Commercial steam piping design

JimGPE_3

I am designing a 15 psig steam line. Because of existing conditions, the line is running 51 feet pitched in direction of flow, then jumping up 6" with a double 45, then running 71 feet pitched in direction of flow, then jumping up 1'9". The entire line will have 2" of fiberglass piping insulation. The line is sized at 9,000 FPM, not for reverse return.

Do I need a drip before either of these two offsets, or will there be little enough condensation that water hammer will not be a problem in this run?

Thanks.

Tony Conner

Every Time...

...the line rises, you'll need a drip and trap.

Have you sized the line to run at 15 PSIG, or that where the safety valve lifts? If the safety lifts at 15 (and it likely should, to keep you out from under pressure piping code requirements), your actual operating pressure will be about 12 PSIG max.

JimGPE_3

Hmmmm

Even at the 6" rise?

Kevinj

Yep

Tony said it well.

JimGPE_3

RATS!

I don't have sufficient head room to get a thread-o-let, a nipple, a trap and a dirt leg in. Any suggestions as to how I can drip the main in 6" of vertical space?

Thanks for your quick responses!

Tony Conner

It's Not Good Practice...

...but in a jam, you can omit the drip leg, and likely get away with it. Get the welder to stub a half-nipple into the bottom of the main (I don't think that this is a pressure piping installation anyway and even if it is, this should be permitted if a full penetration weld is used), and you might get a float & thermostatic trap in. Spirax Sarco makes one with the inlet and outlet at the same elevation on opposite sides of the body. It's about as skinny as I've seen, but other people may know of different makes or styles that will fit better.

Rod Johnson

6\" space for trap

you could weld in a 1-1/2" thrd.olet use a 1-1/2"sch.80 shld. nipple then 1-1/2"x1/2" tee and plug the bottom of the tee. from bottom of pipe to center of tee =4"then put on your valve union prependicular to your main then put a 90 looking up and use a armstrong 1010 inverted bucket trap
the top of your trap will be about center of your 6".as long as there is no control valve before this trap it will work fine.the 1010 is a little expensive it is stainless stl.