What is a BCA Section J Report?
A BCA Section J report summarises and explains the requirements of the section J of the building code of Australia for a particular building by considering the national and local area regulations. This report is a the result of comprehensive analysis of the proposed building project against the requirements of the section J provisions. An expert consultant compiles this report by studying the design of the proposed development and address the findings of the design based on the energy efficiency requirements of the ‘Deemed To Satisfy’ provisions of the section J of the BCA. If those requirements are not possible to comply with due to the particulars of a project, an alternative approach using a JV3 assessment method can be formulated which is then being compiled in form of a BCA section J JV3 compliance report instead of a Deemed to Satisfy report.
This report is commonly used at the Construction Certificate (‘CC’) stage of a development for non-residential buildings. Despite the fact that local area councils and private certifiers require this compliance report at the CC stage, Eco Certificates recommend that our valued clients choose to compile this report at the DA stage because of the fact that some areas of the Section J requirements are particularly stringent (mainly glazing) and could potentially affect the overall design of the project. If you have been asked by your local council to provide a BCA Section J report it is necessary that you engage the services of an experienced and qualified BCA Section J consultant to provide you with this service in a suitable format to guarantee a successful council approval at the CC stage. This is where our years of experience and diverse resume of complex projects shine above our industry sector so please contact us today for a competitive fee and a first class, quick service from Eco Certificates.
Background to BCA section J report (history and future)
Certain sections of volumes One and Two of the BCA list the energy efficiency requirements of various types of developments. These provisions are aimed at targeting and reducing greenhouse gas emissions resulting from the construction industry activities within Australia.
This plan of action has been envisioned since 1997 when the Federal government released a report stating that a range of requirements were needed to address global warming through energy saving from built environment. This was heralded in 2000 when the Federal government prompted the States and Territory governments to introduce mandatory energy efficiency standards into the BCA.
The first of these introductions was made in January 2003, with energy efficiency requirements for housing in BCA Volume Two. Multi-residential building requirements were introduced shortly afterwards, into the BCA Volume 1 in May 2005 with the second stage of introductions.
The third stage of these introductions involved creating energy efficiency requirements for all other classifications under BCA Volume One in 2006. In addition to this, in 2006, the requirements for housing were increased to 5 star NatHERS rating or equivalent.
The push to increase all building ratings to be increased was further promoted in 2009, with the housing rating being increased to a 6 star rating However, since 2010 there have been only minor changes to the energy efficiency provisions as a result of the Proposal-for-Change (PFC) process and ABCB project work
The NCC now has a 3 year amendment cycle, from the previous yearly amendment cycle. This means that the NCC 2016 updates stand as valid through till 2019. This has been done to reduce red tape within the industry practice and provide more certainty in the decision making processes.
How is the Section J Report written?
The first stage in BCA Section J reporting is to classify the building according to BCA standard classification and then determine the climate zone of the development. These considerations affect the requirements which would apply to certain building elements mainly envelope elements. The building design documents are analysed and studied carefully to create a clear understanding of the type and scope of the proposal and the areas of the section J of the BCA which are applicable to the building. In an alterations and additions project, only the parts of the building which are being modified or replaced need to be addressed under the section J requirements as well as any new relevant envelope and systems.
For a Deemed to Satisfy assessment of the BCA Section J, each one of the 8 parts of the it is addressed separately for the relevant building elements it addresses and the requirements applicable to that particular elements are recognised and documented. These requirements require calculation of the conditioned area, heat gain and heat loss through windows, as well as the maximum allowable lighting power for the building- considering the allowances from lighting control devices and space geometry. At the end of our reports at Eco Certificates we also compile an easy to follow, readable summary which can be conveniently placed in a prominent text area on the building design plans to be followed by the construction team. The compilation of a BCA Section J JV3 compliance report follows a different path. Initially, a DTS report must be completed for any JV3 assessment because the purpose of a JV3 report is to formulate an alternative solution to justify deviation from the DTS requirements of the BCA section J. The major component of any JV3 assessment is the building energy modeling using EnergyPlus building energy modeling software. Following the guidelines of the JV3 section of the BCA, two models will be created for reference building and alternative design solution and the results from energy simulation of these models are then documented. These results as well as calculations for any renewable energy source solution are then compiled in a BCA Section J JV3 alternative verification solution report by a qualified building energy efficiency consultant.
