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Wire insulation safety

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Richard Henry

Jan 1, 1970
0
I am not allowed to use PVC-insulated wire on a current project due to
hazardous chemical components in the smoke should there be a fire.
Teflon-insulated wire is ok.

My question is about radiated olefin insulation. Where does this fit
in the chemical exposure/safety spectrum?
 
R

Robert Baer

Jan 1, 1970
0
Richard said:
I am not allowed to use PVC-insulated wire on a current project due to
hazardous chemical components in the smoke should there be a fire.
Teflon-insulated wire is ok.

My question is about radiated olefin insulation. Where does this fit
in the chemical exposure/safety spectrum?
Ohhh..when Teflon gets really hot, you want to ba *far* away.
Have you heard of Phosgene?
Consider the flurine version; *much* worse!
 
R

Richard Henry

Jan 1, 1970
0
Ohhh..when Teflon gets really hot, you want to ba *far* away.
Have you heard of Phosgene?
Consider the flurine version; *much* worse!
From wikipedia article on Teflon: "the toxicity of fumes given off by
the coated pan on dry heating was less than that of fumes given off by
ordinary cooking oils".
 
G

Glen Walpert

Jan 1, 1970
0
the coated pan on dry heating was less than that of fumes given off by
ordinary cooking oils".

The MSDS however says "During a fire, irritating and highly toxic
gases may be generated by thermal decomposition or combustion."
Wikipedia would not be one of my top 100 sources for toxicity data.
There is a lot of reliable data on the toxicity of fumes produced by
burning teflon which can be easily found, just not on wikipedia.

Usually when the contribution of wire insulation to smoke from a fire
is a concern some particular standard is invoked and wire must pass
the appropriate tests in order to be used. Guessing what the smoke
contribution of particular compounds would be is a rather poor way to
spec wire insulation IMO.
 
R

Richard Henry

Jan 1, 1970
0
The MSDS however says "During a fire, irritating and highly toxic
gases may be generated by thermal decomposition or combustion."
Wikipedia would not be one of my top 100 sources for toxicity data.
There is a lot of reliable data on the toxicity of fumes produced by
burning teflon which can be easily found, just not on wikipedia.

Usually when the contribution of wire insulation to smoke from a fire
is a concern some particular standard is invoked and wire must pass
the appropriate tests in order to be used. Guessing what the smoke
contribution of particular compounds would be is a rather poor way to
spec wire insulation IMO.- Hide quoted text -

- Show quoted text -

The specification we are following is from the US Army. They have
more funding to pursue these tests than we do. Specifically it says
PVC=No, Teflon=Yes. My guess would be that PVC is toxic at a lower
temperature or in a higher lethality than Teflon.

But my original question was about irradiated polyolefin insulation.
Where does that fit on the safety spectrum?
 
G

Glen Walpert

Jan 1, 1970
0
(Sure, Phosgene is manufacturered in large quantities for use in the
manufacture of certain plastics, and shipped around the country in
tank trucks with the standard "corrosive" placard. I did some lab
testing on a phosgene compressor seal long ago, and the co-worker who
installed it in the field reported that phosgene makes cigarettes
taste terrible.)
The specification we are following is from the US Army. They have
more funding to pursue these tests than we do. Specifically it says
PVC=No, Teflon=Yes. My guess would be that PVC is toxic at a lower
temperature or in a higher lethality than Teflon.

But my original question was about irradiated polyolefin insulation.
Where does that fit on the safety spectrum?

I would guess that polyolefins, consisting only of hydrogen and
carbon, would be fairly good as far as smoke toxicity. But this is
precisely the sort of guess I don't think you should be basing design
decisions on. What does the Mil-Spec say? I would expect major wire
manufacturers to be able to answer questions about what insulations
meet your specifications; possibly you could call Belden or your
preferred wire supplier and discuss the matter with their applications
engineering department.
 
H

Homer J Simpson

Jan 1, 1970
0
Ohhh..when Teflon gets really hot, you want to ba *far* away.
Have you heard of Phosgene?
Consider the flurine version; *much* worse!

Try burning PVC sometime. HCl will make you cry - and rust.
 
S

Spehro Pefhany

Jan 1, 1970
0
Try burning PVC sometime. HCl will make you cry - and rust.

There's a movement afoot to get rid of PVC entirely, at least in
applications where there are reasonable substitutes. Hard to believe,
considering all the PVC extrusions that are all around us.


