Summer is here again and the temperature is rising.Heat Stress

This brings with it the added problem of coping with this heat whilst at work.

Last July I covered working in the heat (download the leaflet here) where I looked at:

  • The risks from working out in the sun;
  • The risks from working in hot areas indoors in this weather, for example in loft spaces;
  • The precautions and controls you should adopt both as employer and employee.

This time I am going to look at what you, as an employer, may need to do to protect your employees from heat stress in the workplace.

I also look at risks to people from overheating when working in hot conditions (such as bakeries, dry cleaners, hot offices or even when stuck in a car in heavy traffic) and I try and give practical guidance on how to avoid it.

In many jobs heat stress is an issue all year round but this information also applies during the hot summer months where there may be an increased risk of heat stress for some

The two HSE cases this week both look at tragic accidents that shouldn’t have happened

As ever, if you have a subject that you would like us to cover one week, please contact us by phone 01458 253682, email or via our Facebook page, or by Twitter


Heat stress in the workplace.

You and your employees must be aware of how to work safely in heat, the factors that can lead to heat stress, and how to reduce the risk of it occurring.

What is heat stress?Overheated

Heat stress occurs when the body’s means of controlling its internal temperature starts to fail. Air temperature, work rate, humidity and work clothing are all factors which can cause heat stress. It may not be obvious to someone passing through the workplace that there is a risk of heat stress.

How does the body react to heat?

Here’s the scientific bit:  The body reacts to heat by increasing the blood flow to the skin’s surface and by sweating. This cools the body as heat is carried to the surface from within by the increased blood flow and sweat evaporates. Heat can also be lost by radiation and convection from the body’s surface.

Typical example of a heat stress situation

Someone wearing protective clothing and performing heavy work in hot and humid conditions could be at risk of heat stress because:

  • Sweat evaporation is restricted by the type of clothing and the humidity of the environment.
  • Heat will be produced within the body due to the work rate and if insufficient heat is lost deep body temperature will rise.
  • As deep body temperature rises the body reacts by increasing the amount of sweat produced, which may lead to dehydration.
  • Heart rate also increases which puts additional strain on the body.
  • If the body is gaining more heat than it can lose then the deep body temperature will continue to rise. Eventually it reaches a point where the body’s control mechanisms start to fail.

What are the effects of heat stress?

Heat stress can affect individuals in different ways and some people are more susceptible to it than others.

Typical symptoms are:

  • an inability to concentrate;
  • muscle cramps;
  • heat rash;
  • severe thirst – a late symptom of heat stress;
  • fainting;
  • heat exhaustion – fatigue, giddiness, nausea, headache, moist skin;
  • heat stroke – hot dry skin, confusion, convulsions and eventual loss of consciousness. This is the most severe disorder and can result in death if not detected at an early stage.

Where does heat stress occur?

Examples of workplaces where people might suffer from heat stress because of the hot environment created by the process or restricted spaces are:

  • glass and rubber manufacturing plants;
  • mines;
  • compressed air tunnels;
  • conventional and nuclear power stations;
  • foundries and smelting operations;
  • brick-firing and ceramics plants;
  • boiler rooms;
  • bakeries and kitchens;
  • laundries.

In these industries working in the heat may be the norm.

For others it will be encountered less often depending on the type of work being done and changes in the working environment, e.g. seasonal changes in outside air temperature can contribute significantly to heat stress.

  • construction sites
  • agricultur
  • driving

What do I need to do about heat stress?Scaffolding in the sun

Over time people can adapt to hot conditions by sweating more and changing their behaviour to try and cool down, e.g. removing clothing, taking cool drinks, fanning themselves, sitting in the shade or a cool area, and/or reducing their work rate. However, in many work situations such changes may not be possible, e.g. when protective clothing has to be worn.

Where there is a possibility of heat stress occurring you will need to consider this when carrying out your risk assessment.

What do I need to look at in the risk assessment?

When carrying out your risk assessment, the major factors you need to consider are:

  • work rate – the harder someone works the more body heat they generate;
  • working climate – this includes air temperature, humidity, air movement and effects of working near a heat source;
  • worker’s clothing and respiratory protective equipment – may mean that sweating and other means of the body regulating its temperature are less effective;
  • worker’s age, build and medical factors – may affect an individual’s tolerance.

Firstly, talk to the workers involved and their safety representatives (if there are any in your workplace) to see whether they are suffering early signs of heat stress. If there is a problem, you may need to get help from others who are more experienced in determining the risk from hot environments, e.g. occupational hygienists or occupational health professionals.

How can I reduce the risks?Water Bottles

Remove or reduce the sources of heat where possible:

  • Control the temperature using engineering solutions, e.g. change the processes, use fans or air conditioning, use physical barriers that reduce exposure to radiant heat.
  • Provide mechanical aids where possible to reduce the work rate.
  • Regulate the length of exposure to hot environments by:
  1. allowing workers to enter only when the temperature is below a set level or at cooler times of the day;
  2. issuing permits to work that specify how long your workers should work in situations where there is a risk;
  3. providing periodic rest breaks and rest facilities in cooler conditions.
  • Prevent dehydration. Working in a hot environment causes sweating which helps keep people cool but means losing vital water that must be replaced. Provide cool water in the workplace and encourage workers to drink it frequently in small amounts before, during (where possible) and after working.
  • Provide personal protective equipment. Specialised personal protective clothing is available which can incorporate personal cooling systems or breathable fabrics. The use of some protective clothing or respiratory protective equipment may increase the risk of heat stress.
  • Provide training for your workers, especially new and young employees, telling them about the risks of heat stress associated with their work, what symptoms to look out for, safe working practices and emergency procedures.
  • Allow workers to acclimatise to their environment and identify which workers are acclimatised or assessed as fit to work in hot conditions.
  • Identify employees who are more susceptible to heat stress because of an illness, condition or medication that may contribute to the early onset of heat stress, e.g. pregnant women or those with heart conditions. You may need advice from an occupational health professional.
  • Monitor the health of workers at risk. Where a residual risk remains after implementing as many control measures as practicable, you may need to monitor the health of workers exposed to the risk. You should then seek advice from an occupational health professional.

Remember it doesn’t have to be unbearable!

Hot dog

Most of us look forward to the summer and enjoy the sun and the warmth. If you follow the advice here and take steps to keep cool and hydrated then you can avoid becoming ill as well.

Is there any subject you would like covered in this newsletter? Please contact us by phone 01458 253682, or email.



Training Courses

We have just finished our present run of open CDM2015 courses, we still have 3 private courses to run in July in Wiltshire, Birmingham and London, but we have been asked to consider running a shorter version aimed primarily at the Smaller Builder

These will be coming soon!

We are also being asked to organize:

  • First Aid Courses
  • Health & Safety Management courses
  • Health & Safety Awareness courses
  • Asbestos Awareness courses

These will also be coming soon!

For more information and to book and pay on line please visit our training pages.

If you have any questions about these courses or any other training or would like us to run a particular course for you, call Jon Wilkins of the Wilkins Safety Group on 01458 253682 or email him.


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