Below is an example of extraordinary engineering luck. A few years ago, a contractor made a plug for a thermal oil installation TS = 230C, which works on an open expansion tank. The plug was made under the roof, and on the roof there is a tank, where the pressure in the installation is equal to atmospheric. So at the point of the plug there is only a temperature load, but not pressure.
This black coating under the flange is leaks of thermal oil from the flange , which then evaporated. They have to be lucky though, because in the event of a failure, a dozen or so cubic meters of oil would spill out onto the floor.
This installation is not subject to a notified body. So there was no one who may ask the most important question to this happy contractor, namely: What is the SIF for this tee-on-bend connection ?
