The focus of this video is how to use the energy efficiency provisions in NCC Volume One.
[voice over] Using the energy efficiency provisions in NCC Volume One.
The focus of this presentation is on how to use the energy efficiency provisions in NCC Volume One.
This module is best viewed with a copy of the NCC on hand – to access the NCC, visit abcb.gov.au and register or log in to freely access it.
In this presentation you will learn:
The energy efficiency Performance Requirements in Volume One
Compliance solutions for energy efficiency in Volume One
Energy efficiency ratings for Single Occupancy Units
Energy efficiency DTS Provisions in Volume One, and
Assessment Methods for energy efficiency inVolume One.
We will also examine a number of useful resources.
Where is energy efficiency covered in NCC Volume One?
Section J Energy efficiency is where we can find the energy efficiency provisions.
The single Performance Requirement, JP1 energy use, reflects the key focus 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 and out of the building, as needed to maintain a comfortable temperature in the conditioned spaces of the building, and
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 DTS provisions also reflect the key energy efficiency concerns, with particular DTS provisions that relate to the different factors that can affect the thermal performance of a building. This includes provisions for the construction of the building fabric, building sealing, ventilation, lighting, power and heating.
J2 and J4 are no longer used. The provisions that were in these parts have now been incorporated into other Parts. However, the numbering has been retained.
Section J also contains four Verification Methods and five Specifications, which are discussed later in this module.
Let’s take a look at the energy efficiency Performance Requirements. As mentioned previously, JP1 Energy Use is the single Performance Requirement for energy efficiency in Volume One.
The key objective of the NCC Volume One energy efficiency provisions is to reduce the greenhouse gas emissions that a building produces over its lifetime. An additional benefit of the provisions is that an energy efficient building can be more comfortable to live in or work in and cheaper to operate.
The energy efficiency provisions in NCC Volume One addresses two key aspects:
Firstly, the thermal performance of the building envelope – that is, the ease with which heat flows into and out of the building. It is assumed that improving the thermal performance of the building fabric will reduce the need for artificial heating and cooling. 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 reduce greenhouse gas emissions over the life of the building.
Secondly, the efficiency of the building’s services – that is:
How much energy is used to run things like air-conditioning, heating and lighting and to heat water and
The source of the energy used, particularly the use of renewable energy, reclaimed energy or low greenhouse gas intensity fuels.
Let’s look at some key terms and definitions in this Performance Requirement.
First is services.
A service is a mechanical or electrical system that uses energy to provide air conditioning, mechanical ventilation, heated water supply, artificial lighting, vertical transport and the like within the building.
This is not cooking facilities, portable appliances or systems used solely for emergency purposes.
The next term that we need to understand is features that facilitate the efficient use of energy.
This might be, for example, energy efficient appliances, electrical equipment, smart meters, and renewable energy sources.
The next is the level of human comfort. Human comfort is the maintenance of a comfortable temperature in the condition spaces within the building with minimal use of artificial heating and cooling.
The next is solar radiation. The intent is to use passive solar design to warm the building in cooler weather and reduce the entry of unwanted sunlight and heat in warmer weather.
The next term is energy source. Here we're talking about onsite renewable energy generation. This includes solar, wind, wave action, and geothermal generation as well as reclaimed energy. This is not a green power type energy contract.
The next concept here is sealing of the building envelope. The intent is to seal the building fabric between the conditioned spaces and non-conditioned spaces to prevent unwanted entry and loss of heat.
The next is conditioned space. This is a space within a building, including a ceiling supply air plenum or return air plenum where the environment is likely by the intended use of the space to have its temperature controlled by the air conditioning.
The next concept is regulated energy. This is the amount of energy consumed by building services minus the amount of renewable energy generated and used on site.
The last term we'll look at is the annual hours of operation. This is the number of hours when the occupancy of a building is greater than 20% of the peak occupancy. Occupancy and operation profiles for different classes of buildings are in specification JV(c).
The building envelope in Section J
Let’s now look at an example of how the building envelope applies in Section J of NCC Volume One.
For the purposes of Section J of NCC Volume One, which parts of the building in the image here on the right are within the building envelope?
Pause the video and take a moment to consider your answer, when you are ready to see the answer restart the video.
As we can see here, the building envelope is shown in this example in the blue dotted line. What we see here is that it specifically excludes the plant room and the access stair. When we look at the definition, we can see here that the envelop for the purposes of Section J in Volume One means that the parts of the buildings fabric that separate a conditioned space or habitable room from the exterior of the building or a non-conditioned space including; the floor of a rooftop plant room, lift machine room (or the like) and the floor above a carpark or a warehouse and the common wall with a car park warehouse (or the like).
