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The Truth About UV Clothing
By:
Rob Parker
Curiously, a number of light
and laser testing facilities do not currently use the
latest pending standard involving the averaging of
invitro (lab) and invivo (human) field-testing
and instead, choose to measure using the single standard
Menzies/Az 1994 protocol, which is much more economical
but far less accurate for the lightweight but complex
yarn fabrications such as those employed in some highly
regarded apparel products). Based on the laboratory
credentials, some manufacturers have chosen to use an
independent photonics lab that is well respected
internationally in their field and is known to be very
comprehensive in their test results. The facility
created disciplined parameters for UV testing based more
on the future interests of the industry. However, this
method is also a much more expensive testing process.
The method employed by textile manufacturers seeking UV
ratings for “woven yarns” is perhaps the one that is
more incorrectly but commonly used today – and the test
protocol is measured for stretch type fabrics used
mainly for swim and active-wear. As leno fabric is a
woven, with various degrees of porosity, such tests can
still produce erratic results, especially with
ventilated weaves and if the dyeing process involves
optical brighteners and/or titanium dioxides in the
pigments. These variables can wreak havoc on accurate
results.
What can create controversy with the new fabrics?
As with any consumer goods purchase involving new and
evolving technologies, one must be careful in relying on
poorly researched magazine or newspaper articles, which
can be quite misleading. Be sure to read the product
detail descriptions on clothing tags or, if purchasing
on-line, the description of a product on the web site.
If a product does not say, for example, that it offers
up to a 97% block, one should not assume that it does,
even if other items within that product line so say so
on the tag or in the on-line product description.
Do colors affect the UV protection level?
Yes, color is also an important point when considering
clothing for the purpose of sun-block: Darker colors
(especially indigo, navy and black) perform better
because they can absorb more UV; however the trade-off
is that they can create heat as a by-product. Lighter
colors will reflect more, especially fabrics with
optical brighteners. All everyday existing fabrics can
be considered to have a sun-protective value, but unlike
the creams that can have lower values, the current UPF
rating system begins at the minimum UPF level of 15 to
permit an independent classification.
When the ASTM D13.65 committee was created for the
addendum to sun-protective fabrics in 1996, a number of
textile manufacturers and light and laser specialists
invested about 5 years in planning the testing protocol.
Even today, it is still a work in progress and will be
updated annually because the results are still
inconclusive and merit more study. Naturally, some of
the unique textiles being created today are, under
current lab conditions, misunderstood.
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.
Article Source:
http://articleselections.com
J.
Christopher (Chris) Carnovale is CEO of Sunveil Sunwear,
a manufacturer of innovative
sun protective clothing
and
UV protection clothing
since 1986
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