Briefly running engine in garage

[OutbackL130]

I was adjusting throttle linkage on a small 9hp engine while briefly running it inside my shop with the garage door down, but had my 10,000 CFM exhaust fans going. When I first started the engine there was a significant amount of smoke that filled the shop from burning oil in the cylinder, but the air cleared out within 20 seconds. The complete air exchange rate of my shop with the fans going is less than 30 seconds and the breeze generated is like being at a windy beach. Is it safe to operate an engine inside if exhaust fans are on?

I don't work on engines often but it got me wondering what are some ways mechanics stay safe from carbon monoxide when running an engine indoors while doing engine repairs? I know some mechanics clamp a hose to the exhaust to bring it outside. I read that having the garage door open is not enough as the carbon monoxide levels can still become dangerous in just a few minutes.

 

[Tollster]

I believe brief use is acceptable but not over a repetitive short course of time, but none the less should be prevented is you have alternatives. CO2 is an odorless gas that will build up over time in the body, so chronic intake can be just as deadly as an acute intake as your body cannot release the gas as fast as it builds up.
Same with exhaust leaks, long term expose can creep up on you and you may never know it, at least that what I was taught when I raced two stroke dirt bikes.

 

[OutbackL130]

I want to mention the engine was not idling, I just started it up and shut it off several times to check throttle adjustment.

It probably would be a good idea to buy a co meter just to be safe for next time I work on an engine or even for checking co levels inside vehicles due to possible exhaust leaks.

 

[Coyote machine]

I want to mention the engine was not idling, I just started it up and shut it off several times to check throttle adjustment.

It probably would be a good idea to buy a co meter just to be safe for next time I work on an engine or even for checking co levels inside vehicles due to possible exhaust leaks.

Odorless, tasteless, colorless DEADLY gas. There is NO acceptable level over repeated or single episodic exposure. I ran a foreign auto repair service for over ten years and had to get out of the business due to health issues, one of which was exposure to co and other chemicals. I still get severe headaches if exposed to any co fumes, even if outdoors in otherwise fresh air environment.
Forget the co meter of interior levels, just don't allow yourself to be exposed. It will kill you and you won't 'see' it coming.

 

[Coyote machine]

I believe brief use is acceptable but not over a repetitive short course of time, but none the less should be prevented is you have alternatives. CO2 is an odorless gas that will build up over time in the body, so chronic intake can be just as deadly as an acute intake as your body cannot release the gas as fast as it builds up.
Same with exhaust leaks, long term expose can creep up on you and you may never know it, at least that what I was taught when I raced two stroke dirt bikes.

BTW, it's NOT CO2, which is carbon dioxide, but CO which is the deadly gas, carbon monoxide, to which you refer.

 

[OutbackL130]

I'm surprised more people aren't hurt by co after looking at a chart on the cdc website of how quickly co builds up in a room even with ventilation such as open doors and blowers. There was one test result they did that showed co rises to harmful levels within 10 seconds of the engine being turned on. **** it takes me longer than that to back my riding mower out of the garage while maneuvering around everything in there.

Is it a bad idea to park the car or lawn mower in the garage unless they are pushed in and out without starting the engine?

 

[ericher69]

Odorless, tasteless, colorless DEADLY gas. There is NO acceptable level .Forget the co meter of interior levels, just don't allow yourself to be exposed. It will kill you and you won't 'see' it coming.

Gotta say this is Terrible advice.

It is law just recently in Ontario to have a CO monitor in the home if you have ANY fuel burning device.

I have one in my shop. Cheap insurance for $20

 

[Coyote machine]

I want to mention the engine was not idling, I just started it up and shut it off several times to check throttle adjustment.

It probably would be a good idea to buy a co meter just to be safe for next time I work on an engine or even for checking co levels inside vehicles due to possible exhaust leaks.

I'm NOT saying don't have a co detector. I am saying that knowing you're working around/in a co polluted environment is CRAZY AND relying on a meter to tell you it's at a harmful level is also nuts. Interior of the car monitored with a co meter is also a problem. Presence of co is DEADLY period. Drive the mower in, immediately shut off engine, push or roll it to where it needs to go.

Gotta say this is Terrible advice.

It is law just recently in Ontario to have a CO monitor in the home if you have ANY fuel burning device.

