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Nomex

Mike S

Mike S

Senior Curmudgeon
Hi there, with the current fire storm of discussion concerning safety issues, one of the things that is getting mentioned a lot is Nomex.

As a career fireman, with 37 years of experience, I have a bit of knowledge about this stuff, and would like to share.

Please understand that everything I am saying is related to fire service Nomex----Race car stuff could have different specifics. Ditto flightsuits. I just simply have no knowledge about them.

First off, Nomex is designed to be a protective outer layer, that will not support combustion. It is self extinguishing. It does provide a bit of insulation from the heat of a fire, but unless it is layered with something designed to insulate, the effect is minimal.

In the fire service, we had a light weight single layer nomex setup for wildland firefighting, and the heavy multi layer turnouts (sometimes called bunker gear) with a nomex shell, for structural, automotive, and other fires requiring more protection.

Nomex is a synthetic material, it will burn:eek: but only if heat is continuously applied to it. Remove the heat, and the fire goes out.

Single layered nomex should always be worn over a layer of something to insulate the skin. Many $$$ and much time has been put into testing this, and plane old cotton is the choice of material for the layer next to your skin. At work we were mandated to have long sleeve cotton T shirts, and then later someone figured out that the cotton sleeve itself could be installed in the nomex jacket. The lined sleeve jacket is now the only one allowed where I worked.

There were a lot of burn injuries to body parts only protected by nomex, before we went to the inner linings.

The other thing that is important is that there be air between the nomex, and the cotton layer------they should not be bonded together. The cotton acts like a wick, and picks up perspiration, and the evaporation helps in cooling.

Nomes long underwear has been mentioned here, as have nomex gloves. I have never seen nomex long johns in the fire service, and as to gloves----some nomex is used on the back of our turnout gloves, but the palms are all leather. Wildland fire gloves were all leather.

Anyway, to put all this into something that folks might benefit from, for the use we are concerned with, I think the best outfit would be cotton jeans, long sleeve cotton shirt, and a nomex outer layer like a jumpsuit. If the jumpsuit is already lined with a cotton layer, then just the jumpsuit.

Nomex can help prevent injury is used correctly, but it is not magic.

Hope this was informative, and helps folks to understand this stuff a bit.
 
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My $.02: wearing Nomex is useless in our aircraft. If the airplane is on fire, the floor is going to melt. Nomex won't save you if your feet are on fire and/or the cockpit is filled with smoke.

The better solution is to buy a piece of .016" stainless for the belly and fit it onto the belly of the airplane to prevent a fire from burning through the floor.

My rocket has a Nomex cover on the engine side of the firewall, and I have .016" stainless on the belly to the spar. I purchased the foil-faced Nomex material from a local race car supply shop and did some burn tests with a propane torch. The Nomex blanket is very effective at blocking a direct flame. The back side will just glow red.
 
Excellent Post Mike!

I only spent 25 years in the fire service, and that was volunteer, but it did affect the way I dress (which, as a geeky engineer, is badly, according to fashionistas I suppose....). because i never knew when I was going to get a call (volunteers are 24 hours a day), I generally where cotton. At night, I would pull on a Nomex jump suit, as for much of my time in the Service, I was an officer, and as likely to be running around outside the fire as running in, so I didn't always pull on my Bunker gear, and wanted some protection from embers, etc. I liked my Nomex flight jackets becasue they always gave me good protection for this, which is why folks frequently see me in one if it is jacket weather.

I have seen first hand the affects of polyester melted into someone's skin. I don't pull on a Nomex jump suit for routine flying, as I am generally already wearing cotton, and we jump in and out of the planes pretty regularly, living on an airstrip. For professional flying we are required to wear Nomex flight suits, of course, and if I am doing test flying of any sort, I use Nomex - including gloves.

It is very, very rare that I look down at myself in the cockpit and find that i am wearing polyester, as it just isn't in the wardrobe. that's just years of habit.

Oh, one other thing about Nomex (at least much of what I have sued) is that it does not like long-term exposure to sunlight - it decomposes. So don't just keep a suit rolled up in the back of the cockpit where it sees sun all the time - or you could be embarrassed when you pull it on and you hear this splitting noise.....:)
 
one thing to keep in mind, is that cotton is useless for insulation when wet. So if you are traveling over inhospitable country during anything other than summer in much of the country(anywhere except the deep south i guess), you might want to consider some wool layers, both for warmth and fire protection, or gamble on synthetic fleece for keeping you alive after you safely land your airplane off field somewhere.

aren't there more off field landings than in flight fires?
 
