Seamless PP/FRP - RPS Composites

Seamless PP/FRP Dual Laminate

Dual Laminate pipe systems incorporate a thermoplastic liner in an FRP structure combining the enhanced corrosion resistance of thermoplastics with the higher strength and load carrying capabilities of FRP.

Our PP/FRP seamless dual laminate uses only virgin Polypropylene (PP) and meets the requirements of ASTM D-4101. It may include less than 1% inorganic pigment for identification.

Polypropylene is chemically inert to a broad range of commercial chemicals including the following:

Mineral acids


Salt solutions


Considering all the dual laminate on the market, it’s our bonding layer that sets us apart. A knit fiberglass fabric is melt-bonded and partially embedded into the O.D. surface of the PP liner using a proprietary process.

This bonding technology eliminates air gaps between the PP liner and the vinyl ester structure, thereby preventing condensation between the liner and structure, a common problem in lined steel pipe. Since these gases/ liquids are not trapped between our PP liner and vinyl ester structure, no weep holes are required and internal corrosion of the structure is eliminated.

  • Resin: INEOS DERAKANE 411™ Bisphenol A Epoxy Vinylester (™ Trademark, INEOS Composites or its subsidiaries, registered in various countries.)
  • Glass: ‘ECR’ Glass
  • Pressure Ranges: suitable for continuous operation from full vacuum to 150 PSI for 1½” dia. through 12” dia., and full vacuum to 100 PSI for 14” dia. through 24” dia..
  • Maximum Test Pressure: 225 psi (15 BAR)
  • Temperature Range: 15°F (-10°C) to 200°F (93°C).
    PP/FRP piping systems with a continuous operating temperature above 180°F (82°C) should be evaluated by RPS Engineering to determine if the process conditions are acceptable.
  • Manufactured via combination of contact molding and filament winding. Available in sizes 1½” – 24” diameter; seamless through to 20″ dia.. Refer to our specification bulletin below for dimensions.
  • Minimum Barcol hardness of 90% of resin manufacturer’s specified value
  • External resin coating containing paraffin, pigment, and ultraviolet absorbers to assure proper surface cure and inhibit ultraviolet light degradation.
  • Pipe and fittings are shop and field assembled using butt joints, accomplished by welding the liner sections and then laminating the components together as per ASTM D6041. The liner weld is accomplished by flow fusion, hot plate, extrusion, or hot gas welding. Welds are spark tested to detect pinholes prior to laminating.
  • Flanges available in either full face or lap joint style. Drilling in accordance with ASME B16.5 Class 150.
  • The type of pipe support to use for a specific application will depend upon a number of factors, the most important of which are the intended function of the support and the configuration of the available structural steel.

What To Do Next

If you have a question or would like to make a purchase, please contact a Sales Rep, below. If you’d like us to respond to your RFQ, please click on REQUEST QUOTE at the top of this page.

Contact Your Sales Rep:

Bob Gordon

Bob Gordon

Southeastern US, Gulf Coast, Midwest and Western US

Dave Chapman, P. Eng.

Dave Chapman, P. Eng.

Northeastern US, Canada, International