What method is commonly used to check the operation of various boiler safety devices?

Calibration tests are crucial for ensuring that boiler safety devices function correctly and reliably. These tests involve adjusting and verifying the precision of the safety devices to make sure they operate within specified parameters, which is essential for the safe operation of the boiler system. Proper calibration can help to identify any deviations or malfunctions early on, preventing potential safety hazards.

While visual inspections are important for general oversight and can help in spotting obvious issues, they may not provide a comprehensive assessment of the operational integrity of safety devices. Benchmark testing, on the other hand, often involves comparing performance against a predetermined standard, but it might not specifically address the operational readiness of the safety devices. Routine maintenance encompasses various tasks to ensure the boiler operates smoothly but is more general and may not include the detailed checking that calibration tests provide. Thus, the use of calibration tests is specifically designed to verify that safety devices are working correctly, making it the best method among the options presented.