2.1.2.2
Perforations
All fiberglass well screen shall be [mill slot][continuous wire wrapped rod
base]. All relief well screen shall have smooth, sharp-edged openings free
of burrs, chipped edges, or broken areas on the interior and exterior
surfaces of the pipe. [The [_____] mm inch diameter well screen shall have
a number [_____] slot, [0.0__] mm inch open slot.] [The length of the
slots measured on the inside of the pipe shall be [_____] mm inches.]
There shall be a total open area not less than [_____] square millimeters
inches per linear meter foot of [_____] mm inch diameter well screen. The
slots or groups of slots shall be distributed in a uniform pattern around
the periphery of the pipe and shall be oriented with the length of the slot
[parallel to,] [normal to,] [or] [diagonal with] the axis of the pipe.
2.1.3
Steel Pipe Screen
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NOTE: Metal pipes, plugs, screen and joints for
most installations may require a coating to protect
the metal from corrosive ground water and soil. The
type of coating selected to accomplish this purpose
will depend upon the corrosive characteristics of
the ground water and soil. The Contracting Officer
should therefore make complete analysis of the
corrosive characteristics of the ground water and
add to these specifications such requirements as are
necessary to protect the pipe. The coating should
be applied after perforating or slotting and should
completely cover all exposed metal. Care should be
taken to ensure that the openings are not closed or
reduced in required size by the coating.
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Steel well screen shall consist of perforated or slotted sections of steel
pipe conforming to the requirements of ASTM A 53/A 53M, Type [_____], Class
[_____]. [The well screen, pipe, and fittings shall have a minimum
collapse strength of [_____].] [The screen, pipe, and fittings shall have
a clear inside diameter of [_____].]
2.1.3.1
Couplings
Couplings for steel pipe screen shall be welded joints or threaded
couplings. Welding shall be performed in accordance with requirements in
ASME B31.9. Couplings shall meet the material requirements specified for
steel pipe screen, except perforations shall be omitted. All threaded pipe
and fittings shall be threaded in accordance with ASME B1.20.1. All
threaded pipe sections may be field connected. Couplings shall be given
the same protection against corrosion as specified for the well screen
pipe. Protective coatings damaged while making couplings shall have the
areas recoated.
2.1.3.2
Perforations
All steel pipe to be used as relief well screen shall be provided with
perforations which shall consist of either machine-cut slots; drilled or
punched openings. The slots shall have a width of [_____] mm inch with a
tolerance of plus or minus [_____] mm inch. The length of the slots
measured on the inside of the pipe shall be [_____] mm inches with a
tolerance of plus or minus [_____] mm inch. For slotted openings there
SECTION 02525A
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