Commercially Marketed Clothing
For marketed sun protective clothing, the following categories are used to describe the protection value of American or Australia/New Zealand tested fabrics. The UPF ratings coincide closely with the SPF values given to sunscreen products in Canada and elsewhere. Of note though, since some companies may test only dry, unstretched fabric samples, be mindful of the “hole effect” if not indicated.
| UPF Ratings and Protection Categories | ||
|---|---|---|
| UPF rating (ultraviolet protection factor) |
Protection category | % UVR blocked (ultraviolet rays) |
| 15 – 24 | Good | 93.3 – 95.9 |
| 25 – 39 | Very good | 96.0 – 97.4 |
| 40 – 50 | Excellent | 97.5 or more |
The “Hole Effect” *
By understanding the “hole effect” one can better grasp which clothing choice can offer better UV protection. All fabric that is woven has holes between the individual threads. The tighter the weave and denser the fibre, the better protection this clothing can offer. Should your clothing become worn out, tight fitting or wet, these altered states will increase the size of the holes and the amount of UV exposure.
* Phrase attributable to Menzies S, Lukins P, Greenoak G, et al.
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