ASME B31 Question

Not to speak for any other standards, but mine wouldn't allow this.

So, am I correct to assume that you have a commercially sold filter housing that is rated for 3900 psi (or greater) with an operating temperature of 500F ?

What is the pipe size of this threaded connection ?

Can you give us the website for this device ?

You are in the operating range of a supercritical boiler.

I am having trouble understanding that this is a real project and not some idel speculation by someone that has time to waste

My "quickie" calculation for carbon steel piping indicates that even schedule 160 is not adequate.

More information ?

See the provisions of ASME B31.3 on threaded connections. I believe this will assist you in your decisions. However I will not subscribe to using thresded connections considering the operating temperature and pressures of your process fluid.

Chike.

314 THREADED JOINTS

314.1 General

Threaded joints are suitable for Normal Fluid Service

except as stated elsewhere in para. 314. They may be

used under severe cyclic conditions only as provided

in paras. 314.2.1(c) and 314.2.2.

(a)

Threaded joints should be avoided in any service

where crevice corrosion, severe erosion, or cyclic loading

may occur.

(b)

When threaded joints are intended to be seal

welded, thread sealing compound shall not be used.

(c) Layout of piping employing threaded joints

should, insofar as possible, minimize stress on joints,

giving special consideration to stresses due to thermal

expansion and operation of valves (particularly a valve

at a free end). Provision should be made to counteract

forces that would tend to unscrew the joints.

(d)

Except for specially designed joints employing

lens rings or similar gaskets, threaded flanges in which

the pipe ends project through to serve as the gasket

surface may be used only for Category D Fluid Service.

For high pressure, high temperature and hazardous service I would never use a threaded connection regardless of what codes say. The forseeable dangerous failure modes dictate the use of intelligent assessment, not adherence to codes or expediency.

If a component is only available with threaded connections, either it is not suitable for the severe service you describe, or the connection should be seal- or orbital-welded prior to startup.

I am surprised that a manufacturer of a filter rated for 3900 pisg service would make a threaded connection available since it's not suitable for the service you describe, and because of potential liability.