Polyguard SP-6 Slip Plane Wrap
POLYGUARD SP-6™ UNBONDED OUTERWRAP is an integral part of the RD-6® Coating System. It consists of a strong non woven, felt-like polypropylene fabric. Its high tensile strength and low elongation properties provide a slip-plane that results in an outerwrap which mitigates soil stress.
- There is no adhesive on the surfaces of either side of the fabric. For years, the pipeline coating industry relied on bonded outerwraps. However, the permanent adhesion to the corrosion coating underneath is not desired. The fabric, when unbonded, has the freedom to be moved by the forces of soil stress, independently of the coating over which it has been applied. If the fabric had been bonded to the coating underneath, the soil stresses would be transferred to the corrosion coating underneath, and could cause deformation of the corrosion coating.
- The fabric permits water and cathodic protection currents to pass through it. This porous property keeps the outerwrap from contributing to the cathodic protection shielding problem. Solid film back corrosion coatings and outerwraps have been proven to shield (block) the passage of protective currents.