TM 10-6640-216-13&P
1-13. FUNCTIONAL DESCRIPTION OF LABORATORY SYSTEMS - continued.
(e)
Timer Bypass Switch (S1). This switch is used to bypass the operation of
the time delay relay.
(2)
Lighting System. Laboratory lighting is provided by four fluorescent ceiling
lights. Each light contains one blue lamp and two white lamps. During normal
operations, all lamps are lit. CB17 is the lights’ circuit breaker in the panelboard
assembly. The lights are turned on and off using the LIGHT switch (S3) located just left
of the laboratory entrance door. A junction box (A4) provides a point of connection for all
four ceiling lights. This box is located on the roadside wall above the copper strip
corrosion bath.
(a)
Blackout Lighting. Blackout lights (blue lamps) are provided when
blackout conditions are necessary. When the BLACKOUT OVERRIDE switch,
(S10), (located next to the LIGHTS switch) is in the OFF position (down) blackout
conditions are set. Whenever the entrance door is opened, a micros witch (S9),
located at the bottom of the entrance door, is activated, This will turn off all white
lamps. When the door is closed again the white lamps will come back on. When
the BLACKOUT OVERRIDE switch is in the ON (up) position, the operation of
the microswitch is bypassed and all lamps remain lit.
(b)
Emergency Lighting. An emergency light fixture is mounted on the
curbside wall of the laboratory above the pencil sharpener.
During normal
operations, power is supplied to it from CB17. While power is available, the
charging circuit maintains the batteries in a fully charged condition. Upon loss of
power the emergency light instantly connects the lamps of the fixture to the
batteries. The batteries will allow a minimum of 90 minutes of operation. Upon
return of power the lamps are turned off and power is supplied to the charging
circuits to recharge the batteries to a full charge. If the batteries have been
completely exhausted, it will take approximately 16 hours to return them to a full
charge status.
(3)
Water System. Pressure for the water system is supplied by a water pump driven
by a 3/4 hp motor, The motor operates on 110 VAC and draws approximately 5 amps. It
is protected by CB16 in the panelboard assembly. The pump motor is turned on and off
by a pressure switch mounted next to the water pump. When pressure is below a preset
value, the switch turns on the pump motor, when the pressure is at or above the preset
pressure, the pump motor will turn off. A switch (S5), located next to the sink, is
provided to turn power off to the pressure switch when the water system is not required.
(4)
Purge System. The purge system is activated by relay K2 in the panelboard
assembly. (Refer to paragraph 1-14. a.(1)(b).) The purge system is used to exhaust any
contaminated air inside the laboratory to the outside. This is accomplished using the
environmental control units. A blower assembly mounted inside cabinet No. 5 is used to
assist the automatic purge cycle.
(a)
Environmental Control Units (ECUs). The function of the ECUs during
purging operations is to pull air from outside the laboratory and exhaust it into
the laboratory. This will overpressurize the laboratory forcing the contaminated
air to the outside via the open secondary exit. This is accomplishcd by motor
driven dampers inside the air plenums.
When a purge cycle is initiated, two
motors in each air plenum position dampers inside the air plenum to route air
1-19
