Calculating date/time overlap for multiple equipment

Hello every one;
I am new on this board. first, I want to thank you in advance for all your support. Now to my problem.

Let's say I have multiple equipment. I calculate down time for each equipment based on date and time of occurrence.
Each equipment can have more than one down time.
I need to calculate all overlap down time periods (in minutes),

• some down times start at the same time but end at different time
  some down times start at different time but end at the same time
  some down times start and end at different times
  down times maybe common among all or some equipment

need to calculate non overlap times

I have attached the sample sheet.

any help is appreciated.