What exactly is done in-lab to obtain a UPF rating? Is it different from “SPF”?

Yes, UPF involves a different criterion. While still a work in progress, the UPF [ultraviolet protection factor] is based on an entirely different curriculum of testing methods than the “SPF” measurements used for creams. For reasons of economy, the new rating system will use an invitro (lab) technique only, and includes wash, stretch and abrasion testing controls - as textiles are generally static in nature and do not change over time.

However while consistent in protocol, standard control testing methods may not yield similar results from lab to lab.  While it is currently the most cost effective method to determine UPF, the test method will not recognize a textile with an averaged number less than UPF 15: for example, even if the fabric might test average a “19”, this number is always rounded down by 5 digits, in this case - rendering a “14” . Because of the minimum UPF level of 15, mentioned above, this result will render say a “19" to become a "0". Therefore, this example would view the swatch or article as under the minimum value for a UPF rating, and not yield a rating at all even though averaging a 19 in the initial tests. The same could be said for a tested level of “20”, which by the prescribed margin of error would result in a UPF of 15. The maximum rating designate for a textile is UPF50+; however, 30 is more than adequate for the majority of individuals with sun-sensitive conditions.

What are the differences in fabric types available?

Today, people interested in sun-care products have different demands. Like the protective blocks and lotions, there are many types of textiles used in apparel that are available to meet various degrees of desired performance based on lifestyle. Tighter (opaque) weaves and darker colours are usually designed to be worn close to the skin, and can assist in blocking a higher proportion of ultraviolet light for longer periods. Whether stretch or woven, these fabrics are used in clothing that is opaque and is worn alone as a fashion lifestyle or as swimwear. A drawback to the tighter weaves and stretch fabrics is reduced ventilation and increased heat retention - which can be a serious liability to certain individuals in hot climates.   Other fabrics employ a complex lightweight weave and design structure that is somewhat looser to encourage cooling airflow, and will provide additional coverage. These garments are designed to be worn over other favourite summer-weight weather apparel. This type of clothing is a sun-care “booster” but might not be an appropriate recommendation for persons requiring a high degree of opaque protection or have prescriptive conditions that renders one particularly light sensitive – a drawback to the looser weaves and (lighter colours) will be the allowance of more UV transmission than the opaque fabrics for areas of bare skin under a single layer of fabric, especially if the area is pulled tightly over the skin and exposed to prolonged time in the sun. This drawback is remedied in the careful construct and loose design of such apparel, as the UV light transmittance decreases exponentially and dramatically, every millimetre away from the skin.

Some manufacturers’ hats and accessories, through their fabrication, have a much higher level of protection, and certain styles with multiple layering and fusing agents will afford a UPF rating up to 40+. While the clothing is a protective & effective adjunct as long as it is worn as designed, with the appropriate size chosen by the individual for the particular activity and worn loosely over other summer-weight apparel.

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