PDF | 8 MB - Australian Building Codes Board

The reality, however, is that commercial
energy analysis is a complex topic
and needs a substantial amount of
engineering judgement to ensure
maximum accuracy. Commercial
building software models the
interactions of the building services
systems with the physics of the building,
whereas home energy rating software
doesn’t have anywhere near this level of
complexity.
Only competent engineers and building
services engineers should be using this
type of software.
Software that can be used in BCA
performance modelling is already
‘accredited’ against ‘best-test’, as I
understand it.
Two steps to user accreditation and
capability are desperately required. The
first is an accreditation to demonstrate
competency in applying the modelling
process and engineering principles
–irrespective of which software is used.
The next level of training should be a
tool-specific scheme, aimed at those
who have passed the first level, who
can then learn how to use individual
software packages.
AIRAH is well placed to develop
and administer such a system, in
collaboration with the eight building
control administrations, and with
funding from the government.
Many countries are grappling with these
issues, and given its strong international
links, AIRAH is well placed to learn from
overseas experience.
Q: Do you see the modellers who
using energy analysis software being
specialists in building sustainability/
energy analysis, or is there a need
for them to first have gained HVAC
experience as designers or installers?
PW: The programs used for building
energy analysis are very complicated,
and users need a very good level of
understanding of HVAC systems.
The software is considerably more
complex than that designed to measure
house energy rating, which most
building practitioners can master quite
quickly.
It’s easy to select totally inappropriate
systems or other inputs from the various
menus, delivering a result that would
look impressive and creditable to
somebody not trained in HVAC system
design.
Q: It would seem that the current
software programs need to make
certain assumptions, such as
whether the systems have been
properly commissioned, or whether
the building is well constructed to
reduce infiltration, or whether or
not the building is likely to be well
maintained. How realistic are the
assumptions being made?
PW: These are aspects where building
and HVAC design and construction
experience is essential. Good
engineering judgement is crucial in
estimating what the inputs should be.
The detailing of facades or roof-to-wall
interfaces as well as air-locks and other
seals give a good indication of the likely
infiltration that needs to be an input
and not a hypothetical ‘ideal’ value.
We are starting to see some buildings
pressure tested and gaps in the building
envelope sealed to prevent uncontrolled
infiltration.
Commissioning and good maintenance
are extremely important in
achieving the assumed ongoing
energy consumption. No one is held
accountable for this currently, and until
they are there will be continuing market
failures in this space. Both of these issues
have been talked about for years, and
unless they are regulated or energy
prices skyrocket, I don’t believe they will
be genuinely addressed. Perhaps the
introduction of mandatory disclosure
will start to drive some good outcomes.
We certainly hope so.
What I’ve said here is my opinion, but
it’s based on discussions I’ve had with
– and input from - stakeholders across
our industry. This includes several
prominent AIRAH members, who are
daily working with building simulation
software at the vanguard of measuring
the built environment’s performance.
These are professionals helping to shape
the future of our cityscapes by making
sure our buildings perform as they
should in the present.
INDUSTRY PERSPECTIVE
Australian Building Regulation Bulletin
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