ASME B16.5 High Temperature Bolting Usage

[JKyoungWon]

Hi, all

According to ASME B16.5(2013) para. 2.5.2, there are some requirements for high temperature.
At temeprature above 200 deg.C for Class 150, flange joints may develop leakage problems.

1. Then, what can be done for preventing leakage of flange joint at temperature above 200 deg.C for CL.150?
2. I wonder why the CL150 flange joints only are considered at temperature above 200 deg.C.
(As per ASME B16.5, I thought that the basic problem is decreasing bolt load due to high temperature. And it can be also happened to other class rating of flange such as CL300, CL600, etc.)

Please some body give me answers or your kind opinions.
Thanks

 

[nickelkid]

Besides being a flange with high temperature, I am not clear on your application. Regardless, the paragraph you site mentions the two major issues to address to reduce this concern, minimize external loads and avoid thermal gradients. So keeping the flange temperature as constant as possible and reducing the forces and moments that are applied to the flange should keep you out of trouble.