Question about heat: LED/ Standard Lighting ceiling mounted

[Dakell12]

Hi everyone, I just mounted 12v lighting in the ceiling of my 96a3, and there is insulation up there that seems quite flammable. The lighting is not LED, it is standard, and the units get pretty hot when they are on for an extended period. Does anyone think that this heat alone is enough to start a dangerous situation, or will I be alright? The sides I have drawn up are "its just as hot up there from the sun in the summertime" or "get LED bulbs". Thanks!

[WEC4104]

I'll take a guess and say the the lights you have installed are the halogen "hockey puck" lights.  If so, these do get quite hot, and I believe they come with minimum installation distances and temperature warnings. I would error on the side of caution and double check the distances, ratings, and adjacent materials.

Yes, LED bubs are available as replacements, but they are not nearly as bright.  But they are your "coolest" option temperature-wise, and you should have no fire hazard.

I'll suggest you look at a third option: Xenon bulbs.   They are a little harder to find, but you should be able to get 12V Xenon bulbs that plug directly into your existing fixtures.  They run significantly cooler, have a longer lifetime, and still produce high light output.  Unlike halogen bulbs, you can also handle Xenon bulbs with your bare fingers without damaging them with skin oils.

Even with the Xenons, I would however make sure you follow installation and safety guidelines from the manufacturer, and keep them away from combustable materials.

The website listed below has a lot of good info.  (I have no affiliation, and haven't ever ordered anything from them [yet])
  http://www.pegasusassociates.com/XenonBipinLightBulbs.jsp

Wayne

[DrivingMissLazy]

Make doubly sure there is no passage or cabinet door that can get in proximity of the lights when they are opened. I have direct knowledge of at least three luxury yachts that burned to the waterline due to a fire started by these lights. Always a passage way door that when open was directly below the lights.
Richard

[TomC]

I use surface mount hockey puck lights.  5 down the center and three on the side.  The 5 down the middle have 20 watt halogen, and the sides have 10 watt Xenon.  The Xenon is a bit less bright, but for the savings of power and they are much cooler, it is worth it.  Good Luck, TomC

[Dakell12]

Also, I should note that the lights are recessed 2inches into the ceiling, touching the insulation. The packaging says they could get to 200 fahrenheit. uh oh.

[Nick Badame Refrig/ACC]

Hi again Dakell12,

I also have the recessed halo puck lights, all 10 watt. And they are installed against the insulation but, I also cut 8" X 8" squares of 26ga. steel

as added heat barriers. This was also a concern when I was building. After testing the temps with the steel barriers, it was quite

cool at the insulation. The Halo lighting is much easier on your eyes then the LED's....

Good Luck
Nick-

[Sojourner]

About fire safety of mounting Halogen...If you have laser pointing temperature gun. Check it out by recording temperature on backing of lamp assembly in stand alone position (un-mounted) & with the beam down. If it reach near 700°F after 30 minutes (or till it stabilize) duration in still air movement in warm environment....you are very close to igniting point of burning wood or paper. It depend of moisture content in wood will determine how long it take to start ignition (flame) during burning (glow) point.

FWIW
I was the only technician at General Motor APE lab to test "catalytic converter" grass fire project in mid 70's. That when I begin learning the burning-point. The only way we start grass fire in steel basket with dry hay under car's converter is to remove 3 spark-plugs wire to cause engine run miss fire...equal enough raw fuel into hot catalytic-beads to glow hotter than normal. Soon surface hay reach about 715°F...it smoke till flame then pull out from under car to let it burn till gone. Since then I learn the test results of most combustibles have very close burning point.

So watch out for areas that can be expose to a 700°F heat. Even Halogen light beam can get combustible surface to ignite.....check it out for your safety with temperature gun till it reading stabilize temperature. The closer Halogen beaming to surface the hotter. Caution never leave a tall enough cardboard to touch or close to Halogen lamp above kitchen counter.

One more thing to be concern.

Sojourn for Christ, Jerry

PS...if anyone care to report the above test procedure on this board about Halogen lamp unit actual temperature...would greatly appreciated

[WEC4104]

Jerry:

As a GM APE lab tech, you certainly have more experience in this area than me. However, I am reading you comments as indicating that the igniting point of wood and paper to be around 700 degrees F.  My understanding is that paper can typically ignite at a little over 450 degree F (about 232 degrees C).   [Some may recall Ray Bradbury's book "Fahrenheit 451" which was a reference to book burning temperatures]

Help me undertand why your comments reference concerns around 700 degrees, rather than 450-500F.  Thanks

[coolbus]

It's called pyrolysis..

The combustion point is lowered over time after exposure to high heat. The combustion point is reached at a lower temp if previously exposed to high temps.

So the longer the problem of exposure to heat; the more likely of spontaneus combustion!

Mark

[Don4107]

Not hard at all to set a fire with a catalytic converter in a properly running vehicle.  Happens all the time around here.  Has a lot to do with how long and how hard the engine has been running. 