Racing Background

I spent a few years in racing so I can add a tiny amount to the pool of data here.

Racing suits here in the US are rated by 2 separate standards. They are: SFI 3-2A/5 and SFI 3-2A/1. The 3-2A/1 suits are usually single layer suits and are used for karting applications. The 3-2A/5 suits are multi-layer suits which are used for all of the more dangerous sports. (not to say that karting isn't dangerous but you're not trapped inside of it if there's a fire.)

In Europe the standard is set by the FIA. The standard is FIA 8856-2000 which is roughly equivalent to the 3-2A/5 here in America.

I too, am not really sure if a nomex suit will help you if there's a fire. But I'm pretty sure it won't hurt. If it makes you feel more safe...go for it.

Also from the racing world...there are fire suppression systems that are pretty prevalent in some racing circles. Has anyone ever put one of these in their aircraft? It's basically a fire extinguisher that has lines that run up into the engine bay. If there's a fire, you hit the button and it discharges directly into the bay. There are also systems that have dual zones where one will discharge into the engine and one will discharge into the passenger compartment. I don't believe they weigh all that much. Maybe 20-30 lbs? That's a guess I haven't really looked.
 
NOMEX

NOMEX also has it's care requirements.

I just happen to have a new Air Force issue flight suit on my desk.
Quoting from the label:

Coveralls, Flyers, Summer, Fire Resistant CWU 27/P
92% Meta-Aramid, 5% Para-Aramid, 3% Conductive

1. Wear as outer garment.
2. WARNING: Launder with slide fasteners and hook and loop engaged. Do not press hook and loop fasteners. Hand or machine wash in cold water, Gentle cycle. Flat dry or machine dry on low heat, short cycle. DO NOT DRY CLEAN.
3. Pockets are designed to accommodate operational items and personal effects.
4. Lubricate slide fasteners with wax pencil.
5. For thourough cleaning, return unit for machine washing in accordance with established laundry procedures. Coveralls may be hand laundered using mild detergent and warm water. All detergent shall be thouroughly rinsed out.
6. DO NOT USE STARCH, BLEACH OR FABRIC SOFTENER. This process will deteriorate the flame resistance.
 
Phlyan Pan said:
Also from the racing world...there are fire suppression systems that are pretty prevalent in some racing circles. Has anyone ever put one of these in their aircraft? It's basically a fire extinguisher that has lines that run up into the engine bay. If there's a fire, you hit the button and it discharges directly into the bay. There are also systems that have dual zones where one will discharge into the engine and one will discharge into the passenger compartment. I don't believe they weigh all that much. Maybe 20-30 lbs? That's a guess I haven't really looked.
Click to expand...

I have two AFFF fire systems on the shelf that were given to me by a friend who had another friend who was developing these for use in experimental aircraft. Unfortunately that gentleman passed away from cancer. He was marketing the systems 10 years ago, and acually did a real test in his Pitts to show the effectiveness of the system. I believe I might be able to scrounge up a video of it in action. These systems were rebranded SPA systems used on race cars...see http://www.pegasusautoracing.com/productselection3.asp?Product=2436 I've debated about installing one in my rocket but haven't done so because I believe the mods I mentioned earlier will be effective for an in-flight fire.
 
Living in AZ and flying all year round I can tell you that full Nomex protection without air conditioning, ain't gonna happen. I try to wear cotton at all times but often wear shorts when flying. For the past couple of years, I ALWAYS wear Nomex gloves. I figure if something goes bad I will be able use my hands to help. Also, if I get other burns I'll still have my hands safe.

I wear full Nomex at work. Flight suit with gloves, helmet and leather shoes with cotton socks. I even fold up the collar to go under the helmet. However, we have great air conditioning in the helicopter. It really bothers me that some of our pilots cut the sleeves off their flight suits.

When I flew in law enforcement I had a shoulder holster with a 9mm. I made it clear to my family and friends if I crashed and was on fire the 9mm would get used before I burned to death!!!

With all of this thought, I'm now convinced I'm going to install a fire suppression system in my new 390 equipped 7.

Hey, maybe a group buy!!!
 
Nomex on the firewall?

