Sch 7 pipe and other thinwall pipe
Sch 7 pipe and other thinwall pipe
(OP)
I am thinking of making a change to use more sch. 7 pipe, we do mannnnny jobs that have no or limited specs, many design builds and VE nearly everything.
I want to make the move to use more Dyna Flo type pipe or other thin-wall pipe. I have found that a stick of 4" x 21' dyna flow pipe is $6.00 cheaper, this means cheaper pipe and better sizes hydraulically.
I remember back in the days mid 90's - early 2000's we used a ton of Allied thin-wall pipe. Our supplies have said many companies in Georga & Florida used tons of this stuff.
Just trying to get some input. Perhaps from your experiences??
Thank you,
I want to make the move to use more Dyna Flo type pipe or other thin-wall pipe. I have found that a stick of 4" x 21' dyna flow pipe is $6.00 cheaper, this means cheaper pipe and better sizes hydraulically.
I remember back in the days mid 90's - early 2000's we used a ton of Allied thin-wall pipe. Our supplies have said many companies in Georga & Florida used tons of this stuff.
Just trying to get some input. Perhaps from your experiences??
Thank you,
Eric Hendrix, SET
NICET Certified
Design Manager





RE: Sch 7 pipe and other thinwall pipe
Up here on the Canadian prairies, lightwall always sold at a discount to import sch. 10, so that was all anyone ever installed. That changed a few years back, and now everyone uses import sch. 10 exclusively. I thought the price increase coincided with Allied's exit from the market, but I could be wrong.
RE: Sch 7 pipe and other thinwall pipe
From my research both of my fabricators can get sch 7 pipe and it is much cheaper.
Eric Hendrix, SET
NICET Certified
Design Manager
RE: Sch 7 pipe and other thinwall pipe
Anecdotally speaking, my last boss told me that they made the change from sch. 7 to sch. 10 before everyone else because his North Alabama welder kept warping the pipe from the heat.
RE: Sch 7 pipe and other thinwall pipe
Yes I have heard of this also, I could see where you might want an additional hanger here and there to help support the pipe from sagging
Thanks,
Eric Hendrix, SET
NICET Certified
Design Manager
RE: Sch 7 pipe and other thinwall pipe
Mechanically it might be fine but looks sloppy when installed.
I imagine one could save some money on the fabrication but I stick to sch. 10 and 40. I've seen a few sch. 7 systems rot out after a short amount of time. Most sch. 10 has been treated to have a corrosion resistance ratio of 1 which is equivalent to sch. 40. For this secondary reason we don't use sch. 7.
RE: Sch 7 pipe and other thinwall pipe
I typically design with Sch 10/40. That allows the customer to go 07/30 if they prefer as the hydraulics are typically better. Now, there are some jobs where it can be worse, but those are rare and it is due to issues balancing areas.
Travis Mack
MFP Design, LLC
www.mfpdesign.com
"Follow" us at https://www.facebook.com/pages/MFP-Design-LLC/9221...
RE: Sch 7 pipe and other thinwall pipe
RE: Sch 7 pipe and other thinwall pipe
We use a lot of Schedule 7 and it's common for us to purchase 60,000 feet at of 2 1/2" at a time.
My favorite is Wheatland Tube specifically Mega Flow.
The Schedule 7 is either Wheatland or Bull Moose Eddyflow.
With the exception of 6" the UL CRR is equal to or better than sch. 40 pipe.
As a company policy we do not purchase any foreign pipe and for 6" we do purchase sch. 10 simply because of the CRR.
We have two certified welders in our shop and we do not use machines and we haven't had a problem with warping. When we used an automated machine to weld we did have warping problems but since everything is done individually by hand we haven't seen it. This said the smallest light wall pipe we use is 2" so that might be part of the answer as well.
Surprisingly our biggest experience with corrosion is with galvanized pipe.
RE: Sch 7 pipe and other thinwall pipe
http://www.sfpe.org/page/FPEExtraIssue6
RE: Sch 7 pipe and other thinwall pipe
I have had more issues with corrosion in galvanized pipe than regular black steel.
UNIFIED FACILITIES CRITERIA (UFC) for the Department of Defense https://www.wbdg.org/FFC/DOD/UFC/ufc_3_600_01_2016_c1.pdf now prohibits the use of galvanized pipe on all standard wet and dry pipe systems found on page 94 of the document:
Does anyone know FM Global's latest stance on dry systems and galvanized pipe?
RE: Sch 7 pipe and other thinwall pipe
Travis Mack
MFP Design, LLC
www.mfpdesign.com
"Follow" us at https://www.facebook.com/pages/MFP-Design-LLC/9221...
RE: Sch 7 pipe and other thinwall pipe
I am still very iffy about using Sch. 7 but I do think I am going try and steer us toward using it in wet systems on a trial basis. Some of the questions folks here brought up is will the fitter's know how to properly groove sch. 7 pipe?
Thanks,
Eric Hendrix, SET
NICET Certified
Design Manager
RE: Sch 7 pipe and other thinwall pipe
FM 2-0 Section 2.5.2.5 also states where galvanized or stainless pipe must be used (black steel only allowed on dry pipe with inert gas btw).
FM have however done a very intensive technical report (in 2014) called "Corrosion and Corrosion Mitigation in Fire Protection Systems". The report is not favourable at all to galvanized pipe, however they have not updated their datasheet accordingly and any of the FM projects I've been on in recent times has still had galvanized pipe for dry type systems. However FM criteria is so project specific (from what I've seen - some extreme variations from their datasheet occur if their customer has a big enough stick), that I would specifically look into the pipe specs for every project.
RE: Sch 7 pipe and other thinwall pipe