UPF info

Sun-protective clothing: what does the UPF mean?

Most people are familiar with the term ‘SPF’ (sun protection factor), which describes the effectiveness of a sunscreen in protecting skin from UVB radiation, but what does 'UPF' mean?

The UPF (ultraviolet protection factor) is a numerical rating given to clothing to indicate how effectively the fabric blocks ultraviolet (UV) radiation.

Unlike SPF, which only expresses a sunscreen's protective value, UPF applies to a range of broad spectrum UVA and UVB radiation protection.

The highest UPF rating a garment can be assigned is 50+, a piece in this range is determined as providing “excellent” protection from UV radiation.


What Affects UPF?

The specific UPF of a garment results from a complex interaction between the fabric, with its specific properties, and its use under certain environmental conditions. The following is a list of factors which can influence the UPF of textiles:

  • Type or composition of the fabric (i.e. cotton, wool or polyester)
  • Weave: tightly knit garments allow less UV radiation to pass through
  • Colour: darker colours generally offer greater protection
  • Weight: heavier garments tend to be more impermeable to UV radiation
  • Stretch: extending a fabric tautly over the body can expand the spaces between the fibres, allowing more UV radiation to penetrate the skin
  • Moisture: wet clothing blocks less UV radiation
  • Condition: fabric which has become faded or worn by use may offer reduced protection
  • Finishing: during manufacture, treatment of garments with UV absorbing chemicals (colourless dyes) can enhance their UPF.
  • Design: Sun protective clothing must meet certain coverage requirements: for the upper body, clothing must extend from the neck to hip, plus down three-quarters of the upper arm, and from the waist to below the knee on the lower body.

Published in 1996, the Australian and New Zealand Standard for the evaluation and classification of sun protective clothing is considered the benchmark of the industry. Below is the classification scheme for UPF ratings included in this standard:

 

UPF Ratings and Protection Categories

UPF Rating

Protection Category

% UV radiation Blocked

15, 20

Good

93.3 – 95.9

25, 30, 35

Very Good

96.0 – 97.4

40, 45, 50, 50+

Excellent

97.5 or more


Information supplied by

http://www.clinuvel.com/en/blog/discourse/sun-protective-clothing-what-does-the-upf-mean/

References:

Australian Radiation Protection and Nuclear Safety Agency, 2009, Clothing and Solar UV Protection, accessed 3rd November 2010, <http://www.arpansa.gov.au/radiationprotection/factsheets/is_UVProtection.cfm>.

Gambichler, T et al., 2001, ‘Protection against ultraviolet radiation by commercial summer clothing: need for standardised testing and labelling’, BMC Dermatology, 1:6.