pipe span design for weight supports

[alizafari1]

Hi;
In piping support design specs & codes we see tables of pipe spans, as distance between two weight supports in a straight horizontal line cannot exceed this amount. Now the question is if the line is not straight and there is a change in the direction of line (for instance by elbows), what amount shall be used for pipe span.

 

[Duwe6]

Simple -- consider the ell as two separate, cantilevered runs of pipe. Treat your support spacing / pipe span as if the ell does not exist. If your spacing exceedes the length of cantilever allowed for that size and wall-thickness of pipe, move the support closer to the ell.

 

[MJCronin]

As I recall, from the old piping Grinnel text, 2/3rds of the maximum span length shall be used.

Can't put my finger on the text....

Also, see:

http://www.eng-tips.com/viewthread.cfm?qid=49424

 

[Duwe6]

I use 50% for max cantilever. With pipe "if it looks good, it is good". Industry standard is a nominal max. deflection of 1/2" 12mm while operating. Meaning 1/2" droop when dry will probably become unacceptable when filled with liquid.

Just look down the line, with your head at the top or bottom of the installed line. You can easily see if the droop exceeds 1/2".