Replies

1. 
   htra | May 26, 2004 10:00pm | #1

   Interesting question. In short, I don't know, but you might call the manufacturer of the lights for a quick answer. I'm sure they have been asked that before.

2. 
   BillHartmann | May 27, 2004 01:39am | #2

   My speculation is that the rate are rated for direct contact with APPROVED insulation. That is insulation that has met certain standards for use as a building material.

   The peanuts have no such approval and thus nobody know what what will happen in contact with the light.

   My guess is that they will either smoke or disintegrate.

3. 
   4Lorn2 | May 27, 2004 02:22am | #3

   Was the material that fell down Styrofoam or was it perlite. Can't say as that I have seen Styrofoam beads used as insulation. Perlite, on the other hand, is common in some areas.

   To find out what you have for sure a couple of tests will help identify the material. In each case you can compare to a Styrofoam coffee cup.

   You can take a piece of the mystery material and try to crush it in your fingers. Styrofoam will compress like a sponge while Perlite will crack and shatter like a tiny bead of ceramic.

   The other thing is to hold a small piece of the material and touch it with a lighter. Do it outside as the foam releases toxic and noxious gasses and will melt into any flooring leaving a mark. Styrofoam will melt, blacken and burn with a sooty yellow flame. Perlite will not catch or burn. Some types have a retardant coating sprayed on that may burn off but it won't burn long or keep burning once the flame is removed. It might melt if you keep heating with a very hot flame but it will not melt easily. The difference between the Styrofoam and Perlite exposed to fire is pretty obvious.

   If it is Styrofoam I would be reluctant to mount a recessed can, even a IC rated model, in close proximity to it. Perhaps you could push the Styrofoam away from the fixture. Be careful that shoving it away from one unit doesn't push it into another. Perhaps removing it for a distance of a foot or so would be a workable option. I would substitute fiberglass for the insulation removed. With a IC can the fiberglass can be stacked around and over the new can.

   If the material turns out to be Perlite, as I suspect it is, then the only change I would make is to use a good make of foil tape to seal any holes big enough to allow the Perlite into the enclosure. Perlite getting into the case is not usually a big problem but it can make replacing bulbs, lamps in electrospeak, messy as the beads tend to fall onto your face and carpets. 

1. 
   JKalk | May 27, 2004 07:34pm | #4

   Thanks very much for the insight! 

   It's definitely styrofoam from your description of the difference.  Haven't tried the burn test but it's very light and compressible.  the pellets are the size of BBs. 

   I pushed the stuff back as much as I could and then stapled some vapor barrier I had left over from another job around where the can will sit to keep the styrofoam away -- leaving a fair amount of room so that the can shouldn't touch the plastic vapor barrier either. 

   Putting the fiberglass insulation around the light sounds like a good idea also, as further insurance against both the pellets working their way in, and to prevent the cavity lined with plastic vapor barrier from getting too hot (which I think is probably unlikely anyway since the lights don't burn THAT hot, right).

   Thanks!

   Jed.

1. 
   4Lorn2 | May 28, 2004 07:40am | #5

   How hot the can gets is subject to a few variables. First you choose the can. IC ones are rated to be covered in insulation. Non-IC ones are not and they can overheat if buried in insulation. Keep the insulation 4" or the recommended distance from the recessed can. Given energy costs IC cans make more sense in most situations where the cans are going into the building envelope, as opposed to spaces between floors.

   Key here is to read the labels within the can to determine which trims are allowed. Once you find that out check each trim to find out what style and wattage of bulbs, lamps in electrician language, are rated for that trim.

   These three factors, type of can, trim and lamp determine how hot a fixture will get in any given situation. Each factor it important in determining how much heat is generated and how fast the fixture can get rid of it. Generally speaking larger cans or enclosures, smaller form factor lamps, lower wattage lamps and trims that are open and allow more air movement all tend to make everything run cooler.

   Any good electrical supply house or lighting designer should have catalogs that bring all this information together. Most major companies have 1-800 numbers and will send a catalog to you for free or at a nominal cost. These also give you numbers on how much light and the distribution of it that each combination of lamp and trim put out.

   These can be very helpful when designing installations because these numbers can be plugged into charts recommending the amount of light for any particular task from mood lighting to assembling watches.

   All IC fixtures I have seen have a thermal limit switch. If it runs so hot that there is danger this switch is supposed to turn off the lamp. These units are designed to recover and switch back on when the temperature goes down again. A recessed can that is turning itself on and off is a sign of danger and should prompt a close look at the situation.

   Most often a too high a wattage or wrong form factor bulb has been installed for the can, trim combination. These situations need quick attention as these thermal limit switches are not infallible. Should one fail on, rare but not impossible, the next sign of an overheated fixture might be a fireman at the door.