Corrugated stainless tubing useful for gas piping: manufacturers, sources, installation specifications & building codes. Field report of CSST gas leak. CSST gas piping protection measures.
This informative article describes CSST: corrugated steel pipe tubing employed for gas piping in buildings. Since 1990 CSST has been used within many buildings both in exposed and enclosed areas to put in new gas system piping. This content discusses CSST uses, sources, installation specifications, and safety precautions to guard the gas piping from damage by abrasion, puncture, lightning strikes or some other hazards. Gas piping codes and industry sources of CSST are included.
Our page top photo, provided thanks to Carson Dunlop Associates, a Toronto home inspection & education firm, illustrates an improper setting up standard yellow CSST gas piping – routed in ground contact in the wet area. Yellow “Standard” CSST gas pipin galso requires special electrical ground bonding to lower chance 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 point of confusion: CSST used as gas piping runs in buildings is just not the same product since the flexible gas connector tubing (shown below) utilized to actually connect gas appliances for the gas supply system, and other installation and product protection measures are essential. CSST gas piping is commonly used to route gas or LP gas supply through a building as the flexible gas tubing shown below is specifically made for the connection of gas appliances to the gas piping system.
Look for corrugated stainless-steel tubing (CSST) used as gas piping in buildings constructed inside the Usa or Canada after 1990 plus look for it in older buildings where gas piping was newly installed or modified since 1990. CSST is additionally installed in other countries.
Collapsing building © Daniel FriedmanStandard “yellow” or newer black CSST may be recognized in (usually) long runs in between the building gas source and its particular point of use at gas appliances. The gas appliance connector itself (shown from the photo just above) may be connected directly between your end from the CSST and also the appliance, or perhaps the CSST may terminate or perhaps be combined with black iron gas piping in the same building.
CSST gas piping is run both in exposed locations and through building cavities including walls, ceilings or floors.
How many homes have CSST installed? We had trouble relating industry estimates around Census data and Usa Energy Information Agency data, but there is no doubt the piping has been set up in many homes in Canada, the usa, and Japan.
Based on the CSST Safety Website (below), corrugated steel tubing is placed in about 500,000 new homes every year. As the U.S. Census Bureau and U.S. HUD February 2015 New Construction Data news release reports a seasonally adjusted annual rate newest construction inside the U.S. of about a million homes, that shows that half of brand-new homes are increasingly being created with CSST gas piping.
Or maybe we look at the February housing start data because of this almost 100% of the latest homes are using CSST gas piping – which sounds somewhat dubious. In 2014 the Usa EIA reported that 27% of all United states homes were supplied with gas and much less than 1% with some other gases.
I’m a dwelling contractor in Wisconsin, I would like more info on elliptical tube employed for gas piping in buildings. It feels like manufacturers don’t require it to be secured or strapped significantly by any means. ‘m uncertain just what the codes say with that. I’ve seen it snaked just about everywhere without support — and this is a story of a single consequence (quoting from a message into a manufacturer):
I wonder if you could supply an understanding about support and protection requirements for CSST. I really came back from helping my Brother-in-Law with a few issues within his Condo in Boston — he experienced a sprinkler pop on the winter, so a lot of the drywall had to be removed to dry things out. Once the restoration contractor removed one part of drywall, the odor of gas poured out. CSST ended up being snaked through floor trusses and had looped up in one location, where a pneumatic nail in the hardwood flooring installation had punctured it.
Presumably, they have leaked since the building was constructed (ten years ago), and been a hazard the whole time. Any “gas” smell people may have noticed was probably masked with the odor of the garage, because the leak is in the ceiling higher than the garage.
Reading a few manufacturers’ installation guides, there doesn’t are most often a requirement to SECURE the gas line by any means — it really has to be supported every 8′ roughly horizontally, right? In my Brother-in-Law’s condo, the gas line was snaked around and not really strapped anywhere, even though it was protected by nail plates at stud and joist penetrations. Is that this acceptable, based on your guidelines and then any applicable codes?
I ask, because checking this out may be covered with insurance, if it’s viewed as a hazard or not around code or manufacturer’s specifications. Thanks, J.
The manufacturer’s reply was essentially that this CSST needed to be kept 3″ from finished surfaces or protected by nail plates if also within 5″ of some constraint (just like a penetration through a framing member). Beyond that, it has an “escape” for nail penetrations. This did not stop the leak I described, as the dexopky14 looped up and was hit by way of a pneumatically-driven flooring nail… CSST looks like a fantastic thing — simple to install, etc. I wonder when you would do a post onto it?
The background and field experience with CSST use in America led to concerns about possible pitting, corrosion or perforation of the original yellow CSST gas piping in areas where lightning strikes were common. Kraft and Torbin (2007) explained that arcing between poorly-grounded CSST gas piping and also other nearby metal pathways develop a potential which may encourage electrical arcing problems for the CSST gas lines. Such lightning-related electrical arcing can weaken as well as perforate the gas piping ultimately causing dangerous gas leaks.
The risk of arcing damage to CSST is increased in areas where lightning activity is greatest and in which the CSST is just not well bonded to your grounding system.
The authors demonstrated that lightning-related electrical arcing damage risk to CSST could be reduced by direct-bonding of your gas piping system on the building’s electrical ground system: the level of the electrical charge from an indirect lightning strike was reduced (with their study) from 97% in the charge down to 20% by direct electrical bonding for the building’s electrical ground system. Their 2007 report concluded by using a recommendation for direct ground bonding of CSST like a proposal on the National Fuel Gas Code. In 2009 a similar authors reported that CSST could perform acceptably but made important and detailed tips for the floor 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 minimize the danger 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 just for this gas piping system. Stringfellow (2013) continued to report on electrically-induced gas distribution piping.
Currently (2015) the manufacturers have virtually switched for an improved, more durable CSST gas piping whose design incorporates a protective outer jacket and then for which extra manufacturer-specified ground bonding is not needed. I do believe that only Ward continues to produce the yellow CSST accessible in the U.S.
Based on Jim Narva, executive director from the National Association of State Fire Marshals, that association is centering on informing homeowners of the necessity for retrofit ground bonding of older CSST installations.
OPINION: I agree that CSST should be shielded from damage, including or maybe especially after it is run through building cavities where, hidden from view, it’s otherwise too easy for a future building occupant or worker to shoot a nail or screw with the material. One could feel that excluding concerns for corrosion, similar worries relate to (and customarily prohibit using) flexible copper tubing when used for gas piping: it is far from routed within building cavities. Instead in those situations it’s present with use steel piping for such gas lines.
Inside the CSST installation example specifications listed below you’ll see that the manufacturers typically require a variety of installation details to guarantee safe reliable operation of your gas piping system, including nail plates, flexible corrugated steel armor in some locations, support, and other measures. Some local jurisdictions further detail CSST gas piping installation specifications like where and how it may be routed.
Below at left is an illustration of this a regular steel gas pipe routed via a wall cavity during building renovations of any New York City Home. And at below right you will see the standard change from flexible copper tubing to stainless steel gas pipe once the gas piping system were required to penetrate the construction wall.