Plate type flat welding flange and necked flat welding flange

Thread Content

I encountered a situation recently, and I hope all sea friends will take action.: The styrene stainless steel pipe, PN16, was previously made of 304 necked butt welding flange. The owner wanted to reduce costs. At that time, he also asked an experienced master to help them change it to a necked flat welding flange. Now they have bought plate flat welding flanges in the factory and they have arrived. I want our design institute to help modify the design documents. It is said that there are "unsuitables" in GB50316-2008, 13.2.6. Please actively participate and discuss the "unsuitable" here. Under what circumstances can it be used? So there is the following solution: At the pump outlet, use neck flat welding in places with severe vibrations, and let us change to plate flat welding in other places. There are two situations mentioned in GB50316, 5.6.3. Please help me read this article. Why didn't I see that board style can be used here? In addition to GB50316, I also found several other specifications or reference books: See attached picture. It's too weird. I can't accept this change. I want to stick to the original design, but I also want the leaders to accept my ideas and not let me modify the design documents or issue change orders. Please give me some advice, how should I deal with this matter?