Reuben's Home Inspection Blog


Corrugated Stainless Steel Tubing (CSST) - The New Gas Line

Several months ago I wrote a blog about how great PEX tubing is, and today I'm going to discuss the equivalent for gas piping - Corrugated Stainless Steel Tubing, which is commonly referred to as CSST.  This is a product that can be used for the distribution of natural or LP gas throughout buildings.

A very brief history of CSST

CSST was invented in 1988, and gained approval for use in all commercial and residential installations throughout the United States in 2003.  Since then, CSST has quickly gained in popularity, and is estimated to be used in more than half of all new homes built today.

CSST Installed

The main attraction to CSST is that it's flexible and relatively easy to install when compared to standard gas piping.  The fittings for rigid gas piping need to be tediously screwed together, and the piping itself must be measured, cut, reamed, threaded, then cleaned.  With CSST, the piping just gets cut to length and a fitting attached to the end.  It's easy to understand why it has become such a popular product.

CSST doesn't seem to be as popular in Minnesota

Unlike many other parts of the country, Minnesota allows the use of flexible soft copper for gas piping.  The installation procedure for flexible soft copper is comparable to CSST, making it far easier to install than rigid gas piping.  For plumbers in Minnesota that have always installed soft copper and are comfortable doing it, I'm guessing there's probably no point in changing products.  CSST is also more expensive than standard gas piping or flexible copper tubing.

Another reason that I probably don't see as much of this material is that it's not readily available to the handy homeowner.  While most building products can be easily purchased at any home improvement store, CSST can't.  That's probably a wise thing for the CSST industry, because it means there will be less improper / unskilled installations.

How to identify CSST

CSST looks similar to a gas connector, but is easily distinguished by a flexible yellow polyethylene jacket on the outside.  Gas connectors will often have a coating on the outside - not a jacket.  CSST will also be identified as such on the jacket itself.  The most common type of CSST that I see here in the Twin Cities is Gastite - in fact, that's all I can ever recall seeing.

CSST vs Gas Connector

CSST Installation Requirements

The general rule for CSST is that it must be installed in accordance with the manufacturer's instructions.  Because I only see Gastite CSST, I'm listing a few of their installation requirements.  Every other manufacturer has similar requirements.  These requirements come directly from Gastite's 102 page installation manual (fun reading).

  • Tubing shall be supported in a workmanlike manner with pipe straps, bands or hangers suitable for the size and weight of the tubing, at intervals not to exceed those shown in Table 4-3.   The referenced table requires support every 4' for 3/8" pipe, every 6' for 1/2", and every 8' for anything larger.  "J" Hooks may not be used.
  • Tubing routed on top of ceiling joists and other structural members which comply with the horizontal support spacing requirements will be considered sufficiently supported.
  • Any portions of the exposed stainless steel tubing shall be wrapped with tape or sleeved to prevent threats by acids or chloride based cleaning solutions for masonry. Self-bonding silicone tape is recommended here for durability.
  • The Gastite® Mechanical Fittings have been tested and listed per the requirements of ANSI LC-1 for concealed use.  I include this reference because I've heard other home inspector say that the fittings are never allowed to be concealed.  The manufacturer says they are.
  • Outdoor installations - Along side a structure – When installed along the outside of a structure (between the ground and a height of 6 ft.) in an exposed condition, the CSST shall be protected from mechanical damageinside a conduit or chase.
  • When it is necessary to install Gastite through masonry materials the tubing shall be routed through a conduit that is a ½" larger in diameter (to ease routing) than the OD of the CSST and appropriate for the application. The sleeve must maintain a continuous watertight barrier between the masonry material and the CSST, up to or past the edge of the masonry hole.
  • Where all three of the following conditions exist mechanical strike protection must be used: Concealed, Constrained, and Within three inches of a potential thread.  That means strike plates must be used.
  • For use with movable appliances, Gastite® must be rigidly terminated before the appliance connection. This means CSST is not an acceptable substitute for an appliance connector.
  • Where it is necessary to install Gastite through sheet metal enclosures (such as fireplaces) the tubing should be routed or supported to prevent physical contact with the enclosure. If direct contact cannot be avoided a rubber grommet may be used to prevent physical contact with the enclosure. Otherwise a Gastite angle stub or rigid pipe components must be used.
  • Bonding CSST Direct bonding of Gastite® CSST is required for all gas-piping systems incorporating Gastite® CSST whether or not the connected gas equipment is electrically powered.  This last item has been the topic of many blogs and articles, and is apparently one of the more important things to look for.  Gastite has a great video on their web site showing how it's done - click here to see it.


