NCC Tutor lesson - Using the energy efficiency provision in NCC Volume One

Slide 1: 

Welcome to using the energy efficiency provision in NCC Volume One

Slide 2: 

The focus of this presentation is on how to use the energy efficiency provisions in NCC Volume One.

Slide 3: 

What you will learn. Energy efficiency Performance Requirements in Volume One. Compliance solutions for energy efficiency in Volume One. Energy efficiency ratings for SOUs. Energy efficiency DTS Provisions in Volume One. Assessment Methods for energy efficiency. Other useful resources.

Slide 4: 

Where is energy efficiency covered in NCC Volume One?

Energy efficiency provisions have been in Volume One since 2005 for residential buildings (multi-residence). Provisions for non-residential buildings were introduced in 2006.

Minimum requirements have increased over time with major changes introduced in 2010 and 2019.

The Performance Requirements in NCC Volume One reflects the key concerns for energy efficiency in the NCC, which are the performance of the building fabric/envelope, specifically how it works to reduce and allow heat flow into or out of the building, as needed to maintain a comfortable temperature in the conditioned spaces of the building. The efficiency of the building’s services. Building services is a defined term in the NCC, and in Section J it relates to how much energy is needed to operate the building’s services. The ability to monitor energy use, and easy retrofit of renewable energy and electric vehicle charging equipment. 

Slide 5: 

What are the energy efficiency Performance Requirements in NCC Volume One?

The overall objectives of the Performance Requirements in Section J are to reduce energy consumption and peak energy demand, reduce greenhouse gas emissions, improve occupant health and amenity. 

J1P1 Energy use. This Performance Requirement is applicable to all building classes, except a sole-occupancy unit of a Class 2 building or a Class 4 part of a building. 

It’s not mandating the use of specific technologies or materials – note the term, “appropriate to” –  you can decide what’s appropriate for the building given its intended purpose. 

Energy features - For example, energy efficient appliances, electrical equipment, smart meters and renewable energy sources.

Solar radiation - Use of passive solar design to warm the building in cooler weather, and reduce the entry of unwanted sunlight and heat in warmer weather.

Energy source of services – for example - onsite renewable energy generation. Includes wind, wave action and geothermal generation and reclaimed energy but not “Greenpower” energy contracts.

Services - Mechanical or electrical system that uses energy to provide air-conditioning, mechanical ventilation, heated water supply, artificial lighting, vertical transport and the like within a building. Not cooking facilities, portable appliances or systems used solely for emergency purposes.

Sealing of the building envelope - sealing the building fabric between conditioned spaces and non-conditioned spaces to prevent unwanted entry or loss of heat.

Regulated energy consumption – the amount of energy consumed by a building’s services minus the amount of renewable energy generated and used on site. 

Regulated energy consumption is quantified in J1P1, with varying values based on the class of building. 

The actual target energy use for conditioned spaces within a building is quantified based on the building class.

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

Applies only to Class 2 buildings and Class 4 part of a building as per the title.

Thermal performance is about the ease with which heat flows into and out of the building. 

Improving the thermal performance of the building envelope will reduce the need for artificial heating and cooling of conditioned space and habitable rooms. 

As heating and cooling are key contributors to the total energy use of a typical building, improving the building’s thermal performance should reduce its energy use and therefore should reduce greenhouse gas emissions over the life of the building.

This Performance Requirement provides values for the heating, cooling and total thermal loads in the referenced Specification 44.

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

Applies only to Class 2 buildings and Class 4 part of a building as per the title. Suggest trainees look up the actual wording of the requirement in Section J. 

Intent is as per the slide description. 

Energy value is quantified by providing a maximum for different heat pumps, water heaters and lighting power density.

J1P4 Renewable energy and electric vehicle charging. This Performance Requirement is aimed at providing allowances for future on-site renewable energy generation equipment and storage such as solar panels and electric vehicle charging. 

Given the complexities in retrofitting commercial and high-rise buildings, it’s about making any future retrofitting of these or other new technologies easier and more cost effective - should a decision be made by building owners or tenants to add them. 

