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Fire Sleeving?

T

TXFlyGuy

Well Known Member
Does everyone recommend fire sleeving all lines fire-wall-forward? We are looking at that right now.
Is there any reason not to do this, other than cost?
 
There are a few ways to answer this. One is to look at the current guidance in FAR 23 and build to that.

Much of FAR 23 has been written in blood, so take that into consideration. It is also meant to look at an overall picture of the general aviation fleet, so it might not apply to your particular airplane or operating situation. Bottom lin is that it is guidance, not an absolute.

You are the manufacterer here, so it is really up to you and your individual risk analysis.
 
Check with your A/W inspector.

DARs have the option of not signing off on anything they consider a safety factor. I consider no firesleeving on flexible fuel lines forward of the firewall a safety factor.
 
TXFlyGuy said:
Yes, that is the plan as of now.
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The main reason for the fire shield is to (a) protect the lines from excess heat during normal operation and (b) lengthen the time that the lines will withstand a fire before becoming compromised. Once compromised both fuel and oil lines both provide additional fuel to the fire. And the engine will stop shortly afterwards. I protect both for the extended fire resistance.
 
And here is where the "particular situation" comes into play - you are no doubt talking about your T-51? If so, your entire intake manifold is made of plastic - itself a flamible material. Your high pressure fuel rails (and injectors) are secured by bolts threaded into this plastic manifold.

Firesleeve may buy you some time before the hoses fail, but there are PLENTY of other things to worry about under your cowl that dont play well with fire. In your case, if you even suspect a fire, step one is to shut the engine down and then be prepared to find a place nearby to dump the ship or bail out.
 
As some RV's are powered by auto engines, just wondering what the standard practice is here? I know there are a number of V8's flying.
 
Firesleeve oil lines too

I recommend firesleeving both the flexible fuel AND oil lines. Both are important. If you have a FWF fuel fire in flight you can turn off the fuel at the selector and possibly starve the fire ....not so with an oil fire. Even if you've killed the engine, if the prop continues to windmill the engine will continue pumping out oil to feed the fire. You just can't turn the oil supply off in the air. And oil fires produce more smoke than fuel fires and it will most probably be the smoke coming back through the firewall that will incapacitate you in flight before the fire does.
 
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Captain Avgas said:
I recommend firesleeving both the flexible fuel AND oil lines. Both are important. If you have a FWF fuel fire in flight you can turn off the fuel at the selector and possibly starve the fire ....not so with an oil fire. Even if you've killed the engine, if the prop continues to windmill the engine will continue pumping out oil to feed the fire. You just can't turn the oil supply off in the air. And oil fires produce more smoke than fuel fires and it will most probably be the smoke coming back through the firewall that will incapacitate you in flight before the fire does.
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Good advice. Thanks.
 
sglynn said:
Sorry but the purpose of the fire sleeve is not to protect but to soak up fuel if a line leaks. The inner white cloth absorbs fuel in case a line leaks and prevents it from running lose in the engine compartment and catching on fire.

So yes on all fuel lines including around the RedBox.
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That's a new one. I have never heard that before.
 
although i firesleeved my fuel lines i talked to someone who made a pretty good case not to. he said inspection is way better and if you are looking you will catch lines that are beginning to be not perfect rather than out of sight, out of mind. he said if a fire starts you are to be shutting off fuel supply immediately and the few feet of rubber fuel line burning will not contribute anything to the way bigger problems you have going on.
 
sglynn said:
Sorry but the purpose of the fire sleeve is not to protect but to soak up fuel if a line leaks. The inner white cloth absorbs fuel in case a line leaks and prevents it from running lose in the engine compartment and catching on fire.
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Please tell us where you got that information from ? :rolleyes:

The primary reason for using firesleeve on fuel and oil lines is to protect the hose (for a limited period) in the event of a general FWF fire. But there are many other advantages including:

1. Protecting the hose from flames and hot gasses emanating from an exhaust failure.
2. Minimising the potential for vaporlock.
3. Providing the hose with additional abrasion resistance.
4. Preventing failing electrical components from arcing onto steel braided hose.
5. Ensuring longevity of the hose by protecting it from the accelerated ageing associated with extreme temperature cycling.
 
