truck exhaust near operators seat


Active Member
We have a k-boom crane mounted behind the cab, and the truck has an upright exhaust stack. The operators seat is the same height as where the fumes come out and, when the wind is in the right direction, the fumes cause the operator to get sleepy and, yesterday, led to a sore throat, an ear ache and other symptoms of carbon monoxide poisoning. We've tried redirecting the stack, but wind direction and speed can still direct the fumes directly at the operator. We are going to try using a hose, like what is used when mechanics work on a truck indoors, over the exhaust, but the hose is not that long so I'm not sure how well it will work.

How long can the hose be before it causes back pressure and impacts how the engine runs?

Any other thoughts on how to divert the fumes?

Tom Dunlap

Here from the beginning
Hi Mahk

An inline booster fan could be added to the hose too

Is it a vertical pipe? Make the smoke stack taller. Maybe with a swivel el at the top??


Active Member
Hey Tom!

The flexible hose that we tried (10 feet long) didn't move the fumes far enough away. After it was mounted it ended up about five feet off the ground, just a few feet from the passenger door. Wind still directed the fumes towards the operator. I'd like to get a 25 - 30 foot pipe and direct it on the ground out behind the crane. The 10 foot pipe isn't double the diameter, but I'll keep that in mind if we make it any longer.

Yes, its a vertical stack. A swivel won't help because the operator's seat is fixed and we always want it directed away from there, regardless of wind direction. Extending the height of the stack is a good idea, and maybe have it vent straight up rather than directed to one side.

We do have a remote, but 99% of the time the best vantage point by far is from the operator's seat.

And I should make a correction--drowsiness is a symptom of carbon monoxide poisoning, but the sore throat and ear ache are due to breathing the hot, noxious fumes for several hours.
Best thing to do is convert it to a grassburner, except then guys on the ground get it, and, well, you burn the grass. If stack is on opposite side, yes, make it as tall as practical and straight up (13'6 is legal but probly not practical. Could route all the way to the back of the truck underneath and then up unless dump body.


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Out with bad air, in with the good - Usually what we’ve done in situations like these is to try and provide fresh air to the operator’s station/ breathing zone - including sometimes air conditioning if the guy is in a hard sided little cab enclosed, or a little flex duct and a fan system maybe combined with a screen (even a little three sided “cab” or screen like a snow blower) so the worker’s breathing zone is a little more “enclosed” or separated from the general environment and the supplied fresh air goes into his breathing zone. Watch the velocity you supply the air at so you don’t excessively cool the face or upper body too. Further down the choice list perhaps are fresh air hoods/ helmet types of things that supply low pressure air over the front of the face from the top. When exhaust bugs the operator, he just plugs in the hose , dons the helmet and turns on the fan - there’s no face seal or anything, just air at reasonable volume and ambient pressure (you can even heat or cool this air but that’s getting fancy). With both these types of setups you always have to watch were you get the fresh air from - that it stays fresh - and that somebody doesn’t park idling equipment right beside the air pickup!

May seem like a weird reminder but . . . if the engine is diesel, the emissions might contain carbon monoxide, but more to the point they contain small particulates (carcinogens) and oxides of nitrogen (NOx), the latter which are very irritating to lungs if levels are high enough for a long enough time. Why this is important is that NOx (and SOx) are both pulmonary irritants known to be capable of causing pulmonary oedema (edema in the US) - fluid accumulation in the lungs. Someone can feel ill, go home and lay down and fall asleep and not wake up again due to fluid building up. I was part of a fatality investigation years ago where a summer student who was a non-declared asthmatic fell ill at work after working in an area where diesel exhaust (and other things) were present, he went home and his parents found him passed away that evening from pulmonary oedema. It happens. At the least, it could be like operating equipment while slightly impaired, again depending on pollutant levels, and tree work is the type of job where you want everybody sharp and wide awake (CO from smoking doesn’t help either). Hope that helps a bit. Stay safe ’n sound everybody.
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Run a hose long enough and don't loose any sleep. If you want to reduce the back pressure use as much smooth non corrugated metal tubing as you can and only use the flex sections for the bends and joints.
Keep in mind the exhaust pipe is sized to allow for maximum power when wide open in the upper rpm ranges, I assume (ex car mechanic, but I have never run a crane) your not running wide open while using the crane.
Remember when school buses had the engines in the front, lots of them had rear exhaust and they got along just fine.
Search around for a deverter valve that goes in the exhaust pipe ,they use them on the big triaxle dump trucks to direct the hot exhaust into the body so the load won't freeze to the sides of the truck body. Switch it so the exhaust blows out the side when operating the crane and up when driving down the road. Or something like that!
It's a fact of industrial ventilation that you can blow air/ exhaust many more duct diameters than you can suck so blowing out a pipe gets better dispersion . . . also in the case of diesel exhaust, you have heat to work in your favour, so my advice is for exhaust to remain in an upwards direction. Dilution is the solution to pollution. Where we've re-routed exhaust alongside truck trailer bodies etc., or to the rear, has caused a bunch of other problems for other workers on the ground. Just my two cents (used to do oilpatch industrial hygiene for many years). Up is more better! Sorry