Question: “OK, so how do you decide the Failure Developing Period?” (FDP)
– Maintenance Supervisor, International Paper
Answer: It comes down to an educated guess unless you have very good historical data. Even then, there are many factors that decide the Failure Developing Period. A practical suggestion is to try to estimate day, week, month, quarter or year.
- Example 1: Foundation for a 125 HP pump-motor-coupling probably takes at least a year to develop from initial crack to failure.
- Example 2: Sprocket for chain drive (small, low load, 900 rpm).. at least a month, perhaps a quarter
- Example 3: Bad sounding bearing if we are using stethoscope? Days perhaps hours
- Example 4: Initial high vibration with vibration pen? Months (that’s why we use VA)
Agree on something that makes sense based on FDP (Not life of component), then try to collect data to learn better over time.