To light a parking lot for security purposes, here is the formula that we use:

1) Determine the illumination level

2) Determine the area to be illuminated

3) Determine the type of lamps needed

4) Determine the area illuminated per floodlight

    (our units all have 4 lamps)

Average parking lot size = 140 yards by 70 yards (420 ft x 210 ft) = 88,200 square feet

For average size parking lots, the illumination Engineering Society recommends  2 foot candles

Therefore, 88,200 square feet x 2 foot candles = 176,000 (closest is 105,000 sq feet)

Lighting Capacity Chart

Light Type        Avge Foot Candles              Sq. Ft.                Acres

HPS                       .06                                 105,000             2.41

MH                        .05                                   82,000             1.88

MV                        .05                                   46,500             1.07

TH                        .05                                   26,500               .31

4 lamps x 105,000 sq feet =420,000 = .42 light towers (one light tower with 4 lamps) is the answer

Each light towers holds 40 gallons of fuel

15 minutes will suffice.

According to the Illumination Engineering Society, 10 to 50 footcandles will suffice.