different targets set for the Commitment Agreement and energy modelling recognises that it is common industry practice to commit to a lower NABERS Energy rating than is likely to be achieved. This is to allow for factors outside the control of the designer relating to the building’s operation, which can impact on its ability to achieve a higher rating.

Thermal comfort

To ensure that occupant comfort is not compromised in the pursuit of energy efficiency, an assessment of the Predicted Mean Vote (PMV) is also a requirement of the Verification Method. PMV predicts the occupant comfort of a given design. The calculation of PMV uses much of the same information that is used in the creation of energy models. The PMV must be achieved across not less than 95% of the occupied floor area for not less than 98% of the hours of operation.

Use of Adaptive Thermal Comfort as a Performance Solution

The PMV metric is designed for fully mechanically ventilated buildings. In situations where a building uses mix-mode or naturally ventilating air-conditioning systems, the Adaptive Thermal Comfort metric may be more appropriate. This can be used as a Performance Solution subject to the approval of the building regulatory authority. Adaptive Thermal Comfort can also be used in combination with PMV in buildings that have both fully mechanical and partially naturally ventilated spaces.

To demonstrate compliance, it is suggested that the equivalent result produced by an Adaptive Thermal Comfort Model should be not less than 80% acceptability achieved across not less than 95% of the floor area of all occupied zones not less than 98% of the hours of operation of the building. Note, this is likely to be appropriate for buildings that meet the applicability criterion in Section 5.4.1 of ASHRAE 55-2013.

(1) For a Class 3, 5, 6, 7, 8 or 9 building, or common area of a Class 2 building, compliance with J1P1 is verified when—

  1. the building complies with the simulation requirements, and is registered, for a Green Star – Design & As-Built or Green Star Buildings rating; and
  2. the annual greenhouse gas emissions of the proposed building are less than 90% of the annual greenhouse gas emissions of the reference building; and
  3. in the proposed building, a thermal comfort level of between a Predicted Mean Vote of -1 to +1 is achieved across not less than 95% of the floor area of all occupied zones for not less than 98% of the annual hours of operation of the building; and
  4. the building complies with the additional requirements in Specification 33.

(2) The calculation method used for (1) must comply with ANSI/ASHRAE Standard 140.

J1V2 Green Star

This Verification Method allows the use of the Green Star rating tool to demonstrate compliance with J1P1 for Class 3, 5, 6, 7, 8 and 9 buildings, or common areas of a Class 2 building. Green Star rates buildings across a range of sustainability categories, including energy efficiency. As with J1V3 (below), the energy efficiency category of Green Star is based on comparing the proposed building to a reference building compliant with the Deemed-to-Satisfy Provisions in Section J. The schedules and assumptions in the Green Star protocols are different to those of J1V3, but are considered equivalent for the purpose of compliance with J1P1. Note, in fulfilling all of the sustainability categories for a Green Star rating a building exceeds the energy efficiency requirements of J1P1.

Registration

The project is required to be registered for a Green Star – Design & As-Built rating to confirm its compliance with the Green Star modelling requirements.

Thermal comfort

To ensure that occupant comfort is not compromised in the pursuit of energy efficiency, an assessment of the Percentage Mean Vote (PMV) is also a requirement of the Verification Method. PMV predictsthe occupant comfortof a given design. Its calculation is based on factors that are used to predict energy consumption.

(1) For a Class 3, 5, 6, 7, 8 or 9 building or common area of a Class 2 building, compliance with J1P1 is verified when—

  1. it is determined that the annual greenhouse gas emissions of the proposed building are not more than the annual greenhouse gas emissions of a reference building when—
    1. the proposed building is modelled with the proposed services; and
    2. the proposed building is modelled with the same services as the reference building; and
  2. in the proposed building, a thermal comfort level of between a Predicted Mean Vote of -1 to +1 is achieved across not less than 95% of the floor area of all occupied zones for not less than 98% of the annual hours of operation of the building; and
  3. the building complies with the additional requirements in Specification 33.

(2) The annual greenhouse gas emissions of the proposed building may be offset by—

  1. renewable energy generated and used on site; and
  2. another process such as reclaimed energy, used on site.