Slide 6: 

The building envelope in Section J

For the purposes of Section J of NCC Volume One, which parts of the building in the image on the right are within the building envelope?

For the purpose of Section J in NCC Volume One, the parts of a building's fabric that separate a conditioned space or habitable room form i)The exterior of the building; or ii) A non-conditioned space including A) The floor of a rooftop plant room, lift-machine room or the like; and B) The floor above a carpark or warehouse; and C) The common wall with a carpark, a warehouse of the like.

Slide 7: 

How can we comply with the energy efficiency Performance Requirements of NCC Volume One?

Almost all of the DTS Provisions in Section J apply to all NCC Volume One building classifications.

However, there is a distinct difference in how reducing energy consumption is treated for sole-occupancy units (SOUs) of Class 2 buildings and Class 4 parts of a building compared with other parts/areas of these buildings, and Class 3 and 5 – 9 buildings.

Class 3 and 5 – 9 buildings and commons areas in Class 2 buildings need to meet required energy intensities outlined in J1P1. The DTS Provisions in Parts J4 to J8 and J9D3 provide a solution for the different elements of a building required to meet the energy efficiency provisions.

For sole-occupancy units within a Class 2 building and for a Class 4 part of a building, the building must effectively meet star rating and heating and cooling load limits as those that apply to Class 1 residences.

Part J3 Elemental provisions for a sole-occupancy unit of a Class 2 building or a Class 4 part of a building contains the DTS Provisions that SOUs (Class 2 or Class 4 part) need to comply with to satisfy J1P2 and J1P3. 

If they want to, a designer or builder can choose to use a Performance Solution instead of the DTS Provisions for any aspect of the Performance Requirements. For example, they could comply with a different standard, such as the Swiss Passiv Haus standard, and present the Approval Authority with evidence that this meets or exceeds the thermal performance and building sealing provisions of the NCC.

Slide 8:

Regardless of the solution used, appropriate and sufficient evidence must be provided to the Approval Authority, to allow them to assess whether the solution meets the Performance Requirements. 

Slide 9:

DTS Provisions in Section J of NCC Volume One. Part J3 Elemental provisions for a sole-occupancy unit of a Class 2 building or a Class 4 part of a building: Given the similarities between an SOU and a Class 1 building, Part J3 provides similar DTS compliance solutions to those offered in Volume Two.

There is the choice between undertaking a NatHERS energy rating assessment using J3D3 or developing a solution using the elemental provisions in J3D4 to J3D10.

Part J4 Building fabric: Although occupant comfort is not a primary goal of these provisions, one of the essential aspects of energy efficiency of a building is to ensure that the building is constructed in a manner that enhances the comfort levels of occupants to the extent that they feel less need for air-conditioning. 

This is even more important in a commercial building that is likely to be air-conditioned for much of the time. 

Part J5 Building sealing: Building sealing is an important part of overall energy efficiency and the control of air leakage will have a major impact on the thermal performance of the building. 

Good building sealing reduces the energy required for artificial heating, cooling and humidity control. 

The DTS Provisions for building sealing have been developed to control unwanted air leakage through the building envelope. 

As with all other aspects of these Provisions, each element within Section J is designed to work as a system to ensure the building achieves the desired level of energy efficiency. 

Part J6 Air-conditioning and ventilation: HVAC (Heating, Ventilation and Air-Conditioning) systems usually constitute the largest energy end-use in a building, estimated at 43%. 

The principles of Part J6 are based on the following 3 key points:

Efficient design of air-conditioning and ventilation systems is an essential part of building environment management.

Increasing demands for internal thermal comfort drive the need for energy efficient systems.

The NCC has a range of measures that remove poor practice from new installations and encourage efficient system design.

NCC Volume One Part F6 also contains provisions for ventilation systems in addition to Part J6.

Part J7 Artificial lighting and power: Research indicates lighting is typically responsible for up to 26% of the electrical energy used in an office building. Therefore, artificial lighting measures are designed to curb unreasonable energy use. 

The provisions for lighting also reflect the ongoing transition by industry and consumers to the use of more energy efficient LED lighting. 

