The aim of sun protective clothing is to reduce a person's UVR exposure.

Many types of radiation emitted by the sun, mainly visible (light) and infrared (heat) reach the earth's surface.  Ultraviolet radiation (UVR) is also present but we cannot see it or feel it.  Ozone in the atmosphere absorbs much of the dangerous UVR before it reaches the ground but we can still receive enough to cause sunburn and more serious health problems. Exposure to UVR can cause not only sunburn but also lasting skin damage. This may result in premature skin ageing and skin cancer. UVR can also cause eye disorders such as cataracts.

1.UPF of a fabric

Different fabrics have different UVR-absorbing properties.

Less UVR passes through tightly woven or knitted fabrics.

• Darker colours usually block more UVR.
• Heavier weight fabrics usually block more UVR than light fabrics of the same type.
• Garments that are overstretched, wet or worn out may have reduced UVR protection.

The UPF rating on many garments indicates clearly how good the fabric is at blocking UVR but the design of the garment also needs to be considered. Shirts with long sleeves and high collars, hats that shade the face and protect the back of the neck and ears are most effective. Loose fitting clothing is usually more protective than tight fitting clothing.

2. UPF Ratings and Protection Categories

The Standard states that the highest UPF rating garments may be labelled with is 50. Garments made from fabrics with ratings higher than 50 are labelled as UPF 50+.

Sun-protective clothing offers another way to protect skin from the harmful effects of the sun.  Sun-protective fabrics differ from typical summer fabrics in several ways:  they typically have a tighter weave or knit and are usually darker in color.  Sun-protective clothes have a label listing the garment's Ultraviolet Protection Factor (UPF) value, that is, the level of protection the garment provides from the sun's ultraviolet (UV) rays. The higher the UPF, the higher the protection from the sun's UV rays.  The UPF rating indicates how much of the sun's UV radiation is absorbed by the fabric. For example, a fabric with a UPF rating of 20 only allows 1/20th of the sun's UV radiation to pass through it.  This means that this fabric will reduce your skin's UV radiation exposure by 20 times where it's protected by the fabric.  Everything above UPF 50 may be labeled UPF 50+;  however,  these garments may not offer substantially more protection than those with a UPF of 50.  Also, a garment shouldn't be labeled "sun-protective" or "UV-protective" if its UPF is less than 15.  Sun-protective clothing may lose its effectiveness if it's too tight or stretched out, damp or wet, and if it has been washed or worn repeatedly.

3. Protection from UV radiation

Avoid going outdoors in the middle of the day (10am to 2pm) when the sun is highest (11am to 3pm during daylight saving). This practice can dramatically reduce your UVR exposure.

• When outdoors, choose shaded areas where you cannot directly see the sun or the open sky.
• Wear well designed clothing that covers the arms and legs as well as the body.
• Wear a broad-brimmed hat which shades the face, ears and back of the neck.
• Wear sunglasses when outdoors.
• Apply at least SPF 15 sunscreen to all areas of the body that are not covered by clothing. 
• Reapply sunscreen every two hours and after swimming or activities causing heavy perspiration as sunscreens do wear off.
• Young children do not understand the dangers of UVR. Protect them with shade, suitable clothing, hats, sunglasses, and sunscreen. Well designed sun protective clothing is available in children's sizes.