Scott,
I have a copy of the 97 UBC, here is a direct quote of section 1003.2.8.4
1003.2.8.4 Illumination. Exit signs shall be internally or externally illuminated. When the face of an exit sign is illuminated from an external source, it shall have an intensity of not less than 5 footcandles from either of two electric lamps. Internally illuminated signs shall provide equivalent luminance and be listed for the purpose.
There is also an exception for self-luminous signs.
Section 1003.2.8.5 talks about the power source.
1003.2.8.5 Power source. All exit signs shall be illuminated at all times. To ensure continued illumination for a duration of not less than 1 1/2 hours in case of primary power loss, the exit signs shall also be connected to an emergency electrical system provided from storage batteries, unit equipment or an on-site generator set, and the system shall be installed in accordance with the Electric Code. For high-rise buildings,see Section 403.
This section also has an exception for self-luminous signs.
If you are using the 97 UBC then you also have to review section 403 Special Provisions for Group B office buildings and Group R, Division 1 Occupancies
Hope this helps, all I have is the 97 UBC we are now on the 2003 IBC.
Chris
