Lecture 6 - What is Maintenance?

Question 1

What is maintenance?

Answer 1

• The combination of all technical, administrative and managerial actions during the life cycle of an item intended to retain it in, or restore it to, a state in which it can perform the required function.

Question 2

Why are maintenance management systems established?

Answer 2

– Identify maintenance objectives and priorities
– Develop maintenance management strategy (how will we meet objectives, who is responsible and over what time frame)
– Execute the maintenance management strategy
– Control, measure and improve

Question 3

What are the objectives of maintenance?

Answer 3

Generally the following classes of objectives for maintenance:
– Safety objectives
– Technical objectives
– Legal objectives/ mandatory regulations
– Financial objectives

REFER TO SLIDES FOR DIAGRAMS

Question 4

What is mean time to repair?

Answer 4

• One measure of maintenance is MTTR – mean time to repair.
• There are different methods of calculating this
  – Point estimate
  – Algebraic calculations
  – Estimates from distributions
• Data for repair times often has a log-normal distribution

Question 5

What is availability?

Answer 5

• Availability is a key metric for reliability performance
• There are many different definitions
• A common point estimate method is to use
  – Availability = Available time/ 8760
  – Also Availability = Uptime/ (Uptime+Downtime)
• Availability is a function of reliability AND maintainability