Fire Resistant Insulation for Wheel Wells, Engine and Generator Compartments

[sparkplug188]

I posted this question on another bulletin board several days ago, but did not get any responses.

What are you using to insulate your wheel wells, engine and generator compartments?  Mineral wool seems like it may be a good candidate, but not exactly what I am looking for.  Mineral wool is fire resistant to 800F-1200F however, it needs to be protected from water spray by some sort of aluminum or steel sheathing.  I am looking for a type of insulation that can be installed without needing to be sheathed.  The Eagle originally had plastic pans that the insulation rested in.  The drains on the pans got plugged and filled up with water-- talk about fire resistant! 

Has anybody tried mineral wool board, like Roxul Rockboard 80?  It looks like it is exactly what I need. --no sheathing required, fire resistant, 2" is R8, will not absorb water spray, and is rigid enough to attach using screws and fender washers.

The next best insulation I have found is hoodliner insulation.  The good thing about hoodliner is it is designed and tested for this application-- it just works.  The obvious down side is cost at 2 to 5 times the cost of mineral wool board.  Also, the thickest hoodliner I could find is 0.75" thick and has an R value of 2.7.

So, let me know what you are using.  No replies makes me assume you guys either have stock water filled trays or no insulation at all. 

[chessie4905]

   hvac duct board

[Seangie]

I used fire pillows in the chase between my engine and middle of the bus. 

They work well in a pinch and are fire rated and insulate well.

Not cheap unless you buy in bulk or know someone.

-Sean

Fulltiming somewhere in the USA
1984 Eagle 10S
www.herdofturtles.org

[luvrbus]

Whats wrong with closed cell spray fire retardant foam in the pans

[sparkplug188]

I am glad you mentioned fire pillows.  During the demolition phase, I found 20lbs of caulk covered fiberglass insulation batts stuffed in the end of the chase by one of the previous owners.  Sure it worked, but there had to be something better.


luvrbus- Now I am sort of wishing I didn't scrap those algae filled pans.  They could have been cleaned up and filled with foam. It probably would have been the easiest and cheapest solution.  Hind slight is 20/20   

I have ordered a sample of Roxul Rockboard 80 to do some testing on.  Roxul claims it will repel water-- I have a feeling it will repel misting water spray, but will allow forced water spray though.  I will probably sheath the wheel wells to protect the insulation from forced water spray and road grime.