Corrugated stainless tubing employed for gas piping: manufacturers, sources, installation specifications & building codes. Field report of CSST gas leak. CSST gas piping protection measures.
This post describes CSST: corrugated steel pipe tubing employed for gas piping in buildings. Since 1990 CSST has been used within many buildings in exposed and enclosed areas to set up new gas system piping. This content discusses CSST uses, sources, installation specifications, and safety precautions to protect the gas piping from damage by abrasion, puncture, lightning strikes or any other hazards. Gas piping codes and industry types of CSST are included.
Our page top photo, provided thanks to Carson Dunlop Associates, a Toronto home inspection & education firm, illustrates an improper installing of standard yellow CSST gas piping – routed in ground contact within a wet area. Yellow “Standard” CSST gas pipin galso requires special electrical ground bonding to lessen probability of damage & leaks in areas of high lightning strike activity.
Newer black or dark-jacketed CSST gas piping (shown below, adapted from GasTite’s FlashShield CSST sales literature) currently sold by most manufacturers might not require special bonding.
Black CSST gas piping, adapted from GasTite’s FlashShield sales literature cited in this post.
Watch out: Let’s avoid a reason for confusion: CSST used as gas piping runs in buildings is not really the identical product since the flexible gas connector tubing (shown below) accustomed to actually connect gas appliances on the gas supply system, as well as other installation and product protection measures are required. CSST gas piping is used to route natural gas or LP gas supply through a building even though the flexible gas tubing shown below is designed specifically for that connection of gas appliances for the gas piping system.
Look for corrugated stainless-steel tubing (CSST) used as gas piping in buildings constructed in the Usa or Canada after 1990 and also look for it in older buildings where gas piping was newly installed or modified since 1990. CSST can also be placed in other countries.
Collapsing building © Daniel FriedmanStandard “yellow” or newer black CSST can be recognized in (usually) long runs between your building gas source along with its reason for use at gas appliances. The gas appliance connector itself (shown inside the photo just above) could be connected directly between the end of your CSST as well as the appliance, or maybe the CSST may terminate or perhaps be together with black iron gas piping inside the same building.
CSST gas piping is run in both exposed locations and thru building cavities for example walls, ceilings or floors.
The amount of homes have CSST installed? We had trouble relating industry estimates with US Census data and Usa Energy Information Agency data, but it is obvious that the piping has become installed in many homes in Canada, the United States, and Japan.
According to the CSST Safety Website (below), corrugated stainless-steel tubing is installed in about 500,000 new homes each year. Because the United states Census Bureau and Usa HUD February 2015 New Construction Data news release reports a seasonally adjusted annual rate of the latest construction within the U.S. of about 1 million homes, that demonstrates that 50 % of brand-new homes are being built with CSST gas piping.
Or if perhaps we look at the February housing start data which means that almost 100% of the latest homes use CSST gas piping – which sounds somewhat dubious. In 2014 the U.S. EIA reported that 27% of United states homes were provided with natural gas and less than 1% with many other gases.
I’m a dwelling contractor in Wisconsin, I might like more information on elliptical tube utilized for gas piping in buildings. It feels like manufacturers don’t require that it is secured or strapped significantly whatsoever. ‘m not sure exactly what the codes say with that. I’ve seen it snaked just about everywhere without support — and this is a story of merely one consequence (quoting from an email into a manufacturer):
I wonder in the event you could produce a perception about support and protection requirements for CSST. I really came back from helping my Brother-in-Law with just a few issues in the Condo in Boston — he had a sprinkler pop within the winter, so a lot of the drywall needed to be removed to dry things out. As soon as the restoration contractor removed one area of drywall, the odor of gas poured out. CSST have been snaked through floor trusses along with looped up in a single location, where a pneumatic nail from the wooden flooring installation had punctured it.
Presumably, they have leaked considering that the building was constructed (ten years ago), and been a hazard the entire time. Any “gas” smell people probably have noticed was probably masked through the scent of the garage, since the leak was in the ceiling over the garage.
