enamel. Lens shall be white plastic and engraved in black ink. Lettering
shall be 20 mm 3/4 inch high and black. Two lamps per pilot shall be
provided and independently wired. Lamps shall be 6 watts, 24 volts dc, S-6
incandescent type, supplied with color caps, one red and one green per
pilot light. Lens bezels shall be black unless otherwise indicated.
2.8.7
Clock
The clock shall be electric synchronous motor type. The clock shall be for
surface mounting and suitable for operation on 115-volt, 60 Hz single-phase
electric service. The clock shall have a white dial, easy-to-read black
numerals, black hands, red sweep second hand, and external manual reset
knob at bottom of case. The motor gear train shall be sealed in a
permanent oil bath. The clock dial shall be 381.0 mm 15 inch size.
2.8.8
Alarm Annunciator Panel
Layout of annunciator panel shall be as shown. Panel shall consist of a
flush-mounted cabinet, mounting trim with clamps, removable rear cover, and
alarm modules. Cabinet shall be finished with black baked enamel, aluminum
trim, and black alarm bezels. Nameplate size of alarm modules shall be
nominal 70 mm 2-3/4 inches high by 75 mm 3 inches wide in translucent white
acrylic plexiglass and all nomenclature shall be engraved on front surface
in black lettering. Plug-in alarm module shall include epoxy circuit
board, one reversible plug-in relay, one general-purpose plug-in relay,
relays with dust covers, two selector switches for relay contact selection,
and two lamps wired in parallel at 24 volts dc, 6 watts. Flasher module
shall be mounted and prewired with silence and test pushbuttons. Alarm
horn shall be remotely mounted and of general-purpose construction. Input
voltage shall be 120 volts ac, 60 cycle. Power supply of 120 volts to 24
volts dc output of volt-ampere capacity shall be provided to suit load.
Alarm sequences of panel shall provide for "first alert" sequence, with
manual reset and ringback sequences. Annunciator panel shall be prewired
internally to a rear terminal strip.
2.8.9
Combustion Control Components
Components shall conform to the requirements of paragraph COMBUSTION
CONTROL EQUIPMENT.
2.8.10
Steam and Feedwater Flow Measurement
Flow nozzles shall be provided to measure the steam flow from each boiler
and each main steam header outlet. Orifice plates shall be provided to
measure feedwater flow to each boiler. Nozzles and orifice plates shall be
flange-mounting type and made of stainless steel. Orifice plates shall be
of the square edge, concentric, paddle type designed for flange taps.
Minimum straight pipe runs shall be in accordance with AGA XR0104.
Condensate pots shall be provided for steam service.
2.8.11
Flue Gas Opacity Monitor
A flue gas monitoring system shall provide continuous measurement,
indication, and recording of smoke opacity from each boiler. The stack
units shall include a light source and a light detecting or receiving unit
mounted in the stack or main breeching as recommended by the manufacturer.
The control or transmitter unit shall have electronic solid-state circuitry
and meter or digital type indicator, and provide an output signal of 4 to
20 mA dc for 0 to 100 percent opacity. In addition, the control unit shall
SECTION 15559A
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