Corrugated stainless 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 used for gas piping in buildings. Since 1990 CSST has been used within many buildings in both exposed and enclosed areas to put in new gas system piping. This article discusses CSST uses, sources, installation specifications, and safety measures to shield the gas piping from damage by abrasion, puncture, lightning strikes or another 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 installing 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 minimize 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 point of confusion: CSST used as gas piping runs in buildings is not really a similar product as being the flexible gas connector tubing (shown below) accustomed to actually connect gas appliances towards the gas supply system, and various installation and product protection measures are essential. CSST gas piping is utilized to route gas or LP gas supply via a building even though the flexible gas tubing shown below is specifically designed for the connection of gas appliances to the gas piping system.
Try to find corrugated stainless steel tubing (CSST) used as gas piping in buildings constructed inside the U.S. or Canada after 1990 and in addition try to find it in older buildings where gas piping was newly installed or modified since 1990. CSST is also positioned 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 point of use at gas appliances. The gas appliance connector itself (shown in the photo just above) might be connected directly between your end from the CSST as well as the appliance, or perhaps the CSST may terminate or perhaps be mixed with black iron gas piping within the same building.
CSST gas piping is run within exposed locations and thru 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 Usa Energy Information Agency data, but there is no doubt that this piping is installed in many homes in Canada, the United States, and Japan.
According to the CSST Safety Website (below), corrugated stainless tubing is placed in about 500,000 new homes annually. As 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 within the Usa around a million homes, that demonstrates that 1 / 2 of brand-new homes are now being constructed with CSST gas piping.
Or if perhaps we glance at the February housing start data because of this almost 100% of new homes are utilizing CSST gas piping – which sounds a lttle bit dubious. In 2014 the United states EIA reported that 27% of all the Usa homes were supplied with natural gas and much less than 1% with some other gases.
I’m a dwelling contractor in Wisconsin, I would personally like additional information on steel oval tube utilized for gas piping in buildings. It seems like manufacturers don’t require it to be secured or strapped significantly by any means. ‘m unclear exactly what the codes say about that. I’ve seen it snaked just about everywhere without support — and here is a story of merely one consequence (quoting from an e-mail into a manufacturer):
I wonder in the event you could supply a concept about support and protection requirements for CSST. I recently came back from helping my Brother-in-Law with just a few issues within his Condo in Boston — he had a sprinkler pop over the winter, so a lot of the drywall needed to be removed to dry things out. As soon as the restoration contractor removed one area of drywall, the scent of gas poured out. CSST had been snaked through floor trusses and had looped up in just one location, when a pneumatic nail from the hardwood flooring installation had punctured it.
Presumably, it provides leaked because the building was constructed (ten years ago), and been a hazard the entire time. Any “gas” smell people might have noticed was probably masked through the aroma of the garage, as the leak is in the ceiling above the garage.
Reading a couple of manufacturers’ installation guides, there doesn’t are most often a requirement to SECURE the gas line whatsoever — it just has to be supported every 8′ approximately horizontally, right? During my Brother-in-Law’s condo, the gas line was snaked throughout rather than really strapped anywhere, while it was protected by nail plates at stud and joist penetrations. Is that this acceptable, as outlined by your guidelines and then any applicable codes?
I ask, because checking this out might be covered with insurance, if it’s viewed as a hazard or perhaps not up to code or manufacturer’s specifications. Thanks, J.
The manufacturer’s reply was essentially the CSST needed to be kept 3″ away from finished surfaces or protected by nail plates if also within 5″ of some constraint (like a penetration by way of a framing member). Beyond that, it offers an “escape” for nail penetrations. This failed to stop 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 — simple to install, etc. I wonder should you would do a post upon it?
The background and field experience with CSST use in America generated concerns about possible pitting, corrosion or perforation from the original yellow CSST gas piping in locations where lightning strikes were common. Kraft and Torbin (2007) explained that arcing between poorly-grounded CSST gas piping as well as other nearby metal pathways produce a potential that could 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 danger of arcing damage to CSST is increased in places that lightning activity is greatest and the location where the CSST will not be well bonded into a 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 for the building’s electrical ground system: the level 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 with a recommendation for direct ground bonding of CSST as a proposal for the National Fuel Gas Code. During 2009 the same authors reported that CSST could perform acceptably but made important and detailed ideas for the ground bonding of CSST gas piping systems.
Goodson in the patent application (2009) also reported on the potency of direct bonding of both yellow and black CSST gas piping to minimize the chance of damage from indirect lightning flashing. Goodson explained that CSST was generally not really a good electrical ground, thus lending importance on 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 just about switched to an improved, more durable CSST gas piping whose design includes a protective outer jacket and then for which extra manufacturer-specified ground bonding is not needed. I believe that only Ward consistently produce the yellow CSST for sale in the U.S.
Based on Jim Narva, executive director in 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 should be protected from damage, including or perhaps particularly when it is run through building cavities where, hidden from view, it’s otherwise too easy for a future building occupant or worker to shoot a nail or screw through the material. One would think that excluding concerns for corrosion, similar worries pertain to (and customarily prohibit the usage of) flexible copper tubing when employed 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.
Within the CSST installation example specifications listed here you’ll observe that the makers typically require several installation details to ensure safe reliable operation of your gas piping system, including nail plates, flexible corrugated steel armor in some locations, support, and also other measures. Some local jurisdictions further detail CSST gas piping installation specifications for example where and how it can be routed.
Below at left is a good example of a traditional steel gas pipe routed through a wall cavity during building renovations of a New York Home. And at below right you will notice the standard vary from flexible copper tubing to stainless steel gas pipe as soon as the gas piping system needed to penetrate your building wall.