As has already been discussed in; What is a Section J report?, the main function of Section J is to reduce greenhouse gas emissions. Minimum standards of design to new developments and renovations help achieve these government goals. However there are many aspects that contribute to energy efficiency of buildings.
Section J of NCC 2019 considers the following aspects:
- J1 - The building's fabric performance
- J2 - No longer considered and instead captured by J1
- J3 - Sealing of the building
- J5 - Heating, ventilation and air-conditioning systems
- J6 - Performance of artificial lighting
- J7 - Heated water supply system for heating and pumping of swimming pools and spas
- J8 - Facilities used to monitor energy use.
An important difference between BCA Section J 2016 and 2019 is the way walls and glazing are considered. In NCC 2016 the fabric of the walls (level of insulation) and how the window performed (single glazing, double glazing) were considered separately. They each had their own individual performance requirements.
NCC 2019 Section J consolidated the performance of the windows and walls into a single term dubbed façade. They still need to individually reach a minimum requirement for each element, but also needed to reach a requirements as a whole. Think of it like a weight lifter lifting weights without clamps on each end securing the weight. To achieve the goal the weight must lift evenly above their head. However, lift with one hand too much, then the weights will fall, and they will fail to achieve their goal. The NCC 2019 façade requirements must also have an even balance when considering glazing and walls.
As the National Construction Code (NCC | BCA) is a body of rules and regulations that govern the requirements of how either a house or commercial building is built. Therefore it makes logical sense to include a set of rules in these documents that tell someone how to construct a building that is energy efficient. NCC Section J describes all the energy efficiency requirements that need to be met for a particular building.