Working in Heat: Summer Construction Safety in Perth

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Perth summers are brutal. Temperatures regularly exceed 40°C, and construction workers are exposed to the worst of it — on rooftops, on roads, in trenches, and on scaffolding with little shade. Heat-related illness is a serious and preventable risk on construction sites in WA.

Here’s what workers and employers need to know about working safely in Perth’s summer heat.

The Risks of Working in Heat

Heat-related illness ranges from uncomfortable to fatal:

Heat Cramps

Painful muscle cramps caused by loss of salt and fluid through heavy sweating. Usually affects the legs, arms, and abdomen. A warning sign that the body is struggling with the heat.

Heat Exhaustion

More serious than cramps. Symptoms include:

  • Heavy sweating
  • Weakness and fatigue
  • Dizziness and lightheadedness
  • Nausea or vomiting
  • Headache
  • Cool, pale, clammy skin
  • Fast, weak pulse

Heat exhaustion requires immediate action — move to a cool area, remove excess clothing, drink water, and apply cool wet cloths.

Heat Stroke

A medical emergency. The body’s temperature regulation fails and core temperature rises above 40°C. Symptoms include:

  • High body temperature
  • Hot, red, dry skin (sweating may stop)
  • Rapid, strong pulse
  • Confusion, altered mental state
  • Loss of consciousness
  • Seizures

Heat stroke can kill. Call 000 immediately. Move the person to the coolest area possible and cool them rapidly with water while waiting for paramedics.

Who Is Most at Risk?

Some workers are at higher risk of heat-related illness:

  • Workers new to hot environments (not yet acclimatised)
  • Workers returning after time off (holidays, illness)
  • Workers on medications that affect heat tolerance
  • Workers who are dehydrated before starting work
  • Workers performing heavy physical labour
  • Workers wearing heavy PPE or impermeable clothing
  • Workers in direct sun with no shade
  • Workers in enclosed or poorly ventilated spaces
  • Older workers and those with pre-existing health conditions

Employer Obligations

Under WA’s Work Health and Safety Act, employers (persons conducting a business or undertaking — PCBUs) have a duty to manage heat-related risks. This includes:

Risk Assessment

  • Monitor weather forecasts and plan work around extreme heat days
  • Assess the heat risk for each task — consider temperature, humidity, radiant heat, wind, physical demands, and PPE requirements
  • Use tools like the Wet Bulb Globe Temperature (WBGT) index for objective heat stress measurement

Controls

  • Scheduling: Start earlier (5:00 or 6:00 AM starts), finish before the hottest part of the day, or schedule heavy work for cooler periods
  • Rest breaks: Increase the frequency and duration of rest breaks as temperatures rise
  • Shade: Provide shade structures, tents, or covered rest areas
  • Water: Provide cool drinking water — easily accessible, in sufficient quantity, and close to work areas. Workers need at least 1 cup (250ml) every 15 to 20 minutes in extreme heat
  • Cool rest areas: Air-conditioned site sheds or shaded areas with fans for breaks
  • Buddy system: Workers should monitor each other for signs of heat illness
  • Acclimatisation: New workers and those returning from leave should gradually increase their workload over 7 to 14 days
  • Training: Ensure all workers know the signs of heat illness and the emergency response

Emergency Procedures

  • Have a clear heat illness emergency plan
  • Ensure first aiders are trained in heat-related illness response
  • Keep emergency contact numbers accessible
  • Have cooling equipment available (cool water, fans, ice)

Worker Responsibilities

Workers also have a role in managing heat risk:

Hydration

  • Start the day hydrated — drink plenty of water the night before and morning of a hot day
  • Drink water regularly throughout the day, even if you don’t feel thirsty
  • Avoid caffeine and energy drinks in excessive amounts — they can increase dehydration
  • Avoid alcohol the night before a hot workday — it significantly increases dehydration risk
  • Monitor your urine colour — dark yellow means you’re dehydrated

Nutrition

  • Eat regular meals — your body needs fuel to regulate temperature
  • Include foods with electrolytes — bananas, nuts, yoghurt
  • Avoid heavy, greasy meals that are harder to digest in heat

Clothing and PPE

  • Wear lightweight, light-coloured, loose-fitting clothing where possible
  • Use sun protection — wide-brimmed hat, sunscreen (SPF 50+), sunglasses
  • Wear long sleeves for sun protection — modern UV-protective work shirts are designed to be cooler than exposed skin in direct sun

Self-Monitoring

  • Know the signs of heat illness in yourself and your workmates
  • Speak up if you’re feeling unwell — don’t push through
  • Take breaks when you need them
  • Report to your supervisor if you’re struggling with the heat

Perth’s Heat: The Numbers

Perth is one of Australia’s hottest capital cities for construction workers:

  • Average January maximum: 31.5°C
  • Days above 35°C per year: approximately 28
  • Days above 40°C per year: approximately 5 to 10
  • Record temperature: 46.2°C
  • UV index in summer: Extreme (11+)

But it’s not just about the air temperature. Radiant heat from sun-exposed surfaces — metal roofing, concrete slabs, asphalt roads, and scaffolding — can make the effective temperature much higher than the reading on a thermometer.

Heat Management Plans on Construction Sites

Well-managed construction sites in Perth implement heat management plans that include:

  • Trigger temperatures: Specific actions triggered at defined temperature thresholds (e.g., additional breaks above 35°C, work cessation above 40°C)
  • Modified work schedules: Summer hours that start and finish earlier
  • Task rotation: Rotating workers between heavy and light tasks, and between sun-exposed and shaded areas
  • Cooling stations: Designated areas with shade, water, fans, and seating
  • Monitoring: Supervisors actively checking on workers and watching for signs of heat illness

When Is It Too Hot to Work?

There is no single temperature at which outdoor work must stop in WA. The decision depends on multiple factors — temperature, humidity, wind, radiant heat, physical demands of the task, PPE worn, and individual worker factors.

However, many enterprise agreements (EBAs) in WA’s construction industry include heat clauses — typically allowing workers to stop work when the temperature reaches 37.5°C or above, or at lower temperatures if conditions are particularly harsh. Check your EBA or award for specific provisions.

Regardless of specific thresholds, if conditions are genuinely unsafe, workers have the right to cease work under WA’s WHS laws.

Stay Safe This Summer

Heat-related illness is preventable. With proper planning, hydration, rest, and awareness, construction workers in Perth can work safely through even the hottest summers.

Perth Trades Recruitment is committed to placing workers with employers who take heat safety seriously. If you’re looking for construction work in Perth with companies that prioritise worker safety, get in touch.

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