Hi Ashu,
As far as i have seen there is no categorization in standard SAP other than the system status. But the system status will have a different meaning
AVLB - Equipment is available for use
INST - Equipment is installed to a functional location
ASEQ - Allocated to Superior Equipment
ESTO - Equipment is available in the Warehouse
If you want to specify the equipment status for Erection / Commissioning, then you can make use of User Status.
Regards
Terence