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 article describes CSST: carbon steel oval tube tubing employed for gas piping in buildings. Since 1990 CSST has been utilized within many buildings both in exposed and enclosed areas to set up new gas system piping. The article discusses CSST uses, sources, installation specifications, and safety measures to shield the gas piping from damage by abrasion, puncture, lightning strikes or any 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 installing of 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 reduce probability 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 on this page.
Watch out: Let’s avoid a point of confusion: CSST used as gas piping runs in buildings is just not the identical product because the flexible gas connector tubing (shown below) used to actually connect gas appliances towards the gas supply system, and other installation and product protection measures are needed. CSST gas piping is used to route gas or LP gas supply using a building even though the flexible gas tubing shown below is designed specifically for the connection of gas appliances towards the gas piping system.
Try to find corrugated stainless tubing (CSST) used as gas piping in buildings constructed from the Usa or Canada after 1990 plus try to find it in older buildings where gas piping was newly installed or modified since 1990. CSST is also 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 reason for use at gas appliances. The gas appliance connector itself (shown in the photo just above) could be connected directly involving the end of the CSST and also the appliance, or the CSST may terminate or even be mixed with black iron gas piping within the same building.
CSST gas piping is run both in exposed locations and thru building cavities including 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 that the piping is placed in many homes in Canada, the us, and Japan.
Based on the CSST Safety Website (below), corrugated stainless-steel tubing is set up in about 500,000 new homes each year. As the United states Census Bureau and U.S. HUD February 2015 New Construction Data news release reports a seasonally adjusted annual rate of the latest construction in the U.S. of approximately a million homes, that implies that one half of brand new homes are now being created with CSST gas piping.
Or if we consider the February housing start data this means that almost 100% of new homes use CSST gas piping – which sounds a bit dubious. In 2014 the United states EIA reported that 27% of all Usa homes were provided with natural gas and much less than 1% along with other gases.
I’m a dwelling contractor in Wisconsin, I might like more info on elliptical tube employed for gas piping in buildings. It appears as though manufacturers don’t require it to be secured or strapped quite definitely by any means. ‘m not sure exactly what the codes say about that. I’ve seen it snaked everywhere without support — and what follows is a story of merely one consequence (quoting from a message to your manufacturer):
I wonder when you could produce an understanding about support and protection requirements for CSST. I just came back from helping my Brother-in-Law with just a few issues in their Condo in Boston — he experienced a sprinkler pop within the winter, so a lot of the drywall would have to be removed to dry things out. If 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, when a pneumatic nail from your wooden flooring installation had punctured it.
Presumably, it has leaked because the building was constructed (ten years ago), and been a hazard the whole time. Any “gas” smell people could have noticed was probably masked with the smell of the garage, for the reason that leak is in the ceiling higher than the garage.
Reading a number of manufacturers’ installation guides, there doesn’t appear to be a requirement to SECURE the gas line in any way — it just has to be supported every 8′ or more horizontally, right? Inside my Brother-in-Law’s condo, the gas line was snaked all over and not really strapped anywhere, even though it was protected by nail plates at stud and joist penetrations. Is this acceptable, according to your guidelines as well as applicable codes?
I ask, because checking this out can be covered with insurance, if it’s viewed as a hazard or otherwise around code or manufacturer’s specifications. Thanks, J.
The manufacturer’s reply was essentially the CSST should 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, they have an “escape” for nail penetrations. This did not avoid the leak I described, as being the dexopky14 looped up and was hit with a pneumatically-driven flooring nail… CSST appears like a fantastic thing — an easy task to install, etc. I wonder in the event you would do an article into it?
The historical past and field experience of CSST use within North America led to concerns about possible pitting, corrosion or perforation in 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 other nearby metal pathways develop a potential that could 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 harm to CSST is increased in places that lightning activity is greatest and where the CSST is not well bonded into a grounding system.
The authors demonstrated that lightning-related electrical arcing damage risk to CSST would be reduced by direct-bonding of your gas piping system to the building’s electrical ground system: the quantity of the electrical charge from an indirect lightning strike was reduced (with their study) from 97% in the charge right down to 20% by direct electrical bonding towards the building’s electrical ground system. Their 2007 report concluded using a recommendation for direct ground bonding of CSST as being a proposal towards the National Fuel Gas Code. In 2009 the same authors reported that CSST could perform acceptably but made important and detailed tips for the floor 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 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 just for this gas piping system. Stringfellow (2013) continued to report on electrically-induced gas distribution piping.
Currently (2015) the makers have pretty much switched to a improved, more durable CSST gas piping whose design incorporates a protective outer jacket as well as for which extra manufacturer-specified ground bonding is not required. I do believe that only Ward continues to make 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 working on informing homeowners of the demand for retrofit ground bonding of older CSST installations.
OPINION: I agree that CSST has to be protected against damage, including or maybe in particular when 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 throughout the material. One could assume that excluding concerns for corrosion, similar worries relate to (and generally prohibit the usage of) flexible copper tubing when utilized for gas piping: it is not routed within building cavities. Instead in those situations it’s common to use steel piping for such gas lines.
Inside the CSST installation example specifications listed below you’ll notice that the manufacturers typically require several installation details to ensure safe reliable operation of your gas piping system, including nail plates, flexible corrugated steel armor in a few locations, support, and other measures. Some local jurisdictions further detail CSST gas piping installation specifications including how and where it could be routed.
Below at left is an illustration of a regular steel gas pipe routed by way of a wall cavity during building renovations of any New York Home. As well as below right you will notice the conventional change from flexible copper tubing to corrugated stainless steel pipe when the gas piping system needed to penetrate the construction wall.