extension type with screw or slide-type adjustments. Valve boxes shall be
separately supported, not resting on the pipe, so that no traffic loads can
be transmitted to the pipe. Valves shall only be located in valve boxes or
inside of buildings.
3.9
DRIPS
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NOTE: If gas mains are for the distribution of
high-pressure natural gas (above 400 kPa (60 psig))
only, delete the entire paragraph: DRIPS. Require
drips for lines transmitting natural gas at the low
point immediately following reduction from high
pressure (above 400 kPa (60 psig)) to medium
pressure (400 kPa (60 psig) or less), and at
occasional low points throughout the system, to
provide for blowing out the lines. Require drips at
all low points in lines transmitting manufactured
gas or a mixture of manufactured and natural gas.
Indicate locations of drips. Locate drip points to
provide for proper drainage of pipe system. Detail
drips and discharge terminal (outlet) piping. If
the need to contain and dispose of liquids through
the valve for environmental concerns is required,
delete the first bracketed sentence.
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Drips shall be installed at locations where indicated. Drips shall conform
to the details shown or may be commercial units of approved type and
capacity. A blow off pipe 32 mm (1-1/4 inches) 1-1/4 inches or larger
shall be connected to each drip at its lowest point and shall extend to or
near the ground surface at a convenient location away from traffic.
Discharge for each drip terminal (outlet) shall be provided with a reducing
fitting, a plug valve, and a 15 mm (1/2 inch 1/2 inch nipple turned down.
The discharge terminal (outlet) shall be inside a length of 300 mm 12 inches
or larger vitrified clay pipe, concrete sewer pipe or concrete terminal
box [set vertically on a bed of coarse gravel 300 mm 1 foot thick and 1 m 3
feet square,] [with concrete bottom to contain liquids and a connection to
remove liquids for disposal,] and closed at the ground surface with a
suitable replacement cover.
3.10
PRESSURE REGULATOR INSTALLATION
3.10.1
Main Distribution Line Regulators
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NOTE: Remove reference to bypasses around pressure
regulators for main distribution lines unless
continuity of service is imperative and the bypass
is regulated to prevent possible overpressure of
downstream lines.
**************************************************************************
Pressure regulators shall be installed where shown. A valve shall be
installed on each side of the regulator for isolating the regulator for
maintenance. A bypass line with bypass valves or 3 way valves and an
overpressurization pressure regulating device shall be provided.
Regulators and valves shall be installed in rectangular reinforced concrete
boxes. Boxes shall be large enough so that all required equipment can be
SECTION 02556A
Page 23
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