B31.3 Catergory D Fluid Service
B31.3 Catergory D Fluid Service
(OP)
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.
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.





RE: B31.3 Catergory D Fluid Service
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/
RE: B31.3 Catergory D Fluid Service
RE: B31.3 Catergory D Fluid Service
That is why we normally turn to code.
RE: B31.3 Catergory D 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 ?
RE: B31.3 Catergory D Fluid Service
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.
RE: B31.3 Catergory D Fluid Service
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.