A solenoid valve (a combination control solenoid and three-way air valve) is necessary with a remote, electrical, hand switch or shutdown system.
A de-energize-to-trip or fail-safe solenoid valve is recommended. To prevent spurious trips, back up the power source with an uninterruptible power supply (UPS) (see Section 1300 of the Electrical Manual for more information on UPS) and fireproof the control conduit; or locate the solenoid valve outside the fire zone.
Figure 1300-14 shows how to install dual solenoid valves to reduce even further the possibility of a spurious trip in a de-energize-to-trip system for a critical fuel gas EBV. Both solenoid valves must trip to close the fuel gas valve.
An energize-to-trip solenoid valve, however, must be connected to a power source backed up by a UPS. The conduit must be fireproofed inside the fire zone.
Increase the reliability of an energize-to-trip system by installing dual solenoid valves and routing the conduits separately. Energizing either solenoid valve would actuate the EBV to its safe position.
With a pneumatic pilot valve, take care to ensure that it is not in the fire zone and is suited to the environment.