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Carbon Monoxide Levels

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Moderator, Asst. Line Boy
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Gang,
Per your individual POHs, what sort of emergency/non-normal procedures do you follow based on specific CO levels? Something like:
- Above 35 ppm, I open air vents.
- Above 100 ppm, I find a place to land soon.
- Above 200 ppm, I declare an emergency and land ASAP.

I'm just pulling those numbers from my anal orifice, but hope you get the picture: I'm searching for similar guidelines from any of you who have already researched it.

I mounted a Sensorcon Industrial Pro sensor on my canopy rail right next to my left shoulder, so if the low or high alarm trips, I'll hear it. So far, the highest level I've seen is 9 ppm (ground run-up with a tailwind).
 
CO Levels

My understanding is that CO effects are cumulative and based on a combination of concentration levels (PPM) and exposure time. I understand that altitude may be a factor but I do not know the specifics.
From the manual for the the domestic and recreational vehicle CO detector that I purchased:

Alarm levels as defined by European Norm EN50291-2010*

Parts per Million (PPM) of CO and Time until Alarm sounds
50 60 – 90 minutes
100 10 – 40 minutes
300 Must alarm in less than 3 minutes

Parts per Million (PPM) Effects on Adults
100 Slight headache, nausea, fatigue (flu-like symptoms)
200 Dizziness and headache within 2 – 3 hours
400 Nausea, frontal headache, drowsiness, confusion and rapid heart rate.
Risk to life after over 3 hours of exposure
800 Severe headaches, convulsions, vital organ failures. Death possible within 2 – 3 hours
* EN50291-2010 is a European Standard for "Electrical apparatus for the detection of carbon monoxide in domestic premises - Part 1: Test
methods and performance requirements"


There's probably not going to be consensus on this discussion and hopefully some qualified people will chime in. In the meantime, I would probably want to get on the ground asap and investigate and resolve the cause for 50 PPM upwards. I've briefly recorded 20 PPM while taxiing but have only just started testing and measuring CO during one 1-hour flight.
 
Following this. My Sensorcon was showing 9 PPM in flight the other day when I turned on the cabin heat for the first time this season.
 
An excellent authoritative source of information is Chapter 8 of "Spacecraft maximum Allowable Concentrations for Selected Airborne Contaminants: Volume 5" published in 2008. The chapter is written by Noreen Khan-Mayberry, Ph.D. of NASA. It builds on Chapter 1 of the same title written by Wong in 1994.

You can also look at: https://www.nasa.gov/sites/default/files/atoms/files/jsc_20584_signed.pdf

1 hour limit is 425ppm, and 24 hour limit is 100ppm - in spacecraft (or submarines).

One study reports a reduction in vigilance performance in 80-120 minutes at 50ppm (Fodor/Winecke, 1972). Flying a plane probably qualifies for that. So that might be a good benchmark for being a pilot.

There is a cumulative effect of exposure as CO builds up with time. It binds to hemoglobin and interrupts normal O2 transport. The half-life of it is 4-6 hours depending on activity level when exposure is removed. So no matter how much CO exposure you have in 30 hours it is almost all gone.

LA rush hour CO levels are probably 20 ppm. If you smoke a pack a day you have a 6% or more CO concentration in the blood stream, similar to a perpetual 50ppm exposure.
 
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It's the $169 model purchased directly from Sensorcon. Might be cheaper elsewhere online.

One really nice thing about this model is that the unit's back contour fits perfectly inside the tip-up canopy side frame surface's curved contour. Add Velcro and it stays in place perfectly.
 
Unless you already run LOP then one of your posted remedies might be to run LOP. Much less or no CO if LOP.
 
There is a cumulative effect of exposure as CO builds up with time. It binds to hemoglobin and interrupts normal O2 transport. The half-life of it is 4-6 hours depending on activity level when exposure is removed. So no matter how much CO exposure you have in 30 hours it is almost all gone.

Yes, but the converse is also true...once it's bound to hemoglobin, no amount of fresh air or anything else is going to get rid of it other than time. So if you're seriously impacted by it, it's not going to go away the moment you land, or open a vent, or put on O2 or whatever else you do.
 
Response

Yes, but the converse is also true...once it's bound to hemoglobin, no amount of fresh air or anything else is going to get rid of it other than time. So if you're seriously impacted by it, it's not going to go away the moment you land, or open a vent, or put on O2 or whatever else you do.

True; in terms of response, on detection it would make sense to close any heater vents and open the fresh air vents to reduce the CO PPM, then land and try to identify and resolve the source of the CO.
 
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