Criteria of selecting FLANGE FACE

[sks4338]

What is the criteria selecting flange face?

Sometimes you find large tongue and groove even at class 150 piping spec,
Although you use raised face at class 2500 piping spec.

At class 600, 50% of the case you find ring joint, another 50% of the time
You find raised face spec.

Because of these observation, i was wondering what flange face selection criteria is.

I'd appreciate if sombody let me know selection criteria of flange.
There are 8 kind of flange face in asme b16.5.
So i made up 8 questions. help me, please.

1. When do you use flat face?
2. When do you use 2mm raised face?
3. When do you use 7mm raised face?
4. When do you use ring joint face?

5. When do you use large male and female?
6. When do you use small male and female?

7. When do you use large tongue and groove?
8. When do you use small tongue and groove?

 

[JStephen]

Flat faced is used in water works industry in US. All the AWWA fittings and valves are flat faced. I have heard that you should never connect raised-face fittings to a cast iron valve or fitting because you can crack the cast iron. That being said, I've seen it done a lot without any problems.