Thermal Stress & Lighting

Heat illness prevention and workplace lighting – two hazards, one integrated assessment.

Working in extreme heat is an intrinsic feature of resource sector operations in Western Australia and across northern Australia.

Surface mining in the Pilbara and Goldfields, underground operations where geothermal heat and diesel exhaust contribute to elevated ambient temperatures and outdoor construction and maintenance in summer conditions all expose workers to thermal environments that carry genuine risks of heat-related illness – from heat exhaustion and dehydration through to life-threatening heat stroke.

Lighting is an equally critical – and frequently overlooked – environmental health and safety parameter. Inadequate illumination in working environments causes eye strain, fatigue and increased error rates; in hazardous areas, it is a direct contributor to accident and injury. Excessive lighting, including glare, creates its own set of problems. Meeting the requirements of AS/NZS 1680 (Interior and Workplace Lighting) and relevant mining standards is a baseline obligation, but the goal should be workplaces that are genuinely comfortable and safe to work in – not merely compliant on paper.

RED OHMS Group provides thermal stress surveys, thermal strain risk assessments and lighting surveys that go beyond box-ticking compliance – delivering actionable, evidence-based recommendations that improve conditions for workers and reduce operational risk.

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Capabilities

Measurement of thermal environment parameters (wet bulb globe temperature [WBGT], air temperature, radiant heat, humidity, air velocity) and illuminance levels across your work areas, providing a quantified picture of the actual environmental conditions your workers are experiencing.

Worker-centred assessment of heat strain risk that integrates environmental measurements with metabolic work rate estimation, clothing and PPE correction factors and acclimatisation status to produce task-specific heat stress risk ratings and recommended work-rest regimens.

Thermal Stress in the Australian Context

The Wet Bulb Globe Temperature (WBGT) index is the primary metric used to assess thermal stress in Australian workplaces, referenced in the Safe Work Australia guidance and adopted by industry codes across the resources sector.

However, WBGT measurement alone is not a complete risk assessment – the metabolic demands of the work, the clothing and PPE worn, the availability of cooling and hydration, the acclimatisation status of the workforce and individual health factors all contribute to the overall risk.

RED OHMS Group’s thermal strain risk assessments follow the ISO 7933 (predicted heat strain) and ISO 7243 (WBGT-based) frameworks, adapted to the practical realities of Australian mining and construction environments. We work with site management to develop heat illness prevention plans, acclimatisation protocols and hot weather work procedures that are operationally feasible and genuinely protective.

For lighting surveys, our hygienists measure illuminance (lux) and luminance across task areas, walkways, plant rooms and control areas, evaluating against the maintained illuminance levels specified in AS/NZS 1680.2 for the relevant task category. Findings are presented with specific recommendations for luminaire placement, replacement and maintenance schedule adjustments.

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FAQs

There is no single temperature threshold – risk depends on the combination of air temperature, humidity, radiant heat, air movement, work intensity, clothing and individual factors. WBGT values above 28°C (for moderate work) through to 32°C (for light work) are generally considered to require management intervention, including mandatory rest breaks and cooling access. RED OHMS can assess your specific work tasks and conditions to provide task-specific guidance.

AS/NZS 1680 provides the primary guidance for workplace lighting in Australia. Part 2.5 covers industrial tasks and processing areas; other parts cover offices, outdoor work areas and emergency lighting. In addition, state mining regulations specify minimum lighting requirements for underground environments, traffic areas and working areas on mine sites. RED OHMS will identify the applicable standards for each area of your operation and assess compliance accordingly.

Acclimatisation is one of the most important protective factors in thermal stress management. Workers arriving from cooler environments typically require 10–14 days of graded exposure to develop full heat acclimatisation. RED OHMS can help you develop an acclimatisation protocol that manages the transition period safely – including reduced work intensity, enhanced monitoring and buddy systems for new or returning workers at the beginning of each rotation.