swing joints

Jim B_2

"The Lost Art" refers to the use of swing joints. I am not in th etrade and would like to understand what these are. A picture would be great! Also, I have noticed more and more postings with drop headers. What are the rules to use this design?

Mike T., Swampeast MO

Swing Joints

Are where the old-timers used to dance and party...

...uh sorry, maybe what some of the new-timers use to party with...

Couldn't resist.

Swing joints are a way to deal with two nasty problems--pipes coming in at goofy angles and situations where piping is likely to be disturbed and you want to give a bit of "play".

Image with message shows the first case--it's using a street 90° screwed to a regular 90°. By manipulating the two you can adjust in two planes simultaneously. Many variations on the scheme depending on the situation--sometimes 45° els are used, other times there is a nipple between the two els.

Other image shows the second case--VERY frequently used for irrigation, lawn hydrants, etc.

EBEBRATT_2

swing joints

Good explanation. I was always told that a "swing joint" was using two elbows and a "double swing joint" is with 3 elbows. Used to do this on underground oil tanks piped with threaded pipe. It was used do to the likely setteling of the tank. In fact you were supposed to arrange the piping so that if the tank setteled the joints would tighten. Pretty tough to pipe a steam job properly without them.

gehring_3

Swing Joints

Mike-

In the case of a conventional, straight (non-drop) steam header with two risers and two offsets going to one header, would unions on the risers out of the boiler serve the same purpose?

Mike T., Swampeast MO

I have NEVER piped a steam boiler, but from experience with water, I'd say, "No, a union will not take the place of a swing joint." Unions can deal with a touch of mis-alignment, but steam headers are quite large and unyielding.