Minnesota Boiler License Practice Exam

When multiple boilers are connected to a common steam header, what is the safety requirement for the valves?

1. No valve may be set higher than the S.W.P. of the weakest boiler

2. All valves may be set 20% higher than the lowest S.W.P.

3. Some valves may be set 20% higher than the lowest S.W.P.

4. Set valves according to the S.W.P. of each individual boiler

The correct answer is: No valve may be set higher than the S.W.P. of the weakest boiler

The correct answer highlights an essential safety consideration in boiler operations when multiple boilers are connected to a common steam header. The requirement that no valve may be set higher than the Safe Working Pressure (S.W.P.) of the weakest boiler ensures the integrity and safety of the entire system. If a valve were set higher than the S.W.P. of the weakest boiler, it could potentially lead to hazardous situations where the weakest unit could be overwhelmed or damaged, possibly resulting in a catastrophic failure. This measure helps to maintain a balance in pressure across the entire system, ensuring that all boilers operate safely within their designed pressure limits. The other options suggest settings that do not adhere strictly to the principle of aligning the pressure settings with the operational limits of the weakest boiler, which could compromise safety. A higher setting could increase the risk of overpressure conditions, while setting all valves 20% higher or allowing individual variations in pressure can lead to inconsistencies and the possibility of exposing some boilers to unsafe operating pressures. This reinforces the importance of maintaining safety protocols that prioritize the weakest link in a connected system.