While guidelines may exist that mandate monitoring of an area for any number of toxic compounds, no official government recommendations are made as to the detailed design of such a monitoring system.
In practice, the design of a toxic gas area monitoring system results from a collaboration between the end-user, consultant (if any), monitoring system vendor, and sometimes the regulatory agency involved.
Saying that, a few fundamental design parameters can be mentioned here:
- The location and number of detection points must first and foremost consider the people working in the area, and where they will be located.
- In applications whereby leaks from equipment or upsets in a process could cause problems, points should be located near likely leak points, with ventilation characteristics taken into account.
- Alarm functionality should serve the dual purposes of warning the affected employees in the area, as well as shutting down the process causing the alarm situation.
- In certain cases, emergency ventilation might be utilized to drive the offending toxic out of the area. It is prudent in these cases to sample key intake registers—thus sampling the oldest or most stale air in the monitored area.