ret on fri 10 jul 98
---------- Forwarded message ----------
Date: Thu, 9 Jul 1998 11:51:26 EDT
From: Paul Monaghan
Infra-red burning my eyeballs?
----------------Original message----------------------------
Ward my friend,
Taint so! SNIP
-------------------------------------------------------------
Tis so! Taint so! Tis! Taint!
AREN'T Y0U TIRED OF THE IR/UV THING?
This argument comes up about every three years like it had never
been discussed before. And with just as many errors. Here's
part of what I sent on the subject three years ago.
UV/IR RADIATION
Substances heated until they "glow" emit ultraviolet (UV),
visible, and infrared (IR) radiation. Welding produces more UV
than other types of rays. In glass and ceramic work, IR is the
major hazard. But both sources are a combination of UV and IR.
IR HAZARDS
IR can be thought of as waves of energy that heat substances
that absorb them. If IR heats the skin, we feel pain and can
protect ourselves. If the rays enter the eye, however, we sense
no pain. Damage results from the heat or the "fever" sustained
by various structures in the eye.
Heat damage to the retina from IR is well known. Damage to the
lens resulting in cataract also has been reported but there is
some disagreement about how likely this is to occur. IR can also
cause burns of the cornea and eyelids and can dry the eyes and
skin.
Visible radiation also can damage the retina. Ultraviolet
radiation can "sunburn" the skin and eyelids and cause
conjunctivitis and lesions on the cornea (photo keratitis).
VISIBLE AND IR STANDARDS
To protect worker's eyes, the American Conference of Governmental
Industrial Hygienists (ACGIH) set separate standards (Threshold
Limit Values or TLVs) to limit irradiance in the ranges:
* 400-1400 nm, to limit thermal injury to the retina
* 400-700 nm, to limit photochemical injury to the retina
* 770-3000 nm, to limit possible effects on the lens and cornea
NIOSH recommends the use of welding shades # 3 and #4 for
protection from the glow from kilns and glass furnaces. If you
want instead to try other eyewear, ask the seller for the
transmission spectrum of the lenses from a reputable laboratory
over a range of 0 to 3500 nm. Buy lenses with low transmittance
in the UV (100-400 nm), blue (400-500 nm), yellow (588-590 nm)
and IR (760-3500 nm) ranges.
=================================================================
Monona Rossol, industrial hygienist
Arts, Crafts and Theater Safety
181 Thompson St., # 23
New York NY 10012-2586 212/777-0062
http://www.caseweb.com/acts/
Cindy on sat 11 jul 98
I don't understand all the argument over whether looking into a kiln will
damage your eyes. How important is our eyesight to us, anyhow? A pair of
suitable protective glasses costs around $9.00 US. That's cheaper than
cheap sunglasses. Isn't it worth it?
Cindy Strnad
Earthen Vessels
Custer, SD
USA http://blackhills-info.com/a/cindys/menu.htm
pedresel@3-cities.com on mon 13 jul 98
I started my response to this several times but am having
difficulty trying not to flame. So I'll try again to
keep my IR (ire?) under my collar.
Saying that glass and ceramic work produces both UV and IR
without any consideration of the amounts is meaningless, and
misleading. That's like saying that your electric stove produces
both UV and IR and thus you need welder's goggles to cook.
The the intensity of the different wavelengths in the spectrum
produced are a function of temperature -- a very well known and
predicatable function of temperature as described so well in
previous posts. The wavelengths absorbed by plastics and glass
commonly used in glasses, safety glasses, goggles, and welder's
goggles are also quite well known.
I don't recall anyone saying that IR is not a hazard for
intense exposure or that one should not takes steps to protect the
eyes from IR. I believe you are correct that there is considerable
question that this can cause cataracts. I would be interested in
seeing any data suggesting that common sunglasses are not sufficient
for this purpose.
