Welding pipe support attachments to loaded steel beams

[Mechanical - Piping]

I am a mechanical Engineer, and would like to use the existing building structural beams to weld my pipe support attachment. These attachments for example the Anvil Fig. 66 beam attachment (see pic) are widely available, but there is no help in determining common use of these attachments. Should I contact a Structural Engineer every time i need to use one of these attachments? What I have seen on detail drawings is notes specifying the welds between the attachment and the beam should be in the longitudinal direction of the beam (not the transvers direction). I have also seen some drawings specify that a plate be welded to the toes of the beam and the attachment welded to that (see pic). Also I have seen some companies allow contractors to field run pipe up to 2" NPS and piping greater than this be completely Engineered. My Structural Engineer at work is extremely conservative (I think) and is forcing me to bolt ALL my pipe attachments which is a huge increase in labor. Is there any guidance to help determine if and when it is acceptable to use these welded attachments. Any help is greatly appreciated.

 

[azcats]

I know this doesn't answer your question, but I just yesterday attended a webinar by Lindapter and part of it was on beam clamps for use w/o drilling or welding. Seems like this would be a great application.

Here's a replay.

[URL unfurl="true"]https://lindapter.webinarninja.com/live-webinars/10020455?tok_reg=ddf660d6-1d94-40bd-add3-ee80d33d2508-39838618[/url]

Slides.

[URL unfurl="true"]https://mcusercontent.com/3543826c3dc65cb7e3f0e6d9e/files/93c1c42d-60df-fe64-3ec7-f02bf2978529/Webinar_Slides_18.1.22.pdf[/url]

 

[SteveGregory]

You are correct to run the welds longitudinally as shown. It appears that Anvil has specified a maximum load for their part and the welds. If their welds check out, you should be able to calculate the pipe loads based on the geometry of the pipes and hanger spacing.

I would agree with your engineer that a bolted connection would be cheaper than hiring a welder and welding it. Plus if you use the Lindapter solution noted above, then no drilling either.

 

[JoelTXCive]

Those Lindapter beam clamps are cool.

I think they must be expensive though.......I've spec'd them on 2 projects in the past year and both times the fabricator came back with an alternate setup + RFI asking to switch the connections to conventional welded or bolted setup.

 

[Mechanical - Piping]

Thanks for your input! much appreciated, with regard to price as the mechanical contractor is already welding the piping it is much faster for them to weld the support attachments. When this was brought up in a meeting the contractor replied "doesn't matter to me, I'm paid by the hour!" in other works, it is much more time consuming for the contractor to drill 4 holes in the beam to connect the attachment instead of a couple quick weld.

 

[Mechanical - Piping]

Also, is there any benefit to welding the attachment to a steel plate then welding the plate to the toes of the beam (see pic) instead of just welding the attachment directly to the underside of the beam?

 

[dauwerda]

Also, is there any benefit to welding the attachment to a steel plate then welding the plate to the toes of the beam (see pic) instead of just welding the attachment directly to the underside of the beam?

Yes, it avoids overhead welding which is much more difficult and requires special certifications if welding per AWS D1.1

 

[GC_Hopi]

It makes for easier field welding. Using the plate eliminates overhead welding and you can temporarily clamp the support in place for fit up prior to welding.

 

[Mechanical - Piping]

Great, i never thought of the welding position, i was thinking more in terms of how the strength of the beam would be affected. i.e. i supposed the steel would be temporarily weakened in the area of the weld.

 

[Mechanical - Piping]

Would the amount of heat transferred to the beam due to welding have to be considered with respect to weakening the beam? or would this be inconsequential?

 

[SteveGregory]

"Would the amount of heat transferred to the beam due to welding have to be considered with respect to weakening the beam? or would this be inconsequential?" Yes, that's why you weld longitudinally instead of transversely. Yes, welding position is a big deal.

 

[Mechanical - Piping]

Thanks, yes, i meant that even when welding in the longitudinal direction, would the local weakening of the beam need to be considered?

 

[SteveGregory]

No

 

[strucbells]

Another option for small loads/pipes only is to run a piece of strut perpendicular to the beam below the bottom flange and use strut beam clamps on each side. Can attach your hanger rod to the open channel face using strut nuts. Cheap, easy to install (no field welding needed), and the various strut companies (Unistrut, Superstrut, etc.) publish capacities. Obviously you'll want someone qualified/licensed to do the design based on the manufacturer data.