BCA Section J Report Structure
With introduction of the version 2010 of the Building Code of Australia, BCA Section J has undergone significant changes compared to its previous version and more than any other section of the BCA. The next big change is planned for 2019 release of the BCA and the current version of the BCA which is the 2016 version will be valid until then. The energy efficiency provisions of the BCA Section J are now more stringent and more specific systems and technologies are being recognized. For the first time renewable energy is also recognized in the BCA Section J aiming to reduce the GHG emissions of a building resulting from the consumption of energy. The recognition of the renewable energy sources is only possible by formulating an alternative JV3 assessment.
BCA 2016 is the most recent and current version of the BCA in effect. This recent version does not have major differences with the 2010 version which has undergone major modifications compared to the previous versions of the BCA. The following parts and sub sections are now comprise the energy efficiency provisions required by the BCA Section J 2010:
Part J0 Energy Efficiency: In this part of the BCA Section J performance requirements of class 2 to 9 buildings are described. For sole occupancy units of class 2 buildings or a class 4 part of a building each unit must achieve a minimum 5 stars NatHERS rating and the average of all units in a multi unit development must be at least 6 stars. For class 2 to 9 buildings other than sole occupancies addressed before, performance requirements of the BCA Section J Parts 1 to 8 shall be satisfied. This part of the BCA Section J also requires that ceiling fans which are addressed in NatHERS thermal simulation of sole occupancy units to have certain specifications.
Part J1 Building Fabric: This part of the BCA Section J applies to building elements that form the envelope of a class 2 to 9 building minus a couple of exceptions. Regardless of the utilization place of an insulation, there are several general criteria that must be followed for selection and installation of thermal insulation. Part J 1 sets the minimum R Value performance of insulation elements for Roofs and Ceilings construction, Walls and Floors for each climate zone. Unlike BCA Section J 2009, the 2010 version does not nominates different R Values for different classes of buildings and only considers the climate zone of the development in determining the R Values which seems to be a move in the wrong direction. There is a new table in 2010 version for adjusting the minimum R values required for loss of ceiling insulation due to removal of insulation for installing building elements like ducts, skylights, lighting etc. U-Value and SHGC performance of roof lights is also addressed in this part. BCA Section J 2010 also recognizes the insulation requirements of the envelope walls which are not external walls of the building for the first time.
Part J2 Glazing: BCA Section J Part J2 sets the minimum energy efficiency performance requirements of building glazing elements. The glazing assessment of a building is based on the principle of air conditioning energy value through each glazing element which is the amount of energy lost based on the performance of the glazing and is calculated for each 8 major geographic directions. The sum of air conditioning energy values of all glazing elements for a single facade in each direction for each storey of a building shall not be more than a number which is obtained from multiplying that particular facade area by a certain coefficient. This coefficient has a different value for each climate zone and each class of the building. BCA Section J 2010 for the first time assesses the performance of glazing elements for the internal fabric of the building. This part also sets the requirements of a shading element in order to be able to addressed in the BCA Section J report compilation.
Part J3 Building Sealing: This part of the BCA Section J 2010 sets the requirements for a building sealing in order to prevent unwanted air infiltration which is one of the major sources of energy loss in buildings. Sealing requirements for chimneys and flues, roof lights, windows, doors, exhaust fans and evaporative coolers are addressed in this part of the BCA Section J 2010. Construction of roof, walls and floors for air tightness must also follow the requirements of this part.
Part J4 is Blank: This part of the BCA Section J is left blank in 2010 version and in all later versions up to the most recent version which is 2016. Its previous provisions in BCA Section J 2009 are now being addressed in other parts of the BCA 2010. Part J4 is named Air Movement in BCA 2009 and deals with air movement units energy efficiency requirements, ventilation openings, ceiling fans and evaporative coolers.