Put me down as another who fire sleeved the fuel lines but not the oil lines. I did however fire sleeve my "red cube" fuel transducer as it is essentially part of the fuel line from the mechanical fuel pump to my throttle body (FI IO-540).
 
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bobnoffs said:
although i firesleeved my fuel lines i talked to someone who made a pretty good case not to. he said inspection is way better and if you are looking you will catch lines that are beginning to be not perfect rather than out of sight, out of mind. he said if a fire starts you are to be shutting off fuel supply immediately and the few feet of rubber fuel line burning will not contribute anything to the way bigger problems you have going on.
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The person you spoke to is horribly misinformed and his advice to you is dangerous and goes completely against aviation best practice.
 
sglynn said:
PER YOUR REQUEST TO EXPLAIN FURTHER
My A&P/IA for my Cherokee told me this. He has 40,000 hours in cockpit and a lifetime of A&P work. His father got his license in 1916, barely after the Wright Brothers.

It is logical. He says the most likely scenario is leaky fitting or line crack and fuel needs to be souped up, rather than dripping around. Maybe there are other functions. But fuel hoses have stainless steel mesh with conductive lining. Do they need abrasion protection? Static protection? Aging protection? Really?

Leaking fuel needs to be treated. Leaking fuel needs to be kept from igniting. Thus fire sleeve. When fuel leaks then it needs to be protected from igniting. Sleeve soaks it up and protects the fuel fluid from ignition sources. And so I suppose you can think of the pyro resistant silicone rubber cover as protecting the line from heat, but that isn't necessary until there is a leak. So what is the sleeve doing? It is protecting the leaking fuel from being ignited by soaking it up to prevent dripping and keeping heat away from it. It is not protecting a stainless wrapped, conductive teflon line.

Point is, when do you need fire sleeve? When the potential for a leak to ignite is a potential? Is the potential to ignite exist in the cabin? No. So we don't use it. But could fuel touch something hot in the engine compartment? Yes, so we use it there to prevent fuel from ignition heat source.

If fuel lines/fittings never leaked you wouldn't need fire sleeve.
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Well OK but there's other ways a fire can start FWF that doesn't involve a leaking line. Believe what you want but I'm of the belief fire sleeve is there to protect lines from heat not to sop up gas from a compromised line that has a hole in it. Unless the line fails from the inside, anything that punctured the line would also puncture the fire sleeve as well.

To put this to rest I think we need some sort of actual reference to back up your supposition. not some A&P's opinion, regardless of how long they've been around the block. You and he may indeed be right, but I personally need to see it writing.
 
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I think it is a good recommendation to fire sleeve both oil and fuel. However, Van's "standard", unless they changed things in their FFW kits, has been fuel lines only.
 
The main purpose for the fire sleeve is to hopefully buy enough time to extinguish the fire before the lines are compromised and contribute additional fuel to the fire and/or possibly to get on the aircraft on the ground, althought not likely. Everything else it does is superfluous. When the fire is melting the soles off your shoes is probably not a good time to decide that you probably should have sleeved both the fuel and oil lines. Fires are rare but when they do happen they can do unbelievable damage in an incredibly short period of time. After seeing what a fire did to a turbo 310 once made a believer out of me. Only you can decide how much time you want to buy.

PS: When my fuel line starts leaking I really hope the fire sleeve does a really good job of soaking up the gas so it doesn't drip on the exhaust. !!!!!!!!!!!! LOL
 
FWIW, I just completed a little internet research and looked up a number of aerospace fire sleeve manufacturers and all of the product descriptions focused on their ability to withstand heat:

Here's a typical excerpt: "Our firesleeve sleeve, jacket, tape and fabric products are perfect for protecting hydraulic hoses, pneumatic lines, electrical cables, control wiring, welding cables, electric arc furnace cables, etc., from high-temperatures, heat, flame & pyro exposure, molten metal splash, slag, welding splatter, grinding & electrical sparks and environmental contaminations."

Some even specifically mentioned that their silicone coated fiberglass sleeves were designed to not absorb flammable contaminants. None touted their ability to absorb gasoline in the event of a leak as a product feature.

