CSST uses

[Samjohn]

Hi everyone,
If some of you could shed some light on this matter it would be appreciated.

I've come across many times recently on commercial RTU gas systems that have been installed using CSST (corrugated stainless steel Tubing) "Gas tight" out door use, connecting between the gas shut off valve (blk pipe with drip leg) and the appliance.

Recently, on a York RTU that was installed about 3 years ago, was red tagged by another local contractor for violating code 6.2.21 - CSST cannot be used as a Gas connector.
The contractor said all stationary appliances such as a RTU needs to be hard piped for N.Gas.
Is this true?
The Definition in the code book isn't straight forward in defining it.
Can CSA approved "Gas tight" outdoor use CSST be used in this application?
Thank you for your input.

[Sergroum]

Was the csst connected straight into the RTU? Or was there a piece of black pipe from gas valve to the outside of the RTU with Csst connecting it to the branch?

[Admin]

It really depends on the installation manual but usually you would hard pipe out of the appliance gas valve using black steel to a dirt pocket tee.  Then you could use CSST or a gas flex connector on the outside of the appliance.

There is no requirement that I am aware of that says stationary appliances must be hard piped.

[Samjohn]

Yes there is a piece of black pipe leaving burner compartment where CSST then connects

[Admin]

Just make sure the installation manual doesn't say only steel piping must be used, then clear the warning tag.  I would write on it "invalid".  It passed inspection because there is likely nothing wrong.  The Gastite manual references rooftop applications.

Clause 6.2.21 makes no sense anyway.  Your CSST is not a factory fabricated assembly.

6.2.21
Corrugated stainless steel tubing (CSST) shall not be used as a gas connector.

If the CSST is connected to the steel piping leaving the RTU there is likely no problem.  It's also a myth that you can't use a gas flex connecter on stationary appliances.  See the definition of gas connector.

Gas connector — a factory-fabricated assembly consisting of gas conduit and related fittings designed to convey gaseous fuel from a gas supply piping to the gas inlet of an appliance. A gas connector is not intended for vibration isolation, nor expansion or contraction control. For the purposes of this Code, solid gas connector includes
(a) gas connectors for gas appliances that are certified to ANSI Z21.24/CSA 6.10 and are not designed for repeated movement after being connected nor for repeated disconnecting and connecting and are not intended to be used with quick-disconnect devices or convenience outlets;
(b) gas connectors for movable gas appliances that are certified to ANSI Z21.69/CSA 6.16 and are designed for repeated movement on a regular basis and could be used with quick-disconnect devices or gas convenience outlets;
(c) gas connectors for outdoor gas appliances and manufactured homes that are certified to ANSI Z21.75/CSA 6.27 and are designed for supplying gas to an appliance for outdoor installation that is not frequently moved after installation and to the gas inlet on a mobile home; and
(d) gas hose connectors for moveable appliances that are certified to ANSI Z21.101/CSA 8.5 and are designed for repeated movement on a regular basis and must be used with gas convenience outlets. 

On a sidenote, in Ontario, rooftops are the only appliance where the dirt pocket tee can be installed in the horizontal position.  Most people will say this is wrong but it's allowed as per the TSSA.

[Samjohn]

Great information!
Yes, when looking at the definition of "Gas connector " it says a factory-fabricated assembly. This seems to me to be talking about the yellow CSST used for indoor ovens and gas dryers where the tube had the flare ends already installed (factory-fabricated). Where as products like "Gastite" are field assembled similar to blk steel pipe and copper tubing.

Also as per 6.21.1- check the markings on the tubing/brass connectors for certification.

[Samjohn]

Side question:
Is there information on what these CSA/ANSI certified connectors look like?
Example: a CSA 6.27 certified gas connector looks like what?

[Admin]

That's a good point but I don't think the factory fabricated gas connectors should be referred to as CSST.  You're right though, most gas flex connectors are in fact made of corrugated stainless steel.  I just think as far as the Code is concerned a gas connector is the factory fabricated flex used to connect an appliance and CSST is considered the piping / tubing supply pipe.

CSA 6.10 is your standard gas connector.  CSA 6.27 is the same but coated and approved for outdoors.  CSA 6.27 looks like this,

https://www.hajoca.com/Misc/reports/oqtwqckee4f4ap0jqprqqbvq/s80455147892.pdf#zoom=100


CSA 6.16 are the blue gas connectors you see used on commercial cooking appliances.

[Samjohn]

So, what would a "gastite" or "tracpipe"  be certified as?

