Ventilation Systems Flashcards
ventilation is maintained under what two distinct conditions
normal and emergency
how is ventilation accomplished during an emergency conditions
mechanically
fans are used in either ____ or ____ mode depending upon needs
supply and exhaust
primary method of _____ in the tunnels is the movement of trains
air exchange
what is the piston effect
as a train moves forward it forces air ahead of it and draws air behind it
as a train approaches a station_____ allows air to be moved up and out of the system
vent shafts
the vent shafts contain thermostatically controlled ____ and ____ that allow air movement
louvers and fans
as long as the fans are in the _____ mode the thermostats will operate the fans
automatic operation
during emergencies ____ can remotely activate the fans from their computers
OCC
low temperature mode is below____ degrees and dampers and fans are ________
50 degrees and not operating
normal temperature mode is between____to_____ degrees and dampers are open and fans are not operating
50 to 95 degrees
high temperature mode is above______ degrees and dampers are open and fans are operating
95 degrees
in emergency mode dampers are open and fans are operating under control of OCC but when fire/rescue arrives, fan control becomes the responsibility of __________
incident commander
fans are part of the station air exchange system by which cool air is supplied to the station when the temperature exceeds _____ degrees
70 degrees
when activation is requested it normally takes ____ to ____ seconds for the fans to actually start
40-60 seconds
do all control boxes have found settings
no
tunnel fan shafts contain from _____ to_____ supply fans
2 to 7
the supply fans are approximately ____ inches
60 inches
the supply fans produce _____cfm of exhaust and ____cfm supply
50,000 (exhaust) 35,000 (supply)
domes have how many air inlets/outlets
2 at each end of the platform
platforms have how many air inlet/outlets
40 per platform
how many platform air conditioner units are there
20 per platform
what are the 5 stations where the under the platform exhaust fans only work in exhaust mode
DuPont circle, Farragut north, Metro center, judiciary square* and Gallery placed upper level
FD GUM
*union?
the station under platform ventilation systems have ________ control boxes that control_________
two, one half of the station
where are the control boxes for the under platform exhaust system located
at each end of the station
Tunnel ventilation is achieved by four different modes of operation. During high temperature mode above 95°F, what occurs
Dampers are open, and fans are operating in the exhaust setting