Reuben Saltzman, Structure Tech Home Inspections


Comment balloon 9 commentsReuben Saltzman • April 06 2010 05:01AM


I really enjoyed reading your post this morning. Very interesting

Posted by Harry F. D'Elia, Investor , Mentor, GRI, Radio, CIPS, REOs, ABR (Real Estate and Beyond, LLC) almost 9 years ago

That is the first I have heard about CSST. Thanks Reuben!

Posted by William True, Sarasota Real Estate (True Sarasota Real Estate) almost 9 years ago

Reuben, I see tons of the stuff.  Just had a leaking one yesterday and had to shut off the gas at the meter----very rarely have to do that.

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) almost 9 years ago

Harry and William - thanks for reading!

Charles - but they say if you smell gas, "don't try to turn the gas off, don't try to find the leak, just GET OUT!"  ha ha.  Good for you (huge grin).

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) almost 9 years ago

Never seen the stuff before.  Thanks for sharing with us as always.

Posted by Gene Allen, Realty Consultant for Cary Real Estate (Fathom Realty) almost 9 years ago

Gene - good!  I'm always glad when I can talk about something new. 

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) almost 9 years ago

Dear Sir,

Modern group made a modest beginning in 1995, by stocking and marketing "JINDAL" make Stainless Steel rolled products. Company derives its root in experience of more than a decade's in Stainless Steel business. The group reached commendable business position in the year starting 2000 in western India. After an innovation year 2005 witnessed the establishment of Modern Tube Industries Ltd. With a adequate facilities to manufacture Stainless Steel Welded and Seamless Tubes, U Tubes and Pipes.  Over the years, our product has earned good reputation and being used by reputed companies and recommended by major consultants. 


We are pleased to introduce ourselves as leading manufacturers of Stainless Steel Welded and Seamless Tubes, U Tubes and Pipes include Square and Rectangular tubes in various sizes, thickness, finishes and grades ie. AISI 304, 304L, 316, 316L, 310, 321, 400 & 409Lseries.  Etc.  As per ASTM, ASME, DIN, EN etc... The sizes are ranging from 6 mm to 609.6 mm outside diameter, Thickness 0.5 mm to 20 mm  With we have a most modern plant, sophisticated machinery and equipped with latest technology to manufacture quality product at G.I.D.C. POR Dist. Vadodara, Gujarat. We have well-qualified experienced staff supported by well-equipped Chemical & physical lab, which ensures quality product. The inter-departmental activities are automated for better supply chain management according to the quality standards laid down in ISO 9001-2000 Standards, to supply the best quality products to our clients, consistently and timely.


We accept Third Party Inspection as per customers demand. Our products undergo stringent inspection and testing stages through our quality department before they are released to customers.


As you are a reputed organization, we are much interested to create a sound business alliance with you. You are, therefore requested to please look into the matter and give us an opportunity to carry on our business performance with your organization. We requested you please send your vendor approval form for plant approval (if any).


In case you require any further more clarifications / information please contact the undersigned, we shall be happy in submitting the same.


Thanking you and looking for long and cordial business relationship.


Thanking you,


Yours Faithfully,


For Modern Tube Industries Limited.


Herbert Valles -

Marketing Executive.

Cell: 08128651112, 09427032586.

Posted by Herbet Valles over 8 years ago

a very informative article

Posted by K3U over 7 years ago

a very informative article

Posted by K3U over 7 years ago