Thread: CSST installation

I believe the csst installed the the heating unit is OK, what about the gas logs?

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From what I've read, you're supposed to have a sleeve covering the CSST where it penetrates sheet metal to avoid abrasion, or grommet around the hole. Can't see if the latter is installed.

They are both crap installs and should be redone.
90 degree bend not allowed, no grommet, iron pipe preferred in the unit and firebox.
Burnt plastic in firebox. etc,etc

I was surprised to see it can be used underground and do not know code install details Common sense would tell me the furnace wall penetration should be bushed and code or no code that stuff would not be inside the fire box in my home.

As far as I can tell, besides the bonding bit code mostly just says to install as stated in manufacturers' instructions.

Happened to run across a 54 pg. booklet I have for Pro-Flex CSST. Can't guarantee it, but I imagine the practices are similar for other brands.

GAS FIREPLACES:

"PRO-FLEX CSST may be used to deliver gas directly to the valve for gas fireplaces. This is approved for decorative and heat generating fireplaces and for gas logs used in masonry and pre-fabricated fireplaces. DO NOT use PRO-FLEX to connect gas log lighters or gas wands for use in al-fuel (wood-burning) fireplaces."

If installed through masonry, there needs to be sleeving; if through ceramic liners in decorative FP it's not needed.

Where installed through sheet metal enclosures, grommets, bushing, armor, PVC tape, shrink sleeve material or at least 4 wraps of #10 Mil duct tape should be used. Yellow sleeve should only be removed on the part of CSST that may be exposed to flame.

FURNACES: (I, too, have heard that rigid metal is preferred, but evidently CSST is not prohibited. There's plenty of other stuff in that firebox that could be damaged by high heat, so that alone shouldn't be an issue.)

"PRO-FLEX CSST may be connected directly to non-moveable appliances such as water heaters, furnaces, boilers and island cook-tops without the installation of a termination outlet or flexible appliance connector. All local codes requiring drip legs and shut-off valves must be observed.

"When appliances such as water heaters, furnaces or firplaces have metallic vents which extend beyond or protrude through the roof physical contact between the csst and the appliance cabinet or vent is prohibited. Pro-Flex recommends that all continuous metallic systems be bonded and grounded."

(I found that bit about the metallic vents interesting, was news to me. Also a surprise was that it shouldn't be used with movable appliances like dryers, stoves, etc.)

Recommended minimum bend radius is 3" for Pro-Flex CSST under 1"; or 5" for 1" or 1 1/4". I don't know if that's true of other brands, but at least it gives you an idea.

(When buried or encased in concrete, it needs to be routed inside a non-metallic, watertight conduit with OD min. 1/2 greater than the OD of the CSST.)

black iron only to furnace interior--crap csst to fireplace

cvf

Gastite also allows CSST to be used for fireplaces.

Here's a thread that addresses the furnace issue.

Finally found the pertinent IRC (I'm new at this stuff!). Is CSST semirigid tubing? Or does that mean soft drawn copper?

"G2422.1.2.3 (411.1.3.3) Prohibited locations and penetrations.
Connectors shall not be concealed within, or extended through, walls, floors, partitions, ceilings or appliance housings.

Exceptions:1. Connectors constructed of materials allowed for piping systems in accordance with Section G2414 shall be permitted to pass through walls, floors, partitions and ceilings where installed in accordance with Section G2420.5.2 or G2420.5.3. 2. Rigid steel pipe connectors shall be permitted to extend through openings in appliance housings. 3. Fireplace inserts that are factory equipped with grommets, sleeves or other means of protection in accordance with the listing of the appliance. 4. Semirigid tubing and listed connectors shall be permitted to extend through an opening in an appliance housing, cabinet or casing where the tubing or connector is protected against damage. "

In our area of California, CSST is not a listed connector. No tag, no dating, and never used thru the cabinet or in the interior of the firebox, (notice the burning of the plastic coating. Used as piping system in walls, under floor, in attic and underground with protection as indicated by manufacturers installation instructions. We get certified by the manufacturer for their product and are sometimes requested by inspectors to show that certification. The furnace should be hard piped to outside the cabinet and a "listed" connector used between the shutoff valve and the hard pipe to the appliance regulator. Would not pass any inspector in my counties.

