Firewall Insulation

Firewall insualtion installed

I just wanted to post a pic and a short comment on my insulation progress.



This is what I have been able to get done so far. I went with the Firewall2000 Ceramic Blanket as discussed on this thread along with 2" wide alumninum tape around all the edges and holes. I also used a Thermosheild brand heat shield tape material wrapped around all the wire protrusions coming through the cockpit. I did this to help with insulating the wiring, help with filling the large holes with more fire protecting material so I would not have to use as much red RTV when sealing the holes, and just as important as all that, to protect the wires from being chaffed by the SS edge of the SS foil.

One thing that was mentioned in earlier posts was how to attach the material to the firewall. There was discussion about using stainless steel pop rivets with SS wide area washers. I did not want to open any more additional holes in the firewall as I felt I already had too many. So I did not use any rivets at all to secure this material. There were enough bolts across the span of the firewall to allow for those bolts and the associating battery box, solenoids, etc. to secure the blanket. Along with the aluminum tape this is more than adequate enough to secure the material to the firewall.

A couple of notes to pay attention to. If you are building and can install this prior to hanging the engine and other items on the firewall you are going to be happy you did. I did not do so and ended up installing this insulation after everything was hanging on the firewall. I ended up unbolting everything I could from the firewall and disconnecting any cables I could. Most of the wires were already permanently installed so I could not disconnect those. I had to cut slits in the blanket material to be able to get it around these items. I was able to accomplish all of this with the items already installed in about 3 or 4 hours so it did not take a great amount of time to accomplish but it would have gone much quicker and been a much neater install had I done this before running everything through the firewall.

For anyone with a flying airplane that is interested in doing this I think you can take from my experience the fact that it can be done. My firewall was just about as complete as it was ever going to be. I have not flown yet but am very close to doing so. Because of this I feel I was about in the same position as you guys already flying would be if you tackled this project. It can be done in a few hours. By taking off as many items as you can before attempting to install you will be ahead of the game. I was able to roll up the blanket in a horizontal plane and slide it in between wires, hoses, etc. until I had it pretty much in place. Then I unrolled the top and bottom and slowly began manipulating it into the nooks and crannies between everything that was in the way. Take your time and be very careful around the SS edges. Which leads me to the following point to keep in mind.

Another important thing to pay attention to is the stainless steel foil. The blanket has an aluminum foil on one side and a stainless steel foil on the other side. The stainless steel foil faces the engine. Whenever you work with this material note the SS foil is EXTREMELY sharp. Be very careful in working with this material as it will cut you repeatedly as you work on maneuvering it around all the items on the firewall. Go ahead, ask me how I know! I am keeping BandAid in business after this project.

You might note in the picture the top of my firewall does not have the insulation installed. Well the reason is that I ran out of material and am now waiting for more to be shipped so I can finish this project. The material comes in 24" wide sections sold by the foot. I bought 4' and it was not enough. By the time I cut and pushed and stuffed around things I came up short. I think 5' would have worked good and would have been able to complete the entire firewall. I will have the top covered as soon as the new order arrives.

I think this will really reduce the heat transfer into the cockpit. I also am optimistic this will help in the event of an engine fire but I hope to never have to test that out in real life.

NDrv8r said:

Mark, I don't mean to flame you (sorry bout the pun), but I see some copper tubing in the engine compt pics. Copper is very susceptable to vibration, and a break in a flamable fluid line can cause the very problem you are insulating against. Even if the copper lines do not carry flamable fluid, You may want to re-consider the copper tube in the engine compt.

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I just read this reply and want to make a comment. Although copper can "work harden" easily, it's certainly been used in vibrating enviroments for a long time. My business is HVAC which includes lots air conditioning condensing units which can vibrate to an extent all day long. These units will also be using a lot of 1/8" tubing in addition to 1/4 & 3/8". Overall, the copper holds up quite well.

The priming kit that Van's sells is 1/8" copper tubing. I have that system on my plane as well, and much prefer a three port primer over pumping the throttle. I have formed two or three loops in each copper line thats attached to the engine. I'm good at forming flares in copper lines, as I've done it in refrigeration units for the last 40 years, and feel quite comfortable with it.

