Control valve flange thick ness

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ASME B16.5 covers all dimensions of pipe flanges and flanged fittings, whatever that flange located at control valve, gate, globe, ... etc.

The flange dimensions are : flange thickness, flange OD, no. of holes & its size, RF diameter, ..... etc. All these dimensions depend on the design pressure, design temp. and type of material which define what we call Flange Rating (eg. 150#, 300#, 600# .... etc.).

So, for any flange located at any valve, pipe line or flanged fitting, we have to specify its size and its rating (e.g. Flange WNRF, 4" NPS, 300#), so all flanges at a piping system shall be compatible for easy assembled together.

So, Table no: 10 in ASME B16.5 is not inclusive of any type of control valve, because the table is designed for any flange whatever located in a valve or line pipe.

Notes :

1. When a flanged valve specified in accordance with ASME B16.5, 8", 300# that means the flanges on line pipe shall be in accordance with ASME B16.5, 8", 300# too.

2. I prefer to select the rating of control vale greater than the rating of pipe line flanges, i.e. 2 flanges with a higher rating from the rest flanges of line pipe shall be welded to assemble the control valve. Please fellow the recommendations of ISA (Instrument Society of America) for that selection.

3. Specifying any WN flange for a pipe line requiring to specify the pipe schedule (Sch.) which represents the nominal thickness of pipe wall.

Dear sir,

I conclude from your reply that Flange thickness of Control valve shall be atleast equal or higher than the mating flange thickness, being provided by Piping contractor at site.

I also request to know what is ISA fellow guide line for Control valve, for infomration.

Regards

RROJASARA

I conclude from your reply that Flange thickness of Control valve shall be at least equal or higher than the mating flange thickness.

No, I mean that if you have a pipe line with a designated rating of 150# (e.g.) for its whole flanges, you can select a control valve flanges 300#, and this required you to weld a two flanges 300# to pipeline to assemble that control valve, instead the rest rating of all flanges are 150#. And it is known that the flange with higher rating is thicker.

ISA guide line for control circuits is to specify the control circuit elements, size of control valve related to size of pipeline, bypass and its elevation, circuit main dimensions, height of control valve above the ground/floor, orientation, ...... etc.

I will try to scan such circuit and its table of dimensions for your information. It is very important for any piping designer.

About the standard of flange besides ASME there are also some other standard, for example, BS, ANSI,GB and so on.

Just for refference.