Ups system designed to sustain power outage for how meny minutes?

it depends on the design of the ups and the battery dedicated for it, on full load is5 to minute. 

UPS is usually used for backup power to protect data in computer and to provide backup for telecommunication equipment. UPS backup is minimum for five minute duration. it depends on capacity of the UPS  and battery ratting (Ah) 

U.P.S devices are more types, It depends on capacity of U.P.S and battery support ,and your equipments,Some U.P.S shows backup time on their display

Battery back-up time (Autonomy) mainly depends on the load profile. You may design UPS electronics and battery back up (Ah) for as much hours as you can. You only need to increase the size of UPS capacity and battery Ah to reach on optimal solution.

its depending on capacity of battery , nomber of batteries and load

and it  gives often 5 : 10 minutes at full load . 

standard backup time will be 05 to 10 minutes.

Runtime of the UPS depends upon the load or the equipment connected to the UPS as well as the battery AH rating. Some UPS comes with internal battery modules and external battery modules for longer runtime.  

It depends on capacity of U.P.S and battery support.Some U.P.S shows backup time on their display