neck flange and slip on flange 4

[Jade24]

Can I use a neck flange with a slip on flange?
Both would be ASME B 16.5.
I saw that on a drawing and I don´t know what to think about that.

Thanks a lot

 

[rustbuster]

If you mean bolting them together sure.

 

[pennpiper]

Your question is not clear.
Do you mean can you bolt a Weld-neck flange to a Slip-On Flange? If this is you question then the answer is yes!

Do you mean can you weld a Slip-On flange directly to the taper of a Weld-Neck Flange then the answer is no!

I hope one of these is your real question and your real answer.

 

[Jade24]

Sorry for the unclear question.
I meant bolting the flanges together

Tahnks a lot

 

[Duwe6]

Faces need to match, only. i.e. Raised-Face to Raised-Face; flat-to-flat. For bolting, an approved flange is an approved flange, and anything can be bolted to any other flange. WN to SO, SO to Lap, Lap to WN, etc.

 

[GenB]

Yes it can be done You are trying to make a spool!
Check if sizing is an issue of Slip on.
Some Codes do not allow large Slip-on Flanges.

 

[jte]

B16.5 does not prohibit bolting a raised face flange to a flat face flange. There are some issues to be thought through, but it is not prohibited.

jt

 

[TBP]

125# cast iron flanges are flat-faced, and if I remember correctly, B31.1 requires that 150# steel flanges have the raised face removed, and that a full-face gasket be used, when bolting the two together.

 

[jte]

Cast iron is one issue (cracking due to bending when nuts are tightened), flange rotation and contacting on the outer diameter is another. Either way, B16.5 allows RF to FF. I've worked a Section VIII to B31.3 connection where one was basically a FF while the other was RF. Not a big deal.

jt

 

[moltenmetal]

There IS an issue you must know about when bolting weld neck to slip-on flanges: the ID of the raised faces DO NOT MATCH. The ID of the slip-on is the OD of the pipe, while the ID of the weld neck is the ID of the pipe.

If you use a gasket whose ID is the same as the ID of the pipe, i.e. a typical spiral wound gasket especially with inner ring, you will have an unsupported gasket edge in the flow path. With spiral wound gaskets this IS a problem which can lead to damage and unspooling of the spiral wound gasket into the bore- potentially a big problem. If you choose a composition gasket, or any gasket with an ID equal to the OD of the pipe, such that the unsupported edge is no longer there, you will be fine.