Pipelaying Tender-VOL IV - WorleyParsons.com

EPMC SERVICES FOR REWARI – KANPUR PIPELINE
SPECIFICATION FOR PIPELINE CROSSING ROADS, RAIL AND MINOR WATER WAYS
9. CASING INSULATORS
Pipeline insulators shall be used to support the carrier pipe inside the casing pipe end electrically
isolate the carrier pipe from the casing pipe at the cased crossings. Manufacturer shall obtain prior
approval from OWNER / CONSULTANT on drawing/design of casing insulators.
9.1 It shall be made in segments duly held together with cadmium plated bolts and nuts, to be
supplied with casing insulators.
The number of segments shall be two for pipe diameters upto 12" (generally). For larger diameters, the
number of segments may be more than two, but their number shall be kept minimum.
Casing insulators shall be made of injection moulded high density polyethylene or other material
equivalent or superior as approved by OWNER / CONSULTANT and shall meet the requirements
given in Table-1.
TABLE — 1: Material Properties for Casing Insulators
Property Value ASTM Test Method
Dielectric Strength 450-500 Volts/Mil D-149
Compressive strength 3200 psi D-695
Tensile Strength 3100-5000 psi D-638, D-651
Impact Strength 4. Oft.lb/inch of notch D-256
Water Absorption 0.01% D-570
9.2 CASING END-SEALS
Casing end seals are intended to be used for sealing the annular space between casing pipe and
carrier pipe at casing ends so as to prevent ingress of moisture and water.
Manufacturer shall obtain approval from OWNER / CONSULTANT on design/drawing of end seals.
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