Defination of Category D, Normal and Category M 1

[Timewrap]

Hi All,

Can somebody explain me the defination of the various category listed in ASME 31.3 such as Category D,M and Normal.

I've got a pressure vessel with internal I.D less than 6", Normal operating pressue is 1400 deg F and presure is 30 psig. The design conditions are 1500 deg F and 50 psig. I'm trying to find out the testing and examinations to be carried out as per code.
Also can somebody guide me which category this vessel will fit in. This vessel is used as regenarator.

Thanks in advance,

Timewrap.

 

[nickelkid]

The guide to classifying fluid service for B31.3 piping is in Appendix M (Fig. M300). It is very clear on how to define the category.

Is your pressure vessel going to be built to ASME BPVC or are you considering it a B31.3 process pipe?

 

[nickelkid]

A few notes on Category M Fluid:

• Significant potential for personnel exposure

• Single exposure to small quantity can cause irreversible harm to breathing or skin.

• Requirements same as for piping in normal fluid service. In addition:
– Design, layout, and operation conducted with minimal impact and shock loads.
– Detrimental vibration, pulsation, resonance effects to be avoided or minimized.
– No pressure-temperature variation allowances.
– Most severe coincident pressure-temperature conditions determine design temperature and pressure.
– All fabrication and joints visually examined.
– Sensitive leak test required in addition to other required testing.

• Following may not be used:
– Miter bends not designated as fittings, fabricated laps, nonmetallic fabricated branch connections.
– Nonmetallic valves and specialty components.
– Threaded nonmetallic flanges.
– Expanded, threaded, caulked joints.

 

[Timewrap]

RC Handy, Thanks for the reply. I'm desigining the vessel as per ASME B31.3 Proces Pipe.

 

[JohnBreen]

Fluid SERVICES are addressed by ASME B31.3. There is no such thing as category "M" fluid. The fluid in the pipe is only ONE of many things that determines the fluid service.

Very few piping systems will actually fall within category "M" fluid service - perhaps as few as there are lethal service pressure vessels.

John.