MIL-HDBK-1191
17.5.3.5
Patient Service Elevator Cars. For patient service cars, evaluate
the primary inpatient transportation period to determine if patient service
elevator cars have excess capacity which can augment passenger elevator cars
during peak pedestrian periods. Under normal operation, all elevators, which
operate as a group, have circuitry that monitors cars in operation. When one
or more cars are out of service, the monitoring or dispatching system senses
the condition and automatically selects an available car within the group for
response to hall calls. During an emergency power condition, the ASME A17.1
Code requires all groups of elevators, which are supplied with an alternate
power source, to automatically sequence one at a time to the main egress
level. Once all cars have reached the designated level, the elevator system
must automatically select one car within the group to operate. A manual
override switch must also be provided, so emergency personnel may select a
particular car if desired.
17.5.3.6
Addition/Alteration Projects. For Addition/Alteration projects,
provide specific recommendations on how the addition will augment the existing
building systems. Potential migrations from existing buildings, for the
purpose of using superior transportation elements in the addition, must be
considered in the new building populations.
17.5.3.7
Materials Handling and Logistics Elevators. For materials
handling and logistics elevators (manual systems), base the Elevator Traffic
Study and Analysis on the materials and cart traffic predicted by the
materials management and handling programs, plus 20% spare capacity, during
the peak hour, for non-scheduled moves, plus an additional 20% spare capacity
to allow for materials handling and materials management program flexibility.
In the absence of definitive operational schedules and anticipated commodity
delivery criteria from the user service, assume the peak hourly demand for
material delivery and non-ambulatory patient traffic to be 10 percent of the
combined total daily traffic load for the Elevator Traffic Study and Analysis.
17.5.4
Escalators. Consider escalators for pedestrian traffic where
justified by traffic studies. Consider escalators for frequent vertical
movement of large numbers of people in multi-floor outpatient clinics which
exceed 2,000 patient visits per day, or in hospitals which exceed a 500 bed
capacity and have principal patient entrances on two levels. Escalators are
not subject to analysis or criteria measurements for average intervals. Design
escalators to handle large numbers of pedestrians in a safe and efficient
manner. Designs shall consider that traffic will include persons who may be
slightly impeded by physical disabilities or by virtue of medical /
pharmacological treatment. Design escalators with safe travel speeds and
adequate entrance and exit queuing areas to handle the expected volumes. The
minimum escalator width will be 815 mm (32 inches) and the rated step speed
will not exceed 450 mm/second (90 fpm.)
17.6
Elevator Performance Criteria. Elevators provide the basic
transportation mechanism for most vertical moves in multistory buildings.
Selection of the proper number, type, speed, location and general
characteristics for elevators is crucial to an efficient and effective
transportation system. Provide the minimum number of elevators necessary that
will satisfy the following criteria:
17.6.1
Average Interval. Figure 17.2 provides requirements for average
intervals for passenger cars, combined use and patient service cab and
dedicated materials cars. These average interval times do not specify a
17-6
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