Fittings to ASME B16.9

[mmostafa81]

In the ASME B16.9, clause 6.2.2 about the bore diameter of the fittings, says that the bore diameter away from the ends shall be specified by the purchaser.

Is there any recommendation for the minimum flow area, or any reference for more details regarding the reduction in the area?

Does the area reduces in some fittings other than reducers (i.e. ellbows, tees....)?

Thanks

 

[BigInch]

A reduction to 95% of original pipe ID is often allowed.

What would you be doing, if you knew that you could not fail?

 

[mmostafa81]

Thanks BigInch.

Is this reduction because of bending the mother pipe, and does it affect the wall thickness?

 

[BigInch]

It is caused by ovaling of the pipe in the stretching process. Yes the thickness will be affected. The less you let the original pipe take an oval shape, the more the thickness will decrease. As you stretch an element in one direction, the transverse dimensions of that element (wall thickness and width) are decreased by about 30% (Poisson's ratio) of the distance stretched, if it is held in a flat plane. Since the pipe is circular the transverse shrinkages become somewhat reduced if the surface containing the element is free to displace towards the center of the pipe, hence the ovalization. If you prohibit a lot of movement towards the center, then the transverse dimensions will take the full 30% reduction in their dimensions. I think the limit of maximum allowed stretch is about 2% of the length, so that sets the total length of pipe you will need to form the ell.

What would you be doing, if you knew that you could not fail?

 

[mmostafa81]

Thanks alot BigInch
your reply really helped me alot

 

[BigInch]

Cheers.
Go bend that pipe.

What would you be doing, if you knew that you could not fail?