B At what temperature does paper catch fire?

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93
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If there is a paper glued to cctv camera that is hot (continuous operation)... can the paper just combust? what temperature can it do that?
 

Nugatory

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If there is a paper glued to cctv camera that is hot (continuous operation)... can the paper just combust? what temperature can it do that?
Yes, it can catch on fire if it is hot enough. The temperature you're looking for is called the "autoignition temperature" and Google will find values for many common substances.

As an aside, "Fahrenheit 451" makes for a catchy book title but doesn't have a lot of scientific justification.
 

sophiecentaur

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If there is a paper glued to cctv camera that is hot (continuous operation)... can the paper just combust? what temperature can it do that?
As a possible plot scenario, it's a bit tenuous. At the sort of temperature that a label on the outside of a box of electronics would need, the inside would be in flames and all the semiconductors and fragile components would have stopped working . Over 100C, your average component gives up and many will pack up at 60C. A short circuit inside the box could be a possibility but these devices are supplied with less than a Watt of power so it could destroy itself without heating the box noticeably.
I suggest that a simple experiment would be in order here. Put a plate of metal on the hob of your cooker and see what it takes to char a piece of paper. This will happen long before it bursts in to flames. A jug of water may be handy to stop the process when you've had enough
 
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Only when your camera is tightly surrounded by paper, which isolates it thermally. In reality, much of heat generated is dissipated by radiation and thermal contacts with ambient things, especially solid ones. Autoignitions of a paper sheets are rare, because paper is a composed material, which under elevated temperatures mainly dehydrates and finally carbonized. Carbon practically do not self-ignites below say 400 deg C.
 

sophiecentaur

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If the idea is that a label should ignite then perhaps there is a plastic (a bad choice for the manufacturer) that it could be made of. Perhaps the solvent for the adhesive could start it all off.
 
93
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inside the cctv camera is an IC. I measured its temperature as 176 Fahrenheit or 80 Celsius. If electrical tape wrapping some wires inside the cctv enclosure touch the ic.. what's the temperature a typical electrical tape can combust?
 

Tom.G

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Vinyl electrical tape ( PVC or PolyVinyl Chloride), various sources show ignition temperatures about the same as paper, 430°F to 550°F.
If yoy are Really concerned, the 3M company makes Glass Cloth electrical tape. Won't burn.

Try a Google search for Vinyl Ignition Temperature

Cheers,
Tom
 
93
5
Vinyl electrical tape ( PVC or PolyVinyl Chloride), various sources show ignition temperatures about the same as paper, 430°F to 550°F.
If yoy are Really concerned, the 3M company makes Glass Cloth electrical tape. Won't burn.

Try a Google search for Vinyl Ignition Temperature

Cheers,
Tom
If paper and electrical tape has similar ignition temperature.. then what is the purpose of using electrical tape to wrap wire connections when you can use masking tape to do it?
 

Tom.G

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Paper degrades with age much faster than vinyl plastic, starts degrading at lower temperatures, is not as abrasion resistant, absorbs moisture so it becomes partially conductive, does not readily conform to uneven shapes, being partially porous has a lower breakdown voltage, is dissolved by both acids and alkalies (pollution products). Aww, I'm tired of typing, you get the idea.
 

sophiecentaur

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If paper and electrical tape has similar ignition temperature.. then what is the purpose of using electrical tape to wrap wire connections when you can use masking tape to do it?
The ignition temperature is not usually the main consideration when choosing tape for a job.
 

davenn

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inside the cctv camera is an IC. I measured its temperature as 176 Fahrenheit or 80 Celsius.

without proof, I would seriously doubt that. that would be above the failure temp of most electronics except maybe military or space versions
 

berkeman

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without proof, I would seriously doubt that. that would be above the failure temp of most electronics except maybe military or space versions
Not really. Industrial temperature range is ambient from -40C to +85C, and automotive temperature range is up to +125C. There will be a temperature rise above ambient at the IC die of several 10's of degrees (depending on what the IC is doing), so it's best to look at the datasheet for the absolute maximum junction temperature, and the thermal resistance θja (from junction to ambient).

Now, if the IC is only rated for commercial temperature range of 0C to +70C, then an IC body temperature of 80C could be a problem. Still nowhere near the ignition temperature of common paper, though.
 
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hilbert2

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There also seem to be brands of Teflon tape for sale, based on a Google search. That is not going to ignite at any temperature, but can release toxic vapors if heated really strongly (like, over 350 deg C). Possibly a transparent Teflon film glued on a piece of paper to prevent contact with air would also prevent the paper from igniting, but difficult to be certain about that.
 

davenn

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Not really. Industrial temperature range is ambient from -40C to +85C, and automotive temperature range is up to +125C.

cheers :smile:
 

CWatters

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bob012345

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Oh Noooo! So Ray got it wrong? Did he work on any Mars missions? :eek:
Ray didn't really get it that wrong. Wikipedia appears to quote a source that is an extreme outlier. 451 F appears to be close to the auto-ignition temperature of paper, when something ignites without open flame depending on the exact composition, but is considered to be about 30F degrees higher, around 480F. Time is also a factor. A single sheet of wood pulp paper may ignite in a 480F oven in a few minutes but a thick book wouldn't.

But since 451C is so much hotter than 450F, it's unlikely the error is which scale was used. Anyone could test this in a typical oven at around 480F with a sheet of paper.

http://www.slate.com/articles/health_and_science/explainer/2012/06/ray_bradbury_death_does_paper_really_burn_at_451_degrees_fahrenheit_.html
 
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Ignition temperature of paper is very low. When we try to ignite a paper, all the heat is absorbed by the paper and when it reaches its ignition temperature, it catches fire.
But when the paper is wrapped around a aluminium pipe, aluminium being a good conductor of heat, absorbs most of the heat and it takes more time for paper to reach the ignition temperature. So it doesn't catch fire easily.
 
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