This SAE Aerospace Recommended Practice (ARP) provides criteria for design and location of power supplies, controls, light fixtures, and associated equipment which are used to provide emergency illumination in transport aircraft, designed to comply with 14 CFR part 25 (Reference 1) for operation under 14 CFR part 91 (Reference 11) and 14 CFR part 121 (Reference 2), and also in compliance with FAA Advisory Circulars AC25.812-1A (Reference 3) and AC25.812-2 (Reference 10).