[Admin]

Those are examples of what I call CSST, which must comply with a different standard, CSA 6.26. 

6.2.20
Corrugated stainless steel tubing (CSST) and associated fittings shall comply with ANSI/LC 1/CSA 6.26 or CSA publication CGA Certification Laboratory Requirement LAB-009. 

Either of those could be used as the supply pipe.  For example, you could run 24" of steel pipe off your gas meter and transition to Gastite CSST up to the rooftop.  You just have to follow the specific Gastite rules on supporting and protecting the CSST in some cases.

Then you could use steel pipe out of the appliance gas valve and build a dirt pocket and union / shut off valve assembly and connect the CSST directly to that.

This sounds like what the job you were at looked like.  I see no problem or why the other contractor considers your CSST a gas connector.  The fact is you're not using a gas connector.  You're using CSST as the supply and branch pipe, and approved to do so.

[Samjohn]

Yes, i agree! Thank you

[Hgye]

6.2.21 - CSST cannot be used as a Gas connector.

I agree with Admin.  You cannot use csst behind a range, propane fridge, dryer, or any appliance that gets pulled out.  The csst cannot be used as a flexible appliance connector.

[Admin]

It's just funny now that I read Clause 6.2.21.  The fact is most gas connectors are made with corrugated stainless steel tubing.  The CSST we field fabricate could never be considered a gas connector because it's not factory fabricated.  I think the CSA or TSSA should reword Clause 6.2.21.

"Field fabricated CSST cannot be used in lieu of a gas connector."

And I just checked my gas connector.  it's approved to CSA 6.10 and 6.27 but it's not coated.

[walker]

4.6.2 DIRECT CONNECTION – NON-MOVEABLE APPLIANCES
Gastite®/FlashShield® CSST may be connected directly to non-movable appliances such as water heaters, furnaces, boilers and island cook-tops (Figure 4-60) without the installation of a termination outlet or flexible appliance connector. All local codes requiring drip legs and shut-off valves must be observed. Drip legs and shut-off valves must be securely mounted. Additionally, Gastite®/FlashShield® should not penetrate metallic cabinet of appliance.

[Admin]

Beauty!  I suspect with something like a cooktop, which doesn't require a dirt pocket, we still could not connect the Gastite directly to it because of Clause 6.2.21.

[Samjohn]

Sorry for the delay.

This is the set up of the "issue" or problematic gas connection. See photos.
This is CSA rated 6.26 Gastite.

Does anyone see a code violation with this?
-the CSST doesn't enter cabinet
-supported correctly
-has a means of disconnect with union.

Your thoughts

[Admin]

The other tech is misinterpreting Clause 6.2.21.  There is no problem using CSST like that.

[Samjohn]

I think CSA and TSSA need to clearly differentiate the difference and uses between this type of CSST and the other type.

[Samjohn]

It was good to discuss this topic. Thank you for your professional input.

[scarey8]

Not related to the direct subject of this topic, but the union should be downstream of the gastite or CSST.  Subsequently not disturbing the CSST if for example that the blocking valve needed to be serviced.  The issue with this is that, if gastite connections are disconnected, they need to be cut back and remade, they do not act as a union.    As well, CSST must not be in contact with any metallic item, in this photo it is clearly in contact with the curb. 

[Admin]

The Gastite Guide Section 5.3.2 says,

The Gastite®/FlashShield™ mechanical joint fittings can be removed and easily re-attached.

I do see the requirement to keep the CSST separated from metal.  I would just pull the CSST away from the metal curb.  It's weird they allow the use of metal straps or hangers to support the CSST though.

DIRECT CONTACT between continuous metallic systems and Gastite® yellow CSST is prohibited.  Maintain as much isolation/separation as reasonably possible when planning and installing gas piping from other continuous metalllic systems.

[Samjohn]

Sorry for my lack of knowledge, but what is the correct or approved way to support Gastite yellow or any other CSST tubing?

The Gastite Guide Section 5.3.2 says,

The Gastite®/FlashShield™ mechanical joint fittings can be removed and easily re-attached.

I do see the requirement to keep the CSST separated from metal.  I would just pull the CSST away from the metal curb.  It's weird they allow the use of metal straps or hangers to support the CSST though.

DIRECT CONTACT between continuous metallic systems and Gastite® yellow CSST is prohibited.  Maintain as much isolation/separation as reasonably possible when planning and installing gas piping from other continuous metalllic systems.

[Samjohn]

I found this from Gastite.