In this article, we focus on ‘heat stress’. For more information about the risk of burns, we refer you to the page ‘Fire, sparks and weld spatter’.
Medewerkers raken oververhit door twee belangrijke oorzaken:
1. The environmental conditions in which they work
2. De lichaamstemperatuur gegenereerd door fysieke arbeid.
Hitte gerelateerde problemen ontstaan als de temperatuur van het lichaam stijgt en niet meer wordt beheerst door het lichaam. Hier heeft het dragen van veiligheidskleding en PBM’s ook invloed op. Hittestress komt dus niet alleen voor tijdens de zomer.
The human body uses its own mechanisms to deal with heat. Your body cools off through radiation and convection, but above all by evaporating sweat and bringing blood to the skin surface. However, the higher the humidity, the harder it is for the sweat to evaporate. When wearing poorly breathing clothing (like safety clothing) that evaporation effect is reduced even more. The clothing acts as a ‘greenhouse’, causing the body’s temperature to keep rising.
We distinguish three kinds of heat:
- Conductive heat: High temperature spreads across the entire surface, so it is important to wear clothing with a low thermal conduction.
- Contact heat: When you touch a hot object, you can get burns. Good PPG, like clothing and gloves, can help protect you.
- Radiation heat: When an object gets very hot, it will radiate heat, which, at very high temperatures, will cause burns.
Heat stress starts out small, but can escalate quickly unexpectedly. Do you recognize one of the symptoms listen below? Make sure to take measures immediately!
- Loss of concentration
- Muscle cramps
- Heat rash
- Serious thirst (often a late sigh of heat stress
- Overheating: tired, dizzy, nauseous, headaches, moist skin
- Heat stroke: heat dry skin, confused, absentminded and possible loss of conscience.
- This face can lead to death when not recognized in time.
There are also other consequences: the wellbeing and safety of your employees is put at risk. Loss of concentration increases the likelihood of mistakes and unsafe working practices. If one of your employees suffers from heat stress, they can also pose a risk for their colleagues!
In the NEN-ISO 7243D, it is explained how you can measure the core temperature: using a WBGT matrix. The humidity and ambient temperature together determine the core temperature. For a precise determination you will, of course, have to perform a WBGT measurement with special equipment.
The WGBT index shown below assumes a situation without airflow and without sun or heat radiation. So it can be applied to situations in closed spaces.
The WBGT index assumes a situation with a light airflow and in the full sun or heat radiation. Comparable to a workplace outside, like a construction site.
Below the activities identified on the basis of NEN-ISO 7243:1989
LegislationA lot has been written about work-related risks. However, with regard to heat in the workplace, as yet there is no concrete legislation. The Health and Safety Decision of May 1, 2018 contains no mandatory measures, but it does provide a guideline on which to base your measures.
Article 6 makes it clear that temperature must no damage people’s health. It is important to take the activities and the physical burden into account.
If the temperature can no longer be regulated, the correct PPG has to be provided. In the cold, that helps, but in the heat, it often creates an addition burden. In that case, the time people work in the warm environment must be shortened or alternated with less burdensome activities.
The FNV (a Dutch trade union organization) has developed a Heat Stress Calculator to make a global assessment of the risks. If there is heat in the workplace, that aspect has to be included in the RI&E. When determining which measures to take, use the advice of the company doctor or another expert.
Useful guidelines for offices
With regard to working in offices and workplaces, there are general rules:
- In case of temperatures about 26˚ C, there is an additional physical burden and it is important to think about measures.
- For light physical office work, there is a maximum temperature of 28˚ C.
- For intensive physically demanding work, the maximum temperature is 26˚ C, provided there is a clearly noticeable airflow.
- For very strenuous physical work, there is a maximum temperature of 25˚ C, provided there is a clearly noticeable airflow, otherwise the maximum temperature is 23˚ C.