Section 2:
ESTIMATION OF LOADS
2.1
Preparation of Load Data.
Load data are generally computed in
steps such as:
a)
individual loads,
b)
area loads, and
c)
activity loads.
A particular design problem may be limited to step a), to steps a) and b), or
may encompass steps a), b), and c). This section outlines each step as a
separate entity, dependent only on previous steps for data. Paragraphs 2.2
through 2.4.4 describe the three loads.
2.2
Individual Loads. Individual loads are those with one incoming
service supplying utilization voltage to the premises. In general, these
loads would comprise single structures. Large structures could contain more
than one function; for example, aircraft operations, aircraft fire and rescue
stations, and photographic buildings. Under this condition, factors that
have been developed and keyed to Navy category codes (refer to Table 1) would
be used. In this case, the factors listed under Navy Category Code 141-40,
141-20, and 141-60, respectively, would be combined to obtain the total load.
2.2.1
Lighting. To eliminate lighting loads, divide a facility area into
its significant components by function (for example, office, storage,
mechanical, and corridor). Determine the average lighting level and type of
light source for each area. Consider requirements for supplementary lighting
(for example, floodlighting, security lighting, and special task lighting).
Preliminary load estimates may be made based on the following load
allowances:
a) 1 W/ft2 (10.76W/m2) for each 6 to 8 fc (60 to 80 dekalux) of
incandescent illumination.
b) 1 W/ft2 for each 15 to 20 fc (150 to 200 dekalux) of
fluorescent illumination.
c) 1 W/ft2 for each 12 to l8 fc (120 to l80 dekalux) of mercury
vapor illumination.
d) 1 W/ft2 for each 26 to 36 fc (260 to 360 dekalux) of metal
halide illumination.
e) 1 W/ft2 for each 33 to 54 fc (330 to 540 dekalux) of high
pressure sodium illumination.
2.2.1.1
Small Appliance Loads. Small appliance loads shall include those
served by general purpose receptacles. In general, the dividing of areas by
function for estimating lighting loads will serve for estimating small
appliance loads. The determination of loads requires not only a knowledge of
the function of an area, but to what extent its occupants use small
appliances. For example, an office area demand may average about 1 W/ft2
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