I am building a neat garage for a client... He wants me to figure out a reasonable way to run tailpipe gases out of the building.... Anyone know of a good system?

I will probably have 5 stations and one exaust motor blowing the fumes out the top of the roof... I have a 10" hole already in the roof and was thinking of placing a big blower up there and runing 4" pipes to all the stations.. The client wants me to use PVC... I was wondering if it would take the heat and stand up to time...

Anyone ever made an exaust system?

pvc melts at like 300 degrees?

Your not intending to actually connect to the tail pipes right:confused: This is just for start up and idling prior to exit the garage?? I would think that just a good attic vent in the roof and exterior vents (like for venting under the house on a raised foundation) located in the walls behind where the cars would be parked would work.....Not sure about the PVC??.

On Edit: is this a home or professional structure.

This is a "Play" Garage.... Wish I had the money to "Play" like he does :)

This is a space of 3000 sq feet inside a large office/warehouse space and has 20 foot tall ceilings.... I will try to take some pictures for you guys....

He is going to work on his personal motorcycles, vet, old cars and tractors... He will store cars there and wants to be able to leave them in place and start them up once in a while... So I need 5 or 6 stations in the system....

They make special hoses to slip over the exaust pipe that will take the heat of that.. I was planing on those for the first 10 feet or so.... He wants to use pvc after that and I was worried about the heat and fumes attacking the PVC .... I would like to use metal for the system but he is now fighting costs,,,, We are up to about 70,000.00 on the remodel so far...

Well I would say that the Garage still needs to be vented so that you have an adquate fresh air supply. I'm not sure how the PVC would hold up to the heat although as you said the first several feet would be special hose. Furnaces now days have PVC vents w/ powered blowers. How are you planning on having the blower start - constant or ?? I'm thinking that if you had a restricted tee at the end of the hose (prior to the PVC) so that you were drawing in both the exhaust gas and some lower temp fresh air that you would greatly reduce temps in the pipe. Are the other vents going to be pluged unless in use. I'm sorry I havn't done anything like your suggesting and am just speculating along with you. Here in Calif temp isn't really an issue and the garages are open. Maybe in the colder climates like Eric Merchant in Michigan (dmaxalitech)could tell you what he does in his professional garage.....Bill

Does your client actually need 5 Bays or could he use a longer "hose" that would be able to connect to more then one vehicle or somthing like a central vac system where the hose pluged into an outlet at the various bays. I believe those systems turn on by a switch when you plug in the hose and I suppose they could also be vented to draw in fresh air (reducing pipe temps) as well as the exhaust......just some thoughts

My Dad's shop had little holes in the door that you could put an exhaust tube (the slip-over heat resistant kind) through. The holes had plugs for when they weren't in use. Seemed to work pretty well.

As for PVC heat tolerance, it is generally considered to have a 170 degree upper limit. I know the melt temp is higher, but it will dramatically soften and start to lose its strength as you go over 150 even. If you get much over 225-250, it will begin to off-gas as it decomposes. It is nasty chlorine compounds that you just don't want to breathe. CPVC has a little higher heat tolerance, but even then I wouldn't trust it much above 200.

Another design consideration for any tubing you use is you have to be prepared to deal with the condensate that will form in the pipe. Particularly if you use metal pipe you have to have a way to drain the condensate or it will rust through in no time at all.

Metal stovepipe isn't that expensive. They use it in inexpensive dust collection systems because it dissipates static pretty well (unlike pvc).

Just put it together with some furnace cement to seal the joints and you should be good.

If you want to use PVC, which is possible, I think, only if you're drawing a lot of ambient air through it in addition to the hot gases. Get a 2-3HP centrifugal blower (metal housing and impeller) and pull a lot of cfm....an el-cheapo woodworking dust collector (minus the filter bag) vented outside might work.

At a local dealer they have a fresh air intake and exhaust ducting in the ceiling which is expelled thru the roof. The Tailpipes get connected to a flexible tubehanging from the rafters which is connected to the exhaust ducting. They also have a safety sensor that auto opens all the bay doors if carbonmonoxide levels get too high. I am a builder and thats how my shop will be vented shortly. Contact your local construction officer he can guide as to the proper venting.:cool2:

This http://www.fumeavent.com/ is where we bought the new firehouse system from.
Considering what can happen, sometimes it's worth paying a little extra for something you know will work.