It is a well known and heavily publicized fact that carbon monoxide is a dangerous gas even at low exposure
levels. While measurement solutions for residential applications are fairly simple, industrial and commercial
applications require a much more sophisticated instrument. Problems with the accuracy of many measurement
devices arise due to zero instability and cross sensitivity to other gasses on the sensors especially in industrial
situations where temperature changes and the presence of other process gasses are an ongoing part of everyday
life.
Upper exposure limits for CO in the work place are normally set to provide alarms or warnings at 25-50ppm,
sensor inaccuracies often cause alarms to be triggered when in fact no actual carbon monoxide danger exists.

When higher levels of CO are present, proper safety procedure calls for the halt of production and the
evacuation of all personnel from the area until the levels can be verified, reduced and the source
identified. These precautions taken against this potentially deadly gas show responsibility on the part of the
employer and can save the lives of many who work to make the company profitable. The resulting down time can
however have many detrimental effects including, employee stress, safety concerns from outside agencies, and
reduced production, it is therefore vitally important that we ensure that CO alarms are set off only by actual
increased levels of carbon monoxide. In an effort to reach this goal there are a number of considerations to be
looked at, the following information is provided for that purpose.

The most common types of detectors used for Carbon Monoxide measurements are,

1) NDIR or infra-red which although is very specific to the gas being measured requires a warm-up time, is fairly
large, can consume larger amounts of power making it unsuitable for small or portable instruments, and is more
expensive. For ranges of CO measurement in industrial uses other than Low ppm this technology is by far the
number one choice.

2) Solid State, while this technology is small and cost effective it is not selective enough for CO only
measurements and usually has higher temperature drift making the zero unstable.

3) and Electrochemical which is the primary choice for the majority of Carbon Monoxide analyzers on the market
today due to it