Reading several manufacturers’ installation guides, there doesn’t seem to be a requirement to SECURE the gas line in any way — it just should be supported every 8′ or so horizontally, right? Inside my Brother-in-Law’s condo, the gas line was snaked around rather than really strapped anywhere, although it was protected by nail plates at stud and joist penetrations. Could this be acceptable, as outlined by your guidelines as well as applicable codes?
I ask, because checking this out could be covered by insurance, if it’s seen as a hazard or otherwise not approximately code or manufacturer’s specifications. Thanks, J.
The manufacturer’s reply was essentially the CSST would have to be kept 3″ away from finished surfaces or protected by nail plates if also within 5″ of some constraint (like a penetration by way of a framing member). Beyond that, it offers an “escape” for nail penetrations. This did not prevent the leak I described, as the dexopky14 looped up and was hit with a pneumatically-driven flooring nail… CSST appears like a great thing — very easy to install, etc. I wonder if you would do an article onto it?
The history and field experience of CSST utilization in Canada And America triggered concerns about possible pitting, corrosion or perforation of the original yellow CSST gas piping in locations where lightning strikes were common. Kraft and Torbin (2007) explained that arcing between poorly-grounded CSST gas piping along with other nearby metal pathways build a potential which may encourage electrical arcing damage to the CSST gas lines. Such lightning-related electrical arcing can weaken or even perforate the gas piping leading to dangerous gas leaks.
The chance of arcing problems for CSST is increased in places that lightning activity is greatest and where CSST is just not well bonded into a grounding system.
The authors demonstrated that lightning-related electrical arcing damage risk to CSST can be reduced by direct-bonding of the gas piping system towards the building’s electrical ground system: the level of the electrical charge from an indirect lightning strike was reduced (in their study) from 97% in the charge as a result of 20% by direct electrical bonding towards the building’s electrical ground system. Their 2007 report concluded with a recommendation for direct ground bonding of CSST as being a proposal for the National Fuel Gas Code. During 2009 a similar authors reported that CSST could perform acceptably but made important and detailed ideas for the ground bonding of CSST gas piping systems.
Goodson within a patent application (2009) also reported on the strength of direct bonding of both yellow and black CSST gas piping to reduce the potential risk of damage from indirect lightning flashing. Goodson explained that CSST was generally not a good electrical ground, thus lending importance to the “direct bonding” discussion with this gas piping system. Stringfellow (2013) continued to report on electrically-induced gas distribution piping.
Currently (2015) the manufacturers have basically switched with an improved, stronger CSST gas piping whose design includes a protective outer jacket and for which extra manufacturer-specified ground bonding is not needed. I feel that only Ward is constantly make the yellow CSST for sale in the U.S.
In accordance with Jim Narva, executive director from the National Association of State Fire Marshals, that association is working on informing homeowners of the necessity for retrofit ground bonding of older CSST installations.
OPINION: I agree that CSST should be resistant to damage, including or perhaps particularly after it is run through building cavities where, hidden from view, it’s otherwise too feasible for a future building occupant or worker to shoot a nail or screw from the material. One would assume that excluding concerns for corrosion, similar worries pertain to (and customarily prohibit the use of) flexible copper tubing when employed for gas piping: it is really not routed within building cavities. Instead in those situations it’s common to use steel piping for such gas lines.
From the CSST installation example specifications further down you’ll notice that the makers typically require a number of installation details to guarantee safe reliable operation of your gas piping system, including nail plates, flexible corrugated steel armor in some locations, support, as well as other measures. Some local jurisdictions further detail CSST gas piping installation specifications for example where and how it can be routed.
Below at left is a good example of a traditional steel gas pipe routed by way of a wall cavity during building renovations of a New York Home. And also at below right you will notice the conventional change from flexible copper tubing to CSST tube as soon as the gas piping system had to penetrate the construction wall.