AS 4399:2020

Sun protective clothing - Evaluation & classification

Long days under the harsh Australian sun can be dangerous without the right safety equipment. TRu Garments are UPF50+, reducing the risk of skin cancer and premature aging.

Ultraviolet Protection Factor

The Australian standard for sun protective clothing, AS 4399:2020, measures the Ultraviolet Protection Factor (UPF). UPF refers to the amount of solar ultraviolet radiation (UVR) that passes through an unstretched dry fabric. This includes both types of UV radiation that reach the Earth's surface; UVA and UVB.

  • UVA rays are more abundant and deeply penetrate the skin with damaging effects such as photoaging. There are around 500 times more UVA rays in sunlight than UVB rays.
  • UVB rays are the most potent contributor to causing skin cancers, responsible for the formation of malignant melanoma.

Testing Procedure

TRu Workwear garments are UPF tested under AS 4399:2020. The UPF testing is carried out at the fabric testing laboratory of ARPANSA or the Australian Radiation Protection And Nuclear Safety Agency. ARPANSA's laboratory is accredited by the National Association of Testing Authorities (NATA). These companies issue test reports outlining compliance to the AS 4399:2020 standard. A report will provide the UPF ratings of the materials tested but does not evaluate the design or body coverage of the products. When measuring to the standard, a UPF rating is calculated based on the amount of ultraviolet radiation (UVR) that can pass through a dry unstretched fabric. Wet fabric and the knitted materials create variations in the level of UVR protection on a garment. Denser fabrics with tighter weaves stretch less and therefore offer more robust UVR protection. The standard allows for variations in fabric types on a single garment, such as underarm mesh vents on workwear shirts. However, all fabric used on critical body parts must achieve a UPF rating. The AS 4399:2020 version of the standard specifies three protection classifications, dependent on the amount of UVR blocked as per corresponding table.

UPF RatingClassification
15Minimum Protection
30Good Protection
50, 50+Excellent Protection

The numerical score is based on the amount of UVR blocked, rated on a scale from 15 to 50+. The highest assigned rating for a UPF rated fabric is 50+. If a fabric blocks 95% of the UV rays - allowing 1/20th of the UV radiation through - it would be assigned a UPF20 rating. If the garment is rated as UPF50+ then it is recorded as letting through less than 1/50 of the radiation that hits the garment, meaning it provides excellent sun protection.
For onsite outdoor activity you require materials with a UPF50+ rating, which is capable of all day sun protection

Minimal Skin Exposure

The standard assesses clothing for how well it is constructed to cover the largest area of the body, as explained on the garment's swing tag:
“The UPF rating applies only to the area of skin covered. Protection may be reduced if the material is wet, stretched or from the effects of normal wear or exposure to chemicals. For best sun protection use hats, clothing that provides maximum skin coverage, sunglasses, and sunscreen and shade.”
Garments can be designed to cover the lower body, upper body or all in one. Each category has specific requirements. For 'upper body' coverage, the garment's sleeves must protrude more than 3/4 of the upper arm (i.e. a singlet would not be sufficient) and include the shoulders and torso. For lower body coverage, pants must cover at least halfway down the thighs, extending from the hip. SPF sunscreen must be applied to areas of the body left exposed by the garment to ensure total protection.


The AS 4399:2020 stipulates that all compliant garments be permanently labeled with the following statement:

  • Level of protection - "UPF50+ - Excellent protection"
  • "Maximum skin coverage helps prevent skin damage"