Class 5 Boiler Practice Exam

Is it true that slip-on flanges are welded inside and out on category M?

1. True

2. False

3. Only in specific circumstances

4. Depends on the pipe material

The correct answer is: True

Slip-on flanges are indeed welded both inside and outside when classified under category M. This welding method is applied to enhance the integrity and strength of the joint, ensuring that there is no leakage at the connection point. When these flanges are attached to the pipe, the external weld contributes to the overall mechanical strength, while the internal weld provides a smooth transition that minimizes turbulence and pressure drop within the piping system. This design is particularly crucial in category M applications where the service conditions may involve higher pressures and potential for leaks if not properly secured. As a result, the practice of double-welding slip-on flanges is essential for maintaining safety and reliability in systems operating under demanding conditions.