Double-See® Double Containment

double-see-330x240

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

Materials:

  • 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

Advantages:

  • 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

Specification

Double-See PVC Specification (See CPVC below)

PART 2 - PRODUCTS – MATERIALS

2.1 SECONDARY CONTAINED PROCESS PIPE AND FITTINGS SYSTEM (Above and Below Slab)

  1. PVC primary and secondary pipe and fittings for the double containment process piping systems installed below grade shall be Schedule 80 joined by the solvent cement joining method.  Pipe and fittings shall be manufactured of polyvinyl chloride (PVC). Material shall safely convey flow streams up to 140° F (60° C) and pressure rating of 150 PSI.
  2. All piping (primary and secondary) for this system shall be marked with the following “+GF+ PVC 1120 SCH. 80 (size) xxxx PSI WP @ 73F ASTM D1785 NSF-pw-U.P. Code-G (control #) Made in USA”.
  3. All fittings (primary and secondary components) shall be legibly marked showing GF Piping Systems LLC trademark, fitting size, manufacturer’s part number and symbol indicating the material.
  4. PVC centralizers will be designed with enough space for pass through of leak detection cable in the event the system is specified for same. In this event the manufacturer shall provide (upon request) a “pull” line in all pipe lengths and fittings for ease of cable installation within the interstitial space once the system is in place. Pipe and fittings are ordered from manufacturer with pull line pre-installed by appending part number with "PR" on the end.
  5. Any custom fittings which may need to be fabricated due to field conditions or requirements of horizontal and/or vertical dimensioning shall conform to the standards of this specification. Only custom fittings manufactured by GF Piping Systems LLC shall be acceptable for installation within the system. All valve and flange boxes required to suit project conditions shall be as catalogued and manufactured by GF Piping Systems LLC.
  6. System shall be Double-See®  PVC double containment pipe and fitting system as manufactured by GF Piping Systems LLC (or approved equal).

PART 3 - EXECUTION

3.1 INSTALLATION

  1. A factory representative shall assist the contractor in system layout and “take-off” prior to an order being placed with the factory, for the purpose of ensuring all required components of the system are understood.
  2. For projects requiring conformance with ASME B31.3, the unique closure coupling design of the Double-See™ system allows for visual inspection of all primary joint connections during pressure testing before sealing the secondary pipe joint. Any other manufactured product submitted as an “or equal” to this specification must also meet the B31.3 requirements.
  3. Pipe and fittings shall be installed according to current Double See® installation instructions as delivered in print or found online at www.gfpiping.com . An on site installation seminar shall be conducted by GF Piping Systems personnel who are certified to conduct said installation seminars. Seminar shall include all aspects of product installation (storage, set-up, support spacing, centralizer spacing, system expansion, temperature considerations, solvent cement joining procedure, product testing procedures, etc.). At the conclusion of the installation seminar all installers will be a certification test and, upon successful completion of said test will be issued a certification card verifying they have met the requirements of this specification.
  4. Solvent Cement and Primer used for installation of Double See® PVC system must be compatible with GF Piping LLC requirements as outlined within product installation documentation.

