Reuben's Home Inspection Blog


Forget Code: CSST gas lines need bonding to reduce the risk of a fire.

If you own a newer home or you've recently had gas lines added to your home, there's a good possibility that Corrugated Stainless Steel Tubing, or CSST, was used.  This is a relatively new material that is approved for the distribution of natural gas inside of homes.  The best analogy I can think of to describe this material is that CSST is to steel gas pipes what PEX is to copper tubing, or Romex® is to rigid metal conduit.

CSST needs to be bonded.  The most common issue that home inspectors find with CSST is a system that hasn't been properly bonded.  When CSST is installed without being properly bonded to current standards, there is an increased risk for damage to the material from a nearby lightning strike.  When CSST is damaged, it can leak gas and cause an explosion and/or a fire.  To the best of my knowledge, all manufacturers of CSST began implementing specific bonding requirements around 2007.  Of course, proper bonding won't make CSST immune to damage from a nearby lightning strike, but it will reduce the risk of damage.

What about existing installations?  Building codes have something called 'grandfathering'.   This means that if something was installed to code, it's still a code compliant installation today, even if the codes have changed significantly.  The nice thing about being a home inspector is that we don't need to get hung up on code requirements.  If something is deemed unsafe due to a change in accepted residential construction standards, our Standards of Practice require us to recommend repair.

If CSST was installed to code in 2005 and the manufacturer didn't have any special requirements for bonding at the time it was installed, the installation still meets code... but that won't stop a home inspector from recommending the system be bonded to today's standards.   The manufacturers of CSST have changed their installation requirements because they've learned that the old methods weren't good enough.

What does proper bonding look like?  All manufacturers of CSST require the systems to be bonded in a specific manner - there needs to be a separate ground wire connected either to the rigid gas piping before the CSST, or directly to one of the CSST nuts.   The diagram below shows an example of what this would look like when properly installed to today's standards.

Bonding CSST diagram

The photo below shows an example of CSST bonded at the exterior of the home, with the bonding clamp connected to the CSST nut.

CSST Bonded at nut

The video below, produced by Gastite, shows a couple examples of how to properly bond CSST.

Note: some second generation versions of CSST, such as CounterStrike, do not have any additional bonding requirements.

How would you know if you had CSST in your home?  Look for flexible tubing with a yellow jacket that covers the ridges.  It's doesn't have to be yellow - for instance, CounterStrike has a black jacket, but the majority of CSST in Minnesota has a yellow jacket.  I've never seen any other color in person.  This material is not to be confused with an appliance connector, which might have a yellow coating that follows the contours of the ridges.  The photo below shows the two different materials.

CSST vs Gas Connector

The bottom line is that if you have a home with CSST, you should make sure it's properly bonded to today's standards, regardless of whether the installation 'met code' when it was originally installed.  You can't grandfather safety.

Additional Information on CSST and bonding

Reuben Saltzman, Structure Tech Home Inspections


Comment balloon 18 commentsReuben Saltzman • August 28 2012 03:08AM


Good information for home owners.

Enjoy the final days of summer with your camera in hand.

Posted by Roy Kelley (Realty Group Referrals) over 6 years ago

A large home in my area, built in about 2006, did suffer severe fire damage following a lightening strike on the propane gas system connection at the house.  The house had to be completely rebuilt from ground up.



Posted by Lenn Harley, Real Estate Broker - Virginia & Maryland (Lenn Harley,, MD & VA Homes and Real Estate) over 6 years ago

Roy - I fully intend to.  Thanks.

Lenn - scary!  I assume it had CSST gas tubing?

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) over 6 years ago

TracPipe no longer manufactures the yellow CSST after losing a class action law suit. I have begun seeing the black sheathed "safer" version of CSST on newer installs. 

Posted by James Quarello, Connecticut Home Inspector (JRV Home Inspection Services, LLC) over 6 years ago

James - I wonder how long it's going to be before the other manufacturers follow suit?

