Exhausting out of the roof of a building

[pcbye]

Greetings:

Is it reaonable to exhaust out of the roof of a building rather out the side as I have generally seen.

I have all of the parts I need to do either, although I am thinking straight up through the ceiling of the room and through the roof would possibly be the easiest / best.

I have 15.0JC3CR. The OEM 24" Stainless Accordian that screws into the manifold. The 6-1/2" Can Muffler and various Tee's (moisture trap), Elbo's, and pipe.

The original set up was horizontal out of a buiding with a Tee and a Drop Leg as a moisture trap just after the muffler.

I was thinking I could put in a standard 4" B-Vent through the ceiling of the room, through the Attic Space and out through the roof using a standard gas vent weather boot, and then run the 1-1/2" black pipe exhaust all the way through the center of that and out of the top with a tractor style flapper valve on top of the 1-1/2".

If condensation were a worry, I could come strait out of the genset with the flex and muffler, then into a 90 and into a tee with a drip leg and then straight up through the B-Vent to roof.

Any suggestions are welcome.

Best regards;

Peter

[Gunny]

Roof leaks would be my concern. You are going to have to use a thimble or other means to insulate the pipe as it passes through the roof, A most excellent spot for the roof to leak. If I have a choice, it will always be a wall penetration rather than the roof.

Just my opinion. Your mileage may vary.

[Jim Rankin]

I would be thinking of running it inside wood stove chimney for safety. Engine exhaust can get a lot hotter than gas appliance vent.

there's a LOT of moisture in the exhaust so plenty of place to get it out is a good idea, as is a regular program of draining it all.

[kevink1955]

I have an EM30 on natural gas that is vented up about 30 feet, the condensation is so bad that the drip leg has to have a 3/16" hole in the cap to allow it to run more than 30 min in the winter. Without the hole it fills the drip leg and runs back to the muffler. The hole in the cap drips into a bucket and the CO spews into the generator room. Good thing there is good air movement from the radiator cooling fan or we would be dead.

Side wall vent it if you can.

[pcbye]

Greetings:

You've made up my mind. Thinking about it, I have a 90% 50k Btu furnace in the Garage PVC side vented and an 80% furnace in the house power draft side vented. Both make a ton of water in the winter when cold.

The garage unit has about a 15' run through the building before it exits and it makes a nice stalagmite on the ground and I am sure a lot more goes down the drain.

The house unit is standby on duel fuel and on Genset. It too frosts up the side of the house and shrubs real nice. I suspect running the Genset stack up through a cold attic area through the roof will make for a lot of water that wants to come back down into the muffler or drip leg -- then of course freeze.

The engineering to run it out the side is possibly even less work anyway. Only about a 5' horizontal run and I have an 8' ceiling to fit the rest of the parts above the Genset.

Any suggestions on clearances to walls and ceilings. Both are unfinished right now. I am planning on at least 6" of fiberglass in the walls and ceilings and then I am open to sheathing materials for the walls and ceiling around the Genset. The room is 5' wide and 16' long.

I was thinking either the New fiberglass faced sheet rock 1/2" or 5/8", or fiber cement siding board -- possibly on top of sheet rock. Both are Class A fire rated. Then insulate / shield the muffler and the horizontal run and put it through a B-Rated or a rather large ventilated thimble of some sort???

Any suggestions on minimum clearances. All the codes I dig up say 9" to combustables which seems a little close to just about anything other than Space Shuttle Tiles in my book. Those pipes get darn hot.

BTW: I have a Vacuflow, so there will be a ton of air moving through the room -- 1600 CFM or better. The output of that thing puts a good leaf blower to shame

Regards;

Peter