What is the interval for thickness measurements on a Class 1 piping system?

What is the interval for thickness measurements on a Class 1 piping system?

• A. Greater than 10 years
• B. Over 2 years
• C. Lesser of 5 years or half life of the pipe
• D. Annually

Answer: (C)

For Class 1 piping, thickness measurements are scheduled at the shorter of two timeframes: five years or the pipe’s corrosion half-life. The half-life is the time it would take for the wall thickness to reduce by half at the current corrosion rate. This approach keeps monitoring frequent enough to catch significant thinning early, which is crucial for high-consequence piping, but avoids unnecessary checks when corrosion is slow. If the predicted half-life is shorter than five years, you inspect at that shorter interval; if it’s longer, you cap inspections at five years.

For Class 1 piping, thickness measurements are scheduled at the shorter of two timeframes: five years or the pipe’s corrosion half-life. The half-life is the time it would take for the wall thickness to reduce by half at the current corrosion rate. This approach keeps monitoring frequent enough to catch significant thinning early, which is crucial for high-consequence piping, but avoids unnecessary checks when corrosion is slow. If the predicted half-life is shorter than five years, you inspect at that shorter interval; if it’s longer, you cap inspections at five years.