How much carbon monoxide is too much?

[carusoam]

Seth,

Siri re-spelled your CO to CO_2. 

Best regards,

-a-

 

[Hondo]

http://www.tc.faa.gov/its/worldpac/techrpt/ar0949.pdf 

See page 1

 

[Hank]

The summary of that reports aligns well with what Dan has put in his CO thread. Put the detector on the panel, set the alarm for 35 ppm. That's what the device he set up a discount for is preset to alarm. FAA limit is 50 ppm, don't recall the OSHA 8 hour limit.

[M016576]

I clipped mine to the passenger side leather handle on the forward frame.  It's high (roughly head level), and is somewhat in the line of sight(I can read it when I'm looking right).

one thing I've noticed is that if the cabin vents are all closed during start / takeoff, I get 10-12 during climb and 1-4ppm reading in cruise, but if you open some eyeball vents that drops off to 0 pretty quickly (even in the climb).  It seems like the eyeball vents are pretty effective at venting the cabin.  

[Hank]

I've only made one flight with mine, but I was a little busy before sunset. On my desk at work, it read 1-3 ppm all day long; in my truck going to the airport, it read as high as 5 ppm for the first couple minutes then dropped to 0 regardless of vent / heat / window position. 

In cruise, I saw 1-2 ppm whether in the main very the flow below the quadrant, the eyeball vent in the footwell, a d cabin heat position. Will try to get everything give start, taxi and climb readings next time.

[JohnB]

18 hours ago, Hondo said:

http://www.tc.faa.gov/its/worldpac/techrpt/ar0949.pdf 

See page 1

 

Great summary Hondo. Since this comes up all of the time, as soon as we buy low level detectors (which we all need) and this is good data.. here it is abstracted from your article you linked:

 

Table 1. Symptoms Resulting From CO Exposure [2]

ppm CO         Time                                          Exposure or Symptoms

• 50                8 hr        Maximum exposure allowed by the Occupational Safety and Health Administration over an 8-hour period [4]
• 200            2-3 hr       Mild headache, nausea, fatigue
• 400            1-2 hr       Serious headache, life threatening after 3 hr
• 800           45 min       Dizziness, nausea, unconscious within 2 hr, death within 2-3 hr
• 1,600         20 min       Headache, dizziness, nausea, death within 1 hr
• 3,200       5-10 min       Headache, dizziness, nausea, death within 1 hr
• 6,400         1-2 min       Headache, dizziness, nausea, death within 25-30 min
• 12,800          1-3min       Death

The reason for our low level detectors is to detect a leak hopefully when its small, higher than usual (we will get < 50ppm transiently on certain operations like long taxis, takeoffs with vents closed etc) but usually minimal while flying, I have some personal CO minimums I use, Granted, mine might be a bit conservative as I know what CO can do to your judgement which is not included in the table above. Most of the times, opening cabin vents takes care of the CO in the cockpit to get it less than 50ppm,  but if CO remains at these numbers below after opening your vents, here's what I would do with the readings:

1. lower than 50ppm, open vents. if during typical phase of flight (taxi, takeoff, or operation with all vents closed) just keep an eye on it for a trend, perhaps have your mechanic check for leak next maintenance session. (My mechanic found a worn exhaust clamp when I squawked this right after I bought my detector which was reading around 30-40ppm which I got replaced before it became a problem)
2. 50-100ppm, open vents, if now reduced to less than 50, continue flight, definitely have mechanic check for leak when I get back
3. 100-200ppm, open vents, slow to window opening speed and open window, land at nearest airport within an hour with a likely mechanic available.
4. Over 200ppm, open vents, open window, put on nasal cannula , or better mask oxygen if you have it, and turn up oxygen all the way, land at nearest airport unless the above measures reduce it less than 200ppm, then landing as per #3
5. Over 1,000ppm, do all of the above,  declare emergency, put on high flow oxygen non re-breather mask (with the bag beneath it),  land now. Setup rapid autopilot descent and guidance to nearest airport or flat area if airport not nearby in case you pass out. Consider engine shutdown if you can glide to a landing area safely.

Remember, the pulse oximeters won't help you determine how impaired or poisoned you are and will read normal to high (98%+) no matter how much CO you have in your blood.

 We can all make our own limits, so by no way are these applicable to everyone, and you may want to consider making your own, as these are in no way official by any standards, but just happen to be mine.  I don't believe we have any emergency procedure guidelines in our operating manuals for this (which there probably should be), but just like a checklist, I know in advance what Im going to do if I see CO in my cabin on my low level detector (which I think we should all have when flying!)

 

JB

[JohnB]

On 3/13/2017 at 5:34 AM, nels said:

what is the cost of these detectors? Sounds like a good thing to have. I put a color change detector on my dash that is good for a year but honestly don't look at it too often.

$80-$200 for the portable low level detectors. The color changing dots are absolutely useless to a pilot, as one of the very early things to go away if you have CO poisoning is your sense of color discrimination. So even if you were lucky enough to be staring at your dot when enough CO to change the cards color was in your cockpit, you would have absolutely no idea what color the card was,

IMO, the color changing dots are ONLY useful to NTSB investigators as if it were a different color on a crash, this would determine that CO poisoning was likely the probable cause of the accident.

Edited March 27, 2017 by JohnB