Allowable Vertical Span

[NewMechanicalEngr]

Folks:

I see plenty info on horizontal spans and distance between supports, but nothing so far on what I need.

I will be tasked with installing some small diameter vent piping (1" - 2") and would like to get input from the more experienced people.

Q1) Is there a guideline to use for determining how much pipe can extend beyond the last support?
I will likely have a uni-strut support about 3 feet up in some cases and may need to extend the vent 10 feet beyond that. There will not be any fittings, valves, etc other than a u-bend at the end to prevent rainwater from entering the line.

Thanks

 

[PEDARRIN2]

I generally support vertical piping at each floor level - just above the slab.

I generally do not locate piping where this is not possible. If I did, I probably would support it in the same span that I do for horizontal - which depends on the piping material.

 

[KernOily]

You don't say what your application is. Building? Refinery? Oilfield? Chemical plant? Laundry? The application will determine the code to use. The code will determine the allowable stress. Then apply your foreseeable loads to your unsupported span and see if the span cuts the mustard. Wind, seismic, snow, someone hitting it with a forklift, etc. See what deflection is caused by your load and calculate the stress.

You might be able to assume the pipe behaves as a cantilever beam under a uniform load (for wind) or a point load (for impact by forklift). Hope that helps.

Don't forget vertical thrust if it's of a high enough magnitude...

 

[LSThill]

NewMechanicalEngr (Mechanical)

John Breen, has a excel spreed sheet that has this information enclued, Do advance search John Breen. Also may be poster on

http://www.pipingdesign.com/

L S THILL