I also took a look at TSO-C53a, Fuel And Engine Oil System Hose Assemblies, and TSO-C75, Hydraulic Hose Assemblies, and it's clear to me the primary purpose of fire sleeve is to protect hoses from excessive heat. YMMV.....
 
Are stainless braided hoses not considered to be adequately protected for fire? I was going to put fire sleeve on the fuel lines just to make them less susceptible to vapor lock and leave the oil lines bare.

BTW, ACS has fire sleeve for about double what you pay at Summit Racing.
 
sblack said:
Are stainless braided hoses not considered to be adequately protected for fire? I was going to put fire sleeve on the fuel lines just to make them less susceptible to vapor lock and leave the oil lines bare.

BTW, ACS has fire sleeve for about double what you pay at Summit Racing.
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The stainless braiding will not protect the internal hose (teflon or rubber) from the heat of fire, and when the internal hose burns through the stainless will not contain the fluid that the hose is carrying.

Skylor
 
Auburntsts said:
FWIW, I just completed a little internet research and looked up a number of aerospace fire sleeve manufacturers and all of the product descriptions focused on their ability to withstand heat:



I also took a look at TSO-C53a, Fuel And Engine Oil System Hose Assemblies, and TSO-C75, Hydraulic Hose Assemblies, and it's clear to me the primary purpose of fire sleeve is to protect hoses from excessive heat. YMMV.....
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From the ACS catalogue:

"Aeroquip Firesleeve was specially developed to meet the fire resistance requirements of FAATSO - C53a OR TSO - C75. May be used for all fuel, oil, hydraulic, fire extinguisher & propeller feathering lines. "Fire-proof" hose lines as defined by FAA must withstand a direct flame for fifteen minutes under specified flow conditions without failure. Fire-resistant lines must withstand a 5-minute exposure under these conditions."
 
For sake of discussion -

By definition, AvGas is flammable. It has a very low flash point. All you need is a source of ignition to start a fire. (And air in the correct proportion, which is easy to get in an open system)

Oil is a combustible with a higher flash point. So is common hydraulic fluid.
We know brakes can generate enough heat to flash standard hydraulic fluid and provide a source of ignition. We have seen it on RV's before. It would take a sustained fire to compromise an oil line, flash the oil, and ignite it.

So, what can sustain a FWF fire once the fuel is shut off? Is there enough fuel left in the lines, carb if so equipped, etc...?

I do not know the answer.

I followed Vans standard no fire sleeve on the oil lines when I first built. When I went to Teflon, I fire sleeved all hoses per TS Flightlines recommendations.

I did not firesleeve the Fuel Transducer per TS Flightlines discussion that there was little exposure here.

I read Michaels excerpt from the FARs. They talk about flammables, but not combustibles, at least what I reviewed. I might have missed it.

As with many of the discussions here, there isn't a perfect answer, but firesleeving the fuel lines seems to be the minimum.
 
I fully agree with JonJay. Firesleeve on fuel lines is necessary.
Firesleeve on oil lines is recommended but would not reject for lack of it.
 
Fire sleeves will serve several of the problems identified in this thread but the primary function is to provide an opportunity to deal with a FWF event by protecting hoses with gas or oil in them as long as possible. Well here is my opinion. The best solution is to fire sleeve every oil and gas hose forward of the firewall. Using the proper banding and sealing the ends are equally important.
 
Fire

I have my own personal protocol for engine compartment fires. Shut off the fuel shutoff, the engine will quickly consume any fuel remaining in the carb. If the fuel line is compromised, the fuel line contains a relatively small amount of fuel which is unlikely to do serious damage if the fuel valve is quickly shut off.
 
jrs14855 said:
I have my own personal protocol for engine compartment fires. Shut off the fuel shutoff, the engine will quickly consume any fuel remaining in the carb. If the fuel line is compromised, the fuel line contains a relatively small amount of fuel which is unlikely to do serious damage if the fuel valve is quickly shut off.
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That's a good protocol. The only problem is, How advanced will the fire be by the time you realize it?
 
sglynn said:
If fuel lines/fittings never leaked you wouldn't need fire sleeve.
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Huh, are you for real ?

A common cause of FWF fires is cracking of the exhaust system which allows super heated gases and flames to burn through a fuel hose.

