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NCC2012 Energy Efficiency Summary

The Code has changed many times over the years since this article was written and the information in here isn’t current for today’s requirements. We’re keeping it here for historical reference purposes and to assist others who may want to check an existing building meets the older standard. If you need a second opinion regarding if an older building actually met the then-current energy efficiency requirements we can still do the calculations for any class of building, for any year’s requirements ranging from all the way back to 1999 to the current draft proposal for next year. Contact us for more information!

There are only a few changes from the National Construction Code (NCC) 2011 to NCC2012 concerning Energy Efficiency. One of the changes this year was a direct result of a successful Proposal For Change filed by Dr Clyde Anderson. Here is a summary of the most relevant changes.

Changes for Volume 1 (classes 2-9, Commercial buildings) Section J

Section J0.2
For Class 2 & Class 4 buildings, the software that produces Star Ratings is now accredited by the Nationwide House Energy Rating Scheme National Administrator (NatHERS, The responsibility for software accreditation was transferred when a Memorandum of Understanding was signed between the Australian Building Codes Board (ABCB) and the Department of Climate Change and Energy Efficiency (Commonwealth government) on 11 November 2011. The ABCB now has greater involvement in any changes to NatHERS .

Table J1.3b

The table for adjustment of minimum R-value for loss of ceiling insulation (due to insulation voids associated with exhaust fans, flues, recessed downlights, transformers or services – but not roof lights) has been extended. This table now reads below R2.5 to R1.0. This was a direct result of a successful Proposal For Change filed by Dr Clyde Anderson. Interpolation is usually needed to determine the insulation required for a given situation.

Because the heat from transformers in a Class 8 Electricity Network Substation is a process heat rather than air-conditioning, exemptions have been included in:

  • Part J5.2(b)(iii) mechanical ventilation more than 1000L/s
  • Part J5.3(a) time switch for an air-conditioning system of not more than 10kWr, a ventilation system with an air flow rate more than 1000L/s or a heating system of more than 10kWheating
  • Part 5.5(a) miscellaneous exhaust systems
  • Part J6.2 artificial lighting
  • Part J6.3 interior artificial lighting and power control and
  • Part J6.5(a)(ii) artificial lighting around the perimeter of a building when the total perimeter lighting load exceeds 100W.

Definitions have been added for House Energy Rating Software and Electricity Network Substation.

Changes for Volume 2 (class 1, Residential buildings) Parts 2.6 & 3.12

Part 2.6

Performance Requirement P2.6.2(b) Services has a new explanatory note:

2. The intent of P2.6.2(b) is to constrain the use of a high greenhouse gas intensity source of energy for heating a conditioned space. It does not prevent the use of electricity because the greenhouse gas intensity is related to the thermal load rather than the energy consumption which is covered by P2.6.2(a). P2.6.2 also contains the qualification that it is to be applied “to the degree necessary”, allowing electricity to be used, even by low efficiency plant when there are no reasonable alternatives.

In Part 3.12.0(b) the explanatory information has two options for complying with the energy efficiency Deemed-To-Satisfy (DTS) provisions –Energy Rating or ElementalProvisions. Energy Rating also includes Part 3.12.0(a)(i)(B) to (F) energy-saving DTS features, such as: the testing and installation of insulation, thermal breaks, compensation for downlights, floor edge insulation and detailed provisions for building sealing.

When conducting a Star Rating these DTS features are required. If any of these DTS features are deleted (eg to reduce construction costs), this must be modelled correctly. This data input modification can be performed by certified Energy Efficiency Assessors who have procedures to adjust the input data to still obtain a certified Star Rating. Contact us if you would like more information about this for your project.

Keep in mind that the current Queensland Development Code MP4.1 (27 June 2011) requires Energy Star Ratings for Class 1 and Class 2 buildings that are different to the NCC‘s requirements. There are also differences in the application of credits for a complying Outdoor Living Area with or without a ceiling fan. QDC MP4.1 optionally gives 1 Star credit for larger than 1kW solar photovoltaic systems.

Part 3.12
There are new definitions replacing the ABCB Protocol for House Energy Rating Software:

House energy rating software means software accredited under the Nationwide House Energy Rating Scheme and is limited to assessing the potential thermal efficiency of the dwelling envelope.
Explanatory information: The National House Energy Rating Scheme (NatHERS) refers to the Australian governments’ scheme that facilitates consistent energy ratings from software tools which are used to assess the potential thermal efficiency of the dwelling envelopes.

There is a new definition of Small-scale Technology Certificate replacing the previous NCC 2011 definition of Renewable Energy Certificate.

Part explanatory information 5, the reference to “A light-coloured roof” has been replaced by:

5. A low solar absorptance roof reduces the flow of heat from solar radiation better than a high solar absorptance roof. A roof with a solar absorptance value of less than 0.4 typically corresponds to a roof of light colour such as white, off-white or cream.

As in Volume 1,Table of minimum R-value for loss of ceiling insulation) has been extended below R2.5 to R1.0. This was a direct result of a successful Proposal For Change filed by Dr Clyde Anderson.

Table note 2
has been simplified:

2. A storey has High air movement if the total ventilation opening area serving the habitable room is-
(a) in climate zones 1, 2, 3, 4 and 5, not less than that for Standard air movement without a ceiling fan or evaporative cooler, but with ceiling fans complying with installed in all habitable rooms; or
(b) not less than twice that for Standard air movement without a ceiling fan or evaporative cooler.

and explanatory information 4 is now:

4. Whether a storey has Standard or High air movement depends upon the total ventilation opening area provided to habitable rooms on that storey and the presence of ceiling fans. The additional ventilation opening area required for High air movement without fans can be distributed to any of the habitable rooms on the storey. In climate zones 1 to 5, the storey can achieve High air movement when the total ventilation opening area is as for Standard air movement (without a ceiling fan or evaporative cooler) but with ceiling fans installed in every habitable room. For example, in climate zone 2:

Air movementWith ceiling fansWithout ceiling fans

Part, the explanatory information on the South Australia variation was deleted.

In summary, some small changes but overall achieving nearly the same outcomes.

If you are interested in a Deemed-To-Satisfy, Thermal Calculation, Verification Method or Reference Building assessment for your new building, contact us for a competitive fee proposal. We deal in both Residential and Commercial work throughout Australia, from tiny 1-room house extensions to entire shopping complexes.

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