AS1210 Coupling / Flange temp-pressure ratings

[ENG331]

I am looking at AS1210, and am having trouble interpreting the language of the code.

I have a coupling issue, and a flange issue.

I am looking at 3.19.4, referring to screwed and socket weld connections.

I have a heat exchanger, where I am wanted to put a coupling (B16 3000#) operating at

1000F shell side, at a low pressure 75 psi and Full Vaccum. I read 3.19.4.4, which states

threaded joints other than for screwed flanges should be limited to 260C (500F) where temp fluctuations

could occur and cause relation of the joint. Also table 3.1914, has a Max MPA of 2.1 (305 psi) for taper to

taper thread connections. Are these limits on ASME B16 couplings for AS1210 applications?

For the flange issue- I Look at 3.21.3, and see that for attachments (h), and (j), where (h) looks

like an ASME B16.5 slip-on flange type. It is limited to, for Carbon steel and equivalent- 4.9 MPa(710 psi),

at 50C, and temp shall not exceed 425C (797F). Earlier in 3.21.1 it says that ASME B16.5 may be used up to the

pressure temp limits permitted in the standard.

Any feed back you have would help. I was hoping to use a 300# ANSI slip on flange in 316 Stainless using a spiral

wound gasket, with SA-193 B16 studs, and SA-194 Grade 4 Nuts in this connection at 1000F, 75 psi (Full vac)

Thanks in advance

 

[gr2vessels]

Hi ENG331,
First, you are using the obsolete AS 1210 edition 1997;- should use the 2010 edition which has been significantly re-written.
The clause you mention is now 3.19.4.5 and refers to the particular case of large fluctuating temperatures, which could cause differential thermal expansion in the joint and thus loss of sealing capacity of the joint. Is it your case? If not, then the pressure/temperature rating applies as defined in ASME B16.11 Clause 2.1.1.
The Table 3.19.4 you refer to hasn't change and limits the maximum allowable pressure (hot and corroded) to the figure you mentioned, subject of the size listed in the table. The 2.1 MPa limitation applies only to taper joints of fittings less than 35 mm OD at ambient temperature. The relevant maximum temperature/pressure is again limited by the ASME B16.11 rating.
The flanged attachments of Clause 3.21.3 exclude type 'h' and 'j' for any material in fluctuating temperature application. For 'h' and 'j' type of attachments in 'stainless steel' material, the typical B16.5 flange ratings apply, eg. Table 2-2.2 for grade 316 or Table 2-2.3 for 316L (max.840F). Please note the welded flange should be 316L or 'dual' certification 316/316L.
Sorry, for temperature above 840 F should look for other suitable materials. That includes all other B16.5 flanges you might want to weld on the exchanger...