Tapped Blinds and Tapped pipe caps

Hey Guys,

I was checking a set of drawings a bit ago. I'm not a checker and don't pretend to be one. Work was slow and it was chargeable. One of the things I marked up was tapped pipe caps and tapped blind flanges. On this project they used Flatolets on the blind flanges and sockolets on the pipe caps. I marked them up to use half couplings instead. I believe this is the better more economical option especially on the pipe caps (no grinding and extra welding). They refused to change them and got backing from the piping manager with no explanation other than couplings are too fancy and only used in refineries.....we use olets.

Please let me know what you guys would do and why. If I am right this could become the basis of a challenge for me in the future. I just need to be able to back it up.

HC

Jop.......Is a half coupling not also self reinforced? Its a bought designed fitting just like an olet.

We use half & full coupling all the time for connections! You are right in that it is an easier connection to be make then thread-o-lets. Normally all you do is drill a hole in the pipe (fitting or blind) that matches the O.D. of the coupling, and insert the coupling and do a fillet weld around the coupling. Thread-o-lets (& WOL & SOL) may require more welding (especially in larger sizes) and a 3/4" TOL that fits on a 2" pipe won't fit on a 4" pipe (contour of the O-let has to match the contour of the fitting/pipe to within 1/32")...but coupling don't! ...And are cheaper then O-lets! Not sure where your piping manager thinks they are too "fancy"!?? NOW having said all that IF O-lets are required by the piping spec, or client, then by all means they (O-lets) are the connection to use!

I need to clarify a point here, couplings are used in my area for low pressure systems 150# & 300#, for 2" and below threaded connections, above that it's WOL's & SOL's!

The question is specific to tapped flanges and tapped pipe caps. I should clarify that. I'm not speaking to tapping pipe in any way.

My experience has always been to use a half couplings on tapped flanges and pipe caps and this included 150# thru 900# connections. I was taken a back by my piping manager when he said it was too fancy a connection. I think JOP surprised me now as well.

Like 11echo says you simply cut a hole in the pipe cap or flange, insert the coupling and back weld. At Imperial oil it was typical practice to tap ALL blinded flanged connections with a 1 inch bleeder valve as a back check to verify positive isolation before making a tie-in in the future. Using a half-coupling was standard practice.

To use a 1" Olet on a pipe cap for example my thought is you would need to grind out the curve in the Olet to it being relatively flat because its curved in one direction to go on a pipe. Then you would need to fill it the curve of the pipe cap against the Olet which could be alot of welding depending on size. Correct me if I'm wrong.

The flatolet on a blind flange would work fine but, I would think it would be slightly more costly because the back weld on the olet would be larger than the coupling. Plus the olet is quite a large fitting on the blind compared to the half coupling. Not really a selling feature there but, it makes sense to me that using a half-coupling for these applications just makes sense.