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Drive Retrofit Update Enables Smoke-Removal
System at Atlanta Airport
When the City of Atlanta finalized plans for the capital-im-provement
project at Hartsfield-Jackson Atlanta International
Airport, an integral part of the 10-year, $5.4 billion
project included upgrading the ventilation system of
the underground Automated People Mover (APM). The APM’s
previous ventilation system was adequate when the APM
served the A, B, C, and D Concourses. When Concourse
E was added and the APM extended — now 3.5 miles
long, handling 128,000 passengers an hour — the
fans required upgrading to handle additional flow and
pressure to meet National Fire Protection Association
standards for emergency smoke evacuation. The $3.4-million
set up and installation contract for mechanical and
electrical equipment was awarded to W.B. Wallis &
Co. (Atlanta, GA).
The system was retrofitted with four 6' diameter, 125-HP
reversible vane-axial fans capable of venting/exhausting
the tunnel at 120,000 cubic feet of air per minute.
The fans, manufac-
tured by Twin City Fan and Blower (Minneapolis, MN),
are specially designed for smoke control applications,
able to run in either direction to move the same amount
of air, and are tested to operate for one hour at 500°F.
Supplied by ABB (Norwalk, CT), four 125-HP ABB ACH Series
drives control the fans. The 18pulse design eliminates
harmonic distortion, which can adversely affect voltage-sensitive
electronics, such as those in airports, where RF communications,
computers, and airport tower equipment are in constant
use.
The ABB ACH Series drive interfaces with two Johnson
Controls DX-9100 series extended digital controllers,
which communicate tunnel conditions that determine fan
speed. A digital controller and back-up controller are
located at each of the two tunnel entrances, monitoring
for temperature and fire/smoke. The controllers communicate
with each other and the fan drives via fiber optic cable
installed in an adjacent utility tunnel.
To provide ventilation in the tunnels, one fan at each
end runs for a seven-day time period, then alternates
with the second fan to equalize wear. The drives adjust
to fluctuating load and heat conditions, keeping airflow
balanced. In fire or smoke situations, the fans ramp
up to full speed. The fans’ full-speed operation
is critical during a fire or smoke situation, and to
ensure the fans do not shut down, the drive is equipped
with a standard fireman’s override, which, when
activated, will run ventilation/ex-traction at full
speed, ignoring any alarms or other commands. Without
the drives, the fans would run at the emergency ventilation
flow rate at all times, meaning higher operating cost
and energy consumption.
Results
The tunnel smoke-removal modification project was completed
within a 330day time frame and has been running without
problems since January, 2004.
More Information
For more information about ABB drives, visit http://info.ims.ca/5659-338.
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