Hot box apartments are a health risk

By Sean Car

CBD residents face growing health risks associated with heat stress due to poor Australian apartment design standards, a new study by the University of Melbourne has shown. 

The Living Well – Apartments, Comfort and Resilience in Climate Change study has found that Australian apartments don’t comply with international standards when it comes to protecting inhabitants from extreme heat.

It looked at how apartments would perform in “free running mode” without mechanical cooling systems or air conditioning, such as in the event of a black out.

Researchers tested six common apartment building types ranging from high-rise and low-rise apartments to brick buildings and apartments considered as “best-practice” in the context of current Australian standards.

The study modeled how apartment designs could cope with excessively high temperatures by testing them against the heat wave conditions that hit Melbourne in January and February 2009, which included the Black Saturday bushfire disaster.

It also chose a worst-case scenario by modeling west-facing apartments that are most exposed to the sun. All six apartment samples failed the four standards they were tested against.

Two building types tested that were typical of most apartments in the CBD – being high-rise heavyweight apartments made almost entirely of concrete – measured as the worst performing.

While current overseas building standards in countries such as France and Germany enforce strict rules on mitigating heat impacts, it is not currently addressed within the Building Code of Australia.

The study’s lead researcher and construction scientist Chris Jensen said the results were a wake up call, particularly with scientists predicting longer and more frequent heat waves in the future.

“The research highlights to the public that heat stress inside apartments is a real issue and that we need to do more to control this, not only in new buildings, but also for existing buildings,” he said.

One of the study’s key recommendations calls on the national building regulator to adopt standards that protect people against heat stress by considering variables such as air temperature, humidity, air velocity, metabolic rate and clothing insulation.

The State Government’s Better Apartment Standards, released in December, includes a maximum cooling load, which is calculated using the Nationwide House Energy Rating Scheme (NatHERS) standards. However, Mr Jensen told CBD News these standards didn’t go far enough in addressing heat stress.

“We’re calling on a range of different policy changes,” he said. “It’s addressed really well overseas but it’s not currently addressed in Australia. The apartment standards guidelines don’t address heat stress – the maximum cooling load uses computer energy modeling and doesn’t capture peak temperatures.”

Apartments currently considered best-practice encourage natural ventilation for adaptive comfort, while others recommend windows be kept closed during heat waves.

Many of the inner city’s high-rise apartments don’t have opening windows, posing particular dangers for residents in the event of power blackouts. And not all apartment buildings have back-up generators.

According to the building manager of Freshwater Place in Southbank, Mike Zverina, generators only ensured that power was maintained to lights, air supply, lifts and water. All appliances, including air conditioning, are not connected to the emergency loop.

However, while some generators, such as those installed at Freshwater Place, ensure a temperate pressurised average air of 22 degrees, Mr Zverina said not all buildings had temperate air provided by the central system.

A spokesperson for the Australian Building Codes Board said the National Construction Code did not regulate backup power supply other than for emergency safety equipment.

“The provision of a generator for backup power is a matter that is at the discretion of the building owner/developer or building manager having regard to the nature and use of the building,” the spokesperson said.

“A building does not get sold or occupied without a power source, so it is not something that needs to be regulated.”

The Living Well study recommended a number of retrofit options, which included increasing thermal mass, added insulation, light colouring of external walls, improved ventilation and window shading.

However, the study found that even with the addition of all of these retrofits, some apartments would still fail to comply with some international standards.

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