Lighting inefficiencies also have a compounding effect in warmer climates because the extra electrical load for lighting translates to waste heat that increases the load on the air-conditioning system. 

Lighting designers should also note that there is a range of adjustment factors they can use. These factors can significantly increase the amount of lighting that a space can have above the base line. They involve things like the use of motion sensors to reduce lighting when a room is not in use.

(Note 1 (reference for lighting use in first Part J7 notes): Pitt & Sherry with input from BIS Shrapnel and Exergy Pty Ltd, for the DCCEE, Baseline Energy Consumption and Greenhouse Gas Emissions – In commercial Buildings in Australia, Part 1 – Report, November 2012 (pg. 7).)

Part J8 Heated hot water supply and swimming pool and spa pool plant: The provisions covering heated water supply for food preparation and sanitary purposes are contained within Part B2 of NCC Volume Three.

Part J9 Energy monitoring and on-site distributed energy resources: The provisions cover energy monitoring and facilitating the easy future retrofit of renewable energy and electric vehicle charging equipment.

Specifications: There are also 10 specifications relevant to the Section J. Of these, 6 relate to and support the Deemed-to-Satisfy Provisions. The remaining relate to the Performance Requirements and Verification Methods in Section J.

Slide 10:

Energy efficiency ratings for SOUs/apartments.

NatHERS assessment: One way of meeting the heating and cooling load Performance Requirement J1P2 for an SOU/apartment is to do a house energy rating, which assesses the thermal performance of the building fabric, as a whole. This is the NatHERS building energy efficiency rating that is generally used to demonstrate the compliance of a Class 1 or Class 10 building.

The NatHERS rating system runs from 0 to 10 stars. Zero stars means that the building/apartment has little to no energy efficiency features or savings, while 10 stars means that the building/apartment should not need additional energy to heat it or to cool it to a comfortable temperature. 

Each individual apartment in a building must achieve a minimum of a 6 star rating.

But the average energy rating for all the SOUs across a building must be 7 stars. For example, if a complex had 4 SOUs, then one could have a 6 star rating, as long as the total ratings for the other 3 added up to at least 22, e.g. they could be 7, 7, and 8. (6+7+7+8=28, 28/4 units = 7 star average).

Individual heating and cooling loads: Buildings/apartments in some climate zones must also meet individual cooling and heating load limits, specific to the climate zone. This applies in “mixed” climate zones where both heating and cooling are required at different times of the year. 

It doesn’t apply in climates that are dominated by hot or cold weather, for example the climate zones in much of the Northern Territory, Tasmania and some zones in Queensland and Western Australia.

Where there are specific heating and cooling loads, it means that a building/apartment must meet energy efficiency requirements for both heating and cooling, as well as meeting the overall energy efficiency target. 

So, an SOU that faces west on the top floor of a block of units in a mixed climate, for example in Canberra or Adelaide, might perform really, really well in winter – i.e. it has a very low heating load – while performing badly in summer – i.e. having a high cooling load. When the two loads are added together the SOU might remain under the total required for a 6 star minimum rating, but if the SOU exceeds the cooling load limit, it would not comply with the building fabric efficiency requirements of J1P2. (The builder/designer would have to change the design to reduce the use of energy to cool the building/apartment before the apartment could achieve a 6 star minimum rating.)

The actual heating loads, cooling loads and overall loads that a building must meet vary by climate zone. This is because it is not reasonable to expect a building in a cooler climate zone, for example in Canberra, to use the same energy for heating in winter as a building in a milder climate zone, say in Brisbane. This means that an apartment in Canberra with a 7 star rating will use more energy for heating than a similar apartment in Brisbane which also receives a 7 star rating.

The ABCB Standard 2022: NatHERS heating and cooling load limits, contains the separate heating and cooling load limits that apply to the design and construction of dwellings that are assessed using the NCC’s energy rating assessment pathway.

NatHERS assessment. Only a rating done using a NatHERS accredited software tool is acceptable. 

