When you think of heat, you think of warm, sunny climates. The Middle East, Africa, parts of the Americas, Australia and Asia all spring to mind. Even in places like Europe daytime temperatures can reach dangerous levels given the right conditions, what chance do outdoor workers have in the searing desert heat offered up by the Middle East’s summer months?

And all that’s before considering inescapably hot indoor environments! What could appear to be a warm day to a worker outside might be like an industrial furnace to a worker performing maintenance inside a machine.

As human beings, we are also all very different. Some of us may be able to cope with temperature extremes without too much trouble, whereas others would suffer major problems. The elderly, pregnant women, very young children and lone workers are all people particularly vulnerable to the risks of working in the heat. The same goes for equipment and assets. They could give off large quantities of residual heat, therefore affecting our workforce. Even worse, an additional hazard could occur in the form of fire. So, let us first start by looking at the potential sources of heat.

The Sun

The one that most people would know is the Sun – that giant, yellow fireball in the sky. It constantly bombards the earth with various forms of energy, including heat energy. Some of this energy bounces off the atmosphere and away from the planet. Some of it reaches the surface, and is then reflected away again (think of reflective surfaces such as snow and water). Some, however, is inevitably absorbed by the surface of the earth, heating the ground and air. Some countries will feel this effect more than others, by being closer to the equator (the line on a world map that separates the Northern and Southern Hemispheres). This is because in effect, the Sun is directly overhead of these countries, whereas it is at an angle for others (try and imagine shining a torch on a football). This also means that these places are closer to the Sun, which means the energy has less distance to travel, therefore less energy is lost. So, the sun is one source of heat. What others could there be though?

Machinery and equipment

Machinery and equipment is another potential source of heat to consider.

Rapidly moving parts will produce heat through friction (when two surfaces, materials or elements are sliding against each other), and engines will produce heat as result of fuel combustion. Someone may be working inside, or on top of, a large piece of equipment. In this case, the heat could come through metal surfaces absorbing heat energy from the sun, residual heat energy from equipment that has not long been shut down, or lack of ventilation or air movement (e.g. when working inside a dump tray of a haul truck, or a deep hole or excavation).

Other heat sources could be as a result of manufacturing and industrial processes, such as chemical reactions (laboratory work) and forging of metals (steel foundries). Another common source could be through hot works, such as welding and grinding. So in your workplace, there could be lots of heat sources, or very few, but why could heat be a problem?

“even if a person survives an extreme heat exposure event, there can be lasting effects, such as permanent damage to internal organs”

Effects of heat

First, let us look at the issues our workers could face. The average internal temperature of the human body is 37°C (or 98.6f). If this temperature drops or increases too much, this can have a drastic health effect. In the case of overheating, our body has some natural mechanisms to try and correct this. The one most people will know about is sweating.

The sweat glands of our body release water onto our skin, causing a cooling effect. This, however, will only work for so long. In an average adult, water makes up around 60% of the body (in the natural world, this can be as high as 90% in some animals). Without re-hydration and rest, our workers will be in serious trouble. As the human body becomes too hot, sweating will lose its effect, and our brain will begin to overheat. Organs and systems will begin to malfunction or shut down, muscle cramping will occur, workers will become dizzy, confused, or even faint. Eventually, the body will simply become too badly damaged, and death occurs.

Even if a person survives an extreme heat-exposure event, there can be lasting effects, such as permanent damage to internal organs, and cancers such as melanoma, or skin cancer. Short term effects can also cause issues. Workers will become fatigued both physically and mentally. Confusion, slower reaction times, and lower energy output can all effect the worker. Specific conditions that could affect the worker include heat-stress, heat-stroke, heatexhaustion and hyperthermia. Anyone showing symptoms such as headache, dizziness, increased heart rate and weakness will be suffering from one of these heat-related illnesses, so look to provide appropriate treatment as necessary, and as soon as possible. This could simply be cooling the person down and giving them rest, or they may have to be sent to hospital if they are seriously ill.

How bad is the problem? Well, according to OSHA (Occupational Safety and Health Administration of America) statistics, 31 workers died and 4,120 fell ill due to heat exposure in 2012. Between 2004 and 2014, the average was 36 deaths and 2,810 heat-related illnesses every year. So, from this it’s easy to see that our employees can be badly affected by extreme heat exposure, but there are other problems that could occur.

Equipment overheating Equipment can overheat in various way. It may run for an extended period of time, or not be properly maintained (e.g. a lack of coolant in an engine). It may be working too hard. Overloaded electrical systems will generate a lot of heat, or equipment running beyond its capacity may melt or ignite through overworking (e.g. a PC trying to run a software program that is too complex for the hardware within it). This could result in burns to workers when they touch this equipment, or the equipment itself could actually ignite and start a fire. Again, the residual heat produced from this equipment may be enough to heat the working environment, causing problems.

Confined areas such as pipes, ducting and excavations could also pose a heat issue. This is generally due to a lack of ventilation, or movement of air, in these areas. This is particularly a problem, as only the workers in these areas will feel the heat. Workers outside these areas looking in may not see the problem from their perspective. As you can see, it is not just the sun or environment we have to think about – so what can we do to tackle the problem?