We had two 1 ton Ford brush fire rigs delivered to my department with converters.  Ironic, I know.  Set more fires than we could put out until the converters, uh "fell" off. 

I have set at least two fires with vehicles without converters.  One I caught quick and put out myself.  Other one was a fire truck which died on me in the wrong place at the wrong time, very dry knee high wheat stubble after a hard run to get to the scene, read very hot exhaust.  At least the pump ran long enough to save the truck even though the plastic fuel line had melted.  Embarrassing for a fire department officer! 

Flash point for many things is much lower than 700 degrees.  Even the cotton undergarments we recommend firefighters wear will go at 600.  As Mark said, wood and other things exposed to heat over long periods of time can lower their flash point significantly. 

Another reason to avoid hot light fixtures is it adds to the AC load.  I hope that by the time my new bus is ready to roll that LEDs will have evolved to the point to be practical for general lighting.

[Sojourner]

WEC4104.....I appreciate your respond about paper ignition point.
Yes absolute dry paper can & will ignite at must lower...however in average humid (moisture content) condition...it take longer time to ignite to removed moisture or higher temperature to ignite at same time frame. Another word I am referring in every day average paper in average environment condition.

FIRE HAZARDOUS - II...scroll down to "Ignition Temperature"
http://www.geocities.com/HotSprings/7169/fire.htm

I assume all recording of "Ignition Point" is done with a set guide line as given substance moisture requirement before testing.

You will notice "Wood" in  "Ignition Point" list has large range of temperature....due to compositions of what wood consist of to generate gases.

FWIW...soybean oil is 339°F higher than #2 fuel oil. That explain why it won't start very quickly or  won't & worn diesel won't run well due to lower compression.

You will fine many reports of difference "Ignition Point". So whenever you read about the results...it maybe not accurate. I do know what it take to ignite grass & wood & paper.

Always remember flash point is not same as ignition point.

Sojourn for Christ, Jerry

[WEC4104]

Jerry:

As always, one of the things I enjoy most about this board is the variety of information that gets introduced into discussions and the stuff I learn that goes beyond general bus knowledge.  Today's lesson: fire safety and ignition points. 

From the looks of the chart, there is a considerable temperature range for wood, which only makes sense since they don't specify the type of wood or the degree of greenness.  I noticed the paper (newsprint) was down at 446 F which is what I expected from my earlier Fahrenheit 451 comment.

The one set of figures that really surprized me was when I compared regular gasoline (700F) to #2 Fuel Oil (494F).  Not at all what I would have expected.

Many years ago, while my brother was working his way through school, he spent his summers working on a paving crew. When they were done paving a driveway or parking lot they would clean their shovels and rakes in a "fire bucket".   They would pour some diesel fuel (essentially #2 fuel oil) into a metal bucket and set it on fire.  The trick was that simply throwing a match into the bucket would result in the match going out.  If memory serves, they would pour a small amount of gasoline on top of the diesel.  The match would light the gasoline, which would in turn would fire off the diesel fuel. The diesel fuel had a more controlled burn, suitable for cleaning the tar off the tools. Maybe several decades have clouded my memory, but that is what I seem to recall was the case.  This seems to be opposite of what I would expect from the two ignition points.   

Also, my apologies to everyone, as I am just now realizing how far off topic I have taken this thread. Oooops.

[niles500]

Jerry  brings up agood point about moisture - the relative humidity and moisture content of any fuel somewhat influences it ignition/flash point - HTH

[H3Jim]

WEC4104,

The gas would ignite because the vapor would catch.  Although todays fuel by design  has much less vapor and is safer as a result.  That was why gas was so dangerous.  pour it on a pile of wood, and the vapors would travel to a flame source and ignite, sometimes even if you weren't ready yet. 

Even then you could put a match out in the fluid.

[Sojourner]

Amen! H3Jim!

Also our air we breath contain Oxygen one of many gases is needed to complete the combustion process. So the bigger the chuck of anything will determine the length of time to ignite. Because its heat sink (large mass) to open heat (such as flame or whatever) until it reach it's igniting temperature. Paper is very thin plus is surrounded with Oxygen gas to easily ignite at lower temp.

FWIW....That is why when we cut steel with cutting torch....after acetylene & oxygen is heating metal till it start to glow red...than push down the oxygen lever to burn metal. Another word you can turn off acetylene gas and keep on burning metal as long it still bright red glow and fairly clean pass way.
Bottom line is to only burn metal wherever the direction of pressurize oxygen aim at. It Not to over heat with acetylene & oxygen so it drop & dripping metal to leave a messy cutting edge plus waste gases for taking too much time doing it. I have seen some person have done that.

Over all in everyday living. The subject of "ignition point" is not being taken for seriously but flash point is...which is always lower temperature than IP.

FWIW...I have learn in 60's doing black-smith work to weld 2 steel bars together.  By heating both ends to sparking red hot...then quickly over anvil a large heavy hammer blow onto sparking ends (end on top of other)....welded! The heavy hammer blow also create extra heat to our advantage.

Sojourn for Christ, Jerry