NatHERS assessment can be complex, as a lot of building data needs to be entered correctly into the software. It must be done by a qualified, accredited assessor using the building plans and details that will be submitted for building approval. The NatHERS Assessor provides a formal certificate of the star rating, and stamps the building plans.

Once a star rating has been completed for the building and the plans have been stamped, salient details of the plans cannot be changed without doing another rating.

Some designers and builders will work with a NatHERS assessor early in the design process to ensure that a new building will achieve a high energy efficiency star rating, particularly as more people are prepared to pay a premium for good energy efficiency. 

The NatHERS software can be used to identify the elements of the building’s design that are contributing to poor energy efficiency and a poor star rating. For example, the software can identify that large unshaded windows on the west of the building are increasing the cooling load in one or more apartments. “Tweak” a building’s design and construction features to improve the energy efficiency and therefore the star rating. If this is done early in the design process, then big improvements can be made to energy efficiency relatively easily and cheaply. 

For example, there is a misconception that double glazing is always the solution for achieving good thermal performance, particularly in mixed climates, and double glazing can be expensive. But, in fact, altering the size of windows on different orientations and changing the shading on windows can go a long way towards improving a building’s energy efficiency and therefore its star rating. For example, increasing the width of the eaves on the east and west of a building to provide shade over glazing can help to reduce solar gain in summer. Alternatively, some other kind of fixed shading can achieve the same end, e.g. a pergola.

An experienced NatHERS assessor can identify the key elements contributing to a poor star rating and suggest less expensive improvements that can help to increase the rating.

Other requirements: A NatHERS rating is not sufficient on its own to comply with J1P2 and J1P3 for an SOU. 

The building also has to comply with the other common parts of the DTS Provisions such as J5 for building sealing (J1P2) and J6 for air-conditioning and ventilation (J1P3) to fully meet the requirements of J1P2 and J1P3. 

Points of potential confusion: When the NCC references a climate zone, it is referring to one of the 8 climate zones described in Schedule 1 Definitions in the NCC.

The climate zones used in the NatHERS software are not the same as the NCC climate zones. NatHERS software uses a more detailed set of climate zones (69 as at early 2021) that recognise a wide set of climate differences including wind patterns. This doesn’t change the assessment of which NCC climate zone a building falls into.

Energy efficiency star ratings similar to NatHERS ratings are used for other purposes in some States/Territories. For example, the ACT requires buildings and apartments being bought and sold to advertise an energy efficiency rating, known as an EER. If the apartment is brand new and has never been occupied, a NatHERS rating can be used as the EER (this is usually the NatHERS rating that the apartment received in order to gain building approval). If the apartment has been occupied, however, the EER is not quite the same as a NatHERS rating. It is done using different software and rates the SOU on a scale of 1-6 stars only. 

An existing apartment that receives a 6 star EER rating would not necessarily achieve a 7 star NatHERS star rating. If a trainee is working in the ACT or nearby, they need to understand the difference between these two rating schemes. An EER is simpler and cheaper than a NatHERS assessment, but you can’t use an EER star rating to apply for building approval for a new building or renovations.

NSW uses a similar rating system, for Class 2 SOUs and Class 4 parts of a building, called BASIX. This tool provides NSW apartments with the same level of performance as NatHERS 7 star.

Slide 11:

Interpreting the DTS Provisions in Section J

Question 1: According to Part J3, what DTS Provisions apply to ceiling fans in a sole-occupancy unit of a Class 2 building or Class 4 part of a building?

J3D4 Ceiling fans in a sole-occupancy unit of a Class 2 building or Class 4 part of a building

A ceiling fan must be installed in accordance with Table J3D4 in specified climate zones and certain states permanently installed, have a speed controller.

Question 2: According to Part J4, what is the minimum Total R-Value required for a roof or ceiling in the following climate zones: climate zone 3? climate zone 6? climate zone 8?

J4D4 Roof and ceiling construction. Climate zone 3 = R3.7 for a downward direction of heat flow. Climate zone 6 = R3.2 for a downward direction of heat flow. Climate zone 8 = R4.8 for an upward direction of heat flow.

