Minnesota Boiler License Practice Exam

Steam gauges shall have a dial graduation of at least:

1. 1 1/2 times the M.A.W.P.

2. Same pressure as the boilers

3. 2.0 times the M.A.W.P.

4. 3 times the M.A.W.P.

The correct answer is: 1 1/2 times the M.A.W.P.

The correct answer involves the requirement for steam gauges to ensure they can accurately reflect the pressure that a boiler can produce without being damaged. The minimum dial graduation of steam gauges being set at 1 1/2 times the Maximum Allowable Working Pressure (M.A.W.P.) is crucial for safety and functionality. Setting the gauge at this graduation allows for a margin for error and ensures that the gauge does not register pressures too close to its maximum rating. This is important for preventing gauge failure, as gauges that are rated too close to the M.A.W.P. may not withstand occasional pressure spikes without risking damage, which could lead to inaccurate readings or even instrument failure. On the other hand, options such as the same pressure as the boiler or simply doubling the M.A.W.P. may not provide sufficient safety margins, and setting the gauge at three times the M.A.W.P. could lead to excessively large and unwieldy gauges without any practical benefit. Therefore, the standard of 1 1/2 times the M.A.W.P. strikes a balance between safety, utility, and practicality in boiler operation.