R.I. Gen. Laws § 42-60.1-5: Efficiency standards — Fluorescent lamp ballasts.

The ballast efficiency factor (BEF) for all new ballasts designed for the operation of one F40T12 lamp with a nominal input voltage of either 120 or 277 and 40 total nominal lamp watts shall be at least 1.805. The BEF for all new ballasts designed for the operation of two (2) F40T12 lamps with a nominal input voltage of 120 and 80 total lamp watts shall be at least 1.060, and for the operation of two (2) F40T12 lamps with a nominal input voltage of 277 and 80 total nominal lamp watts shall be at least 1.050. The BEF for all new ballasts designed for the operation of two (2) F96T12 lamps with a nominal input voltage of either 120 or 277 and 150 nominal lamp watts shall be at least 0.570.