Generator Exhaust Stack
Generator Exhaust Stack
(OP)
What is the group's experience with the following? A generator (450W) diesel is being installed to back up a building on a college campus. The generator exhaust is being extended about 4 stories up to get above the building roof line. The exhaust pipe manufacturer is recommending a pressure relief valve, just in case of generator backfire. I've done a lot of generator projects, but don't usually see a pressure relief valve in the exhaust stack. This may be a scam to get another $3k out of the client.





RE: Generator Exhaust Stack
RE: Generator Exhaust Stack
Is sounds as if either the diameter is too small if a backfire builds that kind of pressure or they are making the pipe from gum-wrappers.
RE: Generator Exhaust Stack
RE: Generator Exhaust Stack
RE: Generator Exhaust Stack
RE: Generator Exhaust Stack
RE: Generator Exhaust Stack
RE: Generator Exhaust Stack
2. It's actually hard to make a tube that thin at that diameter.
3. Four stories of sch80 at 8" is fairly heavy. I'd be inclined more toward 316L stainless pipe, sch5S or sch10S.
Mike Halloran
Pembroke Pines, FL, USA
RE: Generator Exhaust Stack
RE: Generator Exhaust Stack
I thought a back fire spit into the intake manifold,
And an after fire made a big bang in the muffler or exhaust pipe. I also do not think you would need an 8" pipe for a 450 watt generator.
B.E.
RE: Generator Exhaust Stack
RE: Generator Exhaust Stack
RE: Generator Exhaust Stack
Mike Halloran
Pembroke Pines, FL, USA
RE: Generator Exhaust Stack
Diesels cannot really do that. Excess fuel under really heavy load just causes black smoke. The injector pump simply cannot run unless the engine is started. So what could possibly fill the whole exhaust system with flammable fuel and cause a diesel to backfire ??
The thin stainless pipe should be o/k after the muffler, and 304 is the material of choice for exhaust tube. It is used on piston aircraft engines, it has very good hot strength and resists cracking. Eight inches sounds reasonable too, as a compromise between noise and back pressure. But black pipe would be my choice from engine to muffler.
I would contact the manufacturer of the diesel engine, and ask one of their engineers for their recommendations. As you suggest, the pipe vendor may be a bit too keen.
RE: Generator Exhaust Stack
I have seen the same thing on a hard to start cold diesel.(system filled with raw vapour.)
The engine cranks without firing, filling the stack with white smoke/vapour, then when the engine does fire, the whole lot goes off with a whoomp, blowing a yellow flame a couple of feet out of the stack.
B.E.
RE: Generator Exhaust Stack
RE: Generator Exhaust Stack
RE: Generator Exhaust Stack
It is usually caused by another mechanical failure of some sort.
RE: Generator Exhaust Stack