11-08-2005, 10:54 AM #1
- Join Date
- Nov 2005
- Fairland IN
melted carpet v. flammable liquid
In my capacity as deputy prosecutor, I have a jury trial where the issue is the carpet melting and pooling and then leaving flammable liquid burn patterns. My experts say this is bogus, and I feel it is too, but the first jury hung on this. This is our second round. The fire was in the incipient phase and didn't have a chance to get too far. This carpet had a plastic backing, not a jute backing. Has anyone done any test burns with carpet, or know of any studies that have done it?
11-08-2005, 12:21 PM #2
I would suggest you check with the National Institute of Standards and Technology. If there has been any scientific testing done of this nature, they've done it. There contact info from their website:
Building and Fire
100 Bureau Drive, Stop 8600
Gaithersburg, MD 20899-8600
(301) 975-5900Steve Gallagher
"I don't apologize for anything. When I make a mistake, I take the blame and go on from there." - Woody Hayes
11-08-2005, 04:58 PM #3
- Join Date
- Jul 1999
- Flanders, NJ
This is a fairly complex issue. There is a USFA Publication (USFA Fire Pattern Burn Pattern Tests) FA 178 that should help you. The NIST suggesiton is always my first stop when I am doing research.
Can I assume that your lab samples are negative? If they were positive I would imagine that you would not have this battle. If they are negative, this is a huge hill to climb.
In my experience, nylon carpet with plastic backing does not pool like a liquid. If a liquid was used, there should be a rather sharp demarcation line between what is burned and what is not burned. Also, what does the floor look like under the carpeting? If the carpet simply melted, I would not expect to see a pattern on the floor under it.
You can email me at firstname.lastname@example.org if you would like some detailed help.
11-14-2005, 06:54 PM #4
- Join Date
- Mar 2005
I'd have fire.nist.gov bookmarked if I were you, but George certainly seems to give sound advice.
Something you might want to think about however:
Nylon is incapable of producing a self sustaining combustion reaction. It will oxidize but the radiant feedback is too weak to continue to liberate comustibles if the ignition energy is removed.
Consider also most Nylon melting points are in the area of 500F, some much higher. A run of the mill compartment fire will generally be incapable of raising the temperature of the carpet that high for any appreciable amount of time before flashover. And once flashover occurs the the compartment is fully developed, the carpet will burn and char, not melt and pool.
I don't know any specifics of the fire compartment or circumstances but it sounds very suspicious to me.
11-14-2005, 06:58 PM #5
- Join Date
- Mar 2005
I should have read better, the fire never reached flashover.
I am no expert but I do have a degree and experience with flammability properties of polyamides and I would be very, very doubtful (read: next to impossible) the flux produced by a fire in growth stage would be enough to melt the plastic backing of the carpet through the insulating properties of the nylon pile, and then find oxygen to burn and leave a pool pattern on the floor?
I smell male bovine excrement.
I wish I could be more helpful in terms of studies, but besides NIST check the SFPE Handbook.
12-11-2005, 02:13 AM #6
- Join Date
- Dec 2005
I have performed multiple test on carpeting and carpet padding. There were a number of factors in these test. One factor was the age of the carpeting and the padding. We found that most the carpeting melted but the padding of the foam and plastic once ignited melted and pooled. One of the test was conducted on a stair case. The padding not only showed pooling but it also produced flaming fall down from one step onto another igniting the step below. I documented these test with pictures. I had no way of telling what type of carpet or padding I was using since it was a section of used carpet from another area of the fire building. I did save a sample of both these materials and would be willing to share them with you if you so desire. Also in these test we used cigarettes to see if we could ignite the carpet and lit matches throwing them on the carpet. We were unable to get the carpet to ignite in this manner. We also used lighter fluid squirting it on the carpet. It seemed once the fluid was consumed the carpet had a burn pattern consisted with the pouring or squirting of the fluid. I seem to recall the fire going out once the ignitible liquid was consumed. Samples were taken and sent to the lab with positive hits of a light distillate consistant with lighter fluid. There were negative results in the areas remote from the fluid. I realize that there could be other variables in this test but it did answer the question, Is it possible to get a burn pattern consistant with a pour from some carpet or padding? The answer I found to the hypothesis in this situation is yes. I had the oportunity to investigate a number of fires where the structure was vacant and the room in question had wall to wall carpeting and padding. Samples were taken with the use of a canine and a hydrocarbon sniffer. The canine hit on multiple areas of the room and a sample was taken from each area and sent away to our lab. All samples came back negative with a minor hint of turpines commonly found in pine wood. Needless to say the floor was constructed with the old tung and groove pine wood boards.
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