UL Standard for Safety Installation@ Operation@ and Maintenance of Toxic Gas-Detection Instruments (First Edition; Reprint with revisions through and including October 13@ 2017)
This standard gives guidance on@ and recommended practice for@ the selection@ installation@ use and maintenance of electrically operated equipment intended for use in industrial and commercial safety applications for the detection and measurement of toxic gases complying with the requirements of ANSI/ISA-92.00.01 and ISA-92.00.04. This standard is a compilation of practical knowledge to assist the user@ and applies to equipment@ instruments and systems that indicate the presence of a toxic mixture of gas or vapor with air by using an electrical signal from a gas sensor to produce a meter reading@ to activate a visual or audible pre-set alarm or other device@ or any combination of these. Such equipment may be used as a means of reducing the risk whenever there is the possibility of a risk to life or health specifically due to the accumulation of a toxic gas-air mixture@ by providing such warnings. It may also be used to initiate specific safety precautions (e.g. plant shutdown@ evacuation@ ventilation). This can be applied to all new permanent installations and@ where reasonably practicable@ to existing permanent installations. It is also applicable to temporary installations@ whether new or existing. Similarly it is applicable to the safe use of portable or transportable equipment@ irrespective of the age or complexity of such equipment. Since much modern equipment of this type also includes other types of gas detection@ some additional guidance is given for these topics. NOTE Equipment intended for use in hazardous (classified) areas should be Listed or Labeled for use within the intended area. For fixed equipment@ installation should be in accordance with the National Electrical Code@ ANSI/NFPA 70. For the purposes of this standard@ except where specifically stated otherwise@ toxic gases shall include toxic vapors. For the purposes of this standard@ equipment includes a) fixed equipment; b) transportable equipment@ and c) portable equipment. This standard is not intended to cover@ but may provide useful information@ for the following: a) equipment of laboratory or scientific type intended only for analysis or measurement purposes; b) equipment intended for underground mining applications (group I equipment); c) equipment intended only for process control applications; d) equipment intended for applications in explosives processing and manufacture; e) equipment intended for the detection of a potentially toxic atmosphere resulting from dust or mist in air.