The code references Kristi provided answer the issue. CSST is allowed under the IRC to run through the cabinet to the appliance combination valve provided it is installed in accordance with the CSST mfrs. listed instructions. That means protect it from damage with a grommet.

CSST is not a 'connector' but is 'piping' and unlike Sch 40 steel, it is listed. The two major gas codes: NFPA 54 and IFGC both allow direct connection of approved 'piping' directly to the appliance valve. Why does your jurisdiction say otherwise? Can you provide a link to a local ordinance to this effect?

As for the fireplace in the OP: the CSST was improperly installed. A hole was made in the refractory floor of the firebox instead of using the factory supplied knockouts. This modification to the fireplace voids the warranty and listing. Fire can be sucked down this penetration and ignite the structure.

The penetration, even if properly done, must be chinked with high temperature rated insulation such as the rockwool ember material then the gap to the refractory knockout hole caulked with a refractory mortar or cement.

All factory built fireplaces state a clearance to combustibles. The polyester jacket on CSST is considered 'combustible', therefore it should be removed. However, the CSST mfr. requires their product be protected with specified wraps of combustible material to protect it. Therefore, in order to legally run CSST through the side of a factory built fireplace, you would have to get specs. from the CSST mfr. on a suitable non-combustible sleeving material. Otherwise, it would not be allowed.

The jacket on the CSST in the OP was painted black. How much of it was heat damaged cannot be determined from a photo but would require palpation to see if it is curling or crumbles.

CSST is NOT approved for direct flame impingement so even if used in a fireplace, it would have to be routed away from the flames, which this is not.

Semi-rigid tubing is soft copper.

HTH

Great info as usual Bob.

In regards to what the manufacturer allows. It is not the CSST manufacturer that is the issue. It is the appliance manufacturer. All appliances are required to be installed according to the manufacturers installation instructions. Some heating system manufacturers state in their instructions to not run flexible gas line into the cabinet but to run solid pipe from the valve to the outside of the cabinet then connect a flex line. Some say it is okay to install the flex line into the cabinet. In which case some type of insulation or a grommet would be required to be installed around the line where it passes through the cabinet. As far as running CSST through walls and floors I don't know of any reason you can't. Flexible gas lines, listed as gas connectors, cannot be run in these locations.

Originally Posted by Ron Tate

In regards to what the manufacturer allows. It is not the CSST manufacturer that is the issue. It is the appliance manufacturer.

Only half correct.

There are two sets of manufacturer's installation instructions to follow:
- a) The manufacturer's installation instructions for the CSST.
- b) The manufacturer's installation instructions for the appliance.
- c) (Hey, wait a minute, didn't I say "two"?) You follow *the most restrictive* of those two. (Okay, that makes for a third choice, so what? )
- d) (Wait a friggin' minute here, what happened to "two"?) Then, you need to follow the code too.
- e) (This is gettin' outta hand here!) Finally, you need to follow the most restrictive of all of the above.

It's not as easy as just saying to follow the installation instructions of the appliance.

I've looked at several furnace installation manuals and none said anything about CSST, though some addressed flexible gas connectors - but that's different. They all said gas connections should follow code - that's a given. From what I can tell (and so I've read), the installation requirements for CSST described by the manufacturers meet or exceed those required by national codes. It seems a lot more realistic to familiarize oneself with requirements for installation of different brands of CSST than of every furnace out there.

If there are furnace brands that discuss CSST particularly, it would be valuable to know which they are.

Correct you are J.P., same with conductors, right! Most restrictive rules.
Kristi, I think you may have made mention of the bonding requirements for CSST, so I'll assume that issue has been covered in another thread

Originally Posted by bob smit

Correct you are J.P., same with conductors, right! Most restrictive rules.
Kristi, I think you may have made mention of the bonding requirements for CSST, so I'll assume that issue has been covered in another thread

Probably many of them.