Hello Naveen,
Operating refers to a scenario where the PRP-2 route processor is installed and running in a 12000 chassis.
Storage refers to when the PRP-2 is kept in a box ready to be used in replacement of another route processor.
As a result of this both the temperature and humidity ranges are more extended for storage then for operating as expected.
For a PRP-2 installed in chassis you have to look at the operating range
Hope to help
Giuseppe