Meaning of onstream-factor
It is the ratio of the number of operating days to the number of calendar days per year, the process unit remained available for production.
On stream factor is in important parameter to check the performance of the process unit with respect to plant reliability. Greater, the onstream factor more is the plant reliable and available for production.
A crude distillation unit remained in service for 340 days and remained out of service or under maintenance for 25 days then on-stream factor of the unit is as follows;
On-stream factor = 340/365= 0.93 or 93 %
On monthly basis on-stream factor for the unit remained out of service for 6 hrs, in a month of August out of 744 hrs;
= 738/744 = 99.20 %