Toxic Gas Monitoring

A continuous gas detection system must be provided to detect the presence of hazardous (toxic or highly toxic) gases at or below the permissible exposure limit (PEL) orthe ceiling limit (see UFC 8003.3.1.6). The detection system must initiate a local audible and visual alarm as well as transmit a signal to a constantly attended plant Emergency Control Station (ECS). Activation of the alarm/monitoring system must automatically close the shutoff valve on highly toxic or toxic gas supply lines. 

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Toxic gas monitors are required to alert workers before the gas reaches a harmful concentration. 

Many toxic gas monitors can calculate the average exposure over time. 

Routine chemical exposures to operators of both diffusion furnaces and ion implanters are low— typically less that the detection limit of NIOSH sampling procedures. Chemical concerns with the process center on the possibility of toxic gas releases (see Ch. 11, Toxic Gas Monitoring ) and exposures to residues during maintenance activities. 

Most industrial hygiene air monitors in the semiconductor industry are used for flammable and toxic gas leak detection (see Ch. 11, Toxic Gas Monitoring). However, some facilities are also using continuous monitoring systems to ... 

Within the semiconductor industry a variety of continuous gas monitors are used (see Sec. 2.5 and Ch. 11, Toxic Gas Monitoring, for additional information). Historically, thesemonitors were primarily used to determine if a toxic gas leak had occurred, rather than actual measurements of breathing zone concentration of chemicals. Sample points for the monitors were located in exhausted enclosures as well as in potential release points in the clean room. 

Today, numerous alarm and monitoring systems are required by codes. These include fire alarm, smoke detection, sprinkler system supervision, emergency (spill) alarm, and continuous toxic gas monitoring and detection systems. 

Thus, a combination of single point and multi-point gas detectors integrated into a central toxic gas monitoring system might be required to effectively and efficiently protect a facility and its occupants. 

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