Toxic gas detection in process safety management provides personnel protection by minimizing the probability of toxic gases reaching hazardous levels. Criteria are developed to establish toxic gas levels to initiate alarms, initiate increase in ventilation rates and to initiate shutdown of processes generating the toxic gas that has breached containment. This Guide provides techniques for the use of toxic gas sensors and controllers to monitor and control sources of toxic gas release into the atmosphere within designated spaces in industrial locations.
1.1 This document provides guidance on the use of toxic gas detection as a method of personnel protection as discussed within the following:
• Title 29 Code of Federal Regulations Part 1910.1000 Sub Part Z Toxic and Hazardous Substances (OSHA).
1910.1000 (a) An employee's exposure to any substance listed in Tables Z-1, Z-2, or Z-3 of this section shall be limited in accordance with the requirements of the following paragraphs of this section
To achieve compliance with paragraphs (a) through (d) of this section, administrative or engineering controls must first be determined and implemented whenever feasible. When such controls are not feasible to achieve full compliance, protective equipment or any other protective measures shall be used to keep the exposure of employees to air contaminants within the limits prescribed in this section. Any equipment and/or technical measures used for this purpose must be approved for each particular use by a competent industrial hygienist or other technically qualified person. Whenever respirators are used, their use shall comply with 1910.134.
NOTE 1 Refer to Title 29 CFR Part 1910.1000 to full guidance provided in the document.
NOTE 2 The tables in sub part Z which apply to toxic gas limits are Table Z-1 Limits for Air Contaminants and Table Z-2 TWA's and Ceiling Concentrations.
1.2 This document provides guidance on the use of fixed, portable and transportable toxic gas detection equipment for protection of personnel in industrial locations.
NOTE Applicable toxic gas detection equipment performance standards include ANSI/ISA-92.00.01 and ISA-92.00.04.
1.3 This document provides guidance on the use of toxic gas detection as a supplement in adequately ventilated spaces.
1.4 For the purpose of this document, equipment includes
portable equipment; and
1.5 This document is not intended to cover the following:
a) Equipment intended only for the detection of combustible gases (refer to ANSI/ISA-12.13.01)
b) Equipment of laboratory or scientific type intended only for analysis or measurement purposes
c) Equipment intended for mining applications
d) Equipment intended for applications in explosives processing and manufacturing
e) Equipment intended only for process control applications.