Gauges shall be replaced or tested by comparison with a calibrated gauge every ________

• A. 1 year
• B. 3 years
• C. 5 years
• D. 10 years

Answer: (C)

Gauges drift over time due to wear, temperature changes, and vibration, so they must be checked against a known, calibrated reference to ensure accuracy. The standard practice is to compare a field gauge with a master or calibrated gauge every five years. This interval strikes a practical balance between maintaining measurement accuracy and avoiding excessive maintenance costs. The test is done by applying a known pressure with a master or dead-weight tester and verifying that the gauge under test reads within tolerance. If it doesn’t, the gauge is replaced or recalibrated. Shorter intervals would add unnecessary maintenance, while a longer interval could allow significant drift to go unnoticed.