Question 3: According to Part J5, when must an exhaust fan have a sealing device like a self-closing damper?

J5D6 Exhaust fans. A sealing device is required when the exhaust fan services a conditioned space, or habitable room in climate zones 4, 5, 6, 7 or 8.

Question 4: According to Part J6, a mechanical ventilation system must have a time switch if the air flow rate is more than 1000 L/s. When does this requirement not apply? 

J6D4 Mechanical ventilation system control. J6D4(4) Time switches—

A time switch is not required for a mechanical ventilation system that serves only one SOU in a Class 2, 3 or 9c building or a Class 4 part of a building, building where mechanical ventilation is needed for 24 hour occupancy.

Question 5: According to Part J7 , what controls can be used for exterior artificial lighting attached to or directed at the façade of a building? J7D6 Exterior artificial lighting

Exterior artificial lighting attached to or directed at the façade of a building must be controlled by either, a daylight sensor, or a time switch that is capable of switching the power to the system on and off at variable pre-programmed times and on variable pre-programmed days, and if the total lighting load exceeds 100 W, use LEDs for 90% of the lighting load, or motion sensor (in line with Specification 40), or a separate time switch (in line with Specification 40) when the lighting is used for decorative purposes).

Slide 12:

Energy efficiency Assessment Methods

Whether you choose to use a DTS Solution or a Performance Solution or a combination of both, you may need to provide some evidence that the proposed solution complies with the Performance Requirements.

For Section J Energy Efficiency, the NCC provides 5 Verification Methods for assessing possible compliance solutions, which are shown on the slide.

DTS Solution can only be assessed with evidence of suitability and/or expert judgement.

Slide 13: 

Understanding Verification Methods for energy efficiency in Volume One

J1V1 NABERS Energy

This Verification Method verifies the energy efficiency of the whole building (but only the common areas in a Class 2).

It Can be used for Class 3, 5 and 6 buildings and common areas in Class 2 buildings. 

NABERS Energy is an energy modelling framework, used primarily to benchmark a building's energy use against a 6-star scale.  It is most commonly used to benchmark the actual performance of a building, but its protocols can also be used to predict how much energy a building would use.

The requirement in the NCC is for the building owner to agree to a minimum star NABERS Energy rating based on the building classification, and demonstrate other services, such as lighting, air-conditioning etc. achieve minimum levels outlined in the Verification Method.

Additional thermal comfort and other DTS Provisions also apply. That is, achieving NABERS Energy compliance does not satisfy all the requirements of J1P1.

J1V2 Green Star

This Verification Method verifies the energy efficiency of the whole building (but only the common areas in a Class 2).

J1V2 can be used for Class 3, 5, 6, 7, 8 or 9 buildings and common areas of Class 2 buildings.

Green Star is a rating tool that compares the proposed building to a reference building compliant with the DTS Provisions in Section J.  In this way it is similar to operation to J1V3.

A building that achieves a Green Star Design and As-Built rating, will exceed the minimum energy efficiency requirements of J1P1. 

Additional thermal comfort targets and other DTS Provisions applying to satisfy NCC energy efficiency requirements. That is, achieving a Green Star rating does not satisfy all the requirements of J1P1.

J1V3 Verification using a reference building. This Verification Method verifies the energy efficiency of the whole building (but only the common areas in a Class 2).

It can be used for Class 3, 5, 6, 7, 8 or 9 buildings and common areas of Class 2 buildings.

It compares the annual 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, J1P1 is satisfied. 

Additional thermal comfort targets and other DTS Provisions also apply. That is, the building owner still has to demonstrate compliance with other parts of J1P1.

J1V4 Verification of building envelope sealing. This Verification Method only demonstrates the compliance of the building sealing with requirements. It does not demonstrate compliance against other energy efficiency requirements.

It can be used for Class 2, 3, 4, 5, 6, 8 or 9 buildings. 

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).

J1V4 provides an option to the prescriptive building sealing requirements in Part J5.

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

This Verification Method verifies the energy efficiency of the Class 2 SOUs.

It can only be used for Class 2 sole-occupancy units.

