Generator Insulation

[Kristinsgrandpa]

Oh, and here is another one.

http://www.defender.com/product.jsp?path=-1|311|302333&id=95982

Ed.

[ArtGill]

David,

Visit some boat yards and you can get good advice from putting generators under the decks of boats.  You might get lucky and get some material.

Art

[Tom Y]

Sivrtnge2,  What type of material are you talking about?  The foil faced foam insulation? When you open the doors is it noticable, the noise?  Thanks Tom Y

[gus]

Google E.H.P., they have a lot of good stuff and advertise in Bus Conversions.

I'm on my second gen using their stuff.

[JackConrad]

Here is "our way". We lined the former AC condenser compartment with 1/2" high density foam, a layer of 1/2" plywood, a 2nd layer of 1/2" high density foam and then a layer of noise reduction "egg crate foam". We also ran our exhaust to near the back of the bus and remoted our radiator to the spare tire compartment with an electric fan. So now the noises of the radiator fan, generator, and exhaust are in separate areas. Depending on where you are standing outside the bus, you hear different noises, but not all at the same time.
I was told the "egg crate" foam absorbs more sound because the convolutions creat a greater surface are than a flat surface. Jack

[niles500]

DML hit on the target - The perfect type of "insulation" to use is dependent on the frequency you target for attenuation. There is more than one frequency band in a genset due to the size and type of mill, intake and exhaust design/needs, head type and operating RPM, and the drive used - HTH

[sivrtnge2]

Hey Tom,
Sorry it took so long to respond. The foam insulation can be bought at any Lowes or Home Depot store. It come in 4 x 8 sheets and is covered on both sides by what looks to be aluminum foil. I used this and just doubled it for thickness. I also used the aluminum tape to join my corners and seal all cracks. Once it is together, it is full of strength. As for as looks are concerned, you can spray the insulation with an industrial strength spray adhesive then cover it with automotive carpet, or upholstery material. It is a very quiet cost efficient way. I did not cover my box because it is enclosed in another compartment.
--
BILL

[NJT5047]

Hey David,
Someone may have already offered this bit, but unless you set the generator on some sort of sound isolator, no matter how much insulation you use around the unit, it'll still resonate. 
Another thing is that your gasoline generator will have much higher operating temps when compared to a diesel.   Be sure and use something that is not flammable.   May want to consider monitoring the genset compartment for heat.  Jack Conrad has temp sensor in his genset compartment....I believe? 
Be good to keep up with the compartment temps.    Also may wish to treat it like a boat...with positve blower ventilation.   A boat bilge blower would be cheap and clear any fumes before lighting up the genset.   
BTW, I lined my condensor compartment with  1" steampipe insulation made by Rubbetex (Sp?). Came from Grainger...will not burn...melts, but I fire tested the stuff with a torch.  Comes in 60" wide roll.   Made a huge difference. 
Best, JR   

[Bob Belter]

Ahoy, BusConverters,

Genset noise // sound //  "noisemaker" (per Fast Fred)

This works great on my -01 Eagle genset.  The genset is on airbags within the box, and the enclosure box is done as follows:

Outer layer is ½" Russian birch plywood.  Then, two layers of 30# roofing felt.  Then, one layer of roofers 2 #/ sqft lead.  Then two more layers of 30# roofers felt.  The inside is one more layer of ½" Russian birch plywood.  There are inlet and outlet air labyrinths lined with fiberglass and expansion metal.  The hot portals use silicon rubber sheet gaskets around the pipes.  These items are very ordinary, and low cost. 

Three mufflers --  two each of Kragen's cheapest 1 ½" in/out plus a glasspack return.  Pipe is out of the roof.  One thing as yet unanswered.  Will the mufflers soot-up and clog due to low temps?  Not so far in ~~200hrs.  If so, they are cheap, and fairly easy to change.

I had planned to put some more sound insulation inside the box, but it is already so quiet that if anyone else in the local is running their genset, I have to place a hand on my bus to know that mine is still running.

It really is not "silent" inside.  Vibration plus some sound, and I'm a "little" deaf. 

Others may think that it is terribly  loud, but I know that is far more quiet than my neighbors. 

Enjoy /s/ Bob

[JackConrad]

Jack Conrad has temp sensor in his genset compartment....I believe? 
Be good to keep up with the compartment temps.    Also may wish to treat it like a boat...with positve blower ventilation.   A boat bilge blower would be cheap and clear any fumes before lighting up the genset.

Yes, I have the RV Safety Sytems Alarm on our bus. One of the temperature sensors is installed in the generator compartment a couple inches below the compartment ceiling directly above the engine. The air intake is passive and enters the compartment near the floor at the generator head end of the compartment. The air exhaust is active using 3  (230 CFM each) 4" bilge blowers installed in the floor of the compartment.  4" aluminum flex duct was installed on the blowers and ran up the compartment wall to near the ceiling to remove the air from the top of the compartment (hot air rises).  The radiator is remoted to the spare tire compartment and the muffler is outside of the generator compartment. The only openings in the compartment are the grilled air intake which has several bbaffles and the 3 bilge blowers.  By monitoring air temperatures inside the the compartment and the outside air temperature, we have found that the compartment stays about 5-10 degrees hotter than the outside air temperature.  Jack

[tekebird]

at this years Annapolis Sailboat show there was a vendor that had some foam insulation.........thier demonstration was a generator enclose with a speaker inside  cranking out generator noise..........it was very loud open...louder than any rv generator I have heard without enclosure......and just a hum closed.

stuff was not especially expensive came in 4x8 sheets, sself adheasive, water and oil proof as well as fire retardant.

would be my choice........when in doubt look to the yachting industry.......it's older than the rv or conversion industry and    items are made for much more severe service.

by the way....they had 7-8kw generators the size of a 30 inch TV......less radiator of course.....seawater cooled.

[TomNPat]

Doug,

Great information.  Do you have a name for the vendor?

TomNPat

[tekebird]

I got a sample ...let me see if I can dig it up this weekend