CMS Equipment Calibration & Maintenance 2 — Questions and Answers
Question 1: Which calibration method uses a known reference standard traceable to NIST to verify instrument accuracy?
- Dead-weight calibration
- Traceability-based calibration (Correct answer)
- In-situ calibration
- Functional calibration
Correct answer: Traceability-based calibration
Traceability-based calibration links measurements to national or international standards through an unbroken chain of comparisons, ensuring accuracy is referenced to NIST.
Question 2: A pressure gauge consistently reads 5 PSI higher than the true value across its entire range. This is best described as:
- Hysteresis
- Repeatability error
- Systematic bias (offset error) (Correct answer)
- Random error
Correct answer: Systematic bias (offset error)
A constant, consistent deviation from true value across the entire measurement range indicates a systematic bias or offset error.
Question 3: What does 'calibration interval' refer to in a maintenance program?
- The time between equipment purchases
- The scheduled period between successive calibration checks (Correct answer)
- The duration of a single calibration procedure
- The gap between two calibration standards
Correct answer: The scheduled period between successive calibration checks
The calibration interval is the defined time period between recalibrations, determined by equipment stability, usage frequency, and regulatory requirements.
Question 4: Which type of maintenance is performed based on the actual condition of equipment rather than a fixed schedule?
- Corrective maintenance
- Preventive maintenance
- Predictive maintenance (Correct answer)
- Breakdown maintenance
Correct answer: Predictive maintenance
Predictive maintenance uses condition monitoring data (vibration, temperature, oil analysis) to determine when maintenance is actually needed.
Question 5: When calibrating a torque wrench, the reference standard used must have an uncertainty that is at least how much better than the device under test?
- Equal to the device under test
- 2 times better (2:1 ratio)
- 4 times better (4:1 ratio) (Correct answer)
- 10 times better (10:1 ratio)
Correct answer: 4 times better (4:1 ratio)
The standard 4:1 Test Accuracy Ratio (TAR) requires that the reference standard's uncertainty be at least four times smaller than the device being calibrated.
Question 6: Which document records the 'as-found' and 'as-left' conditions of an instrument during calibration?
- Maintenance work order
- Calibration certificate (Correct answer)
- Equipment logbook
- Failure mode report
Correct answer: Calibration certificate
A calibration certificate records both the as-found (pre-adjustment) and as-left (post-adjustment) readings, documenting the instrument's condition before and after calibration.
Question 7: Mean Time Between Failures (MTBF) is primarily used to:
- Calculate the cost of a repair
- Estimate equipment reliability and plan maintenance intervals (Correct answer)
- Determine warranty periods only
- Schedule operator training
Correct answer: Estimate equipment reliability and plan maintenance intervals
MTBF measures the average time between failures for repairable equipment, helping maintenance teams assess reliability and set appropriate preventive maintenance intervals.
CMS Equipment Calibration & Maintenance 2
Which calibration method uses a known reference standard traceable to NIST to verify instrument accuracy?