Class 5 Boiler Practice Exam

For blowoff piping from a boiler exceeding 100 psig, what is the minimum schedule required?

1. 20

2. 40

3. 60

4. 80

The correct answer is: 80

The minimum schedule required for blowoff piping from a boiler operating at pressures exceeding 100 psig is schedule 80. This requirement is based on the need for stronger and more durable piping materials that can handle the high temperatures and pressures within a boiler system. Schedule 80 piping has a thicker wall than lower schedule pipes, such as schedule 40 or schedule 20, which provides greater resistance to pressure and potential failure. The blowoff piping must withstand the high-pressure steam, along with the immediate thermal stresses and mechanical loads it may experience during operation. Utilizing schedule 80 piping ensures that safety and operational integrity are maintained, reducing the risk of leaks or catastrophic failures that could occur if lighter schedule piping were used under such conditions. Therefore, for blowoff piping in a boiler exceeding 100 psig, schedule 80 is the appropriate and required specification to ensure both safety and reliability in the system.