The Database Owner or System Administrator can create additional thresholds to monitor free space on any segment in the database. Additional thresholds are called free-space thresholds. Each database can have up to 256 thresholds, including the last-chance threshold.
sp_addthreshold, sp_modifythreshold, and sp_dropthreshold allow you to create, change, and delete thresholds. To prevent users from accidentally affecting thresholds in the wrong database, these procedures require that you specify the name of the current database.