Corrugated stainless steel tubing employed 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: carbon steel oval tube tubing utilized for gas piping in buildings. Since 1990 CSST has been utilized within many buildings both in exposed and enclosed areas to setup new gas system piping. This content discusses CSST uses, sources, installation specifications, and safety measures to guard the gas piping from damage by abrasion, puncture, lightning strikes or any other hazards. Gas piping codes and industry resources for CSST are included.
Our page top photo, provided thanks to Carson Dunlop Associates, a Toronto home inspection & education firm, illustrates an improper installation of standard yellow CSST gas piping – routed in ground contact in a wet area. Yellow “Standard” CSST gas pipin galso requires special electrical ground bonding to lessen 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 exactly 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 the same product as being the flexible gas connector tubing (shown below) utilized to actually connect gas appliances on the gas supply system, and other installation and product protection measures will be required. CSST gas piping is commonly used to route gas or LP gas supply by way of a building even though the flexible gas tubing shown below is specifically designed for your connection of gas appliances towards the gas piping system.
Seek out corrugated stainless tubing (CSST) used as gas piping in buildings constructed in the Usa or Canada after 1990 plus seek out 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 may be recognized in (usually) long runs involving 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 along with the appliance, or maybe the CSST may terminate or perhaps be together with black iron gas piping within the same building.
CSST gas piping is run both in exposed locations and through building cavities such as walls, ceilings or floors.
How many homes have CSST installed? We had trouble relating industry estimates with US Census data and United states Energy Information Agency data, but there is no doubt the piping is set up in many homes in Canada, the United States, and Japan.
In accordance with the CSST Safety Website (below), corrugated stainless tubing is positioned in about 500,000 new homes annually. Since the U.S. Census Bureau and U.S. HUD February 2015 New Construction Data news release reports a seasonally adjusted annual rate of new construction inside the U.S. of about a million homes, that suggests that half of brand-new homes are being built with CSST gas piping.
Or if perhaps we check out the February housing start data this means that almost 100% of the latest homes are using CSST gas piping – which sounds somewhat dubious. In 2014 the United states EIA reported that 27% of U.S. homes were provided with gas and less than 1% with other gases.
I’m a dwelling contractor in Wisconsin, I might like more info on oval tube useful for gas piping in buildings. It feels like manufacturers don’t require that it is secured or strapped greatly at all. ‘m unsure exactly what the codes say concerning this. I’ve seen it snaked almost everywhere without support — and this is a story of a single consequence (quoting from an email into a manufacturer):
I wonder in the event you could give me a perception about support and protection requirements for CSST. I really came back from helping my Brother-in-Law by incorporating issues within his Condo in Boston — he had a sprinkler pop over the winter, so a lot of the drywall would have to be removed to dry things out. Once the restoration contractor removed one portion of drywall, the aroma of gas poured out. CSST ended up being snaked through floor trusses along with looped up in just one location, wherein a pneumatic nail from your wooden flooring installation had punctured it.
Presumably, it provides leaked ever since the building was constructed (a decade ago), and been a hazard the whole time. Any “gas” smell people could have noticed was probably masked by the odor of the garage, as the leak is in the ceiling higher than the garage.
Reading several manufacturers’ installation guides, there doesn’t are most often a requirement to SECURE the gas line at all — it merely needs to be supported every 8′ or more horizontally, right? Inside my Brother-in-Law’s condo, the gas line was snaked across instead of really strapped anywhere, though it was protected by nail plates at stud and joist penetrations. Could this be acceptable, as outlined by your guidelines and any applicable codes?
I ask, because checking this out may be covered by insurance, if it’s seen as a hazard or perhaps not around code or manufacturer’s specifications. Thanks, J.
The manufacturer’s reply was essentially how the CSST must be kept 3″ far from finished surfaces or protected by nail plates if also within 5″ of some constraint (just like a penetration by way of a framing member). Beyond that, they have an “escape” for nail penetrations. This failed to stop the leak I described, as the dexopky14 looped up and was hit with a pneumatically-driven flooring nail… CSST may seem like an incredible thing — easy to install, etc. I wonder if you would do a post on it?
The background and field connection with CSST utilize in The United States triggered concerns about possible pitting, corrosion or perforation of your 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 along with other nearby metal pathways build a potential that may encourage electrical arcing problems for 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 locations where lightning activity is greatest and where the CSST will not be well bonded to some grounding system.
The authors demonstrated that lightning-related electrical arcing damage risk to CSST will be reduced by direct-bonding of the gas piping system towards the building’s electrical ground system: the degree of the electrical charge from an indirect lightning strike was reduced (in their study) from 97% in the charge to 20% by direct electrical bonding on the building’s electrical ground system. Their 2007 report concluded using a recommendation for direct ground bonding of CSST as a proposal towards the National Fuel Gas Code. During 2009 a similar authors reported that CSST could perform acceptably but made important and detailed recommendations for the soil bonding of CSST gas piping systems.
Goodson inside a patent application (2009) also reported on the potency of direct bonding of both yellow and black CSST gas piping to lower the chance of damage from indirect lightning flashing. Goodson explained that CSST was generally not just a good electrical ground, thus lending importance for the “direct bonding” discussion for this particular gas piping system. Stringfellow (2013) continued to report on electrically-induced gas distribution piping.
Currently (2015) the manufacturers have virtually switched to a improved, more durable CSST gas piping whose design incorporates a protective outer jacket and also for which extra manufacturer-specified ground bonding is not required. I feel that only Ward continues to produce the yellow CSST for sale in the United states
In accordance with Jim Narva, executive director from the National Association of State Fire Marshals, that association is focusing on informing homeowners of the necessity for retrofit ground bonding of older CSST installations.
OPINION: I agree that CSST must be resistant to damage, including or possibly specifically after it is run through building cavities where, hidden from view, it’s otherwise too simple for a potential building occupant or worker to shoot a nail or screw from the material. One could feel that excluding concerns for corrosion, similar worries affect (and usually prohibit the usage of) flexible copper tubing when useful for gas piping: it is not routed within building cavities. Instead in those situations it’s present with use steel piping for such gas lines.
Within the CSST installation example specifications listed below you’ll observe 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 such as how and where it might be routed.
Below at left is a good example of a normal steel gas pipe routed by way of a wall cavity during building renovations of any Ny Home. As well as below right you will see the standard change from flexible copper tubing to corrugated stainless steel pipe when the gas piping system had to penetrate the building wall.