1. Scope 1.1 This Standard covers the details of construction, performance, and test for portable and stationary electrical instruments for sensing the presence of combustible gas or vapour concentrations in air, parts of which may be installed or us ed in Class I hazardous locations and gaseous mines in accordance with the Rules of the Canadian Electrical Codes, Parts I and V. 1.2 This Standard applies to instruments energized from power sources rated at 750 V or less, ac or dc, and to battery operated instruments having a battery of a nonrechargeable (primary) type or a rechargeable (secondary) type of the portable, mobile, or stationary type. 1.3 This Standard covers combustible gas detection instruments intended to provide an indication, alarm, or other output function, the purpose of which is to minimize or prevent the possibility of explosion hazards. 1.4 This Standard does not cover gas detection instruments of the laboratory or scientific type used only for analysis or measurement, instruments intended by the manufacturer to prevent hazards due to toxic effects only, or instruments used solely for process control purposes. 1.5 This Standard does not cover the central monitoring, data acquisition, or other similar systems to which the gas detection instrument may be connected. 1.6 For instruments intended to detect the presence of combustible gases as well as other gases, the requirements of Clauses 4, 5 and 6 of this Standard shall apply only to the combustible gas detection features of such instruments. Note: This Clause refers to such instruments as combination oxygen-combustibles instruments, or oxygen-carbon monoxide- combustible instruments.