Lately I have seen a couple specifications require branch lines to have threaded connections and they specifically do not allow grooved, even when Schedule 40 pipe is used and even when most of the armover connections are welded pipe outlets.
These could just be old/outdated specs, but is there a reason/theory that suggests threaded connections are better than grooved? They can be cheaper but also can increase labor costs on large jobs. Just curious if there's a perspective I'm not considering here, thanks in advance. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe
6 Comments
Thomas Jones III
7/29/2019 10:04:18 am
Thread pipes are more expensive to install, more prone to leak, and harder to replace on service work. I would recommend grooving anything over 1". Sometimes it makes sense to thread when you are trying to work with the hydraulics.
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Dominic
7/29/2019 10:19:23 am
I think a lot of times those specs are outdated, but I will say threaded pipe gives a more cleaner look than grooved pipe. You can notice when you weld 1 1/4 and 1 1/2 pipe it can deform the pipe, making it hard to keep the lines straight and to pitch the lines for proper drainage.
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It can be a bad experience with a coupling, some leakage that damages the product and they consider that a threaded accessory is safer.
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Rusty Scott
7/29/2019 02:58:24 pm
I've been on both the contractor and engineering side. My old contractor company liked to use threaded in certain cases and grooved in others, all about the $. It just depended on the floorplan layout size. I will say a lot of the time on tree systems we used threaded branch outlets. Also our labor force is from GA and SC where labor costs are significantly less than lets say TX or CA for example.
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7/30/2019 10:09:39 am
I can't imagine a contractor being happy about installing pipe over 2" diameter threaded. It's hard work doing up those larger connections compared to one bolt for a grooved coupling. Even though the materials might be cheaper the contractor is going to charge more for their trouble.
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