Piping Support Specification

[nikolastrojman]

Hi

I wonder what it takes to built a good piping support specification like the one I've attached to my post. I mean...where does one start from? Which Code's,Standards, Norms, should one use if we talk about piping systems in refinery. I've seen a dozen of piping support specifications, some are very decent others according to my humble opinion are not because they are lacking essential information like allowable support loading.

My opinion is that you have to have a good theoretical and practical understanding of the subject in hand. If you just look at the various pipe support design which are available in this standards you must conclude that a rather impressive knowledge is behind it. At least I think it is.

In my company we don't have such specifications, instead we use pipe supports like clamp bases already manufactured from Manufacturer like LISEGA or BERNECKER or...We use their software and the support loads we've calculated form the stress analysis to select suitable pipe clamp.
Recently we had a case in which there were complaints from the contractor that we used supports for carbon steel piping (A 106 Gr.B) made of very expensive material like 13CrMo4-5, which by the way we got from the software selection, and not the less expensive one like 235JR or 355JR. So we had to "manually" check if the 355JR material is also an adequate material for this situation at hand.

To avoid this kind of situations in the future we are thinking of developing our own piping support specification.

Any ideas?

 

[racookpe1978]

I would never worry about complaints "from the contractor" about any specific support (or group of supports) being "too expensive" - especially if corrosion is an issue! - if the CUSTOMER is not complaining. More accurately, if the contractor is complaining about "price" for supplied items on a contract already signed, then it appears the CONTRACTOR is the one who will be benefiting (perhaps through his fixed priced contract terms ?) from a decrease in short-term price for an increase in long-term maintenance and long-term replacement of the broken, rusted, jammed, immobile, irrepairable/irreplaceable pipe supports in 7-15 years.

 

[david339933]

On the other hand, the Contractor should be informed what material is used for supports during the bid process....if you just had supports included and then replaced with an expensive material...I would complain too. Nobody expects to wrap a 106B pipe in gold......

 

[XL83NL]

We've had the same issue. We needed our own support specs as well.

The industry we serve makes it (somewhat) challenging as we dont do major oil&gas or refinery sites, but our customers are still are those major compamies. So we need some sort of compliance to major O&G specs. Our spec needed to be simple, effective, and a one size fits all. A few more extra bucks doesnt mather to us; the biggest linesize we typically see in our plants are 3" to 4", however weve done as large as 8"-10" on a rare instant. Thats why we ended up with a few support types, actually only 2 or 3 types, which fit all supporting needs.

Our spec is verified by simple hand calculations, and were currently updating our pipe support spec and will be conducting simple FEA calcualtions to verify their strength, both at ambient and at design temperature. The spec calls out either 316 supports or carbon steel (HDG or coated). We never have done CSEF piping systems like 13CrMo4-5 or P11 or P91, so we have no need for such materials in support.
Our spec lists max allowable loads for each support type, both axial and lateral. Our supports are either rigid or sliding. Anything different (trunnions, etc.) are specials and will be designed on a case by case basis. Hangers, both variable and spring, follow from pipe stress analysis; we always by these from LISEGA, we dont go for a buck cheaper with all the less robust designs out there from other vendors.

If you work to B31.3, follow MSS SP rules (#58 being the most important, but also #69, #77, #89 and #90). If you work to EN 13480, review chapter 13 and the applicable appendix N which defines the requirements pertaining to supports. There's a link to the PED in EN 13480 wrt supports.

So I guess it all boils down to the typical application you work to. For us, linesizes are small, and 95% we do is stainless, the rest usually being nickel alloys like C276, 800H, etc. We hardly ever do carbon steel.

Can you explain what you scope of work is in piping systems?

PS; your first post does not contain an attachment.

 

[nikolastrojman]

Here it is, sorry.

 

[mk3223]

Is it the Engineer's responsibility to understand and use the correct and proper material based on the design condition? The cost factor should be also included for the design consideration. The software tools from the Mfr or vendor are good design references, and should be used with good engineering judgements too.
Regarding to the pipe support, IMO, it was either undersigned by the piping engineer or over designed by the civil engineer.

 

[nikolastrojman]

Well, we often design piping systems in Refineries and Power Plants. I do pipe stress calculations and support designs.