Elevator Capacities. Capacities of 1590 kg to 1810 kg
The type of building occupancy will determine the
(3,500 to 4,000 pounds) shall be used for passenger
probable number of stops used in the traffic analysis
elevators. Elevator cab sizes shall be in accordance with
calculations. A single-tenant building will require a greater
the standards established by the National Elevator
probable number of stops than a multi-tenant building.
Industries, Inc. (NEII). Elevator cabs shall be designed to
This is especially true when balanced two-way traffic is
reflect the architectural character of the building design.
considered because the incidence of inter-floor traffic is
much greater in a single-tenant building.
Escalators. Escalators may be installed as supplements to
The anticipated elevator population shall be calculated
elevators when vertical transportation is required for a
based on the occupiable floor area of the building and a
large unpredictable volume of public traffic. GSA prefers
factor of 14 m2 (150 ft2) per person. It shall be assumed
to use escalators only where absolutely necessary because
that 8 to 10 percent of the resulting population would not
of high maintenance costs. They should be used where the
require elevator service during the peak periods. If the
first floor is not large enough to contain the high public
building design requires two or more elevator banks, the
traffic so that the interval for elevators can be calculated
population calculation results shall be apportioned by
with accuracy.
functional layout of the building. These divisions shall
Escalators should be located to be visible from the
then be assigned to the appropriate elevator banks. For
building entry and convenient to the areas they serve.
this purpose an "elevator bank" is defined as a group of
adjacent or opposite elevators that function under a
Fire Protection
common operational system.
See Chapter 2: Site Planning and Landscape Design and
The criteria by which the traffic analysis calculations
Chapter 7: Fire Protection & Life Safety for additional
should be judged are "average interval" and "handling
requirements.
capacity."
Average interval is defined as the calculated time between
Seismic Design
departures of elevators from the main lobby during the
a.m. up-peak period. Calculated intervals during the up-
Seismic design is discussed in detail in Chapter 4:
peak period should not exceed 30 seconds for a typical
Structural Engineering.
elevator bank.
Design Issues Affecting Security
Handling capacity is defined as the number of persons the
elevator system must move in any given 5-minute period
Specific criteria for site and building security are
of up-peak traffic used to measure average interval. GSA
described in detail in Chapter 8. Some of the planning
buildings shall always be designed for a 16 percent
concepts are stated here because of their importance to
handling capacity, even if the building is designed as a
building planning, but architects should familiarize
multi-tenant facility.
themselves with Chapter 8 before developing schematic
design concepts.
60 F A C I L I T I E S S T A N D A R D S
FOR THE
PUBLIC
BUILDINGS
SERVICE
3.1 Basic Building Planning Principles
Revised March 2005 PBS-P100
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