Emergency lighting shall be provided by using a standard fluorescent fixture equipped with a Howard BAL700 emergency ballast. 
This emergency ballast shall consist of a high-temperature, maintenance-free nickel cadmium battery, charger and electronic 
circuitry contained in one 9 3/8" x 2 3/8" x 1 1/2" white metal case. A solid-state charging indicator light to monitor the charger and 
battery, a single-pole test switch, and installation hardware shall be provided. The emergency ballast shall be capable of 
operating with most 17 W through 110 W (2' - 8') T8, T10, or T12 fluorescent lamps without integral starters, including U-shaped, 
HO, VHO, circline, energy saving, and (4-pin) long compact at reduced illumination in the emergency mode for a minimum of 90 
minutes. It is also compatible with most 1, 2, 3, and 4-lamp electronic, standard, energy saving, and dimming AC ballasts. The 
BAL 700 shall produce 600 to 700 lumens initial emergency light output, have 3.5 Watts of input power, a 14.4 Watt-hour battery 
capacity, and comply with emergency standards set forth by the current NEC. The emergency ballast shall be UL Listed for 
installation inside, on top of, or remote from the fixture.

http://www.howardlightingproducts.com/Documents/SpecSheets/Ballast/Emergency/BAL700.pdf