formers, and all equipment associated with distri-

bution of electrical power to utilization equipment.

The most feasible method of supplying and distrib-

Realistic demand factors will be calculated in

uting electrical power will be determined by first

early design stages to provide an economical, cost

quantifying the electrical power requirements (or

effective system while insuring that items of

maximum demand load) for the installation. In the

equipment and materials are adequate to serve

early design stages, this demand should be based

existing, new, and future load demands. Demand

on area or population; in later design stages,

factors utilized in later design stages will docu-

summation of individual building connected loads

ment and reflect the number, the type, the duty

modified by suitable demand and diversity factors

rating (continuous, intermittent, periodic, short

will be used. For early stages, use of kW, kVA,

time, and varying), and the wattage or voltampere

and hp interchangeably on a one to one basis is

rating of equipment supplied by a common source

of power, and the diversity of operation of equip-

sufficiently precise. During final design, hp will be

ment served by the common source. No more than

converted to kVA; and kVA may be multiplied by

ten percent spare capacity will be considered dur-

the estimated power factor to obtain kW if re-

ing design unless spare capacity is authorized by

quired. The calculation of full load amperes will

follow-on projects approved for construction in

utilize kVA.

later years. Demand factor is defined as the ratio

of the maximum demand (largest demand during a

specified time period) to the total connected load.

Load estimation requires analysis of load charac-

teristics and will take into account the demand

plied to the demand loads when calculating the

factor relationship between connected loads and

required ampacity of service and feeder conduc-

the actual demand imposed on the system.

bution system equipment. Typical diversity factors

table 2-1 will be used to compute preliminary

are given in table 2-2 and an illustration of their

estimates of the expected maximum demands and

use is shown in a demand flow relationship in

electrical energy usage. These values allow compu-

figure 2-1. This illustration indicates the load at

tations to be made for either population or build-

substation "X" would be 1/2.24 or 0.45 times the

ing area. Per capita loads are for an average

summation of the demands based on the given

daytime population.

data. Since utilities calculate loads on a less

conservative basis, diversity factors for main elec-

plied to connected loads when calculating the

trical supply stations on military installations will

required ampacity of conductors, capacity of trans-

Per capita

Per 1,000 square feet

Maximum

demand

Usage per year

Maximum

demand

Usage per year

Installation

kW

kWh

kW

Service

kWh

1.0-3.0

7,500-25,000

0.5-2

Development & Readiness

5,000-20,000

Forces

0.5-1.2

3,000- 6,000

1-5

5.000-25.000

Army

0.6-1.2

2,500- 7,500

1-3

Command

Training & Doctrine

5,000-20,000

1.5-2.5

7,000-10,000

2-4

Logistics Command

10,000-20,000

Military Airlift Command

1.0-2.5

5,000-10,000

2-3

Air Force

5,000-15,000

3,000- 6,000

Tactical Air Command

0.5-2.0

2-5

Base

10,000-20,000

1.0-1.5

4,000- 6,000

2-5

Training

10,000-20,000