L.Adamson --- RV6A

I lit up some Thermozite last night. It's the material sold by Flight Line Interiors and I was hoping to use it to insulate the tunnel in the RV-10.

It's a good thing I checked, it lit up like a torch.

Actually it did a pretty good job of insulating until the firewall temp reached 500 degrees. When the temps were approaching 450 degrees on the firewall, the backside of the insulation was still around 130. But as soon as the firewall hit 500 degrees it broke out into some flames that are similar to the previous photos.

I'd use the stuff elsewhere in the airplane where the maximum possible temp wouldn't reach much more than 300-350 degrees, but it's certainly not a good material for the backside of the firewall.

Glad I sacrificed a piece before putting it into the airplane.

Phil

Thermozite

Dan Horton tested a sample for me last year and posted the results here on VAF; check out post #9 on this thread:

http://www.vansairforce.com/community/showthread.php?t=44187&highlight=thermozite

I wrote Abby at Flightline with the results. Her website no longer lists this material as firewall insulation and simply lists it as insulation.

Mike

Note that in Phil's experiment the Flightline insulation (Thermozite, recycled plastic) ignited at 500F, more than 600 degrees below the melting point of aluminum.

Yeah, the aluminum looked completely untouched on the engine side. The interior side was severely blackened by the burning material and the adhesive that bound the aluminum foil to the fabric.

I forgot to mention the fumes coming off of it were pretty bad too.. Thick black smoke that would have cause breathing issues, vision obstructions, and probably burning of the eyes and respiratory system.

Phil

Dan:

Thanks for doing the many hours of research on firewall insulation. I?ve read over a few times and have some questions:

Earlier you mentioned, ?A 0.125" layer of fiberfrax with a 0.003" stainless foil cover sheet will do a good job. A 0.25" layer plus foil will (obviously) insulate twice as well.? But then it looked like the Fiberfrax failed both in front of and behind the firewall. Can I draw from this that the SS foil cover is what makes you feel this way about it? And I assumed you tested this?

And is this how your own firewall is done?

Firewall 2000 was mentioned as being a ceramic sandwich of aluminum on the cold side and ss on the hot side. They list it only up to 1000F. Has nobody sent you a piece for testing?

There are several products at McMaster under ?ceramic insulation? that go to or above 2000F. Have any of these these been tested?

Thanks,
Dan

Here are the 3 McMaster products I found: The 1/8" or 1/4" thick extreme-temp ceramic sheeting and 1/4" ultra-high temp ceramic sheeting on Page 3492, plus the 1/4" thick flexible silica insulation on 3493.

I too was looking at those ceramic sheets available from McMasterCarr, specifically the 1/8 inch millboard good to 2300F. that with a thin piece of stainless sheet to cover it on the engine side of the firewall should dramatically reduce radiated heat into the cockpit and possible cut some noise too without adding any smoke risk to the inside of the cockpit.

Bevan

Bevan:

I looked at what I think you're referring to with the millboard:

1/8" 55" x 55" 9390K12 $78.89

Is that the one? And why would you choose it over the other, flexible ones? I'm just going by a few numbers, but comparing it to a 3'x3' section of the 'flexible silica insulation' at the top of the page, it costs a bit more, and weighs twice as much (even though it's half as thick).

The lightest one rated 2000F or higher is Extreme-Temperature Sheeting, second from the top on p3492. It's 6-9 lbs/cu ft and is available in 1/8". The heat transfer ratings aren't exactly clear to me. They list Btu/hr. x in/sq ft. Seems the heat transfer would be different for the different thicknesses of each material. Seems sometimes it is, and sometimes it's listed the same for all the thicknesses.

Cheers,
Dan

PS: Is Abbotsford anywhere near Sumas?