I have one in my shop. Cheap insurance for $20

Read above in red. This is what I'm saying, not what I didn't make clear enough earlier. Household co detectors register high levels of co. Exposure to lower levels or known to be emitting levels from an engine are way to risky to rely solely on a detector. I'm saying just don't expose oneself for any reason to however 'controlled' an amount one thinks one can 'tolerate.' It will kill you sooner than later. Don't risk exposure, fans or blowers or whatever aside; NOT worth the risk! Hope that's more clear.

 

[sixdogs]

Odorless, tasteless, colorless DEADLY gas. There is NO acceptable level over repeated or single episodic exposure.
...

...

It will kill you and you won't 'see' it coming.

Agreed. This will kill you while you think you are still safe.

 

[Coyote machine]

Agreed. This will kill you while you think you are still safe.

To further press the point about co detectors being largely ineffective, EXCEPT when high levels of co are present, my tenant next door is an assistant fire chief and recently went to a fire call where everyone inside was dead. There were co detectors, but the couple didn't have enough time to get out. And even if they could have escaped the co by very short overall time/exposure many die from smoke inhalation while trying to escape in residential episodes.
Co will render one unconscious, then dead. I had a co detector that was considered real sensitive mounted at the top of my cellar stairwell to alert to low levels of co from the oil fired boiler. I added hard wired co and smoke detectors and attic/garage/ boiler room heat detectors, that alarm on rate of rise in heat. They're all backed up by batteries and redundancy via my security system. co kills, period. Don't temp fate by exposure that can be avoided.

 

[BXinNH]

I'm going to respectfully agree and disagree on this topic. There is no question that CO is dangerous and even deadly in high enough concentrations, however, pushing tractors and mowers in or out of garages is a bit extreme in my opinion. There are a number of verified, established guidelines for what levels of CO are dangerous and what levels are not. Also, modern CO detectors are very accurate and quick to respond to the presence of CO in the home. I would recommend that every home be equipped with at least two detectors, one near the sleeping area(s) and one near the utility area(s) where CO is generated. Many building codes require this in new or significantly renovated homes. There is no truth to the rumors of false alarms from ordinary household products. If your detector goes off, it means there is very likely CO present and the correct course of action is to evacuate the building and call the Fire Department. To address the original question about running small engines in an enclosed area, I would recommend strongly against it. Don't forget when calculating air exchange rates using forced ventilation, in order to get 10,000cfm of air out, 10,000cfm needs to come in, very difficult with the doors closed. I guess my point is, as with most things, awareness and respect for the hazards of CO, proper safeguards and some "common" sense will keep you safe.

Matt.

 

[buickanddeere]

There are health studies that snow small engine shop employees to have the highest civilian levels of CO in their tissues and blood stream.
You can die of CO poisoning even if you are dragged out and given 100% oxygen. Blood hemoglobin has an affinity of 250times greater for CO than O2.
0.1 percent CO in air will drop a person dead in moments.

 

[Coyote machine]

I'm going to respectfully agree and disagree on this topic. There is no question that CO is dangerous and even deadly in high enough concentrations, however, pushing tractors and mowers in or out of garages is a bit extreme in my opinion. There are a number of verified, established guidelines for what levels of CO are dangerous and what levels are not. Also, modern CO detectors are very accurate and quick to respond to the presence of CO in the home. I would recommend that every home be equipped with at least two detectors, one near the sleeping area(s) and one near the utility area(s) where CO is generated. Many building codes require this in new or significantly renovated homes. There is no truth to the rumors of false alarms from ordinary household products. If your detector goes off, it means there is very likely CO present and the correct course of action is to evacuate the building and call the Fire Department. To address the original question about running small engines in an enclosed area, I would recommend strongly against it. Don't forget when calculating air exchange rates using forced ventilation, in order to get 10,000cfm of air out, 10,000cfm needs to come in, very difficult with the doors closed. I guess my point is, as with most things, awareness and respect for the hazards of CO, proper safeguards and some "common" sense will keep you safe.

Matt.

I can agree with most of what you stated except the part about 'rumors' of false alarms from ordinary household products. I have around 18 CO detectors throughout my house, barn and shed. I've had the alarms start and immediately stop; I've had persistent alarms at certain units and not others, and when swapped out with new units of the same brand, BRK, combo smoke/CO the problem resolves. These products have a shelf life and use life, even with changing batteries regularly, usually 5 years. The more sensitive standalone CO detectors have a much greater ability to sense minute amounts of CO for earlier detection in critical areas. With normal wired detectors/monitors the level has to be low enough to warn appropriately, but not so low that it's alarming below the threshold it's set to alarm at.

