Switch emergency shutoff

Escalators have emergency shutoff switches at each end. They have microswitches located at various points along and behind the side wall panels to stop the escalator if something gets caught between the steps and the sidewalls. 

Many vendors now sell gas cabinets equipped with self-closing and latching doors and windows, sprinkler heads and various types of purge assemblies (see Fig. 5). Cabinets should be provided with a minimum flow of 100 feet per minute through the louver on the cabinet bottom. When the window is opened, the face velocity through the window should be maintained at 100 fpm. Purge assembhes may contain many different types of safety devices. An emergency shutoff valve should be located as close to the cylinder as is practicable. An air operated remotely activated cylinder valve is more preferable. System shutoff may be by manual activation of a remote switch in the laboratory or fabrication area or caused by other system defaults interlocked to gas flow. System defaults may include ... 

Pumps, compressors, turbines, drivers, and auxiliary machinery should be designed to provide reliable, rugged performance. Pump selection and performance depend on the capacity required and tlie nature of Uie fluids involved. Remotely controlled power switches and shutoff valves are necessary to control fluid flow during an emergency. The inlets for air compressors should be strategically located to prevent the intake of hazardous materials. 

---