Germes Advisor

What is UPF?
The UV protection factor of textiles, and what it really covers

UPF states how much solar UV a weave keeps off the skin. Three different test methods exist, which can give different numbers for the same material. This page explains the scale, lists the values our fabrics carry together with the standard each was tested to, then says openly where the best known of those standards draws its own boundary.

The basics

What sits behind the number

UPF stands for Ultraviolet Protection Factor. It is a ratio, not a percentage, describing the weave rather than the finished product.

UPF explained in one sentence

UPF is the ratio between the UV dose unprotected skin tolerates before reddening, and the dose that arrives through the fabric. **UPF 50 means one fiftieth of the UV radiation gets through.** UVA as well as UVB are measured together.

Not the same as a sun protection factor

The sun protection factor of a sunscreen is determined on skin, referring to reddening caused by UVB. UPF is measured in a laboratory on the weave, UVA included. The two numbers look alike, arise on entirely different paths, cannot be converted into each other.

UV protection is not UV resistance

Two questions get mixed up. UPF describes how well a person **underneath** the fabric is shielded. How well the fabric **itself** takes the sun without fading is lightfastness, measured in a completely different way, see what is lightfastness.

What raises the value, what lowers it

A dense construction, high weight per square metre, deep dark shades all protect well. Moisture, stretch, wear, thin spots all reduce the protection. A light, pale fabric can drop several classes when wet without anything being visible.

UPF meaning: the three protection classes

The banding comes from the Australian standard, which has become the international convention. Above the top class no further distinction is drawn.

UPF valueRatingShare of UV radiation blocked
15 to 24good protection93.3 to 95.9 per cent
25 to 39very good protection96.0 to 97.4 per cent
40 to 50+excellent protection97.5 to 99.9 per cent
below 15no classificationnot declared as sun protection

Three test methods, three points of view

AS/NZS 4399, the best known
The Australian and New Zealand standard is the most widely used method worldwide, the source of the classes above. Measurement takes place on **new, dry, unstretched** material. The highest class awarded is UPF 50+; nothing above that is declared separately.
What this standard explicitly leaves out
It was written for clothing worn **close to the skin**. Shading held at a distance from the body, meaning shade sails, awnings, umbrellas, is excluded by the text itself: scattered radiation entering around the edges means more UV reaches you underneath than the material value suggests, varying with area as well as distance. The fabric figure stays correct; protection at the sun lounger is a second question.
EN 13758-1, UV Standard 801
The European standard also measures new, dry material. UV Standard 801 takes another route, testing **wet, stretched, after simulated wear**, so under worst-case conditions. Its figure for the same material therefore tends to come out lower, which is why it is recommended for shading textiles. Comparing two UPF numbers starts with comparing the standard.

UPF values in our range

These figures come from the data sheets as well as the test reports of our fabric suppliers, each with the standard it was measured to. How a fabric is dyed is explained under solution dyed.

Fabric groupUPFTested toNote
Agora, solution dyed acrylic (Air, Liso, Lines, Rayure, Panama, Life)50+AS/NZS 4399:1996top class of the standard, manufacturer figure from the data sheet
Agora Liso Waterproof, with backing laminate50+AS/NZS 4399:1996place the laminate facing inwards when making up
Acrisol Liso (Dralon), conventionally dyed acrylic50AS/NZS 4399:1996Eurofins report AR-19-YL-000693-01-EN, UVA as well as UVB at 0.00 per cent transmission
Screen weave for shading20 to 45 depending on colourEN 13758-1deep dense shades protect markedly better than pale ones
Upholstery fabrics for seats, indoor usenot declared-lightfastness matters here, not UPF
In practice

What the number is worth in a garden

The laboratory figure applies to new material held flat. Four points decide how much of it reaches the person underneath.

Distance costs protection

Under a shade sail you receive radiation from above plus scattered light from the sides as well as the ground. The larger the shaded area, the lower the mounting, the closer the effect comes to the material value. A small sail high above the table protects noticeably less than its figure promises.

Wet fabric protects less well

Water fills the gaps in the construction, letting more UV through. On dense acrylic weaves the effect is small, on light pale materials it is clear. After a shower the protection is temporarily lower than on a dry day.

The value ages with the fabric

Measurement happens on new material. Years of sun, washing, abrasion loosen the structure, while thin spots as well as holes cut the protection sharply. Hold a shade up against the light: if sky shines through, replace it.

What to check when buying

Always ask for the standard alongside a UPF figure. A number without one cannot be compared. Ours appears on every data sheet, plus a fabric sample shows density fastest: hold it against the light, see how much comes through.

Frequently asked questions

Frequently Asked Questions

One fiftieth of the UV radiation passes through, roughly two per cent, so about 98 per cent is blocked. That puts the material in the top class. The plus sign only means the standard draws no further distinction above 50, not that protection is unlimited.

Not under the Australian and New Zealand standard, where the scale ends at 50+. UV Standard 801 awards higher figures up to 80, but measures wet, stretched, after simulated wear. A higher number therefore does not automatically mean a better material, it means a different method first of all.

The material lets only two per cent through, yet scattered light also arrives from the sides. That is precisely why the clothing standard excludes shading held at a distance from the body. A shade sail lowers UV exposure considerably, though it replaces no sunscreen during hot midday hours.

On our acrylic weaves the protection sits in the fibre plus the construction, not in a finish that could wash out. What does suffer is the water repellent finish. On materials whose UV protection rests on a coating, frequent washing can indeed lower the value.

Which fabric suits your sunny spot?

Tell us how large the area is, how high the shading will hang. We will name the fabrics that fit, with their tested figures, then send samples on request.