It might be time for you to give less credence to the geriatrics at the local hangar.
 
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jrs14855 said:
I have my own personal protocol for engine compartment fires. Shut off the fuel shutoff, the engine will quickly consume any fuel remaining in the carb. If the fuel line is compromised, the fuel line contains a relatively small amount of fuel which is unlikely to do serious damage if the fuel valve is quickly shut off.
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If an oil line is compromised and feeding the fire then turning off the fuel selector will probably not produce a positive outcome. Even if the engine is starved of fuel and quits, a windmilling prop in flight will continue to pump oil and feed the fire. That is why firesleeving oil lines is important.
 
Mis-information.

sglynn said:
One more attempt.
Fire sleeve will stop that fuel spray and turn it to drops and or absorb it so it is not spraying. Fuel in the lines is under pressure. If it leaks it sprays. Fire sleeve stops the spray. Yes it does protect hose from heat but Teflon is already rated to 1500F.
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Where on earth are you coming up with this stuff? Teflon melts at about 620F.
 
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Captain Avgas said:
If an oil line is compromised and feeding the fire then turning off the fuel selector will probably not produce a positive outcome. Even if the engine is starved of fuel and quits, a windmilling prop in flight will continue to pump oil and feed the fire. That is why firesleeving oil lines is important.
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In the presence of a fire, which component is likely to burn through first: the retatively high mass stainless steel braided hose, or the paper thin aluminum oil cooler?

Not saying firesleeve on the oil lines is a bad idea, but just how much protection do you really gain? Oil lines are often nowhere near the reach of a leaking exhaust, so what failure scenario do they protect against?
 
Fire in Cabin?

Just for Safety sake a comment was made (Is the potential to ignite exist in the cabin? NO.)On the contrary there is a very real threat of cabin fire with a fuel leak in the cabin.We must inspect our cabin fuel lines and any fuel smell or stain must be addressed before further flight it only takes one spark and a fuel fire moves very rapid and in our small confined space there is no where to go to avoid the flame.
Bob
 
Another + for firesleeve on the oil lines. Much easier routing due to abrasion resistance. Lots of wires behind engine that would not last long rubbing on SS. Possible to keep separated, but another layer of protection.

Firesleeved my oil lines at 200 hours. Not difficult, light weight, cheap, little down side.

BTW, Dan, you almost made me spit out my breakfast!
 
Toobuilder said:
In the presence of a fire, which component is likely to burn through first: the retatively high mass stainless steel braided hose, or the paper thin aluminum oil cooler?

Not saying firesleeve on the oil lines is a bad idea, but just how much protection do you really gain? Oil lines are often nowhere near the reach of a leaking exhaust, so what failure scenario do they protect against?
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It's an interesting point. But personally I think I'd be more worried about Vans' "paper thin" aluminium heater box mounted on the firewall than the oil cooler. That's why I upgraded mine to stainless steel.

Having said that, my guess is that in a serious FWF fire unprotected oil hoses will be breached much quicker than the oil cooler. Teflon hoses are the most fire resistant and they melt at 620F. The aluminium oil cooler will start to melt at 1218F.

In the end firesleeving fuel and oil hoses just buys you a little bit of time. You can buy the hoses with firesleeve on them but it's easy and quite inexpensive to do it yourself. In my mind it's just not an area where it makes sense to try and save a few paltry dollars.
 
Captain Avgas said:
It's an interesting point. But personally I think I'd be more worried about Vans' "paper thin" aluminium heater box mounted on the firewall than the oil cooler. That's why I upgraded mine to stainless steel.

Having said that, my guess is that in a serious FWF fire unprotected oil hoses will be breached much quicker than the oil cooler. Teflon hoses are the most fire resistant and they melt at 620F. The aluminium oil cooler will start to melt at 1218F.

In the end firesleeving fuel and oil hoses just buys you a little bit of time. You can buy the hoses with firesleeve on them but it's easy and quite inexpensive to do it yourself. In my mind it's just not an area where it makes sense to try and save a few paltry dollars.
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During a fire that would melt the aluminum heater box, I think the heat would warp the stainless heater box and seal that it would also become useless in keeping smoke and gasses out of the cockpit.

