Emergency Generator Capacity

Scenario

A high-rise building has the following emergency loads: fire pump at 125 HP (93 kW), two stairwell pressurization fans at 30 HP each (45 kW total), smoke exhaust fans at 50 HP (37 kW), emergency lighting and exit signs at 25 kW, fire alarm and communications at 10 kW, one elevator for firefighter service at 50 HP (37 kW), and fire command center at 5 kW. The generator must include a 25% derating factor for altitude and temperature. What minimum generator rating is required?