Hierarchy of control

First, let us look again at the sun. Thinking of the hierarchy of control, maybe we could use elimination. If we were some kind of super-villain in a James Bond film, maybe we could blow up the sun or cover it with something; however, seeing as the governments of the world – and the population in general – might have issues with the world ending, we will instead take a more subtle approach. In terms of elimination, the easiest thing to do would be to not allow workers to work outside in the sun, particularly during the middle of the day, when day-time temperatures are generally at their peak.

We could also give workers regular rest breaks, particularly when performing intensive, physical tasks. Job-rotation would also be a good tool to help prevent over-exposure. Instead of having one person do the same job for two hours, after one hour have him swap with a colleague.

As mentioned earlier, we cannot cover the sun, but we can block some of the energy coming from it. Give workers areas of shade where they can rest. Shaded areas tend to be cooler, again, as they block some of the sun’s rays. Also, try to have as little of worker’s skin exposed as possible. This will help prevent problems associated with sunburn. This can be done easily by having workers wear trousers, and tops with long sleeves.

You may even give workers some kind of half-face mask (similar to those worn by outdoor sports enthusiasts like fishermen and winter sports participants). You can even purchase clothing specially designed for working in the sun. This clothing is made of UV (ultra-violet) resistant materials, which are also breathable, meaning that the worker can still sweat normally, without the clothing becoming sticky and uncomfortable.

Sunscreen is also an option you could use. Applied to the skin, this cream temporarily reflects a lot of the sun’s rays away from the skin. As always, however, sunscreen needs to be applied properly and at regular intervals in order to be effective. You also need to choose the correct sunscreen for where you work, as they all have different levels of protection (called the SPF, or Sun Protection Factor).

Hats and protective eyewear, such as sunglasses, will also offer some protection for your workers, providing shade for the head, and limiting the amount of light that reaches workers’ eyes.

Hydration is also a key aspect of safely working in the heat. Workers should have access to cool, clean drinking water as a minimum. This is a legal requirement in a lot of cases, so check the HSE regulations that apply to your country or locality. You may also consider giving workers isotonic drinks. You could go for popular brands, such as Gatorade or Lucozade, or purchase isotonic drinks specifically made for industry. Not only do these products replace valuable water lost from the body, but they also replace the salt lost through sweating. This will help prevent muscle cramps and limit the effects of fatigue.

Ventilation and air movement are also important points to consider. This could be as simple as a portable fan, or leaving part of the work area open to the environment to allow air to flow into and around it. It could be more complex, involving air-conditioning systems, airextraction systems, or hiring industrial mobile fans. For cooling both people and equipment, you could even use mist or fog systems. These systems spray a “mist” or “fog” of cool water vapour into an area, giving workers relief from the heat (Bangkok Safari Park in Thailand has such a system, to keep patrons cool during the height of summer). Allowing workers access to cool showers is also a relatively easy way to give them relief from working in the heat.

Automation for safety

Automation is becoming a bigger and bigger part of our world, both in our working and public lives, so this is something else we could consider. For example, many military forces now make use of drones, or UAVs (Unmanned Ariel Vehicles). This means instead of a soldier having to scout terrain on foot in the outdoor heat, they can be inside a cooler environment of a tent or control room. This way the mission can still be achieved, but with less risk to the soldier, as the scouting can be done via a camera on the drone. Another example would be in the mining industry. Many pieces of equipment, such as haul trucks, graders and bulldozers, can now operate either totally autonomously, or via a remote control. So again, our workers can be in a relatively cool climate of a control room, or even a small work vehicle with the air-conditioning system running.

Automation also has the advantage of reducing human-error, and optimising efficiency, again reducing the chances of equipment failing through overheating. Instead of an operator pushing the equipment beyond its limits, the computer inside it will shut the equipment down if necessary, to allow it to cool down to a normal operating temperature.

Training and awareness

Training and awareness are also good tools to use to protect the workforce. Often workers will feel pressure not to say anything, as they will look “weak” in front of their peers. Workers often also stay silent, as they believe there is nothing wrong with them, or they wrongly believe they can cope with the situation on their own. Encourage workers to recognise the symptoms of heat-illness, and look out for one another. IOSH (Institute of Occupational Safety and Health) have a great campaign called “No-Time to Lose”. Whilst the campaign focusses on worker exposure to carcinogens (things that can cause cancer), part of the campaign is all about sunburn and the effects of radiation from the sun (www.notimetolose.org.uk). These kinds of campaigns are a great tool to inform and educate the workforce.


Acclimatisation is also something to consider. You may have hired workers from countries with cooler climates, or they have had jobs previously which did not involve heat exposure or strenuous activity. In this case, introduce them to the environment and work slowly. By building them up stage-by-stage, this will allow their body time to adjust to the environment, alleviating some of the effect on their body.

Even those who you think would naturally cope with heat might not be as able as you think. As an example, a Nigerian friend of mine came to work in The Sultanate of Oman, arriving during the summer months. Being of African descent, you would assume that there would not be much of an issue. Unfortunately, however, the person in question fainted as soon as they left the air-conditioned plane cabin and entered the outside environment.


When it comes to working in the heat, there’s more to it than just covering up skin and using sunscreen. If we manage working in the heat properly, we can avoid a lot of the short-term and longterm consequences that could potentially befall our colleagues and workforce. Get the bigger picture about air movement, hydration and rest. Carefully consider each task and the employees involved. Can we avoid working in hot environments all together? If not, can we adjust the work times, duration and reduce the workload? Remember you can always approach your HSE team, peers, outside consultants and the workforce themselves for help and advice. “Beat the heat” by staying cool.