Final answer:
Fuel System Isolation Valves are crucial components in the fuel system of vehicles running on compressed natural gas (CNG). They help ensure safety by shutting off the fuel flow in emergencies or during maintenance. These valves are regulated by the NFPA 52 2019 standard.
Step-by-step explanation:
Fuel System Isolation Valves are a crucial component in the fuel system of vehicles that run on compressed natural gas (CNG). These valves are designed to shut off the flow of fuel to and from the CNG storage tanks in case of emergencies or maintenance operations. They help ensure the safety and reliability of the fuel system by preventing fuel leaks and minimizing the risk of ignition.
One example of a Fuel System Isolation Valve is the Manual Shut-off Valve. This valve can be manually operated to isolate the CNG storage tanks from the rest of the fuel system, allowing technicians to work on the system without any risk of accidental fuel release or combustion. Another example is the Emergency Shut-off Valve, which automatically shuts off the fuel flow when certain hazardous conditions are detected, like sudden pressure spikes or high temperatures.
These valves are governed by the National Fire Protection Agency (NFPA) guidelines, specifically the NFPA 52 2019 standard, which provides regulations and requirements for the design, installation, and maintenance of CNG fueling systems. The NFPA hazard diamond (shown in Figure 1.21) summarizes the major hazards associated with CNG and other chemical substances, helping users identify the potential dangers and take appropriate safety precautions.