Time Constraints

Originally Posted by atrades

D1 (holds the time 09:00)
E1 (holds the time 10:00)
F1 (holds the Total time 1:00) using =SUM(E1-D1)
I would like G1 to highlight as a colour if the time difference between C1 & F1 Exceed 12 Hours (an employee must have a total of 12 hours rest period between shifts.

Slight problem in that C1 is a time of day whereas F1 is a time difference in hours.... e.g.. C1=06:00:00 D1 = 19:00:00 F1 = 13:00:00 <-- The time difference between C1 and F1 is seven hours but the employee has worked 13 hours ....
But what you really need is a 12 hour rest period which means the next "On" time cannot be less than 12 hours from the previous "Off"... i.e H1 must be 12 hours later than D1