Firewall

Dan

did you finally settle on the .125 fiberfrax and stainless. If so what stainless 304 or 309. Also, would the system have better sound reduction qualities if in addition to mechanically fastening the blanket you also glued the fiberfrax to the ss foil and to the firewall. I know what ever glue is used will fail almost immediately between the ss foil and fiberfrax and make fumes but it does not matter at that point because the fumes are on the engine side and the blanket will continue to be held in place by the mechanical fasteners. I don't know if gluing will have a negative effect on the insulation and or heat transfer properties of the fiberfrax. Also, why did you choose the fiberfrax over the high temp products from McMaster-Carr (Extreme-Temperature Sheeting) and finally what glue do you think would work best for gluing the ss foil to the fiberfrax and fiberfrax to firewall. I also ordered the KoolMat material but I tested mineral spirits on it and it melted right away, that was a deal breaker for me, no durability. I looked at the Fire Blanket 2000 but it does not look particularly attractive or durable and curiously it?s only rated to 1000f even though it?s a ceramic fiber. Keep up the great work you input is much appreciated.

Louis P

Messydeer said:

Earlier you mentioned, “A 0.125" layer of fiberfrax with a 0.003" stainless foil cover sheet will do a good job. A 0.25" layer plus foil will (obviously) insulate twice as well.” But then it looked like the Fiberfrax failed both in front of and behind the firewall. Can I draw from this that the SS foil cover is what makes you feel this way about it? And I assumed you tested this?

Click to expand...

Earlier I also mentioned "No detailed testing of that specific combination".

General concepts;
(1) An engine-side firewall insulator is superior to a cockpit-side insulator.
(2) Any ceramic under a steel cover sheet should work well.

Exactly which materials and combinations are optimum will be your decision, so test carefully.

After I got home last night, I shot a video of the Thermozite in action. It was pretty dark, so the video is grainy but you get the idea.

Phil

Dan,

I'm leaning towards the rigid millboard because I think it will be better for what I want to achieve: Thin, hard sheet, good temp range.

I haven't decided yet if I will use any additonal material on the firewall yet or not. But I'm pretty sure I have abandoned the notion of cockpit side insulation.

Yes, Abbotsford is just north of Sumas.

Bevan

I am confused, why are you trying to insulate the firewall?

http://www.vansaircraft.com/pdf/tunnel_temp.pdf

..... and the aluminum structure behind the stainless firewall will melt too from the radiated heat. It's pretty easy make the aluminum puddle behind a stainless firewall.

The firewall does a great job of keeping the flames away, but a lousy job of protecting the other side from the radiated heat. And that heat is enough to melt wires, aluminum fuel and brake lines, and toes...

Thanks, Dan and Bevan

I looked a bit more at the specs of what I feel might be good candidates for the firewall insulation from McMaster. They were all flexible and made from silica (or alumina silica) ceramic and, as far as I could tell, have no glues, fillers, or anything that could burn or out-gas. Here's what I came up with:

Extreme-Temperature*Sheeting, 93285K18 0.125" thick; 2300F; K factor 0.71; density 6 to 9; $32.60 1/4" available, but only in 25' lengths

Ultra-High*Temperature*Sheeting, 93315K51 0.25" thick; 2000F; K factor 0.77; density 6; $23.11; 1/2" thickness tested well by Dan on cabin side

Flexible Silica Insulation 93435K16; 0.25" thick; 2000F; K factor 0.78; density 10; $42.66; $14.22/ft, 3' wide

Just from the specs, it looks like the extreme temp one might work the best IF 1/8" will be enough. If so, then it would weigh less than half as much as the others. If it passes too much heat at that thickness, maybe two sheets could be doubled.

If it doesn't work then the ultra high temp might work at 1/4". Dan tested it at 1/2" thickness on the inside of the firewall in separate thread. Decent results, but I'd rather not have the 1/2" thickness.

The flexible silica insulation looks to be heavier and more expensive than the first two.

So Dan: are you still in the testing business? If I decide to insulate the firewall, I may buy one or two of these materials. I could setup the testing myself, but if I mailed samples to you, that might work better.

And Bevan: I was joking (or trying to) when I asked where Abbotsford was. I got my 2nd hand compressor there. It's only a 30 minute drive from my house in Bellingham.

Cheers,
Dan

PS: I also asked McMaster about getting samples for flame testing. They said, "We do not provide samples or give out information on our manufacturers. You can order this material and if it doesn?t suit your application you can return it to us."

I too am interested in a test (performed by Dan) because then the same rig and methods are used to compare results to the previous tests.

