Corrugated stainless tubing utilized 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 used for gas piping in buildings. Since 1990 CSST has been utilized within many buildings both in exposed and enclosed areas to install new gas system piping. This content discusses CSST uses, sources, installation specifications, and security measures to protect the gas piping from damage by abrasion, puncture, lightning strikes or another hazards. Gas piping codes and industry types of CSST are included.
Our page top photo, provided courtesy of Carson Dunlop Associates, a Toronto home inspection & education firm, illustrates an improper installing of standard yellow CSST gas piping – routed in ground contact inside a wet area. Yellow “Standard” CSST gas pipin galso requires special electrical ground bonding to reduce risk of damage & leaks in parts 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 may well not require special bonding.
Black CSST gas piping, adapted from GasTite’s FlashShield sales literature cited in this article.
Watch out: Let’s avoid a reason for confusion: CSST used as gas piping runs in buildings is not the identical product since the flexible gas connector tubing (shown below) employed to actually connect gas appliances to the gas supply system, as well as other installation and product protection measures are needed. CSST gas piping is used to route gas or LP gas supply by way of a building even though the flexible gas tubing shown below is specifically designed to the connection of gas appliances on the gas piping system.
Seek out corrugated stainless steel tubing (CSST) used as gas piping in buildings constructed in the Usa or Canada after 1990 plus search for it in older buildings where gas piping was newly installed or modified since 1990. CSST is additionally 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 and its particular point of use at gas appliances. The gas appliance connector itself (shown in the photo just above) might be connected directly in between the end from the CSST as well as the appliance, or maybe the CSST may terminate or even be together with black iron gas piping within the same building.
CSST gas piping is run both in exposed locations and thru building cavities for example walls, ceilings or floors.
The number of homes have CSST installed? We had trouble relating industry estimates along with us Census data and U.S. Energy Information Agency data, but there is no doubt how the piping is installed in many homes in Canada, the usa, and Japan.
According to the CSST Safety Website (below), corrugated stainless-steel tubing is set up in about 500,000 new homes each year. As being the U.S. Census Bureau and United states HUD February 2015 New Construction Data news release reports a seasonally adjusted annual rate of the latest construction in the United states of around a million homes, that demonstrates that 50 % of brand-new homes are being built with CSST gas piping.
Or maybe we look at the February housing start data this means that almost 100% newest homes use CSST gas piping – which sounds a bit dubious. In 2014 the U.S. EIA reported that 27% of all the U.S. homes were supplied with natural gas and less than 1% along with other gases.
I’m a dwelling contractor in Wisconsin, I would like more details on elliptical tube useful for gas piping in buildings. It appears as though manufacturers don’t require that it is secured or strapped significantly in any way. ‘m not sure exactly what the codes say concerning this. I’ve seen it snaked just about everywhere without support — and what follows is a story of one consequence (quoting from an e-mail to some manufacturer):
I wonder when you could supply a concept about support and protection requirements for CSST. I simply came back from helping my Brother-in-Law by incorporating issues in the Condo in Boston — he had a sprinkler pop across the winter, so the vast majority of drywall needed to be removed to dry things out. Once the restoration contractor removed one section of drywall, the aroma of gas poured out. CSST was snaked through floor trusses and had looped up in one location, when a pneumatic nail in the hardwood flooring installation had punctured it.
Presumably, it has leaked because the building was constructed (a decade ago), and been a hazard the whole time. Any “gas” smell people could have noticed was probably masked with the aroma of the garage, since the leak is in the ceiling higher than the garage.
Reading a number of manufacturers’ installation guides, there doesn’t seem to be a requirement to SECURE the gas line in any way — it merely needs to be supported every 8′ or so horizontally, right? Within my Brother-in-Law’s condo, the gas line was snaked all over and not really strapped anywhere, although it was protected by nail plates at stud and joist penetrations. Could this be acceptable, based on your guidelines and then any applicable codes?
I ask, because checking this out can be covered with insurance, if it’s seen as a hazard or otherwise up to code or manufacturer’s specifications. Thanks, J.
The manufacturer’s reply was essentially how the CSST must be kept 3″ clear of finished surfaces or protected by nail plates if also within 5″ of some constraint (like a penetration using a framing member). Beyond that, it offers an “escape” for nail penetrations. This failed to avoid the leak I described, because the dexopky14 looped up and was hit by way of a pneumatically-driven flooring nail… CSST may seem like a great thing — simple to install, etc. I wonder in the event you would do an article upon it?
The background and field experience with CSST utilize in The United States resulted in concerns about possible pitting, corrosion or perforation of 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 as well as other nearby metal pathways develop a potential which may encourage electrical arcing damage to the CSST gas lines. Such lightning-related electrical arcing can weaken or perhaps perforate the gas piping leading to dangerous gas leaks.
The chance of arcing injury to CSST is increased in areas where lightning activity is greatest and the location where the CSST will not be well bonded to some 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 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% of your charge as a result of 20% by direct electrical bonding to the building’s electrical ground system. Their 2007 report concluded with a recommendation for direct ground bonding of CSST as a proposal towards the National Fuel Gas Code. During 2009 the same authors reported that CSST could perform acceptably but made important and detailed ideas for the soil bonding of CSST gas piping systems.
Goodson inside a patent application (2009) also reported on the effectiveness 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 towards the “direct bonding” discussion just for this gas piping system. Stringfellow (2013) continued to report on electrically-induced gas distribution piping.
Currently (2015) the makers have just about switched to an improved, more durable CSST gas piping whose design incorporates a protective outer jacket and for which extra manufacturer-specified ground bonding is not required. I feel that only Ward consistently make the yellow CSST easily obtainable in the Usa
In accordance with Jim Narva, executive director of 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 must be shielded from damage, including or possibly specifically after it is run through building cavities where, hidden from view, it’s otherwise too easier for a future building occupant or worker to shoot a nail or screw from the material. One could feel that excluding concerns for corrosion, similar worries pertain to (and customarily prohibit the use of) 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.
In the CSST installation example specifications listed here you’ll see that the makers typically require a variety of installation details to assure safe reliable operation in the gas piping system, including nail plates, flexible corrugated steel armor in certain locations, support, and also other measures. Some local jurisdictions further detail CSST gas piping installation specifications like where and how it could be routed.
Below at left is a good example of a regular steel gas pipe routed through a wall cavity during building renovations of your New York City Home. As well as at below right you will see the traditional change from flexible copper tubing to CSST tube as soon as the gas piping system was required to penetrate the building wall.