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 are some distinct difference in how reducing heating and or cooling loads is treated for sole-occupancy units of Class 2 buildings and Class 4 parts of a building compared with:
Other parts or areas of these buildings, and
Class 3 and Class 5 to 9 buildings.
Meeting the heating and cooling load limits is key to energy efficiency. The loads that must be met and the way performance are assessed and demonstrated is different for different types of buildings.
For sole-occupancy units within a Class 2 building and for a Class 4 part of a building, the building must effectively meet similar star ratings and heating and cooling load limits as those that apply to Class 1 residences, and they must be assessed using a suitable house energy rating software against the heating and cooling load limits in an ABCB Standard.
But the energy rating itself doesn’t satisfy all the DTS Provisions so other parts of Section J must also be met to achieve compliance with the DTS Provisions for energy efficiency. The requirements for Single Occupancy Units are summarised in J0.2, J0.3, J0.4 and J0.5, and they cover things like the house energy rating itself, the building fabric, thermal breaks and floor edge insulation and building sealing. Note that some of these clauses reference other DTS provisions in Section J, for example J1.2, J1.6 and J3.
Other Class 2-9 buildings must comply with Part J1 to meet the required heating and cooling load limits. These requirements also apply to common areas of a Class 2 building, i.e. areas that are not within the SOUs in the building.
In addition, all buildings of all classes must comply with Parts J3, J5, J6, J7 and J8, with a few exceptions which are noted later.
There are a number of different Verification Methods that can use to demonstrate compliance with some or all of the requirements, and these will be discussed shortly.
A Performance Solution may be used instead of the DTS Provisions to meet the Performance Requirement.
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.
All options for compliance must be supported with suitable evidence and or documentation to demonstrate the compliance has been achieved and assessed and approved by the approval authority.
Energy efficiency ratings for Single Occupancy Units and apartments
The first is NatHERS star ratings:
One way of meeting the heating and cooling load and building fabric Performance Requirement JP1 for an SOU or apartment is to do a building energy rating, which assesseses the thermal performance of the building fabric, as a whole. This is the NatHERS building energy efficiency rating that is generally used to demonstrate compliance of a Class 1 or Class 10 building.
The NATHERS rating system runs from 0 to 10 stars. Zero stars means that the apartment or has no energy efficiency features or savings, while 10 stars means that the building or apartment should not need additional energy to heat it or to cool it to a comfortable temperature.
Each individual apartment in thebuilding must achieve a minimum of a 5 star rating.
But the average energy rating for all the SOUs across a building must be 6 stars. For example, if a complex had 4 SOUs, then one could have a 5 star rating, as long as the total ratings for the other 3 added up to at least 19. i.ie. they could be 7, 6, and 6 which gives you an average of 6 stars.Similarly, the complex were to comply if the individual SOUs were rated as 5, 5, 7 and 7 which also gives an average of a 6 star rating.
In terms of individual heating and cooling loads:
Buildings and apartments in some climate zones must also meet individual cooling and heating load limits, that are 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 which are dominated by hot or cold weather, for example the climatesin 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 or 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 well in winter – i.e. it has a very low heating load – while performing poorly in summer – i.e. having a high cooling load. When the two loads are added together the SOU might remain under the total load required for a 5 star minimum rating, but if the SOU exceeds the cooling or heating load limit, then it does not meet the building fabric efficiency requirements of JP1.
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 that a building in a cooler climate zone, for example Canberra, to use the same energy for heating in winter as a building in a milder climate zone, say in Sydney. This means that an apartment in Canberra with a 6 star rating will use more energy for heating than a similar apartment in Sydney that also receives a 6 star rating.
The ABCB Standard 2019:1: 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.
Note that in New South Wale separate heating and cooling load limits (called “caps”) in its Building Sustainability Index or BASIX thermal performance comfort level requirements
Only a rating done using a NatHERS accredited software tool is acceptable. Currently the accredited tools include: AccuRate, BERSPro and FirstRate5 and Hero. To see which software and version is currently accredited, check the NatHERS website.”
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 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.
There are also some other requirements we need to consider,
A NatHERS rating is not sufficient on its own to comply with JP1 for a Single Occupancy Unit. You have to demonstrate compliance with the other requirements for thermal construction, thermal breaks, floor edge insulation and building sealing.