Bob,
the idea of a thin stainless sheet underfoot seems a good idea particularly having read reports of belly skin burn through. What did you do - cut stainless sheets to fit over the floor like an (interior) floor doubler and rivet it in?
Why the Nomex on the firewall - as a heat barrier? The stainless doesn't need that protection, does it?
Bill Brooks
Ottawa, Canada
RV-6A finishing kit
 
Mike + 1

10 years of flying hot air balloons made a believer out of me! Nomex and cotton are the only way to go!
Polyester is absolutely out of the question. At the ballooning events that I participated in and sometimes ran, a pilot in polyester garments was shutdown before he even got a chance to inflate.

P.S. Danny7...That video is absolutely hysterical! Kudos to all the players!
 
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This is an article from the February 2006 Sport Aerobatics magazine on this very subject.

Here is a quote to encourage you to read the whole article:

... a single layer of Nomex carries the lowest protective rating, according to SFI, affording only three seconds of exposure before you get second degree burns.

In addition, Nomex absorbs liquids like a sponge. If you get covered in fuel, Nomex is no better than T-shirt and jeans when it comes to fire protection.
Click to expand...

Before you slip on those Nomex clothes for "protection," be sure you are aware of what the actual amount of protection from that Nomex is, and what it will take to get the level of protection you desire.
 
Just to clarify what might be obvious to many, but others might miss...NOMEX is NOT an insulator, and will NOT prevent you from getting burned! What it will NOT do is melt in to your flesh, like polyester will. Like Mike said in his initial post, you will get heat transferred right through the NOMEX (I have seen folks burned through a Bunker Coat from the heat - but if you ARE in a fire for a few seconds, you won't come out dripping with molten plastic all over you - that stuff is like Napalm.

Paul
 
C-GRVT said:
Bob,
the idea of a thin stainless sheet underfoot seems a good idea particularly having read reports of belly skin burn through. What did you do - cut stainless sheets to fit over the floor like an (interior) floor doubler and rivet it in?
Why the Nomex on the firewall - as a heat barrier? The stainless doesn't need that protection, does it?
Bill Brooks
Ottawa, Canada
RV-6A finishing kit
Click to expand...

I just cut the sheet to fit behind the exhaust area and riveted it to the belly with MS20427F stainless rivets. Its on the outside.

The nomex blanket is on the forward side of the firewall to prevent the rivets from melting which would allow places for flames to propagate inside. I once read about a guy whose airplane caught on fire and this exact scenario happened. This and since the blanket has a foil cover, which helps insulate the firewall. Back side of the firewall will get the insulation that I had on my RV-6 which was very effective at noise deadening. Kevin Horton did some testing with the same insulation and found it very effective.

I got the nomex from Earl's Indy.
 
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Sam Buchanan said:
Just curious....would this discussion be underway if one B-nut had been tightened properly?
Click to expand...

Thinking about Vern Dallman?

Never mind... saw Ted Chang's thread. Still, Vern Dallman's death, apparently from the same problem, in a Harmon Rocket, is relevant.
 
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Don't forget the footware

When I was flying in the Marine Corps, we did not polish our high top leather boots. Shoe polish is very combustible.
Cotton socks, and all leather boots--no nylon or other plastics.
 
rocketbob said:
The nomex blanket is on the forward side of the firewall to prevent the rivets from melting which would allow places for flames to propagate inside. I once read about a guy whose airplane caught on fire and this exact scenario happened. This and since the blanket has a foil cover, which helps insulate the firewall. Back side of the firewall will get the insulation that I had on my RV-6 which was very effective at noise deadening. Kevin Horton did some testing with the same insulation and found it very effective. I got the nomex from Earl's Indy.
Click to expand...

Ahhhh, Bob, nomex isn't a very good choice for firewall insulation, certainly not as good as a ceramic refractory material. Contrary to popular belief, given enough heat it does burn merrily until the heat source is removed.

Here's a nomex wool sample I did for Mark. Note that the nomex is on the cabin side of the stainless panel and is never exposed to open flame, only hot sheet metal. Ignition point:

2chorj6.jpg


A bit later:

15qp645.jpg


On the engine side with a aluminum foil cover? I think it would burn away, although I can't say how quickly because it produces a char at 800F. I didn't test on the fire side.

Strictly opinion, but I wouldn't bet on it to keep sound insulation on the cabin side below ignition temperature. Plus you should consider point heat sources.
 
I wear a single layer Nomex USAF jumpsuit every time I go flying for the reasons Paul said. When I was road racing cars we wore 2 and eventually 3 layer suits, gloves, socks, balaclava. It was said 1 layer gave you 5 seconds of protection with one layer of sweaty cotton underneath, 2 layers about 10 and 3 layers no more than 20. 3 layers would be unbearable in most hot climates on a long flight unfortunately. Your face would be unprotected too because you wont be wearing a full face helmet with Lexan visor like we did in race cars.

