BCA Energy Efficiency for 2010 and Beyond

I’ve just looked through the ABCB’s document outlining their energy efficiency regulations for 2010 and beyond. Its mostly all good, with some lost opportunities. I have a few comments and observations for what its worth – you be the judge. I’m not sure I’ll bother to send to ABCB and ABSA yet – small consulting firms in the regions don’t get much consideration for their points of view. I think this blog might be more effective. Anyway, here are my thoughts:nVol 1 Class 3+5-9 The new conditioned space definition won’t clear up existing ambiguity. This is the single biggest cause for argument, and a means for many, many buildings to avoid fabric insulation and glazing assessments. The BCA should clearly state what is meant by conditioned space in terms of expected comfort conditions for different climates, regardless of whether aircon will be installed or not. As it stands, a passively designed building without aircon, relying on natural ventilation could, according to the way the BCA is enforced, be exempt from insulation and glazing regs! I know this is not the intent, but I’ve had many such debates with clients looking for the path of minimum compliance. Good to see that windows will be caulked in frames. Good to see aircon system specs are tightened up a bit. I would like to see lighting density levels for more typical spaces – often have to guess and interpolate an appropriate figure. The new insulation information has not been identified: but it needs to be re-drawn. There are major conflicts between R-values for air spaces in the tables in the BCA and the R-values for air spaces in the AccuRate database as used in Classes 1,2 + 4 buildings. There should be consistency across all building types. The air gap R-value tables in the BCA are very poorly written, and can be interpreted any number of ways. Don’t’ aggregate the information: show exactly the arrangement of foils and air gaps. The lists of material R-values is very basic – I always seem to be reaching for various manuals and texts to look for the missing thermal conductivities. The glazing tables should be re-written. Many of the tables in warm climates wipe out the U value in the calculation. They effectively say that Low E glass or double-glazing has no role in a warm climate. How wrong is that? What about conductive heat gains from warm air masses against fully shaded glass? Good to see that maintenance manuals are required in J8 – now it will be much more difficult to fudge J8. Do something about differential issues between base buildings and fitouts. Some base building shells are avoiding section J assessments; and the later fitouts have minimal assessments done because it is assumed an assessment was done on base buildings. Many shop fitouts are clearly not being assessed according to section J? How so? There are no systems for Councils and Certifiers to apply energy efficiency properly; rarely is work inspected; rarely are buildings assessed in a comparative way. It is hard to get clients to do things properly when they point to buildings up the road that appear to have avoided the regulations entirely! The BCA must be clearer about substantiation: Councils and Certifiers are now accepting one-page letters certifying compliance with zero substantiation: Tighten this up! Vol 1 Class 2 + 4 part/Vol 2 Class 1 The requirements for Class 1 single dwellings are being raised from 5 to 6 stars; The requirements for Class 2/4 are being raised by more than 2, as the requirements range from 3.5 to 4 stars. This is worth doing, but will be very hard to achieve in moderate climates without some review. Even the ABCB’s own research identified that it is hard to push a block of units to average 5 stars in any climate; it also identified an anomaly in Climate Zone 2 for Brisbane and recommended that Star Rating bands for such zones be reviewed. I agree: it is even worse in the southern part of Climate Zone 2, such as here in Coffs Harbour: I have been calling for this for the last couple of years, but my requests have fallen on deaf ears. In Coffs Harbour, I have found it impossible to pass some blocks of units, with any strategy using AccuRATE. I re-modelled them in NatHERS for an easy pass (This option is gone now). In mild climates our total energy allowance is very narrow ( compared to cold climate with allowances of 300mJ/m2 per year), but we have to design for both summer and winter, with quite different strategies (unlike cold climates, where mild summers are well handled by winter design). It is quite easy to achieve 6 stars in a cold climate, but very difficult in a climate like Coffs – the software identifies that high-mass multi-residential buildings can build-up excessive heat, and cannot cool down (I have modelled such units with permanent holes in the wall and still cannot get a pass, even with sea breezes so strong you can’t stand up!) Also, in mild climates, a lightweight Class 1 building with full energy efficient specification cannot readily reach 5 stars, and often won’t reach it without the addition of internal mass – there is no strategy that will push a lightweight building to 6 stars in such a climate. Its as if a lightweight building has a “set point” in any given climate, beyond which it cannot be pushed, as the summer strategy reduces winter performance and the winter strategy reduces summer performance. This is a sleeper issue for the building industry, and when they discover this, all hell will break loose! I think 6 stars with a 5 star average will be very hard to achieve in multi-residential developments; and in lightweight in single residential construction without a total review of the Star-Rating Bands. There is also an anti-small floor area bias that will prevent small units of lightweight construction achieve 5 stars in any warm climate. I recently did a modelling exercise on a small freestanding unit of lightweight construction with high levels of energy efficiency that did not reach 5 stars in any warm climate in Australia. (Yet, the same building achieves 5 stars comfortably in cold climates) In some places it didn’t hit 4 stars. A 6-star rating for such buildings is totally out of reach with any lightweight specification. This will be hugely significant for affordable housing programs. I think that the COAG view that all residential dwellings be 6 stars is misinformed, and doesn’t understand the limitations of the software, and that there could be errors in the Climate Data and Star Rating Bands. Basix in NSW A pass in Basix will be even more difficult to achieve under the new Code, although it is not yet clear how the revised star ratings will be “transmogrified” into the Basix environment. Basix is hugely problematic for thermal issues. Most single dwellings go through the DIY tool, which is essentially the BCA Deemed-To-Satisfy. However, a building that passes DIY often is under 4 stars when modelled with AccuRATE, and does not pass the Basix caps for the thermal simulation compliance pathway. So DIY is up to a 1.5 star free kick to the project home industry. I hope that this disappears in the BCA 2010 NSW provisions – there is nothing yet to indicate this. Get rid of Basix DIY if it cannot be made commensurate with AccuRATE results. The project home building industry, will find it very difficult if DIY disappears, and we go to full thermal simulation at 6 stars – for them, it will be a jump from 3.5 stars to 6 stars. Again, this is a sleeper issue for that part of the industry The Basix Summer and Winter caps make it very difficult to pass in warm climates with a definable winter – because summer and winter strategies conflict with each other in such climates; the conflict is more significant under Basix with its separate caps than for the national star-rating-based standard. This is even more pronounced in multi-residential developments where the whole development must pass both summer and winter average caps. There is a possibility that the separate Basix caps for specific climate zones have been generated on false assumptions. They should be reviewed along with the national Star-Rating Bands. Final Thoughts (for now)nGoing to a 6 star standard is worth doing. But all the anomalies, free kicks, software errors and Star-Rating bands should be reviewed and fixed before it comes into force. Also, there has to be some clear thinking as to how energy for lighting and hot water are incorporated into the energy rating software, and how Basix is altered to be consistent, as it has water and energy included, but as separate measures, not as part of the thermal software. Also, we’ll have a situation where a cold climate building using hundreds of MJ/m2/annum will achieve 6 stars when a warm climate building using a fraction of the MJ/m2/annum will fail. This is patently absurd.nIf these don’t get fixed, the building industry will revolt against an otherwise worthy raising of sustainability standards. And we’ve fought too long to get the regulations to where they are today. This is not my last word on the subject! There will be more things that come to mind, and I’ll write about these in due course.

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