08 Gezondheids- en werkplekaspecten
 >  What to do in case of a thunderstorm
Discussion > Talk with your colleagues about it!
  • I will go look for a place to hide when a thunderstorm is approaching. I will not wait until it has reached the place where I am working.
  • I know where I can take shelter on this project in case of an approaching thunderstorm.

The dangers of a thunderstorm should not be underestimated. On average, the Netherlands will experience a thunderstorm about 25 days per year. It is key to make employees aware of the dangers of lightning. It is important to be alert to thunder, whether you are working inside or outside. The place and time of lightning striking can never be determined precisely.

Risks > What can happen?
  • Getting struck by lightning
  • Electrical devices can experience failures due to lightning
  • Thunder is often not noticed in a noisy environment
  • Hearing protection equipment blocks out low frequency sounds. The rumble of thunder is also low in frequency and is therefore blocked out as well
Measures > What must you do?



  • Cease crane/piling activities
  • If possible, lower the booms and masts of cranes and piling rigs
  • Make sure you are not near fences, construction hoists, scaffolds, lighting columns and other metal objects
  • Cease work on metal conductive parts (gas, electricity, water and central heating pipes, air ducts, etc.) and stay away from these objects 
  • Stay in your car or cabin and keep the doors and windows closed

Personal measures

  • Make sound agreements with employees when working in a noisy environment and inside. Those who can keep an eye ‘and ear’ on the weather, could end up playing a crucial role
  • Leave workplaces at height (scaffolds; decks and wall formworks)
  • Leave workplaces in open areas
  • Do not stand in front of an open window
  • Do not stay together as a group but spread out

If you are unable to reach a safe place in time, proceed as follows:

  • Do not stand under trees
  • Do not lie down
  • Crouch to make yourself as small as possible
  • Wrap your arms around your knees
  • Keep your head down
  • By keeping your feet together, there is only a small chance that the electricity will pass through your body
  • Avoid using your mobile phone
Tips > For more information

Thunderstorms move fast; their speed can be estimated following the rule of thumb

1 kilometre when there is 3 seconds between the lightning flash and the sound of thunder!

In case of an approaching thunderstorm, cease work immediately and find a safe place to hide!!!


Crouch to make yourself as small as possible
Approaching thunderstorm
In this way there is only a small chance that the electricity will pass through your body