Remember that the building also has to comply with the other common parts of the DTS Provisions, such as those for air-conditioning and ventilation, power and lighting, heated water supply, swimming pools and spas and facilities for energy monitoring.
These provisions were listed previously in this presentation
Now there are some points of potential confusion here:
When the NCC references a climate zone, it is referring to one of the 8 climate zones described in Schedule 3 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 (currently there are 69) 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.
DTS Provisions in Section J of NCC Volume One
Part J0 Energy Efficiency:
This part explains the overall application of the DTS provisions for Section J, for all classes and all types of buildings. It also contains the specific DTS provisions applicable to Single Occupancy Units, in Class 2 buildings, and Class 4 parts of a building.
Finally, it references some DTS provisions within other parts in Section J that also apply to Single Occupancy Units.
Part J1 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 J3 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 increases the capacity to reduce 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 J5 Air-conditioning and ventilation systems:
Heating, Ventilation and Air-conditioning or HVAC systems usually constitute the largest energy end-use in a building and is estimated to be around 43%.
The principles of Part J5 are based on the following three key points:
Firstly, efficient design of air-conditioning and ventilation systems is an essential part of building environmental management.
Next, increasing demands for internal thermal comfort drive the need for energy efficient systems.
And also, the NCC has a range of measures that remove poor practice from new installations and encourage efficient system design.
NCC Volume One Part F4 also contains provisions for ventilation systems in addition to Part J5.
Part J6 Artificial lighting and power:
Research indicates that 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.
Part J7 Heated hot water supply and swimming pool and spa pool plant:
The provisions covering heated water supply for food preparation and sanitary purposes that used to be in Part J7.2, are now contained within Part B2 of NCC Volume Three.
Part J8 Facilities for energy monitoring
This part covers facilities that provide a means for accessing information about abuilding’s energy use. This includes time-of-use consumption of electricity and gas.
In buildings with a floor area over 2500 m2, systems must allow the recording and central storage of individual time-or-use data for key services such as; air conditioning plant, artificial lighting, central hot water supply and appliance power.
This applies to all Class 2 to Class 9 buildings except: Single Occupancy Units within a Class 2 building and Class 8 electricity network substations.
There are also five specifications relevant to the Section J Deemed-to-Satisfy Provisions. The Specifications support the DTS Provisions.
Let’s look at some questions to help us interpret the DTS provisions in Section J.
Question 1: According to Part J0, what DTS provisions apply to ceiling fans, when fans are required to meet other DTS Provisions?
J0.3 Ceiling fans
A ceiling fan must be:
Have a speed controller, and
Serve the whole room, with limits on the size of the room based on the blade rotation diameter.
Question 2: According to Part J1, 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?
J1.3 Roof and ceiling construction
Climate zone 3 is 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 J3, when must an exhaust fan have a sealing device like a self-closing damper?
J3.5 Exhaust fans
A sealing device is required when the exhaust fan services are:
Conditioned space, or
A habitable room in climate zones 4, 5, 6, 7 or 8.
Question 4: According to Part J5, a mechanical ventilation system must have a time switch if the air flow rate is more than 1000 Litres per second. When does this requirement not apply?
J5.3 Mechanical ventilation system control
J5.3(d) Time switches—
A time switch is not required for a:
Mechanical ventilation system that serves only one Single Occupancy Unit in a Class 2, 3 or 9c building or a Class 4 part of a building, or
It is also not required in a building where mechanical ventilation is needed for 24 hour occupancy.
Question 5: According to Part J6, what controls can be used for exterior artificial lighting attached to or directed at the façade of a building?
J6.5 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, or
A motion sensor if the total lighting load exceeds 100 W
For Section J Energy Efficiency, the NCC recognises four valid ways of assessing possible compliance solutions, which are shown here.
All four methods can be used to determine compliance with all or part of the Performance Requirements when you are using a Performance Solution.
The first is Verification Method. This is using one of the four verification methods in Section J, including:
JV1 NABERS Energy for Offices
JV2 Green Star
JV3 Verification using a reference building
JV4 Building envelope sealing
It could also be using another Verification Method, such as an overseas code or standard.
The second is comparison with DTS provisions. This is where we compare a Performance Solution with DTS provisions of Section J.
The next is Evidence of suitability. This is meeting the requirements of an energy rating option in the DTS provisions of Section J and meeting the prescriptive requirements of all of the relevant DTS provisions in Section J.