Best regards,
Spehro Pefhany
 
H

Homer J Simpson

Jan 1, 1970
0
There's a movement afoot to get rid of PVC entirely, at least in
applications where there are reasonable substitutes. Hard to believe,
considering all the PVC extrusions that are all around us.

I worked in a molding factory. PVC and acetal would explode if mixed and
heated.
 
R

Robert Baer

Jan 1, 1970
0
Richard said:
the coated pan on dry heating was less than that of fumes given off by
ordinary cooking oils".
What do they know?
Besides, frying pans are cold relative to the decomp temp of Teflon.
 
R

Robert Baer

Jan 1, 1970
0
Richard said:
The specification we are following is from the US Army. They have
more funding to pursue these tests than we do. Specifically it says
PVC=No, Teflon=Yes. My guess would be that PVC is toxic at a lower
temperature or in a higher lethality than Teflon.

But my original question was about irradiated polyolefin insulation.
Where does that fit on the safety spectrum?
It does seem to withstand a 200C environment.
 
S

Spehro Pefhany

Jan 1, 1970
0
I worked in a molding factory. PVC and acetal would explode if mixed and
heated.

Yes, you have to purge the machine barrel with something else (eg. PE)
when you are switching resins.


Best regards,
Spehro Pefhany
 
H

Homer J Simpson

Jan 1, 1970
0
Yes, you have to purge the machine barrel with something else (eg. PE)
when you are switching resins.

One of our guys didn't and stuck his head over the hopper to see what was
happening. He looked like he had the worst case of measles for a few weeks.
Lucky it missed his eyes!
 
T

Tim Shoppa

Jan 1, 1970
0
Richard said:
The specification we are following is from the US Army. They have
more funding to pursue these tests than we do. Specifically it says
PVC=No, Teflon=Yes. My guess would be that PVC is toxic at a lower
temperature or in a higher lethality than Teflon.

Much more complicated when you're comparing Army/AF/mil-specs with UL/
CSA or building codes.

The worst case army environment has several soldiers in a tiny tank
compartment (OK, not as tiny as they used to be) filled with dozens
and dozens of electronic subsystems, a turbine for propulsion, live
ammo stashed in all kinds of places, and depleted uranium as the
preferred projectile. I'd rather NOT HAVE A SHORT that might spark an
explosion, rather than use something like PVC :).

Note that European building codes are often different than US/Canada,
and in some cases ban PVC while allowing Teflon in the same situations
(risers).

Flame dynamics can be ridiculously nonlinear in response to a small
change in parameters.

Tim.
 
L

legg

Jan 1, 1970
0
I am not allowed to use PVC-insulated wire on a current project due to
hazardous chemical components in the smoke should there be a fire.
Teflon-insulated wire is ok.

My question is about radiated olefin insulation. Where does this fit
in the chemical exposure/safety spectrum?

If the same reservations were held to all other components in the
assembly, I doubt few would be acceptible. Why the emphasis on wire
insulation alone?

RL
 
R

Richard Henry

Jan 1, 1970
0
If the same reservations were held to all other components in the
assembly, I doubt few would be acceptible. Why the emphasis on wire
insulation alone?

RL

The PVC ban applies to all components used. I have no problem finding
usable components.
 
M

MassiveProng

Jan 1, 1970
0
The PVC ban applies to all components used. I have no problem finding
usable components.
You didn't even come close to answering the question he asked.
 
R

Richard Henry

Jan 1, 1970
0
You didn't even come close to answering the question he asked.- Hide quoted text -

Nor he mine. I was asking about radiated polyolefin.
 
I

Ian

Jan 1, 1970
0
legg said:
If the same reservations were held to all other components in the
assembly, I doubt few would be acceptible. Why the emphasis on wire
insulation alone?

RL

Interesting that PTFE is considered as ok in a fire:
http://www.bocedwards.com/pdf/P120-09-025 PTFE .pdf

"at temperatures greater than 350 deg C for emissions of noxious
fluorine compounds (including HF and COF2)"

My recollection was the temperatures required were higher than this,
but any chance of releasing HF is a Bad Idea.

Regards
Ian
 
J

joseph2k

Jan 1, 1970
0
Ian said:
Interesting that PTFE is considered as ok in a fire:
http://www.bocedwards.com/pdf/P120-09-025 PTFE .pdf

"at temperatures greater than 350 deg C for emissions of noxious
fluorine compounds (including HF and COF2)"

My recollection was the temperatures required were higher than this,
but any chance of releasing HF is a Bad Idea.

Regards
Ian
For far more than you ever wanted to know toss "wire insulation fire
toxicity" to a search site / engine.
 
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