I don't understand the point of saying that there are TLVs for various
wavelengths of light without saying what those TLVs are and without
at least providing some indication of how those values compare to the
levels emanating from kilns. If you look at the overlapping wavelengths
with TLVs, all this really says is that too much light of *any*
wavelength is bad for you. Duh! The very reason for setting limits is
that low intensities can be considered safe -- that's why it isn't
sufficient to say that UV protection is needed because the radiation
from a kiln has a slender tail down to the UV wavelengths.
By the way, I did check with an industrial hygenist for the proper
eye protection to use when I had to tune the UV source on a difuse
reflectance spectrometer. I found out that my clear polycarbonate
safety glasses were suitable. I believe that the UV intensity
from that source was far stronger than that from anything I'm likely
to encounter in my studio.
Me? I wear my regular eyeglasses until the kiln gets kind of bright (well
below ^07) then slip over dark green glasses certified to meet some ANSI
standard for UV (who cares?) and IR. Can see the cones fine.
Hey they only cost 12 bucks so it's not a big deal when you put them down
on top of a hot peep-hole plug and melt them.
-- Evan in W. Richland WA where it is unusual to see thunderstorms so the
lively storms of the past couple of days have been enjoyable especially
since they haven't done a lot of damage.
At 10:19 AM 7-10-98 EDT, you wrote:
>----------------------------Original message----------------------------
>
>
>
>---------- Forwarded message ----------
>Date: Thu, 9 Jul 1998 11:51:26 EDT
>From: Paul Monaghan
>Infra-red burning my eyeballs?
>----------------Original message----------------------------
>Ward my friend,
>
>Taint so! SNIP
>-------------------------------------------------------------
>
>Tis so! Taint so! Tis! Taint!
>
>AREN'T Y0U TIRED OF THE IR/UV THING?
>
>This argument comes up about every three years like it had never
>been discussed before. And with just as many errors. Here's
>part of what I sent on the subject three years ago.
>
>UV/IR RADIATION
>
>Substances heated until they "glow" emit ultraviolet (UV),
>visible, and infrared (IR) radiation. Welding produces more UV
>than other types of rays. In glass and ceramic work, IR is the
>major hazard. But both sources are a combination of UV and IR.
>
>IR HAZARDS
>
>IR can be thought of as waves of energy that heat substances
>that absorb them. If IR heats the skin, we feel pain and can
>protect ourselves. If the rays enter the eye, however, we sense
>no pain. Damage results from the heat or the "fever" sustained
>by various structures in the eye.
>
>
>Heat damage to the retina from IR is well known. Damage to the
>lens resulting in cataract also has been reported but there is
>some disagreement about how likely this is to occur. IR can also
>cause burns of the cornea and eyelids and can dry the eyes and
>skin.
>
>
>Visible radiation also can damage the retina. Ultraviolet
>radiation can "sunburn" the skin and eyelids and cause
>conjunctivitis and lesions on the cornea (photo keratitis).
>
>VISIBLE AND IR STANDARDS
>
>To protect worker's eyes, the American Conference of Governmental
>Industrial Hygienists (ACGIH) set separate standards (Threshold
>Limit Values or TLVs) to limit irradiance in the ranges:
>
>
>* 400-1400 nm, to limit thermal injury to the retina
>* 400-700 nm, to limit photochemical injury to the retina
>* 770-3000 nm, to limit possible effects on the lens and cornea
>
>
>NIOSH recommends the use of welding shades # 3 and #4 for
>protection from the glow from kilns and glass furnaces. If you
>want instead to try other eyewear, ask the seller for the
>transmission spectrum of the lenses from a reputable laboratory
>over a range of 0 to 3500 nm. Buy lenses with low transmittance
>in the UV (100-400 nm), blue (400-500 nm), yellow (588-590 nm)
>and IR (760-3500 nm) ranges.
>
>=================================================================
>
>Monona Rossol, industrial hygienist
>Arts, Crafts and Theater Safety
>181 Thompson St., # 23
>New York NY 10012-2586 212/777-0062
>
>http://www.caseweb.com/acts/
>
>
| |
|
