This standard contains the basic requirements for the construction and testing of toxic gas and oxygen depletion gas detection instruments. Instruments used to detect flammable (explosive) concentration of toxic gas(es) when the LEL exceeds the TLV are excluded.

For apparatus used for sensing the presence of multiple gases that are both toxic and combustible, this document applies only to the portion sensing the presence of toxic gas or vapor.

This standard does not address gas monitoring or monitoring apparatus of the laboratory or scientific type used for analysis or measurement, apparatus used for process control and process monitoring purposes, or apparatus used for residential purposes.