Hazmat 5

Natural Gas

False, natural gas is lighter than air meaning that it will rise and diffuse rapidly when it escapes in an open space..

Natural gas is not toxic and tests show that concentrations of 25% mixed with air produces no ill effects. However, if natural gas displaces the air in an enclosed space, suffocation can occur because of the lack of oxygen.

Between 1100 to 1200 degrees F.

Gas escaping outside.
Gas burning outside.
Gas escaping inside.
Gas burning outside.

Communications Division (OUC)

False, the owner/occupant will need to hire a private contractor to conduct this service.

False, do not attempt to extinguish the fire as it is better handled by permitting the escaping gas to burn. Attempting to protect exposures or nearby combustibles with a hoseline is acceptable.

Above the left side of the gas meter, just above the meter bar. If the meter is equipped with lead connections instead of a meter bar, a stopcock is located in the service pipe just ahead of the lead pipe that is connected to the left or inlet side of the gas meter.

Closing the stopcock, usually located in the gas supply line, at the gas range, or other gas appliance located in the individual apartment unit only.

Only in case of an extreme serious condition such as fire involvement at the meter, entire building involvement in fire, etc.

By closing the stopcock located above the left side of the meter.

¼ Turn clockwise or counter clockwise the stopcock so that the operating lug is crosswise to the gas pipe.

Fire valves are found just outside the building wall of large buildings, such as hospitals, schools, and places of public assembly.

The fire valve has a raised operating stem inside a 2 ½ in. diameter pipe; which projects about 12” above grade. The 2 ½ in. diameter pipe is closed on top by a five sided threaded nut.

Remove the cap with a fire plug wrench by turning it counter clockwise. If it doesn’t move readily, tap around the edge of the cap while applying pressure in a counter clockwise direction. After removing the cap use a fire plug wrench to turn the operating head ¼ turn clockwise.

In a stopcock box set at ground level between the curb and the property line, in front of buildings and dwelling units where gas is supplied at high pressure on inside meter installations. It may also be located on some inside low pressure meter installations as well.

Remove the stopcock box cover and turn the valve ¼ turn either direction with a gas stopcock wrench (t-handle). The gas supply is turned off when the operating lug is crosswise to the pipe. Apply gradual pressure to the valve and avoid sudden, excessive force.

A few large buildings are equipped with gate valves, located in a valve box set at ground level between the curb and the property line in front of the building.

Remove the valve box top and turn the hang wheel or 2” square operating head clockwise until the valve resists further turning; 6-20 turns depending on the size of the valve. This type of shutoff is sometimes used in lieu of a fire valve with written approval of the D.C. Fire Marshal.

Transmission lines – 60 to 300 psi
Distribution lines – 1/5 to 60 psi
Low pressure lines – 1/5 to ¼ psi

By the absence of a service regulator.

3,000 psi, with emergency shutoffs located at different locations for each application.

Plastic piping

Keep the exposed plastic surface wet with a water spray or with dripping wet rags. A fine spray is best since it wets the plastic quickly and causes less chance of creating a muddy condition in the ground for gas co. workers.

Cast iron, Steel, Wrapped/Coated Steel, and Plastic piping.

Steel, Wrapped/Coated Steel, Copper, Plastic piping.

From the top and bottom