CSST through inaccessable crawlspace

[Harry Shen]

Hello,

I am looking to have a gas fireplace installed and was looking at the the possibility of running 1/2" CSST for the install. I will have a qualified installer do the connections, however I am doing the planning, layout, etc. I need opinion on whether the below is considered safe.

One portion of my home has a basement and another portion (a later addition) has a crawlspace. There is no access to the crawlspace. There are two exterior vents in the crawlspace for ventilation though. Above the crawlspace is our living room where we want to install a gas fireplace in a corner that is opposite and away from the basement. The gas meter and all gas piping is in the basement right next to the crawlspace. The location of the fireplace is at the further/opposite end of the crawlspace from the basement.

Plumbers have taken a look and suggested a few options such as going through the attic or going from outside the house for running gas lines. However the one option that seems the simplest and the one on which I have done some work so far is as below:

I have made a 2" hole in the sill plate from the basement and pushed a 1" schedule 40 conduit all the way to the other end (its about 20 feet), then made a 1 1/2 " hole in the floor in the corner behind the fireplace right above where the conduit extends. In the conduit I also had already run two strong 1/4" polypropylene ropes that I had made a loop at the end and left sticking out the conduit. I fish for these ropes from the hole in the floor and one of the poly ropes I attach and secure to the the floor with a screw so that the conduit is not resting on the crawlspace floor, but is hung by by the rope. The other end of the rope I secure and attach in the basement to the sill plate. The conduit now rests on the sill plate in the basement on one end and is secured by the nylon rope on the other end and so does not sag nor rest on the crawlspace floor.

All the installer needs to do now is to use the other nylon rope to pull the CSST through the conduit and through the hole in the floor and then terminate it with the CSST termination plate and valve.

Since the crawlspace is vented, any leak of the CSST within the crawlspace is probably going to be aired by the crawlspace vents. Future repairs to the CSST can be made if all needed by pulling only the CSST out of the conduit after unhooking it from the gas value at the appliance end. The CSST is well supported by the conduit thus not hanging by itself nor lying on the crawlspace floor.

I would appreciate any comments on such an installation, especially the safety aspect. I understand this is non-standard but its an older house and have to think outside the box to make such things work, make it cost effective and of course it has to be safe.
Thanks,
Harry

Note the CSST will be bonded.

[Chris McIntyre]

Rope is not an accepted method for securing conduit.
Any leak would leak from the ends of the conduit, (into the basement).
IRC R408.4 Access shall be provided to all under-floor spaces....
That's just for starters.

Adding the required access to the crawl space would allow the installer to install the gas line safely and per code.

[Aaron Miller]

CSST is a poor choice. Why not use real threaded steel gas piping - and have it installed by a real plumber? Gas is not for DIY. Splurge. Save a life; it could be your own.

[Joe Funderburk]

CSST is a poor choice.

Why do you say that?

[Joe Funderburk]

There is no requirement to run CSST through conduit. CSST can be concealed in building cavities. I see no reason code-wise that you can't run the CSST through the crawl space. I believe there is a restriction on couplings in concealed areas, so read the manual. Check the manufacturer's requirements for support methods.

P.S. CSST requires that the gas system be bonded from the rigid pipe to the house ground bus or grounding electrode. I suppose you are aware of that.

[Aaron Miller]

Why do you say that?

CSST is to threaded steel as PEX is to copper tubing. Created by the builders and for the builders. Cheaper is not always better. In fact, it is almost never.

[Aaron Miller]

P.S. CSST requires that the gas system be bonded from the rigid pipe to the house ground bus or grounding electrode. I suppose you are aware of that.

Yes, and no. That depends on the type of CSST used.

[Joe Funderburk]

Yes, and no. That depends on the type of CSST used.

True. Counterstrike does not require it.

[Joe Funderburk]

CSST is to threaded steel as PEX is to copper tubing. Created by the builders and for the builders. Cheaper is not always better. In fact, it is almost never.

I'd rather have PEX than copper water supply myself. No galvanic reactions. No corrosion. Easier to repair.

"CSST was developed in Japan in the 1980s. It was developed as a safety improvement over rigid black iron gas pipes that often failed and started fires during earthquakes. The flexible nature of the CSST system allows it to handle seismic activity without leaking gas. "

http://www.gastite.com/include/languages/english/downloads/pdfs/PipeSupports.pdf

[Aaron Miller]

I'd rather have PEX than copper water supply myself. No galvanic reactions. No corrosion. Easier to repair.

PEX is great unless it is stored in the sun prior to use, or the fittings fail, or it poisons you Polyethylene Tubing and Water Contamination chemical investigation (http://www.chemaxx.com/polytube1.htm), or . . .

And CSST? It's great stuff until a roofer hits it with a nail during a re-roofing or you hit it with a nail or screw while hanging grandma's picture on the wall, or lightning strikes within a hundred meters and a hole blows in it, or the fittings fail, etc. ad infinitum. And those are just the failure modes that I have worked as an expert witness on. Time will almost certainly reveal more.

So you use the new stuff and I will stick with what has stood the test of time.

[Aaron Miller]

@ OP: If you do not use Counterstrike or Flashshield, or their ilk, CSST you will need these:

[Joe Funderburk]

PEX is great unless it is stored in the sun prior to use, or the fittings fail, or it poisons you Polyethylene Tubing and Water Contamination chemical investigation (http://www.chemaxx.com/polytube1.htm), or . . .

And CSST? It's great stuff until a roofer hits it with a nail during a re-roofing or you hit it with a nail or screw while hanging grandma's picture on the wall, or lightning strikes within a hundred meters and a hole blows in it, or the fittings fail, etc. ad infinitum. And those are just the failure modes that I have worked as an expert witness on. Time will almost certainly reveal more.

So you use the new stuff and I will stick with what has stood the test of time.

A lot of what ifs. First, I've never seen CSST installed at the roof sheathing. Second, if the gas piping was installed with a permit and any framing member was pierced that resulted in any exposure to nail strikes, then strike plates were required. Third, a nail can also damage copper tubing. Fourth, steel can be easily damaged and will deteriorate..... Fifteenth, life has risks. Sixteenth, we aren't going to live forever and the house will eventually be torn down.

[Aaron Miller]

A lot of what ifs. First, I've never seen CSST installed at the roof sheathing. Second, if the gas piping was installed with a permit and any framing member was pierced that resulted in any exposure to nail strikes, then strike plates were required. Third, a nail can also damage copper tubing. Fourth, steel can be easily damaged and will deteriorate..... Fifteenth, life has risks. Sixteenth, we aren't going to live forever and the house will eventually be torn down.

Lot of haven't-seens. Live long and prosper.

[Harry Shen]

Thanks all for your very useful comments.

I might want to add that this is an old house that has a lot of things that are not code compliant by today's standards. One of these is that the crawlspace is does not have access.

There is already CSST in another room of the house. When that was installed, the bonding was done with 6 AWG wire clamped to the black iron pipe just after the gas meter. So I think the bonding is good.

And again, I do not plan to make the gas connections myself. They will be done by a qualified installer. I only help him by doing the planning of how to route the line.

I'm not sure I understand the strike plate requirement though in my particular case...appreciate if someone would clarify that. My basement is unfinished and the plan is to run the CSST by making a hole in the sill plate that connects the basement and crawlspace. There are no plans to finish the basement in any way. There is no drywall in the basement and the flooring joists are open and visible in the roof of the basement. Does the strike plate requirement apply to unfinished living spaces as well?

Thanks again for the responses.

[Aaron Miller]

Does the strike plate requirement apply to unfinished living spaces as well?

Yes it does apply.