Optional standby design requirements in the NEC are less stringent than emergency requirements and do not appear appropriate for ICPP loads requiring backup power. All five backup generators reviewed by the staff have a connected load that exceeds the generator rated capacity.
Warblers are integral to criticality alarms which ensure personnel are warned of a criticality.
In the last four years, two battery cells have failed. ICPP is in the process of qualifying an impedance measurement device to help predict battery failure. Backup power systems at ICPP provide power to criticality alarm systems, ventilation systems, instrumentation and control systems and other process related systems during loss of offsite power. Backup generators typically use diesel engines as the source of energy while UPSs use batteries. The only remaining emergency backup power supplies support criticality alarm systems.