B31.3 Catergory D Fluid Service

[colar]

In B31.3 in appendix M it steps through a flow chart to determine the fluid service for the piping application. It has one soft requirement that I am looking for help in defining.
When you get near the end of the chart towards the category D fluid service side, the final question is if the owner has designated it a category D fluid service. This seems a little unclear. As an owner or employee of the owner, I am trying to determine if I can use the requirements of category D, and in then end it is left up to me?

Does anyone have some guidance.

 

[BigInch]

If that falls under your company's job description defined for the position you fill, yes, its ALL YOUR'S.

If you have some doubt whether it is in your job description or not, simply clarify that point with your manager, or his manager, etc. until you get a definite yes or no answer from someone higher up the tree.

**********************
"The problem isn't working out the equation,
its finding the answer to the real question." BigInch

http://virtualpipeline.spaces.live.com/

 

[rneill]

If all the criteria specified in B31.3 are met for Category D, then the Owner or the Owner's designated representative has the option of designating this as Category D piping and following the somewhat relaxed rules. If the Owner does not choose to designate as Category D, then the rules for Normal Service would apply.

 

[colar]

The question really isn't whether it is my decision. The question really is under what basis can I make this decision?

That is why we normally turn to code.

 

[rneill]

The criteria under which you are permitted to classify a fluid service as Category D are contained in Clause 300.2 "Definitions" under the definition for "fluid service".

The subject is also touched on in Code Interpretations 21-47 and also in the Draft interpretation 22-14 although this draft interpretation seems to directly contradict 21-47 ?

 

[ApC2Kp]

colar,

The rationale for Category D fluid services would be based on nonhazardous substances at moderate conditions of the pressure less than 150 psig and temeperature less than 400 deg F. The typical nonhazardous substances would be air, water, nitrogen, and steam less that 150 psig saturated. The 'nonhazardous' materials would be judged for their flammability, toxicity, chemical reactivity, etc.
The fact is water could cause drowning, nitrogen could result in asxphiation, and steam would cause serious burns at 400 F. but the B31.3 Code allows the owner's judgment to be applied up to those limits of pressure and temperature.

 

[StevenHPerry]

Careful... it's 366°F, not 400.

A pool of water and a jet of steam are detectable hazards. Nitrogen is much less so.

I have not yet encountered an owner or an engineer which has lumped nitrogen into Cat D with potable water and instrument air.