It is important to know that ultraviolet (UV) rays can be harmful, even on cloudy days. People who are exposed to UV radiation need to know how to protect themselves.

There are three types of solar UV rays: UVA, UVB and UVC. In this article, we discuss the different types of UV rays, the associated risks and the necessary protective measures.

What are UV rays?

UV rays are a form of electromagnetic radiation emitted by the sun, and that is invisible to the human eye. These rays are categorised into three types according to their wavelength:

• UVA (315-400 nm): This radiation penetrates deep into the skin and is responsible for premature skin ageing and wrinkles. It also plays a role in the occurrence of skin cancer.
• UVB (280-315 nm): Radiation that damages the outer layers of the skin, resulting in the skin being burnt (sunburn). UVB rays are the main cause of skin cancer.
• UVC (100-280 nm): This type of radiation has the highest energy value, and is therefore the most harmful. Fortunately, this radiation is completely absorbed by the ozone layer and does not reach Earth.

Risks from UV exposure

Prolonged exposure to UV rays can cause various skin and eye conditions, including:

• Skin cancer:
• Eye damage such as blurred vision
• Skin ageing such as wrinkles and pigment spots
• Weakened immune system

For people working outdoors, such as roofers, the risk is even greater, as they have less protection from the sun. Additionally, factors such as skin type play an important part in the intensity of sunburn.

Please note: UV radiation is still present on overcast days, and significant damage can be caused unless you protect yourself properly.

Protection against UV rays

1. Workplace adaptations (collective protection)

• Create shady workplaces using tents, awnings or other canopies.
• Whenever possible, schedule outdoor work outside the peak hours of UV radiation (between 10.00 and 16.00 hours). For example, you can carry out preparatory work indoors instead of outdoors in the sun.
• Make sure employees are aware of the level of UV radiation for that day, also known as the UV Index. This is easily checked using the Weather app on your mobile phone. The UV index is indicated by numbers. From UV 2, it's important to apply sunscreen.

2. Make sure your skin is not exposed to sunlight

• Protective clothing: Wear light-coloured protective clothing, such as long sleeves and long trousers. Special UV-resistant clothing is available that complies with the EN 13758 standard. Garments certified to this standard provide UVA + UVB sun protection.
• Head protection: Wear a helmet or bump cap with neck flap to protect your neck and a wide brim to protect your face from sunburn.
• Sunglasses: Use safety sunglasses that protect against UV radiation.

3. Sun cream

Choose a sun cream with an SPF of at least 30 that blocks both UVA and UVB radiation. Regularly apply a fresh layer of sun cream, especially when sweating. An SPF of at least 30 provides effective protection against sunburn caused by UVB radiation, which means that the sun cream protects your skin from sunburn 30 times longer than if you did not use any sun cream. For example, SPF 50 blocks around 98% of UVB rays, which can make a huge difference to the length of time you can safely stay in the sun without becoming sunburnt. It’s important to know that the SPF does not determine how often the sun cream needs to be applied, but rather how long protection against UVB rays will remain effective. This is why it is essential, especially when sweating, to re-apply sun cream every 2 hours to ensure permanent protection against the harmful effects of the sun.

This Physioderm sun cream with SPF 30 protects against UVA, UVB and UVC.

Below you can see the effect of wearing sunscreen.