EI 11C201
CEMP-E
1 March 1997
(1) Wet wells will be provided with a positive ventilation capacity of 30 air changes per
hour during occupancy, based onthe wet well volume below grade and above the minimum
wastewater level.
(2) Unattended dry wells will be provided with a positive ventilation capacity of 30 air
changes per hour. Attended drywells will be provided with a continuously-operated ventilation
capacity of 6 air changes per hour, supplemented with additional ventilation in warm climates to
remove pump motor heat to within 3 o K (5o F). of the outside air temperature. Supply intakes and
exhaust outlets must be located properly to introduce fresh air and remove hazardous gases or
fumes. The wet and dry well sides of the station will be provided with separate ventilation
systems.
9-6. ELECTRICAL EQUIPMENT AND LIGHTING. Pump station equipmentwill be suitable for
operation at either 208V, 230V, or 480V, 60Hz, three phase power supplies. However,
equipment with motors smaller than 0.4 kilowatt (0.5 horsepower), including meters, switches,
timers, clocks, and similar equipment, will be suitable for operation at a 125V, 60 Hz, single
phase power source.
a. Service transformers. Service transformer installations will conform to the requirements
of TM 5-811-1/AFM 88-9, chapter 1.
b. Motor starters and controls. Motor starters and controls will be provided and housed in a
factory assembled, free-standing control center located on the ground floor. The center will
include motor starters, switches or circuit breakers,instrumentation and controls. A pump station
requiring a fewsmall sized starters is an exception, and will employ wallmounted or stand
mounted equipment.
c. Control for submersible pumps. Enclosures for submersible pump controls will be
installed above grade.
d. Trouble alarms. Local trouble alarms will be provided atall pump stations. Alarms will be
annunciated remotely fromunattended stations. Alarm systems will be provided with manual
silencing.
9-7. STANDBY POWER. The requirement for fixed, standby power atwastewater pumping
stations will depend upon the type, location,and critical nature of each pumping facility. For
stationssituated in low lying areas, or in areas, remote from a treatmentplant, standby capability
will be provided if a power outagewould result in flooding of the station, overflows at sewer
manholes, backup of wastes into buildings, or any unlawfulpollution of the environment, or health
hazard to personnel. Pumping stations located at or in conjunction with treatmentfacilities, such
as those required for influent pumping,recycling or bypassing of flows, and pumping of effluent,
willrequire standby power capability if the pumping is essential tocritical treatment processes,
plant flow control, or is necessaryto maintain compliance with the discharge permit. If fixed
standby power is required, refer to paragraph 6-3 for designcriteria when selecting pump drive
units, and descriptions ofvarious arrangements to be used in providing fixed, standby
powercapability at wastewater pumping stations.
9-8. WATER SUPPLY. A potable water supply is required at alllarge pump stations to supply
washroom and toilet facilities,hydrants, hose bibs, and pump seal systems. A wash basin
andtoilet facilities will be provided at pump stations which areattended regularly. Hose bibs will
be provided at wet wells and in dry wells and bar screen rooms. Freeze proof wall hydrants will
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