Air Quality Monitoring
Warning
- Deployment of a monitor/detector is essential for the safe operation of any equipment
that has the potential to produce CO. CO sensors/detectors became available on the mass market
around 1978. The main differences between the technologies involved are battery or electric and
Semiconductor or Biomimetic types. Detectors for carbon monoxide (CO) are manufactured and
marketed for use in either the home or occupational industrial settings. The detectors for home
use are devices that will sound an alarm before CO concentrations in the home become
hazardous. There is an Underwriters Laboratories, Inc., performance standard (UL 2034) for
residential CO detectors. Detectors currently available on the market are battery-powered, plug-in,
or hardwired. Some models incorporate a visual display of the parts per million (ppm)
concentration of CO present in the home. For more information on CO detectors for home use, call
the Consumer Product Safety Commission:
Commission Hotline at 1-800-638-2772
CO detectors for use in residential settings are not designed for use in workplace settings.
Monitoring requirements in an occupational setting are different from monitoring requirements in
the home. In the workplace, it is frequently necessary to monitor a worker's exposure to carbon
monoxide over an entire work shift and determine the time-weighted average (TWA) concentration
of the exposure. It may also be necessary to have carbon monoxide monitors with alarm
capabilities in the workplace. The direct reading instruments are frequently equipped with audio
and/or visual alarms and may be used for area and/or personal exposure monitoring. Some have
microprocessors and memory for storing CO concentration readings taken during the day. It is
significant to note that some of the devices mentioned for workplace CO monitoring are not
capable of monitoring TWAs, and not all are equipped with alarms. The appropriate monitor must
be chosen on an application-by-application basis. For more information on the availability of
workplace CO monitors or their application, call the National Institute for Occupational Safety and
Health at 1-800-35-NIOSH (1-800-356-4674).
Room Size and Time Estimations for Parts Per Million (PPM) CO
The fundamental factors in area CO levels involve:
The concentration and volume of CO production;
The size of the area;
The amount of air exchange if any;
The amount of time CO is produced;
Multiplying length, width, and height will determine the volume or cubic feet in a room. So an
empty building 100ft by 100ft with a 10ft ceiling would be 100,000 cubic ft. in size. Any material
that is in the room and takes space would reduce the cubic feet.
* Air exchange is defined as the exhausting of internal air to the external atmosphere.
The Graph above depicts the relationships of air exchange to time and CO ppm with
cubic feet area and percent CO emissions remaining constant.
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