Lecture 6 - Consideration for Asset Maintenance Tasks

Question 1

What is fixed interval task selection?

Answer 1

• Fixed interval tasks are applicable when:
  – The conditional probability of failure starts to rapidly increase after a specified age
  – Most items will survive until that age
  – We can state with some degree of certainty what
  that age is

Question 2

What is run to failure task selection?

Answer 2

• Run to failure tasks are applicable only for failure modes without safety or environmental consequences when:
  – It is cheaper, in the long run, to allow the item to fail, than it is to prevent it from failing

Question 3

What is failure finding task selection?

Answer 3

• Failure finding tasks are applicable only for failure modes with hidden failure consequences when:
  – It is possible to test the device without destroying it
  – It is possible to test most or all of the device or system
  – Performing the test does not significantly increase the risk of inducing the multiple failure we are seeking to avoid

Question 4

What is redesign?

Answer 4

• Training
• Process/systems
• Operational and maintenance procedures/practices
• Procurement decisions (spares)
• Engineering

Question 5

What is condition monitoring task

Answer 5

• Condition monitoring tasks are applicable when:
  – There is a clearly defined potential failure condition
  – The P-F interval can be reasonably defined
  – The task can be done at a frequency which permits effective action to avoid the consequences of the failure
  – The frequency of a condition monitoring task is determined by the P-F interval

Question 6

What is the process of adopting and adapting?

Answer 6

• What may be the risks of
  – Using “template” tactics from other, similar equipment
  – Cutting and pasting ” tactics from other, identical equipment
  – Using manufacturer’s recommended tactics but be careful that operating context, similar failure causes, consequences and P-F intervals apply

Question 7

What is the general takeaway?

Answer 7

• Not maintenance for maintenance’s sake – it’s to ensure equipment functionality
• Equipment can functionally “fail” even though it’s still running (if it’s not providing the required level of performance)
• Effective Tactics target Failure Modes
• There are multiple ways to identify Failure Modes
• Most equipment does not wear out
• Consequences, failure behaviour and costs are key to tactics
  development
• Timely implementation is the key to success in any asset tactics
  development/review project