MTTR & MTBF Calculation in SAP PM

SAP Plant Maintenance Technical Object Failure Analysis Overview 1. MTTR – Mean Time To Repair The mean time in hours of a machine breakdown. This key figure is calculated by dividing the number of effective breakdowns by the effective time of the nth breakdown:

 MTTR ( hr ) 

1 n

n

 [ ME (n)  MS (n)] 1

2. MTBR – Mean Time Between Repairs Mean time in hours between two machine breakdowns. This key figure is calculated by dividing the number of effective breakdowns by the time between the end of the last breakdown and the beginning of the next breakdown:

 MTBR ( hr ) 

Note:

1 n

n

 [ MS (n)  ME (n  1)] 1

Example Start-up Date from equipment master data.

 MS(0) = 01.10.2011 00:00:00 Malfunction Data from Notification (See Figure 1.1)

 MS(1) = 03.10.2011 08:00:00  ME(1) = 03.10.2011 12:00:00  MS(2) = 07.10.2011 10:00:00  ME(2) = 07.10.2011 12:00:00  MS(3) = 15.11.2011 10:00:00  ME(3) = 15.11.2011 16:00:00 n=3 Calculation: Using MTTR Formula for above data:

 MTTR 

1 3

[( ME (1)  MS (1))  ( ME ( 2)  MS ( 2))  ( ME (3)  MS (3))]

 MTTR 

1 3

[( 4  2  6)]  4 hr 

Figure 1.1

Figure 1.2

Figure 1.3 Prepared by: