B31.3 Category 2

[Pulpeng]

I'm going over a design for effluent from our mill and trying to determine if Category D or M should apply.

My thoughts are that although there is potential for biological (bacteria) harming a person coming into contact with it I wouldn't consider it damaging or irreversible. Temperature and pressure fit with Cat D. There is this nagging thought that because there "could" be an excursion in neutralization causing high or low pH or maybe H2S generation that it might classify as Cat M. Right now its Cat D but I want to be sure before proceeding - what do municpal plants categorize their sludge and effluent?

 

[C2it]

That's a tricky call for an engineer. Perhaps you should seek the advice of a health and safety expert ?

 

[JohnBreen]

It IS NOT Category M if your follow the guidance in B31.3, Appendix M. Your system is however a good candidate for being designed as a double containment system (with leak detection).

Regards, John

 

[moltenmetal]

There are FOUR fluid categories: Category D for non-hazardous (low hazard) materials like potable water, instrument air etc., Category M for lethal substances, and Category (K?) for high pressure services.

...and everything else is "normal fluid service". That's the fourth category.

Your effluent is normal fluid service, no different than any other material which, if spilled, could represent a hazard but not kill people at a distance.

 

[JohnBreen]

.........and it must AGAIN be mentioned that there is NO SUCH THING as a Category M fluid. Quoting from B31.3, paragraph 300.2 - fluid service, Fluid service is "a general term concerning the application of a piping system considering THE COMBINATION OF fluid properties, operating conditions, and other factors which establish the basis for design of piping systems". The fluid contained by the pipe is ONLY ONE factor that must be considered in determining the systems fluid service. Also, be aware that it is the responsibility of THE OWNER to decide what fluid service a piping system complies with.

Regards, John