I would like to see 1/8 ceramic millboard with a stainless steel cover sheet sparingly pop riveted to the front side of the firewall.

I was considering ordering two 8X10 sheets of stainless from Vans as the price is very reasonable along with some alum angle and rivet up a sample firewall. They stock this for filling the center firewall. Then send the mini firewall to Dan for his thermal havoc.

The problem for me is shipping two ways across the Can border. Maybe we can get together in Bellingham and join forces.

Bevan

Sorry guys, my own firewall is a done deal and I dismantled the burn rig a few weeks ago. It is very easy to duplicate; just a steel frame and a propane weed burner. Go for it.

Dan:

I could prolly buy a cheap weed burner at the farmers' coop. I don't have an IR thermometer, but maybe it wouldn't be super critical to have one. I'd place my hand close to the cold side of the test plate. And I think I read earlier that copper melts at 2000F and go from there.

For successful tests, they'd be run the full 15 minutes? Let me know if there are any other pointers I'll need. And thanks again for your efforts in this area.

Bevan:

I'd love to work with you on this. I think I can get your email address from VAF, so I'll email you directly.

Cheers,
Dan

Hi Dan,
Aircraft Extras is advertising Contego Fire Protection for firewalls. Did you do any testing or know anything about the pros/cons of using this product?
Best regards,
Steve Dickinson

Contego: post #37, this thread. Easy to do better.

Wow, I'm amazed I missed this thread. Very informative...thanks for taking the time to experiment, Dan. I only wish I would've known to apply some type of fire barrier 2 years ago! As much as I'd like to go with some type of fire proof matting, it seems like it would be a lot of work compared to rolling on the Contego product.

From my first reaction, I would almost feel bad for using Contego when there are more effective ways to protect the firewall...BUT, as it stands now, I have absolutely nothing on my firewall. Well, maybe a very light mist of exhaust fumes!

My question is, how many RV's out there have firewall protection at all? Obviously, there isn't a need for it, but it makes a lot of sense if you value your skin and you're smart enough to plan ahead for a fire. With that in mind, the solution only needs to be good enough to work once, and be durable enough to not fall apart for the life of the airplane. Compared to no protection at all, Contego seems like a huge step in the right direction...even if it's inferior to some of the fireproof sheeting, at least it will be easy to apply.

I have the Koolmat on my firewall and was semi surprised at your results...I used it mainly to isolate the heater boxes, which I replaced with the stainless steel ones from the firewall to help eliminate the dreaded hot tunnel on the RV-10, which BTW I don't have I believe because of this material seperating the box from the firewall.

My thoughts are that (Koolmat) it would buy some time to allow you to shut off the fuel supply and eliminate the fuel portion of the triangle, except maybe a cracked something that allowed for an oil fire. The tests are really informative but I can't wonder if they may be a bit skewed by using that nice perfect torch produced flame against the test patch. No way am I debunking you Dan..your stuff is always spot on...I just wondered how the materials would perform inside a cowl with turbulent or disrupted airflow.

What I want is a method to clear the windscreen of oil in the event af a catastrophic engine failure..I don't want to bonk a guy on the head walking on the beach cause I can't see him through the windscreen

1/2" McMaster ultra high temp RCF on inside

I?m thinking of insulating the inside of my firewall with 2 layers of the 1/4" thick ultra high temp sheeting 93315k51 at McMaster.com. It could go on the outside, but I?d rather not add another ?? to everything hanging off the firewall. It would make for an easier installation on the inside and I wouldn?t have to worry about a wrench poking a hole in it. And Dan already tested this ?? thick blanket with an aluminum cover already. The only difference I?d make would be using 0.002? SS foil, which would be a third lighter than the 010 aluminum used in the test.

Page 3715 in the McMaster catalog shows different types of SS foil. I could get full hard temper 304 (Rockwell C40). It?s a fair amount harder than the much softer (B92) annealed 321. Since it?s on the inside, it would never see temps close to lower 304 max temp. Rivets placed about every foot.

I?d put a single ?? blanket on the front part of the cabin floor and place a piece of 025 aluminum on top of this. The blanket could be a continuous piece from the firewall.

