Working Safely in Heat – What You Need to Know

Why it matters

As temperatures rise, heat stress can affect anyone, often sooner than expected. It reduces concentration, slows reaction times, increases the likelihood of errors, incidents and medical emergencies. In severe cases, heat stress can escalate to heat stroke, a life-threatening condition that requires immediate action.

Heat-related illness doesn’t only occur during extreme heat. Warm or humid conditions, physically demanding work and the use of PPE can significantly increase risk, even on days that don’t feel particularly hot.

Key Risks

Not only hot but also humid weather, hard physical work, along with the use of PPE can quickly lead to heat stress/stroke.  This can happen on days that don’t feel “extreme.”

Heat exhaustion occurs when the body overheats and activates its protective mechanisms (such as sweating, thirst and reduced urine output).

Heat stroke happens when the body can no longer regulate its temperature and the core temperature rises above 39.4°C. This is a medical emergency and can be life-threatening.

Heat stress impacts how you think, move and react. As a result, increasing the risk of mistakes, incidents and medical emergencies. Encourage your team to speak up and keep a watch on other team members

Assessing Heat Stress Risks

Before starting any work where heat stress or thermal discomfort has been identified as a hazard, a risk assessment must be completed by a competent person. This assessment should consider:

The general work environment – this includes:

• Air temperature
• Humidity
• Radiant heat sources
• Air movement
• Physical landscape
• Work rate – the harder someone works, the greater the amount of body heat generated
• Worker clothing and personal protective equipment (PPE) – heavy clothing and PPE may limit the efficiency of sweating and other means of temperature regulation

The individual workers conditions- this includes

• Workers age
• Physical build
• Body weight
• Physical fitness
• Mental fitness
• General health (including any underlying conditions). Medical factors may affect an individual’s tolerance to heat and may vary across workers.

Early warning signs for Heat Exhaustion leading to Heat Stroke

Move to shade and notify your supervisor if you notice:

• Headache, dizziness, confusion and becoming irritable
• Heavy sweating, muscle cramps, weakness and nausea
• Fast heartbeat, shortness of breath and feeling faint

Preventative Measures

SLIP:                     Long‑sleeved shirt

SLOP: Broad-spectrum sunscreen (SPF 30+), reapply every 2 hrs

SLAP: Wide-brimmed hat that works with your PPE

WRAP: UV-blocking sunglasses

SLIDE:                  Use shade whenever possible

HYDRATE:         Drink water/electrolytes often.  Avoid excess caffeine, energy drinks and alcohol

What your employer (PCBU) should provide

• Plan work around weather forecasts and heat alerts
• Provide PPE that protects from UV exposure while promoting thermal comfort
• Avoid heavy work during peak heat hours
• Provide shaded or cooled rest areas
• Supply cooling equipment such as air-conditioning or fans where practicable
• Ensure good airflow throughout the workspace
• Schedule regular breaks, increasing frequency if temperatures cannot be adequately controlled
• Ensure cool drinking water is readily available close to the work area
• Adjust work tasks, pace, and break schedules during extreme heat

What You Can Do

• Drink small amounts of water often – don’t wait until breaks
• Avoid excess caffeine, energy drinks and alcohol
• Use shade whenever possible
• Report if controls (shade, water, ventilation) aren’t working

Sun & UV with long-term protection

• NZ has very high UV levels – always wear a hat if possible, protective clothing, sunglasses and sunscreen
• Limit direct sun exposure during peak UV hours

Emergency Heat Stroke

Call 111 immediately if someone shows:

• Internal body temperature greater than 39°C, severe headache and/or nausea/vomiting
• Fast pulse, rapid breathing, along with dry flushed, hot skin
• Muscle weakness, cramps, dizziness and/or fainting
• Confusion, agitation, seizures and/or collapse

While waiting for help:

• Move to the shade, lay down then remove excess clothing
• Cool with water, fanning, cold packs placed around the neck and armpits
• If conscious: sip cool water and or electrolytes slowly
• If unconscious: place in recovery position, do not leave them unattended

Heat injury can occur quickly

Monitor yourself and others and react early