Underground Pipe and tubing size

[Steve.Keelan]

So I was out to a client's place to quote on a new unrelated heat pump system at this time I also disconnected and capped 2 80k btu furnaces,  (1500 sq ft farm house) when I eventually was able to locate secondary reg to shut off supply downstream I noticed the copper supply line from primary reg was noticeably small. For reference the primary reg and torpedo tank are located approx 60' from secondary, the line as it turns out is 3/8" copper tubing, it does not appear to be run in a channel, is buried almost immediately from tank, it goes beneath a gravel driveway and an enclosed deck/sunroom/cut wood dry storage where it comes back above ground and is supported to the exterior wall of home. After a bit of code review and referencing I flagged it as undersized. Being that both propane appliances had been disconnected and the line capped and that they are friends, I did not tag it at that time but did advise that to install another line to supply an outdoor range the line would require replacing as its currently under sized. I advised itd be a fair bit more expensive for me to perform the work as itd involve renting a mini exc scheduling locates etc where if they had the company whom installed the line (15 years ago) but is still also their propane provider,  come out and make their line compliant then it'd be significantly cheaper for my client. I referenced clause 6.15, 6.15.1 from b149.1-15 and clause 5.9 from b149.2-15.

A guy from the supply company comes out and tells my client "city folk dont know propane, thats for natural gas propanes higher pressure" then he leaves his card and a note saying 2ndry regs rated for 2mil btu, 3/8 copper is good for 450kbtu, and the last line on note in bold underlined was propane vs nat gas code??? I get this from client and think maybe theres something im missing but immediately am skeptical of this guys proclamation of city folk dont know propane and higher pressure, to me logically and scientically higher pressure requires larger pipe not higher pressure validates use of smaller pipe and his indication of 450k btuh on 3/8" copper. I check the tables for 1" pressure drop on 11"wc and read that max btu for 3/8 copper is 23k btu. Am I missing something here or am I correct in my original findings?

Tldr  propane Supply (11w.c. 1 drop) 3/8" copper tubing ran underground 60', I flagged as undersized. 6.15.1 Piping having a nominal pipe size of less than NPS 1/2" shall not be used. B149.2-15,  5.9 - Piping shall comply with clause 6 of csa b149.1

Kelly propane says 3/8 copper good for 450kbtu city folk dont know propane.

Is there something im missing or am I correct in saying minimum pipe/tube size.for burial is 1/2" and they should fix their own deficiency?

[Hgye]

You are wrong. He is right.  3/8" copper at 10 psi and 60' is good for 448,000 btu.

Copper is TUBING not PIPING.

[Porcupinepuffer]

to me logically and scientically higher pressure requires larger pipe not higher pressure validates use of smaller pipe

Nope. Think about it. On propane, we're barely trickling 11" w.c. through residential tubing/piping. When we open it right up, the tiny flow rate can only let so much escape a small pipe that we can easily block it with our finger. We're talking less than a quarter of one PSI.
Now take that same pipe and have it pushing 10psi instead of 11" w.c. and you'll have a hell of a lot more flow coming out. So since that same size pipe at the higher pressure can obviously deliver more because of the excessively higher velocity that can flow through it, it will have a lot more it can supply.

Just look at all the older natural gas meters with the copper. They're fed with a high pressure 1/2" line before the reg. It easily supplies the btus required for the 1" and larger black iron after the regulator.

...And anything smaller than 1/2" pipe cannot be buried. Not tubing. Make sure to pay attention to those differences with piping/tubing. It's easy to get them mixed up.

[Steve.Keelan]

update. After consulting with tssa field inspector, he confirmed what I had interpreted. Minimum burial size is 1/2" regardless of tubing or piping.

Your logic is flawed as well...you dont think you'd be able to pump 10psi through 3/8' malleable over 60'? We all have encountered (if we have any experience at least) client set ups that have undersized piping (sometimes ridiculously undersized) that has been operating just fine for decades in some instances.

The question was never; is it capable of delivering the required m3 of lp. The question was,  is 3/8" tubing buried, code compliant? The response tssa provided to me was no, it is not compliant.

[Admin]

What Clause did the inspector use that says 3/8 tubing cannot be used in a propane system?

This is from the B149.1-15,

6.3.8.1
For natural gas, threaded piping less than NPS 1/2 used in a piping system shall be Schedule 80.

6.3.8.2
For propane, piping less than NPS 1/2 shall not be used indoors, except that NPS 3/8 piping may be used as a branch line not exceeding 25 ft (7.5 m) in length.

6.3.9
Piping less than NPS 1/2 shall not be used in a concealed location.

6.15.1
Piping having a nominal diameter of less than NPS 1/2 shall not be used underground.

I never considered piping and tubing to be the same thing and thought 3/8" copper tubing or CSST can be used underground.

[Hgye]

The question was never; is it capable of delivering the required m3 of lp.

A

After a bit of code review and referencing I flagged it as undersized. the line would require replacing as its currently under sized. I check the tables for 1" pressure drop on 11"wc and read that max btu for 3/8 copper is 23k

Actually, that is exactly what you said.

[Hgye]

update. After consulting with tssa field inspector, he confirmed what I had interpreted. Minimum burial size is 1/2" regardless of tubing or piping.

Your logic is flawed as well...you dont think you'd be able to pump 10psi through 3/8' malleable over 60'? We all have encountered (if we have any experience at least) client set ups that have undersized piping (sometimes ridiculously undersized) that has been operating just fine for decades in some instances.

The question was never; is it capable of delivering the required m3 of lp. The question was,  is 3/8" tubing buried, code compliant? The response tssa provided to me was no, it is not compliant.

Can you post the actual response from TSSA?  My TSSA inspector says that 3/8 copper CAN be buried, and that it is tubing, not piping. If it is their official position that it cannot be buried, then there is going to be a lot of non-code compliant installations around here, as we are in a huge propane area with a lot of buried 3/8 copper.

This is one of the problems with TSSA. it depends whom you talk to.  Usually when I email TSSA tech support with a code question, they say "Refer to the code book for your answer".

[Hvacpimp]

Just because "you asked a Tssa inspector" doesn't mean he would know. I have a feeling you owe your friends an apology and you need to stop being such an hvac hero! Looks like city folk don't know propane lol
+1 for Kelly propane!