It compares the annual greenhouse gas emissions of a proposed building to that of a reference building which is based on the Deemed-to-Satisfy Provisions. 

If the heating and cooling loads of the proposed building do not exceed that of the reference building, J1P2 is satisfied. 

J1P3 can also be satisfied by J1V5(2) by comparing the energy usage of the proposed building with the reference building.

Additional requirements which need met to be fully comply with J1P2 and J1P3 can be found in Specifications 33 and 45.

Slide 14:

Match each Part in Section J with its subject. Part J4 equals Building fabric, Part J5 equals Building sealing, Part J6 equals Air-conditioning and ventilation, Part J7 equals Artificial lighting and power, Part J8 equals Heated water supply and swimming pool and spa pool plant, Part J9 equals Energy monitoring and on-site distributed energy resources

Slide 15:

True or False? For an SOU in a Class 2 building, a minimum 6 star energy efficiency rating is not sufficient to demonstrate compliance with J1P1. If you answered True - Yes, that’s right. 

A minimum 6 star rating for an SOU demonstrates compliance against just some requirements. 

You also need to demonstrate compliance with other DTS Provisions for things like thermal breaks and building sealing. 

Slide 16:

Which of the following meets requirements? Which of the Class 2 buildings shown on the right meets the minimum energy efficiency ratings required by Section J of NCC Volume One?

If you answered building A you are correct!

Building A meets the minimum NatHERS energy efficiency star rating requirements

Building B does not meet requirements because the average rating is less than 7.

Building C does not meet requirements because one SOU has not achieved the minimum 6 star rating.

Slide 17:

Which building classifications can each Verification Method be used with?

J1V1 NABERS Energy - Class 3, 5 and 6 buildings, and common areas of Class 2 buildings

J1V2 Green Star - Class 3, 5, 6, 7, 8 or 9 buildings, and common areas of Class 2 buildings

J1V3 Verification using a reference building - Class 3, 5, 6, 7, 8 or 9 buildings, and common areas of Class 2 buildings

J1V4 Verification of building envelope sealing - Class 2, 3, 4, 5, 6, 8 and 9 buildings

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

Slide 18:

Other useful resources. These resources are not mandatory. They provide guidance and help, but nothing in them needs to be complied with in order to comply with the NCC.

The calculators are guidance tools and are not intended to be used as evidence of compliance. This means that you should not present evidence from the lighting calculator, for example, to demonstrate compliance with the lighting energy efficiency requirements in Volume One.

The façade calculator assists in understanding J4D6 Walls and glazing DTS requirements.

The fan system calculator allows a range of inputs, including various fan system characteristics, fouling risk, role of selected fan system, duct sizes and runs, flow rates, roughness, motor input power and more. 

The pump system calculator allows a range of inputs, including pump system characteristics, speed control, operating hours, pump design, pump stage, pump speed, pump configuration, pipe details and more.

The lighting calculator allows a range of inputs, including floor areas, perimeter of space, ceiling heights, design illumination power load, space type, light colour, and more.

Slide 19:

Summary. Section J Energy Efficiency. 4 Performance Requirements. 5 Verification Methods

DTS Provisions. 9 Parts in Section J. DTS Provisions. 10 Specifications supporting Section J. 6 of these Specifications support DTS Provisions. 

Different DTS Provisions apply to Sole-occupancy units in Class 2 buildings and a Class 4 part of a building, Common areas of these buildings and other Class 3, and 5-9 buildings, You can get more information and access the NCC from the ABCB website (ncc.abcb.gov.au). 

Slide 20:

Key points. The overall aim is to reduce greenhouse gas emissions from commercial buildings in Australia

Compliance with requirements reduces energy used to maintain a comfortable temperature and operate the building

Heating and cooling loads are key, and evidence of compliance is commonly provided through some kind of energy rating

Other elements must be met using DTS Provisions or a compliant Performance Solution

Slide 21:

Thank you for your time. That brings our presentation on using the energy efficiency provisions in NCC Volume One to a close. If you’d like more information please visit abcb.gov.au