I also started looking at sealants for the firewall. Take a look at the repair putty for SS and the gasket sealing adhesive on page 3377. They're both good to 2000F. They might not bond to the aluminum or might get shaken loose after a bit. Seems like it would make for a much smaller crack for silicone to seal up.

Lemme know what you guys think.

Thanks,
Dan

Stainless foil offers no advantage over aluminum foil when used on the cabin side.

RCF needs to be fully encapsulated if used inside the cabin, as the MSDS says it is a cancer risk. Seal it in an aluminum foil envelope with folded edges, attach with rivets, no adhesive please.

BTW, the 0.010" aluminum sheet seen in the RCF test was merely a handy reflector. Foil will do the same thing.

lostpilot28 said:

As much as I'd like to go with some type of fire proof matting, it seems like it would be a lot of work compared to rolling on the Contego product.

Click to expand...

Don't forget the Contego test sample was carefully prepared; without good adhesion Contego will be a waste of time for sure. You're unlikely to get good results by simply rolling it on a populated and dirty firewall.

I think (but cannot prove) the real problem with Contego would be keeping the insulating char on the firewall under dynamic conditions. The char is very fragile. I think moving air and vibration will strip it, and then you would have no protection. The stripping would be worst near the cooling outlet, which is exactly where the fire would concentrate.

Great stuff for a static application, like painting a divider wall between a garage workshop and a house.

My question is, how many RV's out there have firewall protection at all? Obviously, there isn't a need for it, but it makes a lot of sense if you value your skin and you're smart enough to plan ahead for a fire.

Click to expand...

A rational examination of the statistics says the "no need" argument has merit; the chance of engine compartment fire is probably lower than many other routine risks. A plain bare stainless firewall with good penetrations isn't unreasonable.

The problem begins with a desire to insulate against ordinary operating heat and noise. Some common builder choices have turned out to be horrible. Primum non nocere.

Very few.

lostpilot28 said:

My question is, how many RV's out there have firewall protection at all?

Click to expand...

Most have the basic blanket type radiant heat and sound proofing but I have never seen any with true firewall protection. I am sure a few out there have something.

My solution to this problem is pretty simple, and only gets mentioned occasionaly in this and other related threads. Turn the Fuel Off! Sure, there are other things that can fuel the fire, like oil, but all of the accidents I have read about where fuel fed. Perhaps someone can point us to something different.

Amen, Amen,

First sign of a fire, turn off the fuel!!!! Oil burns like crazy if hot and atomized but bet most engine fires are not oil fueled in the beginning.

Turn off what is most likely the source!

JonJay said:

My solution to this problem is pretty simple, and only gets mentioned occasionaly in this and other related threads. Turn the Fuel Off! Sure, there are other things that can fuel the fire, like oil, but all of the accidents I have read about where fuel fed. Perhaps someone can point us to something different.

Click to expand...

JonJay said:

My solution to this problem is pretty simple, and only gets mentioned occasionaly in this and other related threads. Turn the Fuel Off!

Click to expand...

Turning off the fuel tap is certainly #1 on the fire checklist, but there's a perspective gained with burn tests I think most have missed.

Some cabin insulation samples burst into flame very quickly after lighting the burner on the opposite side of the firewall stainless (for example, Thermozite, which apparently Flightline still sells, lit up with vigor in 15 seconds). Others boiled out large volumes of black smoke well before reaching ignition. Turn off the heat and many others wouldn't stop burning until the firewall stainless had time to cool.

Ok, you spring a leak in a fuel line and it starts burning. The clock is running. Ask yourself a question.....when will you know you have a fire?

Is it when you smell smoke? Even if you turn off the fuel tap right then, immediately, without a moments hesitation, the engine compartment fire won't immediately extinguish.....and the bad insulation choice is already near ignition.

DanH said:

Ok, you spring a leak in a fuel line and it starts burning. The clock is running. Ask yourself a question.....when will you know you have a fire?

Is it when you smell smoke? Even if you turn off the fuel tap right then, immediately, without a moments hesitation, the engine compartment fire won't immediately extinguish.....and the bad insulation choice is already near ignition.

Click to expand...

