Minnesota Boiler License Practice Exam

What happens when a safety valve is set lower than the maximum allowable working pressure?

1. It will not open properly

2. It may lead to an operational failure

3. It can cause the boiler to explode

4. It will open too frequently

The correct answer is: It can cause the boiler to explode

Setting a safety valve lower than the maximum allowable working pressure poses a significant risk to boiler operation. The primary function of a safety valve is to protect the boiler from overpressure conditions by releasing excess steam or pressure. When the safety valve is set too low, the valve may open at pressures that are still within safe operating conditions, leading to a scenario where the boiler can become over-pressurized as the pressure fluctuates during normal operations. If a boiler is allowed to exceed safe operating pressure, it can potentially lead to catastrophic failure, including situations where the structural integrity of the boiler is compromised. This can result in an explosion, which is extremely dangerous and can cause serious injury or damage. Therefore, maintaining the safety valve at the correct setting is crucial for safe boiler operation. In the context of other options, while opening too frequently might seem plausible, proper calibration should prevent frequent openings under normal circumstances. The risk of operational failure can occur, but it is fundamentally tied to the significant danger of an explosion when a boiler is over-pressurized. Thus, the position of the safety valve in relation to maximum allowable working pressure is critical to ensuring safe and effective boiler operation.