There are health studies that show small engine shop employees to have the highest civilian levels of CO in their tissues and blood stream.
You can die of CO poisoning even if you are dragged out and given 100% oxygen. Blood hemoglobin has an affinity of 250times greater for CO than O2.
0.1 percent CO in air will drop a person dead in moments.

Would have to agree with the dangers, and often IMO, foolishness/ignorance of those who work around persistently high levels of CO in the workplace.

 

[3930dave]

Along with the heavy winter weather in Can/USA, there has been a rise in CO deaths.

Obviously, the best move is to minimize and preferably eliminate all CO exposure. Low level exposure for extended periods is deceptively dangerous.

I'm only aware of two environments where the general public is deliberately exposed to IC engines running in enclosed spaces - underground parking garages, and indoor stadiums with Monster truck (etc) shows.

Both obviously require forced-air exchange - there has to be Code compliant systems in place, at least at the time of construction. I mention this, in terms of accessing specs on Minimum acceptable air-exchange levels - I'm not endorsing running IC engines indoors.

UG parking garages - the assumption there is that people are not in that area for long, so exposure Duration is short.

Despite being a life-long gear head, I have no real interest in attending a major indoor event like a Monster Truck show. While a stadium's air-handling systems may have at one time been adequate, for the risks involved I'll watch motorhead events outdoors.

Rgds, D.

 

[Gary Fowler]

I agree that internal combustion engines should not be ran in an enclosed space, but I am not going to push my car, truck, tractor or mower outside to start it or one reason that I cant physically do it and #2 aint going to try as there is simply no need.
The garage door will be opened, the vehicle cranked, immediately put in gear and backed out under idle conditions. There is one thing to be safe but another to be stupid about it. Everything coming out the exhaust is not CO. Most of it is CO2 and water vapor with a minute amount of CO that could be deadly if concentrations are allowed. 30 seconds to a minute of automobile exhaust in an open door is not likely to cause anyone, even the extremely sensitive to have any problems expecially since the exhaust is right by the open door.

Otherwise those with extreme fear of CO should park their cars in the open weather, wear self contained breathing apparatus at all times even when travelling just in case the exhaust system develops a leak during transit, oh and check the SCBA tank to make sure it was filled with superior clean air each time you get a refill.

Don't you just hate it when folks go to extremes in either direction when attempting to do work or play safely?

 

[buickanddeere]

I agree that internal combustion engines should not be ran in an enclosed space, but I am not going to push my car, truck, tractor or mower outside to start it or one reason that I cant physically do it and #2 aint going to try as there is simply no need.
The garage door will be opened, the vehicle cranked, immediately put in gear and backed out under idle conditions. There is one thing to be safe but another to be stupid about it. Everything coming out the exhaust is not CO. Most of it is CO2 and water vapor with a minute amount of CO that could be deadly if concentrations are allowed. 30 seconds to a minute of automobile exhaust in an open door is not likely to cause anyone, even the extremely sensitive to have any problems expecially since the exhaust is right by the open door.

Otherwise those with extreme fear of CO should park their cars in the open weather, wear self contained breathing apparatus at all times even when travelling just in case the exhaust system develops a leak during transit, oh and check the SCBA tank to make sure it was filled with superior clean air each time you get a refill.

Don't you just hate it when folks go to extremes in either direction when attempting to do work or play safely?

A modern properly operating highway vehicle is one thing. Puttering away in the shop on an old malfunctioning engine during a cold winter day with the doors or windows barley open is another.

 

[rekees4300]

Is it safe to operate an engine inside if exhaust fans are on?

Absolutely not!

"CO can rapidly accumulate (even in areas that appear to be well ventilated) and build up to dangerous or fatal concentrations within minutes."

