MIL-HDBK-1133
Most outdoor lighting falls into the first two
categories. For safety and security reasons, working area and
parking lot lights are seldom extinguished and would therefore be
considered security lighting. However, any lights that do
operate on a less than all-night schedule should be noted on the
lighting inventory. Steps should be taken to ensure that other
special uses of significant outdoor lighting loads such as
airfield and dockside lighting are recorded. Monthly sunrise and
sunset times can be used to estimate the number of hours of
darkness during any analysis period (i.e., monthly). On an
annual basis, average hours, sunset to sunrise, will be 12 hours
per day, 365 days per year.
Most high-intensity discharge (HID) lighting uses a
ballast similar to fluorescent lighting. The ballast draws a
certain amount of energy for its operation. This energy must
also be included when calculating the total energy use for
outdoor lighting. Table C-1 in Appendix C lists most of the
different outdoor light types and typical combined lamp and
ballast wattage. Note that Table C-1 does not include
fluorescent lights. These are usually not used as exterior
lighting as defined here. Fluorescent outdoor lighting is
usually attached to the building and included in building energy
consumption.
The outdoor lighting energy for each lighting type and
hours of use is obtained by
N * Pr * H
E=
1000
(1)
where
E
=
energy consumption in kilowatt-hours
N
=
number of lamps of a given rating
Pr
=
lamp rating in watts (including any ballast)
H
=
illuminating hours per day with H adjusted to
fit conditions at the activity as discussed above
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