In article . com,
wrote:
"The Underwriters Lab standard, which was recently revised upward,
requires CO alarms to signal well ahead of the onset of symptoms for
the "average" person. (That in itself may be a moving target, since
response to CO varies by individual.)
Specifically, UL requires an 85-decibel alarm signal to sound within
189 minutes if 70 parts per million CO is detected. If the level is 150
PPM, the alarm limit is 50 minutes and it's 15 minutes at 400 PPM.
The old requirement was 90 minutes for 100 PPM and 35 minutes for 200
PPM. "

70ppm is way, way too high for prolonged exposure in aircraft at
altitude. In cruise, you should see ZERO.

Personally, my subjective observation is that AC is sometimes right and
sometimes wrong with their conclusions. Often, they don't provide
enough information, or provide incomplete information, so it's difficult
to make an informed decision. I suggest that you look up some of Mike
Busch's old articles from AvWeb (back in the good old days) for some
additional analysis on the subject of CO detection.






JKG