90/10 CuNi for Sect 8, Div 1 Heat Exchanger

[stanrick]

Hello All,

We are designing a heat exchanger for marine service. The customer has asked that the tubeside meet ASME Code Sec8 Div1 and be made of 90/10 CuNi. I'm making the Domes and Flanges out of SB171-C706. I don't see any CuNi in Sect 2 Part D for B16.5 flanges and B16.11 fittings. So I'm making couplings out of SB467-C706 XXS pipe. The required 1-1/2" NPT plugs are undefined however, because SB151-C706 is not permitted. My only other option seems to be to machine them out of SB171-C706.

Am I missing something? My google-searches for 90/10 fittings have come up empty, as have my searches in Eng-Tips for guidance. Are there 90/10 CuNi fittings and flanges available for Code use? Or can I propose an alternate material to the customer?

Thanks for helping me move up the learning curve here.

 

[SnTMan]

stanrick, you might take a look at Table U-3, ASME B16.24 flanges, ASME B16.15 fittings. I don't have these standards, can't confirm 90/10 is within the scope.

I just design the flanges per Appendix 2. Don't know about fittings.

Regards,

Mike

 

[eyec]

ok, i will ask a silly question; does he mean for you to use 90/10 for the tubes - not the shell?

 

[TJOrlowski]

Plugs? Several US manufacturers make them out of MIL-C-15726F barstock, they may be able to give you some guidance on an equivalent ASME spec.

Google "copper and brass fittings". Several of the vendors we've used in the past for C706 and C715 fittings and flanges are on the first page of the results. I'm sure they have some answers.

-TJ Orlowski

 

[MrBTU]

I've run into the same issue in the past, and we ended up making flanges, couplings, and plugs out of plate SB-171 C706. All the leads I had for finding 90/10 forged fittings were dead-ends or were not allowed per Code, as you mentioned for the SB-151 bar stock.

 

[stanrick]

Thanks all for your input and guidance. In answer to eyec, the tubes, tubesheets and waterboxes are 90/10. The shell is carbon steel.