What you need to be aware of when…

…zeroing your CO2 detector

Without wishing to sound accusing, where were you the last time you zeroed your CO2 detector?  In your vehicle?  In the office before you travelled to the location you were working in?

It might not have caused you problems so far, but the air around you can make a big difference to the performance of your CO2 detector.

What is zeroing?

Zeroing your detector means calibrating it so its ‘clean air’ gas level indication is correct.

When is zero not really zero?

Many CO2 detectors are programmed to zero at 0.04% CO2 rather than 0%, because 0.04% is the normal volume of CO2 in fresh air.  In this case, when you zero your detector, it automatically sets the baseline level to 0.04%.

What happens if you zero your CO2 monitor where you shouldn’t?

If you zero your detector where you shouldn’t, the actual CO2 concentration could be much higher than the standard 0.04% – up to ten times higher, in some cases.

The end result?  An inaccurate reading, and no true way of knowing how much CO2 you’re actually exposed to.

What are the dangers of CO2?

CO2 is already in the earth’s atmosphere, but it doesn’t take much for it to reach dangerous levels.

  • 1% toxicity can cause drowsiness with prolonged exposure
  • 2% toxicity is mildly narcotic and causes increased blood pleasure, pulse rate, and reduced hearing
  • 5% toxicity causes dizziness, confusion, difficulty in breathing, and panic attacks
  • 8% toxicity causes headaches, sweating and tremors. You’ll lose consciousness after five to ten minutes of exposure.

What can I do to make sure I’m safe?

Only zero your instruments if you really have to, and make sure you zero your detector in fresh air – away from buildings and CO2 emissions, and at arm’s length to make sure your own breath doesn’t affect the reading.

What if I think my zero reading is incorrect?

It’s best to test the instrument with 100% nitrogen to check the real zero point, and then with a known level of CO2 test gas. If the zero gas reading is incorrect, or any other gas reading for that matter, the detector will need a full service calibration – contact your local service provider for help.

If you have a Crowcon detector, you can use our Portables Pro software to correct its zero reading.  For further information, call Crowcon customer support on +44 (0)1235 557711.

Leave a Reply

Your email address will not be published. Required fields are marked *