Corrugated 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: corrugated steel pipe tubing utilized for gas piping in buildings. Since 1990 CSST has been used within many buildings within both exposed and enclosed areas to set up new gas system piping. The article 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 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 lower likelihood of damage & leaks in regions 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 on this page.
Watch out: Let’s avoid a point of confusion: CSST used as gas piping runs in buildings is not the same product as the flexible gas connector tubing (shown below) employed to actually connect gas appliances for the gas supply system, and other installation and product protection measures will be required. CSST gas piping is used to route natural gas or LP gas supply by way of a building while the flexible gas tubing shown below is specifically made for your connection of gas appliances towards the gas piping system.
Look for corrugated steel tubing (CSST) used as gas piping in buildings constructed from the U.S. or Canada after 1990 plus seek out it in older buildings where gas piping was newly installed or modified since 1990. CSST is also set up in other countries.
Collapsing building © Daniel FriedmanStandard “yellow” or newer black CSST can be recognized in (usually) long runs in between the building gas source and its reason for use at gas appliances. The gas appliance connector itself (shown within the photo just above) might be connected directly between your end from the CSST and also the appliance, or the CSST may terminate or perhaps be blended with black iron gas piping inside the same building.
CSST gas piping is run both in exposed locations and through building cavities including 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 that the piping continues to be positioned in many homes in Canada, america, and Japan.
Based on the CSST Safety Website (below), corrugated steel tubing is placed in about 500,000 new homes each year. As being the Usa Census Bureau and United states HUD February 2015 New Construction Data news release reports a seasonally adjusted annual rate newest construction within the Usa around 1 million homes, that suggests that one half of all new homes are increasingly being created with CSST gas piping.
Or if perhaps we glance at the February housing start data this means that almost 100% of the latest homes use CSST gas piping – which sounds a bit dubious. In 2014 the Usa EIA reported that 27% of U.S. homes were supplied with gas and much less than 1% with other gases.
I’m a dwelling contractor in Wisconsin, I would like more info on oval tube useful for gas piping in buildings. It appears as if manufacturers don’t require it to be secured or strapped significantly in any way. ‘m unclear just what the codes say concerning this. I’ve seen it snaked just about everywhere without support — and listed here is a story of merely one consequence (quoting from an e-mail into a manufacturer):
I wonder when you could deliver an understanding about support and protection requirements for CSST. I simply came back from helping my Brother-in-Law with a few issues in his Condo in Boston — he possessed a sprinkler pop over the winter, so a lot of the drywall would have to be removed to dry things out. If the restoration contractor removed one portion of drywall, the odor of gas poured out. CSST had been snaked through floor trusses along with looped up in just one location, where a pneumatic nail in the wooden flooring installation had punctured it.
Presumably, they have leaked since the building was constructed (10 years ago), and been a hazard the entire time. Any “gas” smell people probably have noticed was probably masked through the odor of the garage, since the leak was in the ceiling above the garage.
Reading a few manufacturers’ installation guides, there doesn’t are a requirement to SECURE the gas line by any means — it merely must be supported every 8′ approximately horizontally, right? Inside my Brother-in-Law’s condo, the gas line was snaked across and not really strapped anywhere, though it was protected by nail plates at stud and joist penetrations. Could this be acceptable, according to your guidelines and any applicable codes?
I ask, because checking this out might 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 that this CSST must be kept 3″ 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 prevent the leak I described, because the dexopky14 looped up and was hit with a pneumatically-driven flooring nail… CSST may seem like a fantastic thing — very easy to install, etc. I wonder should you would do a post into it?
The history and field experience of CSST utilize in Canada And America generated 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 create a potential that could encourage electrical arcing damage to the CSST gas lines. Such lightning-related electrical arcing can weaken and even perforate the gas piping creating dangerous gas leaks.
The potential risk of arcing problems for CSST is increased in areas where lightning activity is greatest and where CSST will not be 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 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 the charge to 20% by direct electrical bonding to the building’s electrical ground system. Their 2007 report concluded by using a recommendation for direct ground bonding of CSST being a proposal for the National Fuel Gas Code. In 2009 the identical authors reported that CSST could perform acceptably but made important and detailed strategies for the ground 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 lessen the potential risk of damage from indirect lightning flashing. Goodson explained that CSST was generally not 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 manufacturers have basically switched with an improved, stronger CSST gas piping whose design includes a protective outer jacket and also for which extra manufacturer-specified ground bonding is not required. I believe that only Ward is constantly produce the yellow CSST accessible in the United states
In accordance with Jim Narva, executive director of your National Association of State Fire Marshals, that association is working on informing homeowners of the necessity for retrofit ground bonding of older CSST installations.
OPINION: I agree that CSST needs to be shielded from damage, including or simply specifically 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 through the material. One could believe that excluding concerns for corrosion, similar worries pertain to (and generally prohibit using) flexible copper tubing when used for gas piping: it is not necessarily 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 here you’ll notice that the manufacturers typically require numerous installation details to ensure safe reliable operation of your 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 how and where it may be routed.
Below at left is a good example of a regular steel gas pipe routed using a wall cavity during building renovations of the New York City Home. As well as at below right you can observe the standard differ from flexible copper tubing to corrugated stainless steel pipe when the gas piping system needed to penetrate the property wall.