Page 394 - Trenchless Technology Piping Installation and Inspection

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Each of these products has specific QA/QC procedures for
joining pipe sections.
12. Postinstallation: A successful installation using HDD is largely
determined during the installation process. The product pipe
condition at the exit end of the installation must be examined
for gouges, cuts, or abrasions. Water and gas pipelines must be
tested against leaks as specified specifications. The jobsite must
be restored and all materials including drilling fluids must be
disposed of, as required by local ordinance or as specified.

8.6.2 Pipe Material Standards
Pipe used for HDD must be smooth, flexible, and have sufficient
strength to resist tension, bending, and external installation pressure
loads. This method requires structurally strong joints that resist elon-
gation or cross-section reduction.
HDPE pipes must conform to the current ASTM D1248-05,
ASTM D3350-10, and ASTM F714-08. Steel pipe must conform to
the current ASTM A 53-07 and ASTM 139-06. Ductile iron pipe must
confirm to the current ASTM 716-95 and ASTM 746-95. PVC pipe
must confirm to the current ASTM F1962-99 and ASTM D2321-09.

Allowable Forces
In case of HDPE pipe, an extra 6-ft section of the pipe must be pulled
out of the borehole to check for any sign of stress or damage. Allow-
able pulling force for all diameters must be determined depending
on the pipe size, wall thickness, manufacturer, field conditions, pull
distance, bearing capacity of soils, adjacent infrastructure, and all
other related considerations.

Pipe Dimensions
1. HDPE pipe may require a minimum DR of 11.
2. Pipe must be round. Steel pipe must have a roundness toler-
ance, so that the difference between the major and minor out-
side diameters must not exceed 1 percent of the specified
nominal outside diameter, or 0.25 in., whichever is less. Like-
wise, HDPE, ductile iron, and PVC pipe must have similar
roundness tolerances.
3. Pipe must have square and machine beveled ends. The pipe
end maximum out-of-square tolerance must be 0.04 in.
(measured across the diameter).
4. The maximum allowable straightness deviation over any 10-ft
length of steel casing pipe is 0.125 in. Likewise, ductile iron
and PVC pipe must have similar straightness tolerances.
HDPE pipe does not need to be straight.