The last is Expert Judgement. Using the expert judgement of a suitably qualified person, and the expert themselves must have demonstrated knowledge of technical issues and peer recognition.
Understanding Verification Methods for energy efficiency in Volume One.
The first is JV1 NABERS for Offices
This Verification Method verifies the energy efficiency of the whole building.
It applies to only Class 5 buildings (that is offices).
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 5.5 star base building Energy Commitment Agreement with the NSW Department of Planning, Industry and the Environment, AND
Obtain a NABERS Energy Modelling Report, that demonstrates that the base building component will produce greenhouse gas emissions of no more than 67% of the total building energy use at a 5.5 star level.
The “base” building means excluding tenant supplementary heating and cooling systems, external lighting and carpark services.
Additional thermal comfort and other DTS Provisions also apply. That is, achieving NABERS Energy for Offices compliance does not satisfy all the requirements of JP1.
JV2 Green Star
This Verification Method verifies the energy efficiency of the entire building.
JV2 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 of JV3.
A building that achieves a Green Star Design and As-Built rating, will exceed the minimum energy efficiency requirements of JP1.
Additional thermal comfort targets and other DTS Provisions also apply to satisfy NCC energy efficiency requirements. That is, achieving a Green Star rating does not satisfy all the requirements of JP1.
The next is JV3 Verification using a reference building
This Verification Method verifies the energy efficiency of the whole building.
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, JP1 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 JP1.
The final one is JV4 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.
JV4 provides a method of demonstrating compliance with the building sealing requirements in JP1(e).
JV4 provides an option to the prescriptive building sealing requirements in Part J3.
Match each Part in Section J with its subject.
Here we are looking at;
Artificial light and power
Air-conditioning and ventilation systems
Heated water supply and swimming pool and spa pool plant
Building sealing, and
Facilities for energy monitoring.
Pause the video, and when you are ready to look and the answers, commence the video again.
- Artificial light and power: Part J6
- Air-conditioning and ventilation systems: Part J5
- Building fabric: Part J1
- Heated water supply and swimming pool and spa pool plant: Part J7
- Building sealing: Part J3
- Facilities for energy monitoring: Part J8
True or False?
For a Single Occupancy Unit in a Class 2 building, a minimum 5 star energy efficiency rating is not sufficient to demonstrate compliance with JP1.
Yes, that’s right. A minimum 5 star rating for an Single Occupancy Unit demonstrates compliance against just some requirements. You also need to demonstrate compliance with other DTS provisions for things like thermal breaks and building sealing.
Which of the Class 2 buildings shown on the right meets the minimum energy efficiency ratings required by Section J of NCC Volume One?
Only Building A meets the NatHERS energy efficiency requirements for a minimum average of six star rating. Buildings B or C both have an average star rating below six stars, and so do not meet the minimum requirement. Building C also has an SOU with an energy rating of four stars – the minimum NatHERS rating required for any SOU is five stars.
It should also be noted that buildings still need to meet additional heating and cooling loads and requirements of other DTS Provisions.
Which Classes of buildings can each of the following Verification Method be used with?
JV1 NABERS for Offices
JV2 Green Star
JV3 Comparison with a reference building
JV4 Building sealing
Take a moment to consider your answer, you may need to pause this video. When you are ready to see the answers, commence the video again.
- JV1 NABERS for Offices: Class 5 buildings (offices) only
- JV2 Green Star: Class 3, 5, 6, 7, 8 or 9 buildings, and common areas of Class 2 buildings
- JV3 Comparison with a reference building: Class 3, 5, 6, 7, 8 or 9 buildings, and common areas of Class 2 buildings
- JV4 Building sealing: Any Class 2-9 building
We will now examine some other useful resources. ABCB calculators can help with the calculations used in DTS Provisions. There are calculators for:
The Facade Calculator assists in understanding and applying the NCC Volume One Part J1.5 Building fabric DTS Provisions, and the JV3 Verification Method (Verification using a reference building).
The Fan System Calculator assists in understanding and applying NCC Volume One, Part J5.4, Fan Systems DTS Provisions.
The Pump System Calculator assists in understanding and applying NCC Volume One Part J5.7 Pump System DTS Provisions.
The Lighting Calculator assists in understanding and applying the NCC Volume One Part J6 Artificial lighting DTS Provisions.
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 and guidance tools are not intended to be used as evidence of compliance.
The key points from this presentation are:
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
This brings us to the end of this presentation.
Thank you for viewing this NCC Tutor module. Check out the other NCC Tutor modules available to build your understanding of the NCC.
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