Previews of all volumes of the NCC2019 have been published and can be downloaded from the ABCB website. As previously mentioned Section J Energy Efficiency incorporates a number of changes including variations to performance requirements, calculations methods, and acceptable verification method pathways and associated protocols.
Here we summarise some of the major changes included in Section J of Volume One.
Verification Methods
Three new verification methods have been included. These are JV1 NABERS Energy for Offices, JV2 Green Star and JV4 Building envelope sealing. The inclusion of the first two pathways helps streamlining the assessment requirements, thus reducing the doubling up in simulation protocols. The last method, namely JV4, helps assessing with greater certainty compliance with the building sealing provisions of Part J3.
Further, in recognition of the importance to design and build buildings that are energy efficient AND comfortable for their occupants, the Verification Method JV1, JV2 and JV3 include a requirement to demonstrate that PMV levels of -1 to +1 are achieved across at least 95% of the floor area of occupied zoned for not less than 98% of the annual operating hours.
Roof Lights
The table outlining the performance requirements for roof lights has been simplified. In this version of the NCC the Total U-value for roof lights is 3.9 regardless of the roof light / floor are ratio, while the total SHGC remains a function of shaft index and roof light / floor are ratio (even though overall the requirements have been tighten).
Walls and Glazing
As mentioned in a previous article Part J2 has been removed and glazing provisions are now included in Part J1.5. This requires walls and glazing to be assessed together as part of a wall-glazing construction that must comply with the specified Total U-value, SHGCs and solar admittance values.
Floors
The table specifying the performance requirements for floors has been simplified with only two types nominated: (1) floors without an in-slab heating or cooling system and (2) floors with an in-slab heating or cooling system. Further, slab on ground are now required to achieve a Total R-value in all climate zones.