(3) The calculation method used for (1) and (2) must comply with—

  1. ANSI/ASHRAE Standard 140; and
  2. Specification 34.

J1V3 Verification using a reference building

This Verification Method compares the greenhouse gas emissions of a proposed building to that of a reference building which is based on the Deemed-to-Satisfy Provisions. If the greenhouse gas emissions of the proposed building do not exceed that of the reference building, compliance with J1P1 is achieved.

Through this modelling process, it must be demonstrated that the Performance Solution is equivalent to, or better than, the Deemed-to-Satisfy Provisions. This equivalency is also one of the Assessment Methods recognised in the NCC.

J1V3 includes provisions in J1V3(1)(a)(ii) which are designed to protect the thermal performance of the building’s envelope from “trading” off its performance with that of the building services.

The steps to using this Verification Method are:

  • Determine the annual greenhouse gas emissions allowance by modelling a reference building, i.e. a Deemed-to- Satisfy complying building based on the criteria in S34C2, S34C3 and S34C4.
  • Calculate the theoretical annual greenhouse gas emissions of the proposed Performance Solution u sing the criteria in S34C3 and S34C4.
  • Calculate the theoretical annual greenhouse gas emissions of the proposed Performance Solution, with the services modelled as if they were the same as that of the reference building. This tests the performance of the facade.
  • Compare the theoretical annual greenhouse gas emissions calculated in steps 2 and 3 to the annual greenhouse gas emissions allowance calculated in step 1 to ensure that in both cases, the annual greenhouse gas emissions are not more than that allowed.

The same software must be used in all modelling runs.

J1V3 can be used for all buildings using the occupancy profiles and other assumptions provided in Specifications 34 and 35.

Figure J1V3 illustrates how J1V3 can be used to assess different Performance Solutions.

(1) Compliance with J1P1(e) and J1P2 is verified for building envelope sealing when the envelope is sealed at an air permeability rate, tested in accordance with Method 1 of AS/NZS ISO 9972, of not more than—

  1. for a Class 2 building or a Class 4 part of a building, 10 m³/hr.m² at 50 Pa reference pressure; or
  2. for a Class 5, 6, 8 or 9a or 9b building, other than a ward area, in climate zones 1, 7 and 8, 5 m³/hr.m² at 50 Pa reference pressure; or
  3. for a Class 3 or 9c building, or a Class 9a ward area in climate zones 1, 3, 4, 6, 7 and 8, 5 m³/hr.m² at 50 Pa reference pressure.

(2) In a sole-occupancy unit of a Class 2 building or a Class 4 part of a building, where an air permeability rate of not more than 5 m3/hr.m2 at 50 Pa reference pressure is achieved—

  1. a mechanical ventilation system must be provided that—
    1. can be manually overridden; and
    2. provides outdoor air, either—
      1. continuously; or
      2. intermittently, where the system has controls that enable operation for not less than 25 per cent of each 4 hour segment; and
    3. provides a flow rate not less than that achieved with the following formula:
      Q=(0.05×A+3.5×(N+1))/pMathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyuaiabg2 da9iaacIcacaaIWaGaaiOlaiaaicdacaaI1aaccaGae831aqRaamyq aiabgUcaRiaaiodacaGGUaGaaGynaiab=Dna0kaacIcacaWGobGaey 4kaSIaaGymaiaacMcacaGGPaGaai4laiaadchaaaa@497F@
      , where—
      1. QMathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyuaaaa@36CA@
        = the required air flow rate (L/s); and
      2. AMathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamyqaaaa@36BA@
        = the total area of the sole-occupancy unit of a Class 2 or Class 4 part of a building (m2); and
      3. NMathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamOtaaaa@36C7@
        = the number of bedrooms in the sole-occupancy unit of a Class 2 or Class 4 part of a building; and
      4. pMathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaamiCaaaa@36E9@
        = the fraction of time within each 4 hour segment that the system is operational; and
  2. any space with a solid-fuel burning combustion appliance must be ventilated with permanent openings directly to outside with a free area of not less than half of the cross-sectional area of the appliance’s flue; and
  3. any space with a gas-fueled combustion appliance must be ventilated in accordance with—
    1. clause 6.4 of AS/NZS 5601.1; and
    2. clause 6.4.5 of AS/NZS 5601.1.

(3) For the purposes of (2)(c), the volume of the space is considered to be 1 m3 for determining ventilation requirements.

