Pole  mounted floodlights are commonly used for general area lighting applications such as parking lots and storage yards.  The factors to be considered are:

Mounting Height

The recommended mounting height is one half the distance across the area to be lighted.  If the area to be lighted is 40 feet across, the lowest recommended mounting height is 20 feet. 

Mounting height = 1/2 distance to be lighted
1/2 (40 ft.) = 20 ft. 

Spacing

When more than one pole is added, pole placement is a concern.  The "4 times" rule of thumb for spacing indicates that a pole should be placed four times the mounting height from the adjacent poles.  If a flood is mounted on a 20 foot pole, space the poles 80 feet apart. 

Pole Spacing = 4 x mounting height
4 (20 ft. pole) = 80 feet between poles

Vertical Aiming

A single floodlight uses the two-thirds rule of thumb for vertical aiming.  The fixture is aimed 2/3 of the distance across the area to be lighted and at least 30 degrees below horizontal.  If the area to be lighted is 40 feet across, the recommended aiming point is 27 feet.

Aiming point = 2/3 across distance to be lighted
2/3 (40 ft.) = 27 ft. aiming point

Additionally, to  minimize glare, the recommended aiming point distance should never exceed twice the mounting height.  If a pole is 20 feet high, the vertical aiming point should not exceed 40 feet out.  

2 (20 ft. mounting height) = 40 ft. 

Horizontal Aiming

When an additional floodlight is added to a single pole, horizontal aiming also must be considered.  First, each floodlight should be vertically aimed according to the two-thirds rule above.  As long as the floodlight has a horizontal NEMA 6 or 7 beam spread, the floodlights can be aimed up to 90 degrees apart.