I still have thoughts of the fiberglass cowl & windscreen, if it actually does get to the point of ignition temps through the firewall. I do believe there would be signs of smoke through the cowl/firewall hinge line, that would be a resonable indicator of problems.

L.Adamson --- RV6A

DanH said:

Even if you turn off the fuel tap right then, immediately, without a moments hesitation, the engine compartment fire won't immediately extinguish.....and the bad insulation choice is already near ignition.

Click to expand...

... and it's safe to say that your first reaction isn't to shut off the fuel and shut down the engine.

Most likely it will be:
1) Recognition 5-15 seconds?

2) Determine where it is and source of fuel? 5-10 seconds?

3) Evaluate the immediate risks. Low, slow, and over the forest? Might need to keep power for a few more seconds to get setup for a field. High and in cruise? 5-10 second?

4) Evaluate the corrective action? Master off, Fuel off, etc? 5-10 seconds?

Then at that point, you're draining the lines and I don't know how long that's going to take.

I've caught one spam can on fire already and fortunately extinguished it before we got off the ground. When all the sensations of sound, smell, and sight hit you at the same moment; it's confusing and not as simple as a flip of the master switch or twist of the fuel valve. By the time you understand what's going on and determine the course of action, you're already several seconds into the event.

Phil said:

... and it's safe to say that your first reaction isn't to shut off the fuel and shut down the engine.

Most likely it will be:
1) Recognition 5-15 seconds?

2) Determine where it is and source of fuel? 5-10 seconds?

3) Evaluate the immediate risks. Low, slow, and over the forest? Might need to keep power for a few more seconds to get setup for a field. High and in cruise? 5-10 second?

4) Evaluate the corrective action? Master off, Fuel off, etc? 5-10 seconds?

Then at that point, you're draining the lines and I don't know how like that's going to take.

I've caught one spam can on fire already and fortunately extinguished it before we got off the ground. When all the sensations of sound, smell, and sight hit you at the same moment; it's confusing and not as simple as a flip of the master switch or twist of the fuel valve. By the time you understand what's going on and determine the course of action, you're already several seconds into the event.

Click to expand...

Phil, I really like your analysis here! I might offer some additional food for thought in the manner in which we might be able to all evaluate this type of situation in a way that will help prepare us to react in a successful way when faced with such a dire situation.

We all want to think we are the smartest, strongest, prettiest of all (ok, so that last one we may not all think about.). We think we are 110% sure of our behavior and our ability to maintain total control of our situation at all times. This is a built in mechanism of our psyche (we know it as our EGO). This mechanism serves an extremely valuable purpose but in the wrong situations it becomes a detriment.

In the event of such a fire we do not want our EGO directing our thoughts because our EGO will always be attempting to convince our conscious brain that we have everything under control without having to worry ourselves about anything like a checklist, other people's ideas, any outside mechanisms that would be directing us toward a resolution to the problem, or for that matter, any internal mechanisms that may be directing us toward a resolution. EGO would be always trying to take control of our thoughts and would not necessarily direct us to a safe conclusion. In fact, as far as our EGO is concerned, death or serious injury really doesn't matter near as much as does the notion that we appear smart, strong, pretty, etc. As long as we look good when we die that is all that is import to EGO.

It is important to all of us Type A personalities to recognize situations when we have to wrestle control of our thoughts away from EGO and rationally evaluate the situation in order to safely resolve it. Emergencies are no place for EGO to take control. If we can be honest with ourselves in these situations and accept that we are human and therefore fallible, we can analyze this type of situation as you describe and realize for ourselves we need to be able to address this type of situation in a rational manner before it happens. Doing so will allow us to build our planes in a safe manner. It will also allow us to prepare ourselves to recognize and appropriately react to such an emergency in a logical practical manner.

I think your analysis is a very good realistic evaluation of how long it may take our illogical EGO directed brain to recognize that we do not have control of the situation. If we also can recognize this as an issue we may be able to more adequately shave some of your estimated times off of this analysis and be better prepared to face these type of dire emergencies. The quicker we are at shutting down our EGO's in such a situation, the faster we will be at reacting to the cues you have described.