Part J5 Air Conditioning and Ventilation Systems: Energy efficiency provisions for HVAC systems and their peripheral systems are listed in this part of BCA Section J 2010. This part addresses areas like sealing and insulation requirements of air conditioning systems and their heating and cooling systems, maximum allowed fan and pump power, time switch requirements, energy efficiency rating of various systems and exhaust system specifications.
Part J6 Artificial Lighting and Power: While for sole occupancy units of class 2 buildings and class 4 parts of the buildings there is a fixed W/m² allowed for illumination power density, other classes of buildings have different values for each functional space of the building in this part of the BCA Section J. For other than sole occupancy units each space in the building is allocated a certain maximum illumination power density which is different for each functional space and the sum of the design illumination power of all spaces shall not exceed the maximum allowed. The maximum illumination power density of each space can be adjusted (increased) by installation of certain energy efficiency mechanisms and also for small spaces. This part of BCA Section J 2010 also has comprehensive provisions for interior artificial lighting and power control, interior decorative and display lighting, artificial lighting around the perimeter of a building and power supply to boiling water and chilled water storage units.
Part J7 Hot Water Supply and Swimming Pool and Spa Pool Plant: This part of BCA Section J 2010 is considering the energy efficiency of spas and swimming pools for the first time. This part has deemed to satisfy provisions for hot water supply, swimming pool heating and pumping and spa heating and pumping. This part no longer allows use of electricity for heating a swimming pool or spa and requires time switches and covers when gas or heat pumps are being used.
part J8 Access for Maintenance and Facilities for Monitoring: Requirements for provision of energy consumption monitoring meters is introduced for the first time in BCA Section J 2010 in addition to previous requirements for access and maintenance. A building with floor area over 500 square meters now requires to have gas and electricity meters installed. A building with floor area over 2500 square meters need to have separate meters to measure energy consumption of different systems in the building like lighting, air conditioning etc.
Specifications: The Specifications parts of BCA Section J 2010 are extensively elaborating on the technical properties and requirements of Construction Materials, Roof and Ceiling Construction, Wall Construction, Floor Construction, Ductwork Insulation and Sealing, Insulation of Piping Vessels, Heat Exchangers and Tanks and Lighting and Power Control Devices. These specifications are being referenced throughout various parts of BCA Section J and must be addressed in a BCA Section J report when it is relevant.
BCA section j performance requirements
The performance requirements under Volume One of Section J BCA, are summarised under two main categories : JP 1, and JP 3.
BCA Section J Report JP 1
JP 1 relates specifically to the requirements to be met within a building to better facilitate the efficient use of energy. JP1 A buildings, including its services, must have, to the degree necessary, features that facilitate the efficient use of energy appropriate to-
- The function and use of the building and services → Each building classification carries with it different standards and necessary information relating to energy consumption rates and this must be taken into account during assessment
- The internal environment → If the environment within the building can be controlled through air conditioning, heating, shading or ventilation, then this is considered within the DTS provisions and through the JV3 method.
- The geographic location of the building → The DTS provisions relate to 8 climate zones, ranging from warm, mild, to cool. Where the building is situated climatically and topographically is a relevant consideration that applies to determining energy efficiency requirements.
- The effects of nearby permanent features such as topography, structures and buildings → The JV3 verification method uses computer modelling to determine the impacts of permanent features observable in the outer development region of the building.
- Solar radiation being (i) Utilised for heating → locating windows in cooler climates towards orientations that provide solar heat gain during winter seasons thus reducing the energy consumption of the building through conditioned heating systems (ii) Controlled to minimise energy for cooling → by reducing the absorption of solar radiation through the building fabric and its transmissions through glazing in hot climates or during summer months. The DTS provisions further provide shading devices that can be utilised along with glass toning or glazing however the type of shading which is being recognised by the DTS is very limited compared to a JV3 computer model.
- The sealing of the building envelope against air leakage → If the building is sealed against infiltration from outside elements, then this will restrict the leakage of unwanted hot or cold air into a conditioned internal building space. This in turn reduces energy consumption from using conditioning to make up for unwanted air leakage.
- The utilisation of air movement to assist heating and cooling → In order to reduce energy consumption through the unwarranted use of air conditioning systems or heating appliances, air movement can be better facilitated in other ways, such as through fans in the summer months instead of the air conditioning unit.
