DISTRIBUTION Below-Grade Valves


Responders must be very careful about shutting below-grade valves. While curb valves and main valves can appear very similar (Illustration), it is very important to understand that main valves are not the same as curb valves. Curb valves are used for gas control of single customers or occupancies; main valves are found in the street or major intersections and are used to control larger areas and to sectionalize the distribution system. Main valves are LDC valves and should not be operated by emergency responders. Utility compa- nies recommend that only trained personnel close any below- surface valves, so responders should contact the local gas utility to determine its recommen- dations.


STREET SMART TIP


use extreme caution when closing any valve below- grade; it may be a main valve. Any valve that is closed in an emergency should never be reopened by responders. Only trained utility personnel should turn the gas back on.


Main Valve FIGURE 3.26 Below-grade main and curb shutoff valves. Curb Valve


FIGURE 3.27 Below-grade curb shutoff valve.


Appliance Shutoffs


Inside the customer’s home or facility are gas-fed appliances. They are con- nected to the gas service by a flexible or rigid pipe. Each of the appliances has a shutoff which is usually an in-line valve. When the handle is in line with the pipe, the valve is open; when it is crosswise, the line is closed. If a leak


49


FIGURE 3.28 Customer service curb valves.

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