Ya'll read this report carefully.

http://www.ntsb.gov/_layouts/ntsb.aviation/brief2.aspx?ev_id=20001211X11589&ntsbno=LAX99LA063&akey=1

.....As the airplane turned wings level onto final, thick black smoke that smelled like burning fiberglass or plastic filled the cockpit. After the airplane came to rest, he observed flames around the pilot and felt high heat.

Foils and Wrapping

Stainless foil offers no advantage over aluminum foil when used on the cabin side.

Click to expand...

I was thinking SS because I thought it would have a better weight to strength ratio than Al, but I'd misremembered their relative densities. At McMaster, they have soft Al foil from 0.0007" on up, and full hard temper 0.001 thru 0.003". Which one would you suggest?

RCF needs to be fully encapsulated if used inside the cabin, as the MSDS says it is a cancer risk. Seal it in an aluminum foil envelope with folded edges, attach with rivets, no adhesive please.

Click to expand...

I place the blanket on the inside of the firewall, then Al foil covering it completely. Seems like it would then have an envelope of SS on one side (the firewall) and Al on the other?

Thanks,
Dan

fire materials

..just have to comment briefly.

If you MUST glue your materials to the firewall, typical spray adhesive melts in seconds, then burns! with smoke etc.
Latex based contact cement showed no appreciable reaction in my test burn plates, slight loss of adhesion, but it held a life-size panel vertically without failing.
Mechanical is best of course.
my $.02

I think Dan's test are an awesome demonstration of the RELATIVE merits of the various types of insulating materials and methods available but I wouldn't leap to any assumptions that the times and heat demonstrated are representative of an actual engine compartment fire. Does a blowing propane torch represent an AVGAS fire inflight under a cowl? The tests were all with a focused and intense heat source blowing under pressure to a very small area. What happens when the flame front is spread out over a larger area with air blowing all around? What temp does an AVGAS fueled fire actually burn during inflight conditions? I've read as low as 600 degrees to as high as 1800 deg. Doesn't a propane torch blow into at least the mid 2500 deg range (I dunno for sure)? You can hold a propane lighter in your hand lit with your thumb only a 1/4" away and it doesn't burn you. If Dan turned the blow torch more tangentially to the test samples I'd guess you'd see better results from all the insulators. His test was truly worst possible case but I'm not sure how likely. Not trying to poo poo his tests, as I said they provide great relativistic data and I'm very appreciated of his efforts (Thanks!). Ultimately space shuttle heat tiles would be the best but unless a test is conducted which duplicates the environment it isn't really fair to rule out some of the types that didn't do as well as others as being ineffective. As always it is a choice of better vs. good enough.

Responding to the previous post listing all the response times...in my experience response times will be far quicker than what you've listed, although it can seem to be an eternity. Time compression phenomena is real and it saves your life!

My approach is three fold:

1. Good build and maintenance practices to avoid the fire.

2. Fire detector and fire suppression system to stop the fire.

3. Parachute (high altitude) and a .45 cal (low altitude) in case #1 and #2 fail

Reynolds Wrap

HD Reynolds Wrap from the grocery store works fine

Click to expand...

From what I can tell this Reynolds Wrap is 0.0045, which is untempered. Going over the hardness and yield strength numbers shows an increase of 2-3x for the full tempered over the annealed. This could mean that 0.003 or even 0.002 tempered would work. Of course, it's $30 plus shipping compared to $5 at the super market for the softer stuff.

Cheers,
Dan

RV8R999 said:

3. Parachute (high altitude) and a .45 cal (low altitude) in case #1 and #2 fail

Click to expand...

I love #3!!

You're right. Time does compress. It did for me because everything went from normal speed to super slow motion.

Even then though, the confusion and amount of time that went by was pretty significant.

For me, my first action was to yank the mixture and get the airplane stopped. It took a while to sort through the confusion and finally get to the fuel valve.

It was all slow motion and it stayed slow until I got the door open and got away. Then it started to go back to real time.

It's not the same experience as an emergency procedure rehearsal; and I practice EP's a lot in my head and in practice. The real-time situation was a completely different ball game.

Phil

RV8R999 said:

..... but I wouldn't leap to any assumptions that the times and heat demonstrated are representative of an actual engine compartment fire.

