scope:

This standard sets performance requirements for switches used as safety devices in combustion, process, and ventilation control systems. They are intended to operate electrical switching devices in order to prevent unsafe startup, initiate a safety shutdown, or initiate an alarm under abnormal conditions.

The requirements of this standard shall be used to measure and describe the performance of these switches in response to input signals, changes in ambient temperature, and hydrostatic pressure. Dielectric strength and durability are also assessed.

Purpose

This standard states testing and certification requirements for flow and pressure safety switches. These switches include, but are not limited to, those used as airflow interlock, pressure limit, or pressure supervisory devices for combustion air, fuel gas, fuel oil, and ventilation air.

Testing and certification criteria may include, but are not limited to, performance requirements, marking requirements, examination of manufacturing facility(ies), audit of quality assurance procedures, and a surveillance program.