Fuel Gas: CSST

Fuel gas systems convey natural gas or propane for laboratories, cooking, space heating, and...

 CSST (Corrugated Stainless Steel Tubing) is manufactured from ASTM A240 300 series (type...

Benefit of Material to Systems Application

CSST (corrugated stainless steel tubing) is a promising alternative to traditional threaded black-iron gas piping for residential, commercial and industrial applications. While still relatively new, CSST is increasing in use. Its light weight, flexibility, and need for fewer connections and fittings can make it easier to install than traditional threaded black-iron piping. These benefits can add up to substantial labor savings for installers and cost savings for builders. In addition, builders and installers have noted a reduction in employee injuries due to elimination of the heavy equipment and apparatus associated with traditional black iron pipe installations.

System Application and Material Usage

CSST requires different design and sizing criteria than the more common rigid systems. Flow characteristics between CSST and a rigid system are very different and sizing the CSST system using the codebook may be inefficient. The corrugated stainless steel system has a number of essential hardware and design differences from conventional gas piping using rigid steel pipe and copper tubing:

•    System uses corrugated stainless steel tubing (CSST) made of 300 series type material, ASTM A240.
•    The tubing is connected using special mechanical brass fittings designed specifically for the manufacturer’s CSST system.
•    In many applications, the tubing is sized for individual gas appliance loads and is, therefore, usually small in diameter.  The tubing may also be installed in a parallel fashion from a central distribution manifold rather than a series layout commonly used for rigid pipe systems.
•    Corrugated stainless steel tubing is suitable for use with elevated pressure systems (1/2 PSI to 25 PSI).
•    Corrugated stainless steel tubing is pulled through the structure similar in fashion to electrical wiring and therefore requires different handling and installation techniques than rigid pipe.

The CSST industry is highly proprietary and the various manufacturers set up their systems differently.  Consequently, once a CSST manufacturer is chosen for a project, no other manufacturer materials should be used.
CSST is most often installed in a central manifold configuration (also called parallel configuration) with "home run" lines that extend beneath, through and alongside floor joists, inside interior wall cavities and on top of ceiling joists in attic space from a gas source to an appliance. The multiport manifold allows for easy, future expansion of the system for room additions or additional appliances. CSST has the potential for higher levels of system safety because connections and joints behind the wall, common in black iron pipe, are essentially eliminated.

Corrugated stainless steel tubing (CSST) systems have been tested in accordance with the American National Standard for Fuel Gas Systems Using Corrugated Stainless Steel Tubing, ANSI LC1.  This standard lists performance requirements for certification of CSST systems for use with all recognized fuel gases, including Natural Gas and Propane, up to 25-PSI operating pressure.

Corrugated Stainless Steel Tubing is available in pipe sizes 3/8”, 1/2”, 3/4”, 1”, 1-1/4”, 1-1/2”and 2” and may be used in combination with all approved fuel gas piping materials using pipe threads at the interface.  System components such as manifolds, tees and stub-outs may be fabricated from other approved materials to be used with CSST.

All Manufactures of CSST are required to comply with the ANSI LC1-2005, CSA 6.26-2005, "Fuel Gas Piping Systems Using Corrugated Stainless Steel Tubing (CSST)" standard.

Manufacturers and Suppliers Participating in OPUS

F.W. Webb Company

F.W. Webb Company is a multi-faceted distributor of plumbing and heating, HVAC and controls,......
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Ferguson specializes in providing PVF, Plumbing, HVAC and Related Specialty Products and......
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Galloup Company

J.O. Galloup Company is a premier distributor of commercial and industrial piping products,......
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Hajoca Corporation

Founded in 1858, the Hajoca Corporation is the largest privately owned wholesale distributor of......
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Jomar Valve

Founded in 1966 by former Navy Commander Joseph Martin, Jomar Valve set out to change the way......
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MORSCO is a leading U.S. distributor of commercial and residential plumbing, HVAC, and PVF, with......
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Omegaflex, Inc.

Since 1975, OmegaFlex has led the piping industry with its high-quality construction and......
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The Commonwealth Group

The Commonwealth Group is the industry’s newest, 100-percent member owned, $8.5......
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Weldbend Corporation

Weldbend Corporation is a manufacturer of carbon steel welding fittings and forged steel......
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WinWholesale, Inc. is comprised of over 525 wholesale distribution locations. Along with Noland......
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Applicable Joining Methods


Corrugated stainless steel tube fittings are mechanical tube fittings manufactured from ASTM B16...
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