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 short article describes CSST: carbon steel oval tube tubing employed for gas piping in buildings. Since 1990 CSST has been used within many buildings within both exposed and enclosed areas to setup new gas system piping. This article discusses CSST uses, sources, installation specifications, and security measures to guard the gas piping from damage by abrasion, puncture, lightning strikes or any other hazards. Gas piping codes and industry causes of 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 within a wet area. Yellow “Standard” CSST gas pipin galso requires special electrical ground bonding to reduce risk of damage & leaks in aspects 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 the following paragraphs.
Watch out: Let’s avoid a point of confusion: CSST used as gas piping runs in buildings will not be the same product as the flexible gas connector tubing (shown below) accustomed to actually connect gas appliances on the gas supply system, and various installation and product protection measures will be required. CSST gas piping is commonly used to route natural gas or LP gas supply by way of a building even though the flexible gas tubing shown below is specifically made for that connection of gas appliances for the gas piping system.
Try to find corrugated stainless-steel tubing (CSST) used as gas piping in buildings constructed within the United states or Canada after 1990 as well as look for it in older buildings where gas piping was newly installed or modified since 1990. CSST is likewise placed in other countries.
Collapsing building © Daniel FriedmanStandard “yellow” or newer black CSST might be recognized in (usually) long runs between the building gas source along with its point of use at gas appliances. The gas appliance connector itself (shown in the photo just above) may be connected directly between your end in the CSST and also the appliance, or even the CSST may terminate or even be together with black iron gas piping in the same building.
CSST gas piping is run in exposed locations and through building cavities such as walls, ceilings or floors.
The number of 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 how the piping has been installed in many homes in Canada, the usa, and Japan.
Based on the CSST Safety Website (below), corrugated stainless-steel tubing is installed in about 500,000 new homes annually. Since the Usa Census Bureau and United states HUD February 2015 New Construction Data news release reports a seasonally adjusted annual rate of the latest construction from the Usa of around one million homes, that demonstrates that one half of brand-new homes are created with CSST gas piping.
Or maybe we consider the February housing start data that means that almost 100% of brand new homes are utilizing CSST gas piping – which sounds a bit dubious. In 2014 the Usa EIA reported that 27% of all the United states homes were supplied with gas and much less than 1% along with other gases.
I’m a dwelling contractor in Wisconsin, I would personally like more information on oval tube useful for gas piping in buildings. It appears as though manufacturers don’t require so that it is secured or strapped greatly whatsoever. ‘m not sure precisely what the codes say about this. I’ve seen it snaked almost everywhere without support — and this is a story of a single consequence (quoting from a message to a manufacturer):
I wonder in the event you could produce a perception about support and protection requirements for CSST. I recently came back from helping my Brother-in-Law by incorporating issues in his Condo in Boston — he experienced a sprinkler pop on the winter, so many of the drywall needed to be removed to dry things out. When the restoration contractor removed one area of drywall, the aroma of gas poured out. CSST ended up being snaked through floor trusses and had looped up in a location, where a pneumatic nail through the wooden flooring installation had punctured it.
Presumably, it provides leaked because the building was constructed (10 years ago), and been a hazard the entire time. Any “gas” smell people could have noticed was probably masked by the odor of the garage, since the leak is at the ceiling on top of the garage.
Reading a couple of manufacturers’ installation guides, there doesn’t are most often a requirement to SECURE the gas line at all — it merely must be supported every 8′ or so horizontally, right? Inside my Brother-in-Law’s condo, the gas line was snaked across rather than really strapped anywhere, while it was protected by nail plates at stud and joist penetrations. Is this acceptable, as outlined by your guidelines as well as applicable codes?
I ask, because checking this out can be covered by insurance, if it’s viewed as a hazard or otherwise up to code or manufacturer’s specifications. Thanks, J.
The manufacturer’s reply was essentially how the CSST would have to be kept 3″ clear of 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 from a pneumatically-driven flooring nail… CSST appears like a fantastic thing — an easy task to install, etc. I wonder should you would do a post upon it?
The historical past and field experience of CSST utilize in America generated concerns about possible pitting, corrosion or perforation from the original yellow CSST gas piping in places that lightning strikes were common. Kraft and Torbin (2007) explained that arcing between poorly-grounded CSST gas piping and also other nearby metal pathways create a potential that could encourage electrical arcing problems for the CSST gas lines. Such lightning-related electrical arcing can weaken or perhaps perforate the gas piping leading to dangerous gas leaks.
The potential risk of arcing injury to CSST is increased in locations where lightning activity is greatest and where the CSST is not really well bonded to some grounding system.
The authors demonstrated that lightning-related electrical arcing damage risk to CSST will be reduced by direct-bonding in the gas piping system on the building’s electrical ground system: the degree of the electrical charge from an indirect lightning strike was reduced (inside their study) from 97% of your charge as a result of 20% by direct electrical bonding to the building’s electrical ground system. Their 2007 report concluded using a recommendation for direct ground bonding of CSST as a proposal for the National Fuel Gas Code. During 2009 exactly the same authors reported that CSST could perform acceptably but made important and detailed strategies for the earth bonding of CSST gas piping systems.
Goodson in a patent application (2009) also reported on the strength of direct bonding of both yellow and black CSST gas piping to lower the danger of damage from indirect lightning flashing. Goodson explained that CSST was generally not really 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 virtually switched for an improved, more durable CSST gas piping whose design features a protective outer jacket as well as for which extra manufacturer-specified ground bonding is not needed. I feel that only Ward is constantly produce the yellow CSST accessible in the Usa
Based on Jim Narva, executive director of the National Association of State Fire Marshals, that association is centering on informing homeowners of the demand for retrofit ground bonding of older CSST installations.
OPINION: I agree that CSST must be protected against damage, including or perhaps especially after it is run through building cavities where, hidden from view, it’s otherwise too simple for a future building occupant or worker to shoot a nail or screw from the material. One could assume that excluding concerns for corrosion, similar worries affect (and usually prohibit the use of) flexible copper tubing when employed for gas piping: it is not necessarily routed within building cavities. Instead in those situations it’s common to use steel piping for such gas lines.
In the CSST installation example specifications shown below you’ll observe that the makers typically require numerous installation details to make sure safe reliable operation in the gas piping system, including nail plates, flexible corrugated steel armor in certain locations, support, as well as other measures. Some local jurisdictions further detail CSST gas piping installation specifications for example where and how it might be routed.
Below at left is an example of a normal steel gas pipe routed using a wall cavity during building renovations of the New York City Home. As well as below right you can see the standard change from flexible copper tubing to CSST tube if the gas piping system was required to penetrate the building wall.