As default, the bearing life is calculated for a reliability of 90%. The required reliability can be changed here with limits 90% and <100%. The life modification factor for reliability a1 is calculated according to this input using the three parameter Weibull relationship as given as formula in (ISO/TR 1281-2, 2008). The table in ISO 281 (2007) is also calculated according to this formula and has changed to previous versions of the standard.