J1V4 Verification of building envelope sealing

Building sealing is essential for facilitating the energy efficiency of a building. J1V4 provides a method of demonstrating compliance with the building sealing requirements in J1P1(e). This provides an alternative compliance option to the prescriptive building sealing requirements in Part J5.

J1V4 quantifies the level of sealing (expressed as an air permeability rate)appropriate for different building classifications and climate zones. The method for testing the sealing level is through a blower door test carried out in accordance with Method 1 of AS/NZS ISO 9972.

J1V4 also sets out mechanical ventilation requirements for a Class 2 buildings or a Class 4 part of a building where an air permeability rate less than 5 m3/hr.m2 at 50 Pa reference pressure is achieved. Further provisions ensure ventilation standards for spaces within buildings, particularly where combustion appliances are present. Compliance with AS/NZS 5061.1 is highlighted for gas-fuel combustion appliances.

Envelope sealing has less impact on buildings that do not operate overnight and which are located within relatively mild climates (i.e. climates zones 2 and 5). Envelope sealing can have a reduced benefit in these circumstances as these buildings are less likely to cool naturally overnight and may require additional cooling energy than necessary the next day. However, if buildings in these climate zones are operated in a manner that expels warm air and draws in cool air overnight as part of its cooling regime (typically known as night purging), then a lower air permeability rate could be beneficial.

NCC Title
Verification using a reference building for a Class 2 sole-occupancy unit
NCC State
NSW
NCC Variation Type
Deletion
NCC SPTC Current
Verification using a reference building for a Class 2 sole-occupancy unit
NCC Notice
J1V5 does not apply in NSW.

(1) Compliance with J1P2 is verified when each Class 2 sole-occupancy unit of a proposed building—

  1. in climate zones 3, 4, 5, 6, 7 and 8, has a heating load less than or equal to—
    1. that of a reference building; and
    2. 120% of J1P2(1); and
  2. in climate zones 1, 2, 3, 4 and 5, has a cooling load less than or equal to—
    1. that of a reference building; and
    2. 120% of J1P2(2); and
  3. complies with the additional requirements in Specifications 33 and 45 as applicable.

(2) Compliance with J1P3 is determined when the energy value of the domestic services, including all centralised domestic services infrastructure, of a proposed building is less than that of a reference building when—

  1. each sole-occupancy unit of a reference building has—
    1. a 3-star ducted air-to-air heat pump, rated under the 2019 GEMS determination, heating all spaces that are provided with heating; and
    2. a 3-star ducted heat pump, rated under the 2019 GEMS determination, cooling all spaces that are provided with cooling; and
    3. a 5-star instantaneous gas water heater, rated under the 2017 GEMS determination, providing all domestic heated water; and
    4. a lighting power density of 4 W/m2 serving all internal spaces that are provided with artificial lighting; and
  2. the proposed building and a reference building comply with the additional requirements in Specifications 33 and 45 as applicable.

(3) The calculation method used for (1) and (2) must—

  1. comply with ANSI/ASHRAE Standard 140; and
  2. not be house energy rating software.

J1V5 Verification using a reference building for a Class 2 sole-occupancy unit

J1V5 covers the verification of Class 2 sole-occupancy units' compliance with J1P2 using reference buildings. For Class 2 sole-occupancy units, energy efficiency is gauged against a 'reference building'.

J1V5 evaluates the energy performance of Class 2 buildings' sole-occupancy units, addressing both J1P2 and J1P3 Performance Requirements. J1V5 enables compliance for either or both of these Performance Requirements through energy modelling, as outlined in Specification 45

J1V5 is particularly relevant for apartment blocks centralized hot water, heating, or cooling systems as specified in J1P3, allowing for the use of a single energy model to represent the entire building’s performance. Depending on the climate zones, the heating and cooling loads of the sole-occupancy units should either match or be better than those of a reference building. These loads also should not go beyond 120% of the values set in J1P2(1) for In climate zones 3 to 8, and J1P2(2) for climate zones 1 to 5 respectively.

This Verification Method ensures that the building's design and domestic services, like lighting and appliances, meet or exceed set benchmarks for energy efficiency. The calculation tools must align with the ANSI/ASHRAE Standard 140 and must not include house energy rating software.