CDC - Carbon Monoxide Hazards from Small Gasoline Powered Engines - NIOSH Workplace Safety and Health Topic

 

[Coyote machine]

I agree that internal combustion engines should not be ran in an enclosed space, but I am not going to push my car, truck, tractor or mower outside to start it or one reason that I cant physically do it and #2 aint going to try as there is simply no need. No one said you should push it outside to start it.
The garage door will be opened, the vehicle cranked, immediately put in gear and backed out under idle conditions. There is one thing to be safe but another to be stupid about it. Everything coming out the exhaust is not CO. Most of it is CO2 and water vapor with a minute amount of CO that could be deadly if concentrations are allowed. 30 seconds to a minute of automobile exhaust in an open door is not likely to cause anyone, even the extremely sensitive to have any problems expecially since the exhaust is right by the open door. Where are you getting these un-likely statistics?! It is known that CO accumulates in the bloodstream, so that statement is just not true.

Otherwise those with extreme fear of CO should park their cars in the open weather, wear self contained breathing apparatus at all times even when travelling just in case the exhaust system develops a leak during transit, oh and check the SCBA tank to make sure it was filled with superior clean air each time you get a refill.

Don't you just hate it when folks go to extremes in either direction when attempting to do work or play safely?

Who are you talking to an imaginary friend?!:confused2:

No one here is saying not to turn on an engine in a garage to back out whatever vehicle may be in it. What was stated in direct response to the OP's question was to run the mower into the garage and immediately turn it off and roll it the rest of the way through the maze of his stuff.
And your analogy is ridiculous; typical useless nonsense about breathing apparatus and other extreme measures no one but you is referring to. You're not helping to make people aware of the dangers of CO.
Within the last year here in VT at least one teenager died in his car, outside, as a result of a leaky exhaust system that had recently been installed. Had people been aware his headaches prior to his death were a result of CO poisoning, (recent exhaust system work,) he could have lived. He died as a result of ignorance about CO, unfortunately.
This is not a topic that is any way funny, people die, needlessly, due to ignorance about CO. No one should have to die because of it, if everyone were made aware how to prevent it and not succumb to it.

BTW, it's run, not ran.

 

[aginn]

There is caution and there is overkill. Seems to me the argument is where that line is. And I am not going to argue for either side. We use a flexible hose on the exhaust to vent it outside and high airflow inside. Beyond that I have no control unless I want to go look for a new job at 60 years old. Too late for this old goat.

 

[OutbackL130]

I appreciate the replies so far. Primarily I was prompted to discuss this topic after being shocked by these research results from the cdc displaying just how quickly co builds up in an area even with "adequate" ventilation such as open garage doors.


CDC - NIOSH Publications and Products - Preventing Carbon Monoxide Poisoning from Small Gasoline-Powered Engines and Tools (96-118)
5hp engine operating in a roughly 12' x 24' building with 8' walls. NOTE: doors were open, cooling fan and ventilation running.

Sure, its common sense to not idle an engine inside a closed garage but that report is talking about having the doors open! To me the results seem extreme given how common garages are and the millions of people who use them everyday. I guess it goes to show how co is not something to mess around with and indeed blurs the line between common sense and an easily avoidable tragic accident.

I totally agree there is caution and overkill. Obviously people aren't going to start pushing their vehicles in and out of their garages. I was curious to learn what precautionary practical measures professional mechanics take when working on a vehicle. My buddy is an ASE Cert mechanic and next time I talk to him I'm going to ask about the precautions they are trained to take. When they have a vehicle up on a car lift and have to listen to the engine, I can guarantee they don't lower it down and drive it outside to let it idle.

Like I said before I'm just surprised how easily exposed people can be to high levels of co without even realizing it. It would be possible to infer from the CDC research that "common sense" is not enough when it comes to staying safe in these situations.



_________________________________________________________________

Contradicting info on the CDC if someone would explain further...


CDC - Carbon Monoxide Poisoning - Frequently Asked Questions

How can I avoid CO poisoning from my vehicle?


- Have a mechanic check the exhaust system of my car every year. A small leak in your car's exhaust system can lead to a build up of CO inside the car.

-Never run a car or truck in the garage with the garage door shut. CO can build up quickly while your car or truck is running in a closed garage. Never run your car or truck inside a garage that is attached to a house and always open the door to any garage to let in fresh air when running a car or truck inside the garage. This information is contradictive of their test results and general advice. I thought you are to never operate/idle an engine inside a building even with the doors open???

- If you drive a vehicle with a tailgate, when you open the tailgate, you also need to open vents or windows to make sure air is moving through your car. If only the tailgate is open CO from the exhaust will be pulled into the car. Just wanted to note I would bet this tip is not common sense to most people. This is a good point that I had often thought about when driving my K5 blazer with its rear glass rolled down.