tranvietnga1905,
The first consideration is safety, then maintenance. If the fluid in the pipeline can cause instant health hazard when its exposed into the environment (i.e H2S or High pressure/temperature steam) go with welded connections.
The next step would be to contact maintenance group...
Have a scenario where 6" ASTM C547 mineral wool was selected to insulate carbon steel plate material. Its recomended to 1200 deg. F, the skin temp of the duct is "supposed" to be operating at 1000 deg. F. However, the insulation is burning or "degrading" if you will.
Any suggestions?
Also...
