Piping Specification 2

[pdp123]

Hello everybody!
Appreciate your help as I have few questions in my mind regarding Piping Specification...

1. How one can decide the maximum and minimum size for a specific fluid/medium. May be based on Client requirements but not exactly.
2. How to find the relevant material group in ASME B16.5 given the base material. This group can be decided whenever there are P-T limits as provided in Client specification but what if not given.

Please give your valuable thoughts and share the info with each.

Regards
PME

Hard Work with Smartness is the key to success

 

[bimr]

Maximum and minimum size for a specific fluid/medium will be based on good engineering practice.

 

[LittleInch]

1 - the max is the biggest size you need to do the process flow. Comes from process design
Min - the smallest size you need for instrument connection

Material to be used is the cheapest you can that meets the process requirement

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[MickMc]

pdp123,

As LI states sizing will come from process design who will do the hydraulics but in practice your Piping Specification should cover all the standard sizes up to the largest expected in project therefore changes in initial sizes can be accommodated without having to re-issue specification.

Material should be based on Material Selection Report and Material Selection Diagrams (MSD) with MSD including stream data from where you can then specify the piping class by material and pressure e.g. Class 150, Class 300 etc and also determine wall thickness based on P/T limits in B16.5. Note that for Class 150 you should include Class 300 flanges which are likely to be required to match Control Valves or sometimes equipment connections which are minimum Class 300.

 

[SNORGY]

1. Pipe sizing is always process-driven, and it's hard to capture all of the scenarios in a single clean set of rules. Some companies follow the API-14E guidelines for maximum velocity; some follow their own (different) criteria; most try to follow whatever guidelines are specified but then make case by case exceptions to their own specifications. Then there are situations in which lines are sized for reasons other than optimizing the flow rate versus pressure drop. Risers with two phase flow going up into certain process columns, for example, might be deliberately downsized in order to avoid slug flow, while piping for fluids with appreciable solids content might be deliberately upsized to prolong the erosion wear life.

2. Not sure I fully understand the question; are you trying to pick flange material to match the base pipe material, or is it just a matter of interpreting the flange material groupings within B16.5?

 

[pdp123]

I would like to say Thanks to everybody regarding the Maximum and minimum size of Pipe but not clear about the material selection or grouping in B16.5 given the base material family (CS/SS/LTCS/DSS.....)and not respective ASTM material.


Regards

Hard Work with Smartness is the key to success

 

[MickMc]

Material selection is independent of B16.5, material will be selected on suitability for fluid service and specified operational life of plant normally 20-30 years. The corrosive properties of the fluid will be taken into account which you will see reflected in different corrosion allowances in carbon steel pipe. For the particular material selected B16.5 is used to specify the Pressure/Temperature limits of that material resulting in Class 150, Class 300 etc.

This is very simplified but hope it helps.

 

[lhwingking]

Hello,

It feels good to open eng-tips after a long time. Hope you all are doing good.

Now, regarding this post, I think MickMc has explained very clearly. Generally, process engineer specifies the material to be used. There is usually a document called "fluid list" that mentions the material to be used against every service. Piping material engineer prepares piping material specifications based on this fluid list. The rating of PMS is derived from ASME B16.5 based on pressure temperature ratings.