Click to expand...

The test standards come from the FAA. Read them, please.

3. Parachute (high altitude) and a .45 cal (low altitude) in case #1 and #2 fail

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Let's hope you don't have your children on board.

I agree completely

DanH said:

Turning off the fuel tap is certainly #1 on the fire checklist, but there's a perspective gained with burn tests I think most have missed.

Some cabin insulation samples burst into flame very quickly after lighting the burner on the opposite side of the firewall stainless (for example, Thermozite, which apparently Flightline still sells, lit up with vigor in 15 seconds). Others boiled out large volumes of black smoke well before reaching ignition. Turn off the heat and many others wouldn't stop burning until the firewall stainless had time to cool.

Ok, you spring a leak in a fuel line and it starts burning. The clock is running. Ask yourself a question.....when will you know you have a fire?

Is it when you smell smoke? Even if you turn off the fuel tap right then, immediately, without a moments hesitation, the engine compartment fire won't immediately extinguish.....and the bad insulation choice is already near ignition.

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the choice of materials is not obvious at all as your tests show. So many items labeled suitable for aircraft that just dont measure up.

Experience with Firewall Insulation

Hi All,

After reading this post, I decided to proceed with insulating my firewall. My engine is easily detached at this point and I don't see how I could have done this very well with the engine on. I bought fiberfrax from ACS and .003 stainless shim stock from McMaster.

I used two layers of 1/8 fiberfrax. This material is very easy to work with. Soft, stretchy easy to cut. Not so the SS foil. You can cut it pretty easily with a pair of scissors but inside cuts and holes are much more challenging. I found that a dremel with a stone is good for making little adjustments. A nippler works pretty well, too. You can polish up the edges with scotchbright.

I was not happy with the pillowing from the clecos I used before riveting. Overkill is my middle name so I ended up getting SS standoffs from Mcmaster and putting them under the screws and rivets. The final result is a surface that is just about as smooth as the original firewall. I rationalize that the insulation comes from the distance you keep the heated surface from the cockpit. I'm not sure the pillowing would really make any difference, but it is esthetically pleasing.

I plan to seal around all the edges with 3M firebarrier as the last step. Anyway, it was a few weekends work but came out pretty nice. Thanks, Dan, for the original research and recomendation.

Regards,

Michael Wynn
RV 8 Finishing
San Ramon, CA

I plan to seal it all with firew

Engine mount considerations

To those of you who insulated your firewalls with Fiberfrax...

Did you leave the fiberfrax intact (sandwiched) between the engine mount and firewall, or did you cut holes in the insulation to allow the engine mount to contact the firewall directly?

I'd definetly cut around the mount to firewall locations and not sandwich

mlwynn said:

Hi All,

After reading this post, I decided to proceed with insulating my firewall. My engine is easily detached at this point and I don't see how I could have done this very well with the engine on. I bought fiberfrax from ACS and .003 stainless shim stock from McMaster.

I used two layers of 1/8 fiberfrax. This material is very easy to work with. Soft, stretchy easy to cut. Not so the SS foil. You can cut it pretty easily with a pair of scissors but inside cuts and holes are much more challenging. I found that a dremel with a stone is good for making little adjustments. A nippler works pretty well, too. You can polish up the edges with scotchbright.

I was not happy with the pillowing from the clecos I used before riveting. Overkill is my middle name so I ended up getting SS standoffs from Mcmaster and putting them under the screws and rivets. The final result is a surface that is just about as smooth as the original firewall. I rationalize that the insulation comes from the distance you keep the heated surface from the cockpit. I'm not sure the pillowing would really make any difference, but it is esthetically pleasing.

I plan to seal around all the edges with 3M firebarrier as the last step. Anyway, it was a few weekends work but came out pretty nice. Thanks, Dan, for the original research and recomendation.

Regards,

Michael Wynn
RV 8 Finishing
San Ramon, CA

I plan to seal it all with firew

Click to expand...

Michael, was there any concern with putting standoffs under the battery tray that it may compromise the integrity of the mounting? I am concerned if I put in standoffs that the tray will not be secured as well as if it where bolted directly to the firewall.

-- Matt