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Protection of CSST in walls

Beniah Naylor

SAWHORSE
Joined
Sep 10, 2020
Messages
661
Location
Manhattan, Kansas
I would be interested to know how other jurisdictions handle the protection of CSST inside walls, especially in exterior walls.

The 2018 IFGC says

404.7.2 Piping installed in other locations. -Where the piping is located within a framing member and is less than 11/2 inches (38 mm) from the framing member face to which wall, ceiling or floor membranes will be attached, the piping shall be protected by shield plates that cover the width and length of the piping. Where the piping is located outside of a framing member and is located less than 11/2 inches (38 mm) from the nearest edge of the face of the framing member to which the membrane will be attached, the piping shall be protected by shield plates that cover the width and length of the piping.

CSST is to be installed according to the manufacturers instructions and the IFGC according to 404.2. The CSST manufacturers say that if the CSST is not secured in place, it can move out of the way of fasteners and does not need protection in those areas where it is free to move. However, the IFGC makes no exception for the protection of CSST that I can find.

I have also heard reports of CSST getting penetrated by pneumatic nail guns when the siding is being installed, but that's just what someone told me.

404.1 Installation of materials. - Materials used shall be installed in strict accordance with the standards under which the materials are accepted and approved. In the absence of such installation procedures, the manufacturer’s instructions shall be followed. Where the requirements of referenced standards or manufacturer’s instructions do not conform to minimum provisions of this code, the provisions of this code shall apply.

So, my reading is that CSST is included in 404.7.2, and would need to be protected for the entire length and width that is within 1 1/2" of the exterior siding or the drywall, it would need to be protected. So, pretty much any time it's installed in a wall, it would need protected from both sides.

But, that is not what the contractors around here are used to, so if we start enforcing it this way, we can expect a lot of push-back.

So, in other jurisdictions, do you accept CSST installed to manufacturers specifications as an acceptable alternative that complies with intent? Or do you make them protect the CSST for it's full length? Or some other method?
 
Build 2x6 walls and fasten the CSST to the center of the stud
CSST manufacturers instructions say to provide 3” of clearance away from screws or nails, which cannot be achieved in an exterior wall with siding on one side and drywall on the other in a 2x6 wall.
 
CSST manufacturers instructions say to provide 3” of clearance away from screws or nails, which cannot be achieved in an exterior wall with siding on one side and drywall on the other in a 2x6 wall.
But it would give you an 1 1/2” on each side, which would comply with the IFGC. So, an AHJ might make a judgment call and decide the IFGC requirements are good enough to satisfy intent. I personally think that 3” is a little overboard.
 
Install per code and manufactured installation instructions.
So, you are saying that you would enforce the most restrictive elements of the IFGC and the manufacturers instructions together? So, protect the CSST for it's entire length and width (IFGC) any time it is within 3" of getting nailed or screwed (Manufacturers Instructions)?
 
I personally think that 3” is a little overboard.
Why? Lots of examples of water lines being hit by nails and screws with supposedly 1-1/2” cover. Results are messy, sometimes expensive. With a gas line, the results range from catastrophic to deadly.
 
So, you are saying that you would enforce the most restrictive elements of the IFGC and the manufacturers instructions together? So, protect the CSST for it's entire length and width (IFGC) any time it is within 3" of getting nailed or screwed (Manufacturers Instructions)?
Yes. The more restrictive requirements apply - after all, we are talking about a serious and potential fire/life/safety risk.
 
Why? Lots of examples of water lines being hit by nails and screws with supposedly 1-1/2” cover. Results are messy, sometimes expensive. With a gas line, the results range from catastrophic to deadly.
You aren’t wrong, the things happen and the stakes are high. The only reason I said that is that it isn’t consistent with the 1 1/2” or 1 1/4” clearance that we enforce on all other MEP, and it isn’t in fuel gas code either. When I read that in the installation manual, it sounded to me more like a lawyer was involved than a subject matter expert.

You have to admit, if you tell a court that you were hanging Sheetrock with 4” screws, you won’t get any sympathy for hitting a gas line.
 