Hands get it first, the smoke is a real concern so maybe we should consider having a smoke hood in the plane as well.

In every RV fire I've seen photos of, the firewall is fine and the belly skin in gone in less than 15 seconds in the case of fuel fires. I agree than a .016 stainless belly skin running back past the seats would be the best defense with perhaps an on board fire suppression system.

With a tunnel fire in an RV, I'd be getting the fuel off first before the aluminum feed lines to the selector melt through and give you no options to shut off the fuel feeding the fire.
 
time, material, weakest links

Ron,
appreciate your commments and others from the 'real world'. ( Dan)
As much as we all have strong opinions on what is the thing we should cover, we lack many real examples. When we do have examples, we tend to dismiss the obvious, and search for the 'magic bullet' solution.
(mmmmmmm, shiny gadgets & big red buttons like in the movies, eh?)

Of course there are smart, and not-so-smart things to do....but I think guys like me would benefit from a prioritized list of how to make the typical engine fire most survivable.
( I think many would be surprised to find a huge hole in the firewall where cabin heat enters, while we are covering stuff with acres of nomex, ceramix, etc.)
I shopped for hours for leather shoes, but they all have rubber soles.
Cowboy boots are about the closest thing to a leather wrap...no wonder you see some guys still wearing them!

I like the stainless belly pan idea, but when the fibreglas cowl becomes a big torch, aren't the fuel tank inboard leading edges another 'weak link' ?
...sounds like we need an old RV carcass in a wind tunnel to test cook!..maybe we should call 'Mythbusters' eh?
 
The way fiberglass chars it actually seems to last longer than the aluminum skins and fire is often directly mostly aft through the cowling exit, down the middle of the belly skin.

The heater box valves dumping right into the tunnel on an RV10 are a concern, stainless helps here but there will still be leakage through there in a fully engulfed engine fire.

One fellow who had a turbo explode (matched by nitwits) on a Lancair IV years back had an oil fire. He thought his firewall was well sealed but was surprised how much smoke poured through all the same. He got it down ok on a road.
 
Saturday marks the one year anniversary of my explosion. I wear jeans and long sleeve shirts with sneakers/boots and cotton socks. You really have to protect the lower areas. My ankles had really bad burns. Borderline 2nd/3rd degree. It is a very thinned skinned area and doesn't take kindly to fire. I still wear the shoes, shorts, shirt and sunglasses from that day. Had I been fully dressed I would have only been burned on the hands and face. I would rather sweat than burn again. I am just amazed of the amounts of RV-10 fires though. And always carry a big fire extinguisher! The little ones are useless!
 
We carry Nomex Gloves. We have them in Brown, long or short cuff, and black with short cuffs. As someone said, they won't absolutely prevent burns, but they won't melt to your skin.

I often wear a pair while driving too, this is because I find the "grip" keeps my hands from getting so stiff and sore (arthritis already?).

The Nomex gloves can't be found anywhere else. We had them custom made and they are top notch. (Yes, you can find black, long cuff, but not the short cuff. No one else makes brown Nomex gloves. Not tan, BROWN.)

We also carry an aqueous foam fire extinguisher. It is non-toxic and non-corrosive. It won't suffocate you (unless you drown in it) and it is easy to clean up (unlike dry chemical). The only drawback is it will freeze somewhere around 26 deg.F. In that case you use the frozen container to beat the flames out. ;) The nice thing about this foam extinguisher is that you can spray it on your feet, legs, etc if you do have a bad day and it will buy time and minimize burns.

FWIW, you can often find a similar extinguisher at Home Depot, but if you're ordering other items from us, I hope you'll support your local RV/Rocket builder!

If these fail, I plan to bail out and hope the chute works. Yikes!!

YMMV!
 
Carbon X

Any thoughts on the material CarbonX, an alternative to Nomex..

Chris Santschi RV8 627CS Second Chance
EAA 1424 Technical Counselor
Festus,MO
 
Layers.

I think this issue here is, you do not want to wear any type of material that will melt on to your skin for obvious reasons.

The suits we wear at work have about 1/2 dozen layers of various materials that insulate from from the heat. Even this offers protection only for a short period of time when exposed to extreme heat, I learned that the hard way. :eek: I cant imagine trying to fly an airplane wearing a suit that offers the same protection as the turn-out gear we use. For one, you would sweat to death with the sun coming through the canopy n' all.
 
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