Q&A Forums
Recessed lighting Post New Topic | Post Reply
| Author | Comments |
|---|---|
|
Posted: Aug 18, 2008 01:20 PM
|
Recessed lighting
What is the requirement insulating ccSPF around Type TC / air tight recessed light fixtures. Do they have to be wrapped with rockwool?
|
|
mason
Posted: Aug 18, 2008 02:50 PM
|
You need to keep foam off any surface that may go above 200 degrees F. Rockwool or fiberglass will work. Some folks use a gypsum board box around the lights when spraying on an attic floor. I have also seen folks shove a board of higher temperature resistant insulation under the gap in cathedral ceilings. |
|
Posted: Aug 18, 2008 03:32 PM
|
Mason, Thanks for the quick response.. Bud |
|
JohnPeters
Posted: Oct 20, 2008 05:45 PM
|
It was my understanding that "IC" rated light canisters are ok to come in contact with foam insulation. Should I no longer pay attention to the "IC" rating and verify what the maximum operating temp of the light will be? |
|
mason
Posted: Oct 21, 2008 08:45 AM
|
Yes, pay attention to the substrate temperature that the foam will be directly attached. Keep it less than 200 degrees F. Remember that the foam prevents heat from getting out of the light fixture and the substrate temperature that starts at 185 degrees F may go up beyond 200 degrees F if you insulate it with foam. |
|
SPFer
Posted: Oct 22, 2008 07:44 AM
|
We always wrap the lights in fiberglass, then spray to the fiberglass. |
|
Eric Smith
Posted: Oct 23, 2008 12:25 AM
|
Electrical contractors will swear you to death if they ever have to pull one of those fixtures. When we do air sealing, we box the fixture out in sheet metal and then spray foam it. Mason...what are the rules on sprayfoam and chimneys (block or brick), A-vent/L-Vent (triple wall ?), B Vent (double wall), and C-vent (single wall?) as far as clearances go? I think I have read up to 18 inches for single wall? |
|
mason
Posted: Oct 23, 2008 08:36 AM
|
I would have to look up the rules on chimneys. 18 inches seems excessive. I am out of the office and don't have access to my research docs right now. but will look for it when I get back into town on the 27th. |
|
Posted: Nov 06, 2008 07:45 AM
|
cans that are insulation contact are insulation contact... you may foam them... i too do the wrap...the electricians luv it...but only for the electricians... mason,,,this topic comes up often,,,wouldnt it be nice if the spfa or someone had a document with some of these frequently asked questions, with appropriate documentation and answers for us poor old hillbilly foamer to disseminate out to the frequently confused local officals.... you know...buried cans,,,buried romex,,buried low voltage,,buried poopfans,,,air space between foam surface and back of drywall...and the list goes on... |
|
mason
Posted: Nov 06, 2008 07:56 AM
|
Check out SPFA's technical doc AY 112, SPF for Builidng Envelope. There is a detail addressing recessed lighting. Also, SPFA conducted testing on wiring (for build up of heat) many years ago. I have a copy of it, but you should be able to get the report from Rick Duncan at SPFA. The SPFA is currently conducting a study on PVC pipe and foam, wiring may be a part of it as well. |
|
Posted: Nov 07, 2008 07:06 AM
|
greetings from the world!!!! boxed out lights,,, yeah right!! last home had 65 cans,,,,7 phartfans,,,and a managaree other penetreations...6 days later i got em boxed and ready to spray...rofl most typically these cans are not in a place where they can be boxed out...down in trays,,off center in runs,,,under elevated duct runs,,,and the list goes on... i have many applications in cathedrals with insulation contact cans having 4-5" cc around and under them...typically a 2x10 or 2x12 cavity...we have no lights that have thermal limited and gone blinky blinky,,,ever,,, i prefer to cap/wrap with filterglass on flat lids,,again for the electricans piece of mind.. ... psycodude |