The last house I rented had two one-car garages below a 2 bed house, one garage was the landlords. She had a handyperson installing some shelves using 3 inch screws. One hit the feeder and killed the power. She was lucky it didn't start a fire. Had it been a gas line how long would it have gone unnoticed? If gas levels built up to the flammable levels (stoichiometry?) would there be an explosion? Who knows. Incidentally I discovered she covertly had the power for her garage running off of my meter. I moved out a month or two later.
 
Not an excuse ....but do you guys know how many miles of CSST is installed with no oversight? Many is the answer. The usual outcome when I inspect CSST is a switch to iron pipe.
 
404.7.1 seems to imply that you only protect the piping that is within 4 inches of the hole or notch in the framing member that the pipe passes through. Why does section 404.7.1 talk about nail plates overhanging the edges of framing members like top and bottom plates, when 404.7.2 says that any piping located inside or outside of a framing member must be protected?

It seems like 404.7.1 should be deleted from the code entirely, since it is impossible to comply with 404.7.2 without complying with 404.7.1, but not vice versa. Unless I'm missing something...
 
# ~ # ~ #

Beniah,

How are you going to force the use of black iron pipe ?
CSST is an approved type of piping that can be used.
Also, ...in this neck `o the woods, having someone
competent to actually know how to install black iron
pipe & pass a pressure test would be a miracle !.....It

may be the same way in your area as well.........The
art of pipe fitting is a lost skill set for the masses.
Nowadays, ...everything is geared towards fast
installations, which includes CSST piping and protection
plates.


# ~ # ~ #
 
If csst is installed within a wall and clearance can’t be obtained, csst manufactures make a slinky. It’s a protective semi flexible metal slinky like sleeve that is intended for this scenario. It can be purchased on a roll or in sections.

 
With assistance from our gas provider, by policy, we do not allow CSST to be installed in any exterior wall.


We enforce, they do not connect till the inspection passes.
 
With assistance from our gas provider, by policy, we do not allow CSST to be installed in any exterior wall.


We enforce, they do not connect till the inspection passes.


That is quite a stance for a code approved product.
Is that just your municipality or a state prohibition?
Any other areas you know of?
 
The gas suppliers are overstepping IMO....ours here will not hook up or energize unless it has an additional bond (black or yellow) I hear....And then I tell the customer that they really have no authority inside the dwelling if they want to pursue that...
 
"Is that just your municipality or a state prohibition?
Any other areas you know of?"

Just our municipality.

Multiple instances of leaks in exterior walls due to penetrations. Several from siding installers, missing studs altogether, wildly.

Hasn't been a problem, in place for years.
 
# ~ # ~ #

Beniah,

How are you going to force the use of black iron pipe ?
CSST is an approved type of piping that can be used.
Also, ...in this neck `o the woods, having someone
competent to actually know how to install black iron
pipe & pass a pressure test would be a miracle !.....It

may be the same way in your area as well.........The
art of pipe fitting is a lost skill set for the masses.
Nowadays, ...everything is geared towards fast
installations, which includes CSST piping and protection
plates.


# ~ # ~ #
North Star, I do not want to try to force the use of black pipe, for most of the reasons you stated. We do have plumbers who can pass air tests with black pipe, thankfully, but there are inherent disadvantages (like with any material).

However, if we were to enforce the protection of of CSST for it's entire length like 404.7.2 says, any time it is within 3" of a membrane, like Gastite says, that would basically mean that any time CSST drops down in a wall to the gas meter, it would have to be protected from both sides for it's entire length. Cursory investigation online seems to show that it is about twice as expensive (at least in materials) to run CSST and protect it from both sides in a wall with either shield plates or a protective sleeve, than it would be to run black pipe up through the wall until you get above ceiling where you can transition to un-protected CSST, since the CSST would probably be more than 3" from any nailing surface.

I don't mind if contractors want to use CSST in walls if they are willing to protect it from both sides and they can make it sturdy enough to mount a meter on. There are plenty of proprietary CSST meter install kits to make that work if the plumber wants to go that route. In my opinion, it will just be more expensive and difficult for the plumber to do it that way, but if they want to it doesn't bother me.
 
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