3.2 Pipe/Valve Hangers and Supports

  1. Non-Restrictive Horizontal Pipe Clamps
    a.    Plastic pipes shall be supported at distances recommended by the manufacturer according to load, material, temperature, pipe wall thickness and diameter.
    b.     Plastic pipe supports shall be constructed of an exterior metal supporting bracket of gauge 7 or gauge 11 thickness, depending on size, and an independent plastic insert sleeve sized to allow not more than ¼" annular space between supported pipe and sleeve. Only insert sleeves of the indicated size shall be used for the corresponding supported pipe and sleeve. Only insert sleeves of the indicated size shall be used for the corresponding supported pipe. Supports shall be affixed using appropriate mounting bolts, nuts and washers to 12 gauge rolled structural steel channel, 1 5/8" inch by 1 5/8" minimum, or mounted to structurally sound surfaces suitable to accept mounting hardware.
  2. Non-Restrictive Saddle Hangers Pipe Supports
    a.    Saddle type hangers shall be constructed from 12 gauge rolled structural steel channel, 1 5/8 inch x 1 5/8 inch minimum, strut or stronger as required suitable to support an exterior metal supporting bracket and an independent plastic insert sleeve sized to allow not more than 1/4 inch annular space between supported pipe and sleeve.
  3. Non-Restrictive Clevis Hangers Pipe Supports
    a.    Clevis type hangers shall be constructed of an exterior metal supporting bracket and an independent plastic insert sleeve sized to allow not more than ¼ inch annular space between supported pipe and sleeve. Only insert sleeves of the indicated size shall be affixed to an independent clevis hanger bracket with means to be mounted using all thread rod with appropriate nuts and washers and sized per MSS-SP-58.
  4. Non-Restrictive Vertical Pipe Supports
    a.    Vertical supports shall be mounted similarly to horizontal support with the addition of 35 durometer cushion strips mounted to both sides of plastic insert sleeve.
  5. Thermal Compensating Valve Supports
    a.    Valves shall be supported at distances as recommended by manufacturers and/or according to load, material, temperature, pipe wall thickness and diameter.
    b.    Plastic valve supports shall be a two piece construction, with a primary supporting mounting bracket designed to be structurally attached to a flat surface or a steel strut support of 40mm (1 5/8 inches) width with slots to accept mounting hardware and a second, interlocking valve sliding bracket with suitable slots to affix and mount the valve. When assembled, the valve sliding bracket shall be interlocked with the mounting bracket to allow linear movement along a plane that is in-line with the installed pipe.
    c.    Location of the sliding valve support along the mounting bracket shall take into consideration the installation and operating system temperatures to gain maximum valve support throughout an anticipated temperature cycle of the piping system. If equal temperature changes are anticipated (above and below installation temperature) or if conditions are unknown, sliding valve support shall be mounted midway along mountain bracket.
    d.    All valve supports shall be of a two-piece, interlocking construction, manufactured of UV resistant materials and designed to provide full valve support while allowing for linear movement when subjected to thermal expansion or contraction forces acting on the installed piping system. The valve mounting bracket shall provide means of valve attachment without restricting valve movement when affixed to valve mounting support bracket.
  6. Manufacturer
    a.    All supports and hangers specified above shall be Stress Less® Pipe and Valve Support system as manufactured by GF Piping Systems LLC or approved equal.

3.3 Testing

  1. The system shall be installed in such a manner that will allow for the testing of the primary pipe independent of the secondary pipe. Simultaneous testing of both components of the system will not be accepted.
  2. The system shall be tested in accordance with all local plumbing/mechanical codes having jurisdiction in the territory where the installation is to take place. All sections of the primary piping system shall be hydraulically tested to a maximum of 150% of the designed working pressure. All secondary piping (interstitial space) shall be tested pneumatically to a maximum of 5 psi air or hydrostatically to 50 psi or less. Strict adherence to the published testing procedures for the Double-See® must be made by the installer when testing the system.

    The following is a general test procedure for GF plastic piping that can be used to test the primary piping.
    a.    All piping systems should be pressure tested prior to being put into operational service.
    b.    All pressure tests should be conducted in accordance with the appropriate building, plumbing, mechanical, and safety codes for the area where the piping is being installed.
    c.    When testing plastic piping systems, all tests should be conducted hydrostatically and should not exceed the pressure rating of the lowest rated component in the piping system (often a valve). Test the system at 150% of the designed operational pressure. For example, if the system is designed to operate at 80 psi, then the test will be done at 120 psi.
    d.    When hydrostatic pressure is introduced to the system, it should be done gradually through a low point in the piping system with care taken to eliminate any entrapped air by bleeding at high points within the system. This should be done in four stages, waiting ten minutes at each stage (adding ¼ the total desired pressure at each stage).
    e.    Allow one hour for system to stabilize after reaching desired pressure. After the hour, in case of pressure drop, increase pressure back to desired amount and hold for 30 minutes. If pressure drops by more than 6%, check system for leaks. (Note that some pressure loss is normal the first time a piping system is pressurized, due to expansion of the material as described earlier.) If ambient temperature changes by more than 10°F during the test, a retest may be necessary.

