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Lampshades-the long answer
- To: BOOK_ARTS-L@LISTSERV.SYR.EDU
- Subject: Lampshades-the long answer
- From: Castle Paper & Press <castle@CADVISION.COM>
- Date: Fri, 9 Apr 1999 07:21:42 -0600
- Message-Id: <199904091322.GAA22932@palimpsest.Stanford.EDU>
- Sender: "Book_Arts-L: READ THE FAQ at http://www.dreamscape.com/pdverhey" <BOOK_ARTS-L@LISTSERV.SYR.EDU>
Enclosed is a posting I wrote last year regarding safety and handmade
paper lampshades. I will post the name of the largest shade material
manufacturer in the USA tomorrow, (I'll bring it from work) which sells the
adhesive backed paper or styrene. To this you can add your handmade paper,
cloth or just about any material. However it is not required for fire
safety. It does provide support to a weak paper. It also reflects more of
the light down to the table surface.
TESTING HANDMADE PAPER LAMP SHADES
This may come a bit late but I’m following up on the thread regarding
handmade paper lampshades and their flammability. There has also been some
discussion on fireproofing solutions. The following information is somewhat
long and a little technical, so read on only if you are interested in the
safety issues regarding handmade paper lamp shades.
Although I hate disclaimers I feel I must alert you to the following: all
the information included here is to serve as an introduction to the safety
issues surrounding the production of paper shades and is not meant to
replace CSA or UL testing. For a full and proper understanding of these
issues contact the appropriate regulatory authority to obtain the full
In addition to being a papermaker I own and operate a company that
manufactures custom light fixtures. The majority of our production involves
light steel fabrication but we do on occasion manufacture paper lamp shades.
Since I reside in Canada I will deal with regulations governed by CSA, or
Canadian Standards Association, UL or Underwriters Laboratories of the
United States have almost identical standards. The first regulation we will
deal with is the temperature limit for "paper, wood, or ordinary fibre",
which is 90 degrees Celsius (194 degrees Fahrenheit) in an ambient
temperature of 30 degrees Celsius (ambient temperature refers to the
temperature within the room where the testing is being conducted, more about
this later). This means that the surface temperature of the hottest spot on
the inside of the shade when using the recommended lamp (the lamp you have
chosen) cannot exceed 90 degrees C. Not to be confused with the air
temperature immediately adjacent to the inside surface, the shade may be
absorbing and dissipating the heat. If the opening at the top of the shade
is small, heat may collect there but in most cases the hottest spot will be
the shortest distance between the lamp and the side of the shade. In our
shop we measure the temperature by taping thermocouples to the inside
surface of the shade and record the temperature using a digital thermometer.
The lamp is turned on and the temperature is recorded after it has
stabilized (remains the same). Although not as accurate, a simple glass
thermometer or inexpensive digital thermometer can be purchased from a
hardware store. In most cases shades which have an open top never get close
to 90 Cº—that’s hot—for example most people cannot hold their hand on a
surface which exceeds 50 Cº and water boils at 100 Cº. There is no further
testing of the paper itself as one might think. Paper made specifically for
commercial shade production does not contain any kind of fire retardant. I
would guess that, depending on how the handmade paper is finished, it would
be only marginally more flammable than commercial shade material, only
because machine made paper is denser due to calandering (a process where the
paper is pressed between huge steel rolls). Regardless of how flammable the
paper is the only test done is the surface temperature of the inside of the
shade as described above. Here’s an excerpt from the CSA standard describing
what materials can be used to make shades:
CSA Standard C22.2 No. 12 - 1982
4.7 Shades, Diffusers, and Lamp Guards
4.7.1 Shades, diffusers and lamp guards shall be made of at least slow-
burning material, except that those which form an enclosure or a part of an
enclosure shall meet the requirements of clause 4.2.
Note: A slow-burning material is one that has the approximate burning
characteristics of ordinary news-print, including an ignition temperature of
approximately 440 degrees C. Included in the general classification of
slow-burning materials are cellulose acetates, methyl metha-crylates,
polystyrene, polyvinyl chloride, nylon, cotton, silk, rayon (other than
brushed rayon), wood, and paper.
I wouldn’t describe newsprint as a slow burning material, but I don’t
make the rules.
I will point out here that safety regulators are not concerned with the
effect that heat may have on the materials appearance. For instance your
shade may pass all the tests but after a year turn yellow, become brittle,
and fall the floor. It would be considered poor quality, not fire hazard! In
most cases the papers long term durability is not a safety issue, unless the
falling shade may injure someone.
In summary here is how I would test my handmade paper shade:
1) Use a higher wattage lamp for testing purposes, for example if the end
user is to use a 60 watt lamp, test the shade with a 100 watt lamp. If the
shade passes the temperature test, you have an extra safety factor. If it
fails, try again using the 60 watt lamp.
2) Record the ambient room temperature and if it is lower than 30º Celsius,
add this difference to the test result, for example if the ambient room
temperature is 25º Celsius, you must add 5º to the temperature recorded on
the hottest spot of the inside of the shade.
3)Although not required, leave an extra safety factor. The maximum allowable
temperature is 90 degrees Celsius - use a lower wattage lamp if it exceeds
80 degrees Celsius.
4) Always have an opening at both the top and bottom of the shade so that
the heat is not trapped. This allows the air to circulate—as hot air rises
and escapes out the top cool air will be drawn in from the bottom.
Fireproofing solutions are not required by CSA or UL. If your shade does not
pass the temperature test its not safe regardless of any fireproofing
All light fixtures must have a maximum wattage label, for example MAX
Type A 60 W. Type A refers to the shape of the lamp, in this example your
common everyday light bulb. Take a look at the maximum wattage labels on a
store bought fixture to see what they look like. The label
"shall be applied in a permanent manner, the effect of temperature being
considered. The caution shall be located and executed in such a manner that
it is prominent during relamping, and there shall be a contrast between
lettering and the background."
For our fixtures to be CSA certified we have to use maximum wattage labels
that are purchased in 1000 unit rolls from a company that sells CSA
certified labels, which ensures that the glue and the foil label itself
passes certain standards! These are high quality labels of that won’t fall
off. I have no easy solution here for the small manufacturer who only needs
Here’s another smaller consideration: you must ensure that the paper is
securely mounted to the wire frame that makes up the shade. You don’t want
the paper come off the frame and lay against the lamp if it’s bumped.
One final issue is the necessity of obtaining CSA or UL approval.
Everything that leaves our shop is CSA approved, because our clients require
it and because an electrician can loose his license if he installs a light
fixture that is not approved. Most lighting stores will not purchase light
fixtures that have not been approved. On the other hand I often see handmade
paper lamps made by local craftsmen sold in specialty type stores that bear
no approval labels. The concern is the issue of legal liability if a your
table lamp is the cause of a fire. Here again I can offer no simple answers.
The cost to obtain full CSA approval is between one to two thousand dollars
with a three hundred dollar yearly fee (which pays for the unannounced spot
checks) plus special CSA labels. This allows the lamp manufacturer to apply
the CSA labels himself (to same model fixtures). CSA has an individual
special inspection service which costs about $250.00 a visit (for as many
units as you have). There are other standards regarding the wiring of a
light fixture itself which I will not go into here. I hope I’ve answers some
of your questions regarding the safety of paper shades.