Civil Remnant Life – Likelihood Examples (Step 4)

Example 1: Asset in Good Condition

• The study is conducted in 2007
• The last inspection was conducted in 2004
• During the inspection it was found that asset is in a very good condition and failure is expected to occur in 2020
• The confidence in this estimation is Intermediate

Result

The Remnant Life RL is 2020-2004 = 16 years, as of the last inspection

The Last Inspection Date LID is 2004

Now is 2007

 Vertical axis: The time RL + LID - Now = 16 + 2004 - 2007 = 13 years, i.e. in 10-15 years range.

Horizontal axis: Confidence class is Intermediate

Result from matrix: Likelihood class B. 

With the information about the condition status that is given it can already be “felt” that the likelihood that this asset would fail in the year that the study is conducted (2007) would be remote, which is confirmed by the likelihood rating B “We would be greatly amazed to see it happen”.

Example 2: Asset in Reasonable/Poor Condition

• The study is conducted in 2007
• The asset was inspected in 2002
• During the last inspection it was observed that the asset was in a reasonable/poor condition and failure would be expected in 8 years, if no maintenance is undertaken
• The confidence in this estimation is Low, since the last inspection was conducted 5 years ago, and the degradation mechanism is not well understood

Result

The Remnant Life RL is 8 years, as of the last inspection, i.e. failure is expected in 2010

The Last Inspection Date LID is 2002

Now is 2007

 The equation RL + LID - Now = 8 + 2002 - 2007 = 3 years, which falls in the range 1-5 years

Using the likelihood matrix, it can be determined that the likelihood of failure is D “We would not be surprised to see it happen”.