Double-See® Double Containment


This vinyl double containment piping system is fast and easy to install, and is available with a complete selection of pipe, fittings, and valves. Additionally, an innovative "valve-in-valve" design is offered which allows full containment pressure rating. Double-See® is available in PVC and CPVC; either material may be primary or secondary (PVC x PVC, CPVC x PVC, CPVC x CPVC) with Clear PVC always being an option for the containment pipe. System size options range from 1/2" x 2" to 6" x 10", meeting virtually any application requirement. Installation versatility allows simultaneous joining throughout a system or in combination with patented closure couplings which enable practical compliance with the ASME B31.3  requirement for visual inspection of all primary joint connections during the pressure test before closing the secondary piping joint.

Double containment piping systems are ideal for ensuring safety when transporting corrosive, toxic, or otherwise hazardous media.

When a leak from the primary pipeline occurs in a double containment system, the fluid is safely contained by the secondary pipe. End-users typically implement a leak detection system to alert operators when a leak has occurred.

These systems can be used in multiple applications, primarily for handling chemical and effluent water transfers.

Product Overview

Technical Data:

Size Range:

  • ½"- 6" inner pipe
  • 2" - 10" outer pipe

Pressure Rating:

  • Varies by Size (primary)
  • PN4 (50 PSI) (secondary)

Operating Temperature:

  • Varies by pipe

Joining Technology:

  • Solvent (Cement) Weld

Standard Ratings:

  • ASTM D1784
  • ASTM D1785
  • ASTM D2467
  • ASTM F441
  • ASTM F439
  • NSF 14
  • NSF 61


  • Polyvinyl Chloride (PVC) Grey
  • Chlorinated Polyvinyl Chloride (CPVC)
  • Clear Polyvinyl Chloride (Clear PVC)

Fields of Application:

  • Water and Wastewater Treatment
  • Chemical Processing, Delivery and Dosing
  • Microelectronics
  • Metal Plating and Surface Finishing
  • Life Sciences


  • Revolutionary closure coupling design for practical compliance with ASME B31.4
  • Innovative centralizer design for thermal expansion compensation
  • Broad use of vinyl materials and ease of installation
  • Pipe cut-length guidance system for easy installation
  • Double containment installation is fast and easy
  • Factory assembled and 100% tested fittings
  • Extensive standard part selection
  • Customer fabrications and pipe spooling available
  • Provides for chemical and effluent water process transfers
  • Improves safety by eliminating chemical interaction with employees
  • Multiple leak detection options
  • Double-See can be applied in either above or below-ground applications


Part Numbers / Dimensions