Published in July 1996, AS/NZS 4399 describes standard laboratory procedures for measuring the SPF of fabrics and for labelling SPF rated clothing. Fabrics are assigned a UPF rating number and also a protection category depending on how much UV radiation they block out. This table shows the rating system.
| 15 - 24 |
Good |
93.3 - 95.9 |
| 25 - 39 |
Very Good |
96.0 - 97.4 |
| 40 and over |
Excellent |
97.5 or more |
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The Standard states that the highest SPF rating garments may be labelled with is 50. Garments made from fabrics with ratings higher than 50 are labelled as SPF 50+.