IS TOWN PLANNING FEELING THE HEAT?

In-House Memo (Factual Information)

Stranded on Heat Island?

As Victoria experiences record high and heatwave temperatures, we are all feeling a bit hot under the collar. But have you considered how town planning in your area may be affecting how you feel the heat? Heatwaves are periods of high temperatures that are likely to impact the health of communities and include physical factors such as humidity, demographics, urban or rural design issues and acclimatisation[1]. Climate change is expected to increase their frequency and intensity[2]. Policy in this area has predominately focused on health impacts[3], however planning can play a crucial role. The Heatwave Plan for Victoria notes a number of planning-related factors which mitigate the impact of heat on population, including:

• multi-storey buildings (p3);
• building standards (p5);
• thermally protective building design (p38);
• fixtures such as passive cooling and external blinds (p23);
• greening built environment, increasing energy efficiency and improving shading and insulation of buildings (p6);
• regulating planning, including building standards and land use planning schemes (p13).

In a planning context, what is termed the ‘Heat Island’ effect is a contributing factor in the severity of heatwaves. ‘Heat Islands’ occur when temperatures in the built environment increase, due to absorption and retention of solar heat,  and remain high, despite subsequent cooling in the external environment: for example, at night. Heat islands are generated by the confluence of a number of factors such as common construction materials, density and massing[4]. ‘Heat Islands’ are most likely to impact vulnerable populations within the community; heat stress may affect older people more than others[5]. Heatwave planning and heat island effects do not form an explicit part of the Victoria Planning Provisions. Building regulations, energy efficiency standards, setback rules and other associated planning controls all influence the effects of heat; despite this, heat reductive and sensitive planning regulation is still poorly integrated. Integration is a matter of choice by individual council planning departments and planning scheme amendment. The City of Boroondara, for example, in Clause 22.12-02 seeks: “to encourage building designs that maximise the use of solar energy, maximise energy efficiency, and minimise summer heat gain and winter heat loss” (Cl. 22.12-02). It encourages Integration of active technological features into building design to maximise energy efficiency and provide energy-efficient heating and cooling and landscaping that: “provides shade, improves air quality [and] … alleviates heat island effect…” (Cl 22.12-02). A recent in-house discussion with a State Government spokesperson has shown that most Councils now have a heatwave plan as part of municipal health and wellbeing programs; this leaves Council planning departments room to improve their heatwave integration. For more information on the science of heatwaves see the Department of Health website: here. Cameron Algie

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