Maybe we need a side by side test.
 
gasman said:
Maybe we need a side by side test.
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Why not just go to the Plane Innovations website?

Click and scroll down:

http://www.planeinnovations.com/product/heater-bypass-valve-hbv-02/

Having done a few similar hot firewall tests, my own airplane has no heater valve, scat tubes, or heat muffs. I wired provisions for hot vests, but I've only used one once in six years. Obviously my northern friends have different requirements. In their shoes, there is no way I'd install an aluminum valve. In fact, I doubt I would install a stainless heater valve with the control lever on the engine side.
 
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gasman said:
During a fire that would melt the aluminum heater box, I think the heat would warp the stainless heater box and seal that it would also become useless in keeping smoke and gasses out of the cockpit.

Maybe we need a side by side test.
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According to the testing done by Plane Innovations (see URL in Dan's post for photos) the stainless heater box is good for at least 10 minutes and the aluminium box is melted goo within 15 seconds.

For the life of me I cannot understand why Vans would provide a stainless steel firewall in their kit with an aluminium heater box in the crucial lower middle area. The logic fails me.

But then again there are 1000s of RVs flying out there with no stall warning device because for decades Vans didn't provide one with their kits. I cannot fathom their reasoning for this considering the negligible cost of the device. In my opinion it was a penny-pinching exercise that bordered on gross negligence. This comment might involve a bit of thread drift but I just had to get that off my chest...it's been bugging me for years. :p
 
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Interesting to note that aluminum melts so fast. Would the SS firewall be of any real help in an engine fire, or a fire anywhere north of the firewall? I only ask as there is a lot of aluminum up there. How long before the entire cowl area melts?
 
Step back and take a look at all the stuff under the cowling that can burn. Hoses, aluminum brackets, wiring, rubber, aluminum oil drain tubes and their rubber hoses, tie wraps, fiberglass plenums, oh, and a fiberglass cowling. Several of many things. But gee----we can take preventative measures to help some of these things, but preventing them all, I doubt it. How are you going to fireproof a cowling? Anyone ever flown an RV with out a cowling?

We can plan for the things we know of, and hope that what we've planned for doesnt contribute to a fire. As Yeager called it, the Ugknown (at least in his book anyway). We all try to eliminate the possibilities, and thats why we tend to firesleeve our FWF hoses. Some disagree with that, and its ok. I thenk we'd have to get really good at forming a stainless cowling. I know some guys that could do it, but do we really want to? The list is endless.

Tom
 
TXFlyGuy said:
Interesting to note that aluminum melts so fast. Would the SS firewall be of any real help in an engine fire, or a fire anywhere north of the firewall? I only ask as there is a lot of aluminum up there. How long before the entire cowl area melts?
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In the few notable in flight FWF fires, the weak link has been the floor behind the firewall. If you think about it, that is where the gross volume of air is going, out and down through where the exhaust pipes exit.
 
....and stupid materials on the cabin side of the firewall, which forms a very effective flame transfer system.
 
DanH said:
....and stupid materials on the cabin side of the firewall, which forms a very effective flame transfer system.
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...and to be even more stupid, marketed and sold by companies to be used in this application!
 
So what material is advisable for the interior, on top of the cabin floor? My nice floor carpet from Classic Aero Designs has foam on the bottom that fits between the stiffeners. Seems similar to the undesirable material a lot of people installed on the inside of the firewall as a sound barrier etc. I like my creature comforts.

erich
 
Mich48041 said:
Firefighters call cushion foam "solid gasoline". LINK
Burning foam gives off deadly cyanide gas and carbon monoxide.
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Very compelling argument against its use for furniture, or seats in large aircraft where you could be trying to escape the area, but in the context of an RV, if the seat cushion you are sitting on is burning and producing lethal gases, I think you are probably already out of luck anyway.
 
rvbuilder2002 said:
Very compelling argument against its use for furniture, or seats in large aircraft where you could be trying to escape the area, but in the context of an RV, if the seat cushion you are sitting on is burning and producing lethal gases, I think you are probably already out of luck anyway.
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This is exactly why I purchased a nomex flightsuit, underwear, leather gloves, and a nomex flight jacket from Cockpit, USA.

Seconds count.
 
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