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Tuesday, February 10, 2015

PQT for WPC100M

WPC100M Pre-Qualification Test Progam


     This program was initiated in order to determine the performance characteristics of Covalence (formerly Raychem) Wrap Around Girth Weld Sleeve WPC100M for a 20" pipeline project.  Testing of the shrink sleeve was conducted in accordance with end user specification. 

Sample Preparation
     The test substrates selected for this program consisted of 3.5" OD x .300 inch wall thickness, X52, ERW steel pipe which had been prepared by a local pipe seller and then shipped to the testing facility for application.  Two different 3.5" OD pipe sections were provided, with the first pipe being a thirty five foot long section of pipe which had been blasted on the exterior prior to shipping, and the second pipe being a five foot long section of pipe which had been externally coated with green fusion bonded epoxy prior to shipping.  The 3.5 inch OD size was chosen for this program in order to accommodate the test equipment being used as well as to facilitate in the design and preparation of the required test specimens. 

     For the requirement of this program, only part of the blasted pipe was used for application and testing.  The blasted pipe had flash rusted during transit to the testing facility, so it was decided to re-blast the pipe prior to application of the shrink sleeve.  As only part of the pipe length was needed for testing, the thirty five foot long pipe section was torch shrunk in half and approximately thirteen foot of the section was blasted using No. 4 silica sand.  The blasting process was performed on the morning of the shrink sleeve application and a near white surface finish was achieved with the anchor profile ranging from 2.4 mils to 2.8 mils.

     The surface preparation on the FBE pipe section consisted only of wiping the FBE with lacquer thinner and allowing the surface to dry prior to the application of the shrink sleeve.

     The provision of the shrink sleeves and the application of the shrink sleeves were courtesy of Joint Specialists, LTD, which is the Master Distributor for Covalence (formerly Raychem).  Two different lengths of WPC100M shrink sleeves were used for the program:  11 inch (Lot # N08099) and 17 inch (lot #s N08088 and N08011).  The determination of whether to use the 11 inch or 17 inch sleeve was based upon which sleeve would best accommodate the specification configuration.

      Joint Specialists' representative heated the pipe substrates and applied the sleeves in accordance with Covalence recommendations for the WPC100M sleeve with the testing facility providing assistance in choosing which sleeve length as well as the sleeve placement on the pipe themselves.  For identification purposes, each shrink sleeve was labeled with a number which corresponded to the test specimens.  Present during the application of the shrink sleeves were representatives of the contractor and the pipeline owner company. 

     Eleven shrink sleeves were installed in order to perform six different tests.  These tests were:  Cathodic Disbondment, Impact, Peel Adhesion to Self, Peel Adhesion to Steel, Penetration and Lap Shear.  For all of these samples, preheat temperature of the steel was measured to be between 221F and 275F.  The manufacturers installation instructions indicate that the preheat temperature should be between 212F and 275F. 

Test Results
Elongation - ASTM D 638 - 639% (Requirement: >400%)
Peel Adhesion to Steel - ASTM D3330 - 54.9 pounds/inch (Requirement: >23 pounds/inch)
Peel Adhesion to Self - ASTM D3330 - 49.3 pounds/inch  (Requirement: >23 pounds/inch)
Peel Adhesion to FBE - ASTM D3330 - 44.5 pounds/inch (Requirement: >23 pounds/inch)
Penetration - G17 - No holiday with 10Kv detector (Requirement: No holiday with 10Kv detector)
Impact Strength - G14 - 58 inch-pounds  (Requirement: >35.4 inch-pounds)
Lap Shear - ASTM D1002 - 12.6 PSI (Requirement: 4.3 PSI)
Cathodic Disbondment - G42 - 10mm (Requirement:  <18mm)
Water Absorption - ASTM D570 <.02% (Requirement: <.2%)
Backing Thickness as Supplied - .032 inches (Requirement: .030 inches)
Backing Thickness Fully Recovered - .040 inches (Requirement: .040 inches)
Adhesive Thickness as Supplied - .040 inches (Requirement: .042 inches)

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