10 CFR §431.202

Basic model means all units of a given type of covered product (or class thereof) manufactured by one manufacturer, having the same primary energy source, and which have essentially identical electrical, physical, and functional (or hydraulic) characteristics that affect energy consumption, energy efficiency, water consumption, or water efficiency. Face means an illuminated side of an illuminated exit sign. Illuminated exit sign means a sign that— Input power demand means the amount of power required to continuously illuminate an exit sign model, measured in watts (W). For exit sign models with rechargeable batteries, input power demand shall be measured with batteries at full charge.

(1) Is designed to be permanently fixed in place to identify an exit; and

(2) Consists of an electrically powered integral light source that— (i) Illuminates the legend “EXIT” and any directional indicators; and (ii) Provides contrast between the legend, any directional indicators, and the background.