Newton Mapowo , Failure/hour ratio if you check, Failure 2 is more serious and should be prioritize first assuming the type of failure remain same for both cases. thanks Doug for highlighting this.

Which failure has more expensive consequences? That one should be addressed first. Perhaps failure 1 causes loss of electrical power to the coffee pot while failure 2 causes loss of electrical power to the radar.

Abhishek Kumar Doesn't the failure/hour have the loophole that as a ratio it may hide the true impact on the production line? For example: failure 1 occurring 5 times and consuming 10 hours versus another failure that occurs 3 times and consuming 6 hours, they both have a failure/hour ratio of 0.5 but I don't think they can be prioritized the same. What should happen in such a case?

Doug A. Hall In this scenario we can consider the failure cost to be fairly the same for each individual failure. In this scenario it basically affects your available time (availability losses) on the production line.

@Newton Mapowo , Availability is a great index for this situation. The more time spent on a failure, the more the availability reduces.

The business is most concerned about the financial impact of failures. Money is lost by the hour. Hence, as an employee you should focus on what is important to the business,first of all.

Newton Mapowo, in addition (or even prior) to checking the financial (and availability) consequences of the failures I believe that you also need to assess if any of the two failures have larger consequences than the other in term of for instance safety or environmental aspects. In my opinion and experience many of those types of consequences overrule the financial aspect and if those types of failures are down-prioritized short-term they might (or most likely will) affect the financial aspect to a greater extent long-term.

you must calculate operational availability.

Both need to be fixed, however, for prioritizing, severity and safety issue could be consider.