Double-See CPVC Specification

PART 2 - PRODUCTS – MATERIALS

2.1 SECONDARY CONTAINED PROCESS PIPE AND FITTINGS SYSTEM (Above and Below Slab)

  1. CPVC primary and secondary pipe and fittings for the double containment process piping systems installed below grade shall be Schedule 80 joined by the solvent cement joining method.  Pipe and fittings shall be manufactured of chlorinated polyvinyl chloride (CPVC). Material shall safely convey flow streams up to 200° F (93° C) and pressure ratings of 150 PSI.
  2. All piping (primary and secondary) for this system shall be marked with the following “+GF+ CPVC 4120 SCH. 80 (size) xxxx PSI WP @ 73F ASTM F441 NSF-pw-U.P. Code-G (control #) Made in USA” .
  3. All fittings (primary and secondary components) shall be legibly marked showing GF Piping Systems LLC trademark, fitting size, manufacturer’s part number and symbol indicating the material.
  4. PVC centralizers will be designed with enough space for pass through of leak detection cable in the event the system is specified for same. In this event the manufacturer shall provide (upon request) a “pull” line in all pipe lengths and fittings for ease of cable installation within the interstitial space once the system is in place. Pipe and fittings are ordered from manufacturer with pull line pre-installed by appending part number with "PR" on the end.
  5. Any custom fittings which may need to be fabricated due to field conditions or requirements of horizontal and/or vertical dimensioning shall conform to the standards of this specification. Only custom fittings manufactured by GF Piping Systems LLC shall be acceptable for installation within the system. All valve and flange boxes required to suit project conditions shall be as catalogued and manufactured by GF Piping Systems LLC.
  6. System shall be Double-See®  CPVC double containment pipe and fitting system as manufactured by GF Piping Systems LLC (or approved equal).

PART 3 - EXECUTION

3.1 INSTALLATION

  1. A factory representative shall assist the contractor in system layout and “take-off” prior to an order being placed with the factory, for the purpose of ensuring all required components of the system are understood.
  2. For projects requiring conformance with ASME B31.3, the unique closure coupling design of the Double-See™ system allows for visual inspection of all primary joint connections during pressure testing before sealing the secondary pipe joint. Any other manufactured product submitted as an “or equal” to this specification must also meet the B31.3 requirements.
  3. Pipe and fittings shall be installed according to current Double See® installation instructions as delivered in print or found online at www.gfpiping.com . An on-site installation seminar shall be conducted by GF Piping Systems personnel who are certified to conduct said installation seminars. Seminar shall include all aspects of product installation (storage, set-up, support spacing, centralizer spacing, system expansion, temperature considerations, solvent cement joining procedure, product testing procedures, etc.). At the conclusion of the installation seminar all installers will be a certification test and, upon successful completion of said test will be issued a certification card verifying they have met the requirements of this specification.
  4. Solvent Cement and Primer used for installation of Double See® CPVC system must be compatible with GF Piping LLC requirements as outlined within product installation documentation.

