Is there any good engineering practice for using spring support at the big pipe line? Lets say above 30'' pipe line.

I'm analyzing power plant connected to desalination plant so the pipe size is bigger than common power plant(combinded or thermal)

When I place a spring support at the pipe(above 30''), Support vendor recommend two spring support at the location.

I agree that using one spring support would look unsafe, spring size will be bigger, and since the size is too huge to use clamp, spring support should be base(bottom) type and its neck or base plate are vulnerable to horizontal movement.

But is there any regulation for this? MSS-SP58 does not specify this.

I guess it is vendor's standard and may differ from support vendor.

Sometimes the load can be outside the range of the largest spring hangers, so you may be forced to use two spring hangers instead of one. The support vendors will guide you on that.

When the diameter of the pipe is large and the clamp is not the solution to transfer the load onto the spring hanger, you may have saddle under the pipe, and spring hangers can take the load from the saddle.

There are more solutions than one. I trust the vendor again will provide you the optimum solution.

Hi Ibrahim

I consulted with other local vendors to verify the concept, but most of them didn't have the standard for this(Such as over certain pipe size and temperature, multiple spring shall be used).

I'll ask big international vendors for this, but I just want to ask stress engineers if they have this experience.

I thought a support designer can manage this kind of jobs. At least the designer/stress engineer can come up with an idea (I suggest that the saddle concept be implemented in case the wall diameter/wall thickness ratio is high with large diameter piping) and provide it to the vendor for the geometry, so the vendor can visualize it and modify with calculation.

LISEGA has large support range, see the following link:

http://www.lisega.de/downloads/catalog-standard-supports-2010.html

Additionally they have LICAD software that you can play with geometry and come up with a concept that they have in their standards:

http://www.lisega.de/downloads/design-development-tools.html

Thanks to Ibrahim I have contacted with Lisega, and here is their response.

'Basically two base supports are used whenever the total load exceeds the possibilities of one single spring or dimensional requirements make it necessary to limit the installation height, where two smaller supports can be used instead of one big support and hence reduce the height dimension.

Apart from that, the load should be distributed 50/50% on both supports at this setup, whereas it should be taken care that the load is distributed evenly between both supports either by centering the center of gravity of the supported pipe/component between both supports or taking other measures to avoid uneven loading of both supports'

I guess this concept varies between vendors and project condition.

Ibrahim and MK,
In addition to load range, just imagine stability of 30" piping. Maximum size of load flange and spring CAN will not be more than 200 mm -350 mm.
I feel that piping will not be stable if a 30" pipe is supported on 8" or 12" spring CAN/ load flange at center.
For stability point of view we should support large bore piping by two or more bottom type springs.

Seniors please suggest.

Regards,

There is one more solution to this.
If you have space available on both sides of a 30" pipe , then have two trunnions on each side with end plate. Use two hangers from those two end plates.
Ensure to check the trunnion strength check using FEA OR suitable tool.