2.1 Diesel-Electric Generating Plant Design. Diesel-electric generating
plants shall be designed to satisfy either prime duty or standby/emergency
duty electrical service requirements in fulfilling the temporary or
permanent mission of a naval activity at the lowest life-cycle cost. This
handbook is not intended for portable generating units.
with several sources of electric power. Sources include commercial and
government-owned electric generating plants. The number and types of
sources required depend on the mission of the facility, activities taking
place there, and the existing equipment. Specific design criteria for
various types of facilities are referenced in their design manuals.
Guidance for sizing, calculating electric loads and requirements for
specific design features are contained in this handbook and in NAVFAC
DM-4.01, Electrical Engineering, Preliminary Design Considerations.
2.3 Duty Types and Loads. Stationary diesel-electric generating plants are
separated into two duty types for design: Prime Duty and Standby/Emergency
2.3.1 Prime Duty Electric Generating Plants. Prime duty electric
generating plants are designed for continuous service and are sized for peak
electrical demand during normal peacetime operations. Continuous service is
defined as operations exceeding 4,000 hours per year or when a plant is run,
or planned to be run, more than 40,000 hours within the initial 10 years of
operations. A generating plant is also considered to be prime duty if it is
the only source of electricity, regardless of the operating schedule.
2.3.2 Standby/Emergency Duty. Any generating plant operating fewer hours
per year than a prime duty plant is considered a standby/emergency duty
plant as long as it is not also the prime source of electric power. Several
types of standby/emergency duty plants are required to satisfy statutory and
regulatory requirements within the United States (U.S.). Types are
explained below but will be addressed simply as standby/emergency throughout
the remainder of this handbook. The standby/emergency source of power shall
be sized to satisfy mobilization and emergency loads in the event of an
outage of the prime source of power.
22.214.171.124 Standby Electric Source. The standby source of electricity for a
facility is sized for the minimum essential operating load. When added to
the capacity of the prime source of electricity, the combined generating
capacity must be sufficient to serve the estimated peak electric demand
126.96.36.199 Emergency Electric Source. The emergency source of electrical
power is to provide electrical service to vital operations whenever there is
an interruption of the prime source of electricity. Vital operations are
those activities wherein an interruption in electrical supply can be
tolerated for only a relatively short period. For certain operations, the