Diesel Truck Exhaust

[STYMIEDPIPER]

Need advise. Please point me in the right direction to locate data, chart, or reference material for ventilation requirements of idling diesel truck in a closed structure.
ASHRAE discusses bus terminals. I did not see anything regarding truck exhaust.
Thanks for any advise / input.
Have a great day

 

[Fabrico]

I've been around this stuff for decades and have yet to see anything formalized. Some shops use funnel shaped collectors with piping through the roof. Others use flexible moderate temperature flex hose routed through a wall or ceiling, or laid on the ground to somewhere outside. Some bus shops have large inlets and plumbing built into the floor, then up or out.

What ever is used to collect, the best setup includes going up and out. Otherwise the wind just blows it back into the shop. Some systems can work great without any fan or boost. If the bureaucracy gets involved, they will likely want fans added. I think McMaster Carr and NAPA still carry the flex hose.

 

[minstrel]

The fire service is very advanced in this area. Studies came out showing how bad exposure to diesel exhaust can be, even to firefighters who are only around trucks while pulling in and out of the station. A company called plymovent makes an effective system (Used in my fire dept.) which suctions out exhaust directly from the tail pipe. It uses flex hoses that are connected to a fan which expels the gas through the roof. The hoses pneumatically attach to the tail pipe, and disengage and shut off when the truck exits the bay.

For more info, check out

http://www.plymovent.com

There are other companies that make similar systems, I just know of this one first hand.

Hope that helps

 

[jbthiel]

A little off subject, but if the system uses a fan make the funnel shaped collectors ~1" larger than the exhaust pipes. This allows the system to mix fresh air with the exhaust so you don't need the ultra-high temp hose.

As for ventilation requirements, in the absence of formal requirements, it would depend on the location. Office workers will not tolerate nearly as much exhaust fumes than mechanics or people used to being around trucks.

If you want to size the system, an estimation for an assumed 800rpm idle speed would be:
number of vehicles x average engine displacement (cubic inches) x 0.227 = cubic feet per minute

 

[STYMIEDPIPER]

Thanks jbtheil.
This is a new truck loading bay within warehouse structure. Room for four (4) diesel trailer trucks. I do not know avg engine displacement. What is a good rule of thumb for design purposes for engine displacement??

 

[Fabrico]

Fans are definately a plus. Many shops with the fanless overhead funnel types have piping 3 to 4 times the size of the exhaust. These also add shop air to the exhaust and work fairly well.

A good rule of thumb would cover the largest engines. Unless it is a captured fleet, the largest engine size could be 855 cu in.

Specific systems are usually for repair facilities. Trucks loading and unloading should not be idling inside the building long enough to need that type of system. It takes time and work to align the intake to the exhaust. It is more common to have a skirted ceiling area with powered general ventilation.

 

[jbthiel]

One thing I forgot to include was an efficiency variable. I'm not sure what to use but I would go with 80-90% depending on the length of run, if it runs horizontal, rain hoods, etc.

And I agree with Fabrico, 855 is a pretty standard size Over-the-road truck engine. Also, the skirted area makes sense if you have a couple of feet over the top of the trucks. This eliminates the hole funnel/hose issue. Just drop a partion of some type to within ~1ft of the top of the trailers. The only issue with this might be heating, but this part of the warehouse will probably be the coldest anyway due to the opening of the garage doors. Consider adding auxillary infra-red heaters.