Page 25 - CNG ESP Participant Guide2024
P. 25
Module 2: High-Pressure CNG Fuel System Components
Pressure Relief
Devices (PRDs) and
Vent Lines
PRDs Vent Lines
▪ PRDs protect cylinder from rupture during fire
o Each cylinder must have at least one PRD
▪ Vent caps required
Fuel System ▪ Isolate shigh-pressure fuel during a fuel line break
Isolation Solenoid ▪ Opens when the engine is in its startup sequence
Valve
Fuel System ▪ Allows first responders to shut off gas to engine in an
Isolation Manual emergency
Valve ▪ Also known as manual or quarter turn shutoff
▪ Used to isolate the cylinder or cylinders from the remainder
of the high-pressure fuel system for maintenance and repair
of downstream components
▪ If valve is too stiff to turn by hand, it should be replaced
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