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 post describes CSST: carbon steel oval tube tubing employed for gas piping in buildings. Since 1990 CSST has been utilized 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 guard the gas piping from damage by abrasion, puncture, lightning strikes or other hazards. Gas piping codes and industry types 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 minimize 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 post.
Watch out: Let’s avoid a reason for confusion: CSST used as gas piping runs in buildings will not be the identical product as being the flexible gas connector tubing (shown below) utilized 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 using a building as the flexible gas tubing shown below is designed specifically for your connection of gas appliances to the gas piping system.
Try to find corrugated stainless tubing (CSST) used as gas piping in buildings constructed inside the United states or Canada after 1990 plus look for it in older buildings where gas piping was newly installed or modified since 1990. CSST is additionally set up in other countries.
Collapsing building © Daniel FriedmanStandard “yellow” or newer black CSST can be recognized in (usually) long runs between your building gas source and its particular reason for use at gas appliances. The gas appliance connector itself (shown in the photo just above) might be connected directly between the end in the CSST and the appliance, or perhaps the CSST may terminate or be together with black iron gas piping from the same building.
CSST gas piping is run within exposed locations and through building cavities for example walls, ceilings or floors.
Just how many homes have CSST installed? We had trouble relating industry estimates along with us Census data and Usa Energy Information Agency data, but there is no doubt the piping has been set up in many homes in Canada, the United States, and Japan.
In line with the CSST Safety Website (below), corrugated steel tubing is placed in about 500,000 new homes annually. As the U.S. Census Bureau and Usa HUD February 2015 New Construction Data news release reports a seasonally adjusted annual rate of new construction in the Usa of around one million homes, that shows that 1 / 2 of brand new homes are now being constructed with CSST gas piping.
Or maybe we look at the February housing start data this means that almost 100% of the latest homes are utilizing CSST gas piping – which sounds a little dubious. In 2014 the United states EIA reported that 27% of all U.S. homes were provided with gas and much less than 1% with many other gases.
I’m a dwelling contractor in Wisconsin, I might like more details on elliptical tube useful for gas piping in buildings. It appears as though manufacturers don’t require so that it is secured or strapped quite definitely in any way. ‘m unclear precisely what the codes say with that. I’ve seen it snaked just about everywhere without support — and this is a story of merely one consequence (quoting from an email to your manufacturer):
I wonder if you could produce an idea about support and protection requirements for CSST. I recently came back from helping my Brother-in-Law with some issues within his Condo in Boston — he experienced a sprinkler pop across the winter, so the vast majority of drywall would have to be removed to dry things out. As soon as the restoration contractor removed one section of drywall, the odor of gas poured out. CSST have been snaked through floor trusses along with looped up in a single location, where a pneumatic nail in the wood flooring installation had punctured it.
Presumably, it provides leaked ever since the building was constructed (several years ago), and been a hazard the entire time. Any “gas” smell people probably have noticed was probably masked through the aroma of the garage, as the leak was in the ceiling over the garage.
Reading several manufacturers’ installation guides, there doesn’t are a requirement to SECURE the gas line in any way — it really should be supported every 8′ approximately horizontally, right? Within my Brother-in-Law’s condo, the gas line was snaked throughout instead of really strapped anywhere, even though it was protected by nail plates at stud and joist penetrations. Is this acceptable, in accordance with your guidelines and any applicable codes?
I ask, because checking this out might be covered by insurance, if it’s viewed as a hazard or perhaps not as much as code or manufacturer’s specifications. Thanks, J.
The manufacturer’s reply was essentially how the CSST would have to be kept 3″ far from finished surfaces or protected by nail plates if also within 5″ of some constraint (just like a penetration using a framing member). Beyond that, it offers an “escape” for nail penetrations. This did not stop the leak I described, as the dexopky14 looped up and was hit by a pneumatically-driven flooring nail… CSST may seem like an excellent thing — very easy to install, etc. I wonder if you would do an article onto it?
The history and field experience of CSST utilize in Canada And America resulted in concerns about possible pitting, corrosion or perforation in 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 may encourage electrical arcing problems for the CSST gas lines. Such lightning-related electrical arcing can weaken as well as perforate the gas piping creating dangerous gas leaks.
The danger of arcing problems for 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 could be reduced by direct-bonding in the gas piping system towards the building’s electrical ground system: the amount of the electrical charge from an indirect lightning strike was reduced (with their study) from 97% in the charge down to 20% by direct electrical bonding to the building’s electrical ground system. Their 2007 report concluded having a recommendation for direct ground bonding of CSST being a proposal towards the National Fuel Gas Code. During 2009 the identical authors reported that CSST could perform acceptably but made important and detailed tips for the floor bonding of CSST gas piping systems.
Goodson inside a patent application (2009) also reported on the potency of direct bonding of both yellow and black CSST gas piping to reduce the risk of damage from indirect lightning flashing. Goodson explained that CSST was generally not a good electrical ground, thus lending importance towards 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 just about switched to an improved, stronger CSST gas piping whose design contains a protective outer jacket and also for which extra manufacturer-specified ground bonding is not needed. I think that only Ward is constantly produce the yellow CSST easily obtainable in the U.S.
According to Jim Narva, executive director of your National Association of State Fire Marshals, that association is working on informing homeowners of the need for retrofit ground bonding of older CSST installations.
OPINION: I agree that CSST needs to be protected against damage, including or possibly particularly after it is run through building cavities where, hidden from view, it’s otherwise too easy for a potential building occupant or worker to shoot a nail or screw with the material. One would feel that excluding concerns for corrosion, similar worries pertain to (and customarily prohibit using) flexible copper tubing when used for gas piping: it is not 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 below you’ll observe that the makers typically require a variety of installation details to make sure safe reliable operation of the gas piping system, including nail plates, flexible corrugated steel armor in a few locations, support, along with other measures. Some local jurisdictions further detail CSST gas piping installation specifications such as how and where it could be routed.
Below at left is an illustration of a normal steel gas pipe routed using a wall cavity during building renovations of your New York Home. As well as at below right you can see the traditional differ from flexible copper tubing to corrugated stainless steel pipe when the gas piping system were required to penetrate the building wall.