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) over 6 years ago

Reuben...I recently cosed on a home where the home inspector had in the report that the CSST gas line needs bonding.  The seller refused to pay for this.  In order for the deal to close I had to reduce commission.  If the house was built to code a few years ago and the CSST wasn't bonded, what were the risks?

Posted by Wayne Bennett, Real Estate...As It Should Be (One Home Team Realty/Charlotte,NC 704-293-3931) over 6 years ago

Reuben, this just makes sense. Did they assume because it was buried, it didn't need to be bonded?

Posted by Michael Setunsky, Your Commercial Real Estate Link to Northern VA over 6 years ago

The other day, on new construction (!), I found that the unbonded line leading from the gas meter to the indoor gas manifold was TracPipe, but the rest of the house was Counterstrike!  You have to wonder.

Great post Reubs.  Great links too.  You give the same links there that I do on my reports!

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) over 6 years ago

And this is why we have city code so we can follow it to avoid accidents

Posted by Harry F. D'Elia, Investor , Mentor, GRI, Radio, CIPS, REOs, ABR (Real Estate and Beyond, LLC) over 6 years ago

Still tons of it around here but of course we barely know what lightning is around here :)  I have also never seen CSST run outdoors.  I don't think there is anything wrong with it---they just don't do it that way around here.

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) over 6 years ago

Unfortunately, in this area there is hardly a gas line to be found. Guess the coal industry out lobbied them.

Posted by Nan Jester, Realtor, Exit Real Estate Gallery (Exit Real Estate Gallery Jacksonville Beach, FL ) over 6 years ago

Reuben, I see quite a bit of this, propane fireplaces mainly. I almost never see it bonded correctly. Like Charlie there I never see on the exterior of a home.

Posted by Donald Hester, NCW Home Inspections, LLC (NCW Home Inspections, LLC) over 6 years ago

Very good points.   Some people thing that if it ain't broke leave it alone. but that isn't always the right thing to do.

Posted by William Feela, Realtor, Whispering Pines Realty 651-674-5999 No. (WHISPERING PINES REALTY) over 6 years ago

Wayne - when CSST is installed without being properly bonded to current standards, there is an increased risk of damage to the material from a nearby lightning strike.  When CSST is damaged, it can leak gas and cause and explosion and/or a fire.

Michael - in one recent case, they assumed that because the installation was approved by the building official in 2005 that nothing else needed to be done.

Jay - I'm glad to hear your starting to see counterstrike.  Sounds like a much better product. I still haven't seen it in person yet.  

Harry - that's the idea :)

Charles - I assume they use steel at the exterior?

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) over 6 years ago

Nan - so everything is electric?

Donald - do they protect the CSST coming in to the gas fireplaces?  

William - exactly.  This is all about safety.


Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) over 6 years ago

I have been seeing Counterstrike for about 6 months now.  What I don't know is this:  on this house, for example, there was no bonding and they used TracPipe from the meter to the manifold.  Then Counterstrike everywhere else.  Does Counterstrike, as advertised, work in that scenario to lessen the lightening danger?  I might contact Omegaflex to see what they say.  I bet they won't answer me.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) over 6 years ago

Thanks for posting this article, Reuben! The issue just arose with a purchase by my client. Our inspector tagged it, the listing agent had NO clue, had never heard of it, called 3 HVAC contractors who all said it didn't need to be fixed. Our inspector was going to check with someone he knew who could fix it but came down with the flu and was out of commission. So I found this post, sent it to the listing agent who showed it to her HVAC contractor. They said they'll fix it now that they know how (!). We'll be going back to see whether they did. Since our inspector is still under the weather we'll take photos and text them to him for his review before we close on the place. 

My kids live in Minneapolis, so when they buy their next house you're the man!

Posted by Judith Clausen, Judith R. Clausen (Buyers Advantage Real Estate of Metro Denver) over 5 years ago

So what is the bottom line on houses built prior to the NFPA 54 code requiring bonding. It is the right thing to do but does it have to be done. Our house was built in 2007, I believe the 2009 was when most of the bonding codes for CSST were revamped.

Posted by Dallas over 2 years ago