3.2 Pipe/Valve Hangers and Supports

  1. Non-Restrictive Horizontal Pipe Clamps
    a.    Plastic pipes shall be supported at distances recommended by the manufacturer according to load, material, temperature, pipe wall thickness and diameter.
    b.    Plastic pipe supports shall be constructed of an exterior metal supporting bracket of gauge 7 or gauge 11 thickness, depending on size, and an independent plastic insert sleeve sized to allow not more than ¼" annular space between supported pipe and sleeve. Only insert sleeves of the indicated size shall be used for the corresponding supported pipe and sleeve. Only insert sleeves of the indicated size shall be used for the corresponding supported pipe. Supports shall be affixed using appropriate mounting bolts, nuts and washers to 12 gauge rolled structural steel channel, 1 5/8" inch by 1 5/8" minimum, or mounted to structurally sound surfaces suitable to accept mounting hardware.
  2. Non-Restrictive Saddle Hangers Pipe Supports
    a.    Saddle type hangers shall be constructed from 12 gauge rolled structural steel channel, 1 5/8 inch x 1 5/8 inch minimum, strut or stronger as required suitable to support an exterior metal supporting bracket and an independent plastic insert sleeve sized to allow not more than 1/4 inch annular space between supported pipe and sleeve.
  3. Non-Restrictive Clevis Hangers Pipe Supports
    a.    Clevis type hangers shall be constructed of an exterior metal supporting bracket and an independent plastic insert sleeve sized to allow not more than ¼ inch annular space between supported pipe and sleeve. Only insert sleeves of the indicated size shall be affixed to an independent clevis hanger bracket with means to be mounted using all thread rod with appropriate nuts and washers and sized per MSS-SP-58.
  4. Non-Restrictive Vertical Pipe Supports
    a.    Vertical supports shall be mounted similarly to horizontal support with the addition of 35 durometer cushion strips mounted to both sides of plastic insert sleeve.
  5. Thermal Compensating Valve Supports
    a.    Valves shall be supported at distances as recommended by manufacturers and/or according to load, material, temperature, pipe wall thickness and diameter.
    b.    Plastic valve supports shall be a two piece construction, with a primary supporting mounting bracket designed to be structurally attached to a flat surface or a steel strut support of 40mm (1 5/8 inches) width with slots to accept mounting hardware and a second, interlocking valve sliding bracket with suitable slots to affix and mount the valve. When assembled, the valve sliding bracket shall be interlocked with the mounting bracket to allow linear movement along a plane that is in-line with the installed pipe.
    c.    Location of the sliding valve support along the mounting bracket shall take into consideration the installation and operating system temperatures to gain maximum valve support throughout an anticipated temperature cycle of the piping system. If equal temperature changes are anticipated (above and below installation temperature) or if conditions are unknown, sliding valve support shall be mounted midway along mountain bracket.
    d.    All valve supports shall be of a two-piece, interlocking construction, manufactured of UV resistant materials and designed to provide full valve support while allowing for linear movement when subjected to thermal expansion or contraction forces acting on the installed piping system. The valve mounting bracket shall provide means of valve attachment without restricting valve movement when affixed to valve mounting support bracket.
  6. Manufacturer
    a.    All supports and hangers specified above shall be Stress Less® Pipe and Valve Support system as manufactured by GF Piping Systems LLC or approved equal.

3.3 Testing

  1. The system shall be installed in such a manner that will allow for the testing of the primary pipe independent of the secondary pipe. Simultaneous testing of both components of the system will not be accepted.
  2. The system shall be tested in accordance with all local plumbing/mechanical codes having jurisdiction in the territory where the installation is to take place. All sections of the primary piping system shall be hydraulically tested to a maximum of 150% of the designed working pressure. All secondary piping (interstitial space) shall be tested pneumatically to a maximum of 5 psi air or hydrostatically to 50 psi or less. Strict adherence to the published testing procedures for the Double-See® must be made by the installer when testing the system.

    The following is a general test procedure for GF plastic piping that can be used to test the primary piping.
    a.    All piping systems should be pressure tested prior to being put into operational service.
    b.    All pressure tests should be conducted in accordance with the appropriate building, plumbing, mechanical, and safety codes for the area where the piping is being installed.
    c.    When testing plastic piping systems, all tests should be conducted hydrostatically and should not exceed the pressure rating of the lowest rated component in the piping system (often a valve). Test the system at 150% of the designed operational pressure. For example, if the system is designed to operate at 80 psi, then the test will be done at 120 psi.
    d.    When hydrostatic pressure is introduced to the system, it should be done gradually through a low point in the piping system with care taken to eliminate any entrapped air by bleeding at high points within the system. This should be done in four stages, waiting ten minutes at each stage (adding ¼ the total desired pressure at each stage).
    e.    Allow one hour for system to stabilize after reaching desired pressure. After the hour, in case of pressure drop, increase pressure back to desired amount and hold for 30 minutes. If pressure drops by more than 6%, check system for leaks. (Note that some pressure loss is normal the first time a piping system is pressurized, due to expansion of the material as described earlier.) If ambient temperature changes by more than 10°F during the test, a retest may be necessary.

Part Numbers / Dimensions

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