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Working in extreme temperatures puts serious strain on the body. Heat stress can cause heat exhaustion, heat stroke and death. Cold stress leads to hypothermia, frostbite and impaired judgment that increases the risk of other injuries. Both conditions are preventable with proper assessment and controls.
Our thermal stress assessments evaluate worker exposure to hot and cold environments and provide practical recommendations to manage the risk.
For hot environments, we use Wet Bulb Globe Temperature (WBGT) monitoring to measure the combined effects of air temperature, humidity, radiant heat and air movement. WBGT gives a single index that accounts for all the factors that contribute to heat stress, not just air temperature.
We assess workload intensity alongside environmental conditions. A moderate temperature can still cause heat stress when combined with heavy physical work, PPE and sustained effort. Our assessments consider the complete picture.
For cold environments, we assess wind chill factors, exposure duration, work intensity and the adequacy of cold weather clothing. Cold stress is not limited to outdoor work in winter. Workers in cold storage facilities, freezers and refrigerated transport face sustained cold exposure year round.
We evaluate your current work rest schedules, warming facilities, clothing systems and emergency procedures for cold weather operations.
Our reports provide specific recommendations based on the conditions measured and the work being performed. For heat, this includes work rest schedules, hydration plans, acclimatisation programs, engineering controls like shade and ventilation and monitoring protocols.
For cold, recommendations cover appropriate clothing systems, warm up breaks, buddy systems, exposure time limits and emergency response procedures.
Thermal stress assessment sits alongside other ergonomic and occupational hygiene services. Our lighting assessments, vibration assessments and manual handling evaluations address other physical hazards that affect worker health and comfort. For a structured approach to all workplace health hazards, explore our health and hygiene management plan service.
A single WBGT measurement gives you a snapshot. A heat stress management program gives you the framework to protect workers across all conditions throughout the year. For businesses with outdoor operations or hot indoor environments, a documented heat stress management program demonstrates due diligence and gives supervisors clear decision making tools.
Heat stress programs include threshold trigger levels based on WBGT, work rest schedules for each threshold, acclimatisation protocols for new and returning workers, fluid replacement guidance, buddy systems and early warning sign recognition. Training for supervisors to recognise heat stress symptoms and respond appropriately is a critical component.
Workers who are new to hot environments or returning from a break are at the highest risk of heat illness. Acclimatisation is the process of adapting to working in heat, and it takes 7 to 14 days of progressive exposure. Many heat stroke cases occur in the first week of hot conditions because acclimatisation programs are not in place or not followed.
Certain medications and health conditions increase susceptibility to heat illness. Workers taking diuretics, antihistamines, antidepressants or certain blood pressure medications may have impaired heat tolerance. Older workers, those with cardiovascular conditions and pregnant workers are also at higher risk. A heat stress management program should account for individual variation in risk.
Wet Bulb Globe Temperature (WBGT) is an index that combines three measurements to assess the total heat stress environment. The natural wet bulb temperature measures the cooling effect of evaporation in still air. The globe temperature measures radiant heat from the sun and surrounding surfaces. The dry bulb temperature measures air temperature. A single WBGT value accounts for all these factors that contribute to body heat loading, unlike air temperature alone.
There is no single legal temperature threshold for heat stress in Australia. The obligation under WHS legislation is to identify and manage heat stress risk, which depends on WBGT, work intensity and acclimatisation status rather than air temperature alone. A worker doing heavy work at 28 degrees WBGT is at significant risk. A sedentary worker at the same WBGT has far lower risk. We assess the complete heat stress risk for your specific work conditions.
Heat exhaustion symptoms include heavy sweating, cool and pale skin, fast weak pulse, nausea, fatigue, headache, dizziness and muscle cramps. The worker is alert and can follow instructions. Heat stroke is a medical emergency. Symptoms include high body temperature above 40 degrees, hot dry or damp skin, rapid strong pulse, confusion, loss of consciousness. Heat stroke requires immediate emergency response.
Effective cold stress management includes appropriate layered clothing systems, shelter from wind, regular warming breaks, buddy systems to monitor for symptoms, reduced exposure times in extreme conditions and clear guidance for supervisors on when to modify or suspend outdoor work. We assess the wind chill conditions for your location and work activities and develop specific cold work guidelines.
Yes. Full acclimatisation takes 7 to 14 days of progressive heat exposure. Acclimatised workers tolerate heat significantly better than unacclimatised workers. Benefits include lower heart rate during heat stress, lower core body temperature, earlier onset of sweating and lower salt concentration in sweat. Acclimatisation is partially lost during periods away from the hot environment, so returning workers need a re-acclimatisation period.