- The energy source of the services → The energy source of a cooling, heating or lighting service impacts the emissions of a building in different ways. The JV3 Method calculates the annual energy consumption in the format of MJ/m2 per annum. This calculated amount can be offset through the use of other sources which utilise solar or wind power or other more unusual sources of renewable or reclaimed energy.
BCA Section J Report JP 3
The performance requirement JP3 relates primarily to the reduction of emissions through efficient heating resources. The utilisation of natural gas over electricity as well as other renewable energy resources is what JP3 aims to foster in all buildings.
The GHG intensity calculated for a source can take account of how efficiently it is used in the building services. High efficiency equipment, such as heat pumps, may make electricity viable as a heating source even though its base greenhouse gas intensity exceeds the threshold nominated in JP3(a).Subclause JP3(a), which sets a limit for the GHG intensity of a source, is primarily targeting the use of resistance electricity for heating of spaces, swimming pools and spa pools. Since the limit is expressed in terms of emissions per unit of thermal energy load, it allows the energy efficiency of services equipment to be taken into account. Limits calculated on this basis can permit the use of grid distributed electricity as the source for high efficiency plant such as heat pumps.
Heating such as for a conditioned space must, to the degree necessary, obtain energy from:
- A source that has a greenhouse gas intensity that does not exceed 100 g CO2-e/MJ of the thermal energy load → This limitation would allow the use of— (a) gas and heating oil as an energy source for heating of a conditioned space; or (b) a combination of electricity and low emission sources such as gas, solar and biomass.
- An on-site renewable energy source → On-site renewable energy sources refer only to those renewable energy sources that are on, or impact upon, the same allotment as the building. In this approach the qualification “to the degree necessary” allows the appropriate renewable energy source not only for the size of the heating required, but the location and availability of the types of renewable energy available on-site.
- Another process as reclaimed energy → Reclaimed energy sources are those that use energy that would otherwise be rejected as waste, such as heat from co-generation, tri-generation or an industrial process. Heat reclaimed through co-generation and Tri Generation systems could be used for the heating of conditioned spaces and can assist with reducing GHG emissions. These systems typically use natural gas or Bio Gas as the fuel for an engine that drives an electric generator. Like Sub Clause (b), the qualification “to the degree necessary” allows the most appropriate reclaim energy process to be used based on the individual design of the building.
There are two main compliance methods within the BCA being the DTS requirements as well as the JV3 Verification method. A DTS study looks at the elements of a building in isolation and disregards the interaction between other elements. It is a list of provisions that apply to the building according to requirements listed under Section J. A DTS study can sometimes deliver an unfavourable result due to the unchangeable nature of the existing provisions it must meet. For example it requires different glazing performance on each orientation and each level which is impractical and aesthetically undesirable and hard to procure. It also sometimes requires very stringent and unrealistically high performance elements which might even not be available in the market.
The alternative process through the JV3 verification method, allows developers to have non-complying elements in the design process according to the BCA, but still demonstrate the building’s compliance with section J. This is done through computer modelling of the building to demonstrate that the alternative design outperforms a DTS complying design although one or more of these elements may not comply to the requirements of the DTS. It makes for a less stringent procedure in one part and increase performance in another area to preserve the energy efficiency of the building. The modelling process can also optimize the design of the building itself.
In general an alternative solution is always less expensive, more practical and eventually more educated compared to a DTS approach as you will have a 3D building energy model which can be optimised toward a better outcome, and takes into account all building elements. In many cases this will introduce noticeable savings in the construction phase. Although the alternative design is always better and less expensive- the exact extent of these benefits cannot be known, before the model and simulation run results of various scenarios. In most cases it outweighs the initial expenses of the study many times over but this cannot be guaranteed due to the nature of this analysis
The study is aimed to deliver a design to perform equal, or better than a DTS and therefore it cannot guarantee that certain requirements will be eliminated entirely- although it can do that where possible. What it can always deliver is a less expensive, and more informed solution which, most of the time, produces enough benefits in the design to strongly justify the initial expenses of a JV3 modeling and assessment.