Pumping facilities shall be designed to maintain the sanitary quality of pumped water. Subsurface pits or pump rooms and inaccessible installations should be avoided. No pumping station shall be subject to flooding.
The pumping station shall be so located that the proposed site will meet the requirements for sanitary protection of water quality, hydraulics of the system and protection against interruption of service by fire, flood or any other hazard.
The station shall be
a. elevated to a minimum of three feet above the 100-year flood elevation, or three feet above the highest recorded flood elevation, whichever is higher, or protected to such elevations,
b. readily accessible at all times unless permitted to be out of service for the period of inaccessibility,
c. graded around the station so as to lead surface drainage away from the station,
d. protected to prevent vandalism and entrance by animals or unauthorized persons.
Both raw and finished water pumping stations shall
a. have adequate space for the installation of additional units if needed, and for the safe servicing of all equipment,
b. be of durable construction, fire and weather resistant and with outward-opening doors,
c. have floor elevation of at least six inches above finished grade,
d. have underground structure waterproofed,
e. have all floors drained in such a manner that the quality of the potable water will not be endangered. All floors shall slope at least three inches in every 10 feet to a suitable drain,
f. provide a suitable outlet for drainage from pump glands without discharging onto the floor.
Suction wells shall
a. be watertight,
b. have floors sloped to permit removal of water and entrained solids,
c. be covered or otherwise protected against contamination,
d. have two pumping compartments or other means to allow the suction well to be taken out of service for inspection maintenance or repair.
Pump stations shall be provided with
a. crane-ways, hoist beams, eyebolts, or other adequate facilities for servicing or removal of pumps, motors or other heavy equipment,
b. openings in floors, roofs or wherever else needed for removal of heavy or bulky equipment,
c. a convenient tool board, or other facilities as needed, for proper maintenance of the equipment.
Stairways or ladders shall
a. be provided between all floors, and in pits or compartments which must be entered,
b. have handrails on both sides, and treads of non-slip material. Stairs are preferred in areas where there is frequent traffic or where supplies are transported by hand. They shall have risers not exceeding nine inches and treads wide enough for safety.
Provisions shall be made for adequate heating for
a. the comfort of the operator,
b. the safe and efficient operation of the equipment.
In pump houses not occupied by personnel, only enough heat need be provided to prevent freezing of equipment or treatment process.
Ventilation shall conform to existing local and/or state codes. Adequate ventilation shall be provided for all pumping stations. Forced ventilation of at least six changes of air per hour shall be provided for
a. all rooms, compartments, pits and other enclosures below ground floor,
b. any area where unsafe atmosphere may develop or where excessive heat may be built up.
In areas where excess moisture could cause hazards to safety or damage to equipment, means for dehumidification should be provided.
Pump stations shall be adequately lighted throughout. All electrical work shall conform to the requirements of the National Electrial Code or to relevant state and/or local codes.
All pumping stations that are manned for extended periods should be provided with potable water, lavatory and toilet facilities. Plumbing must be so installed as to prevent contamination of a public water supply. Wastes shall be discharged in accordance with Section 4.11.
At least two pumping units shall be provided. With any pump out of service, the remaining pump or pumps shall be capable of providing the maximum daily pumping demand of the system. The pumping units shall
a. have ample capacity to supply the peak demand against the required distribution system pressure without dangerous overloading,
b. be driven by prime movers able to meet the maximum horsepower condition of the pumps,
c. be provided readily available spare parts and tools,
d. be served by control equipment that has proper heater and overload protection for air temperature encountered.
Suction lift shall
a. be avoided, if possible,
b. be within allowable limits, preferably less than 15 feet.
If suction lift is necessary, provision shall be made for priming the pumps.
Prime water must not be of lesser sanitary quality than that of the water being pumped. Means shall be provided to prevent either backpressure or backsiphonage backflow. When an air-operated ejector is used, the screened intake shall draw clean air from a point at least 10 feet above the ground or other source of possible contamination, unless the air is filtered by an apparatus approved by the reviewing authority. Vacuum priming may be used.
Booster pumps shall be located or controlled so that
a. they will not produce negative pressure in their suction lines,
b. the intake pressure shall be at least 20 psi (140 kPa) when the pump is in normal operation,
c. automatic cutoff or low pressure controller shall maintain at least 10 psi (70 kPa) in the suction line under all operating conditions,
d. automatic or remote control devices shall have a range between the start and cutoff pressure which will prevent excessive cycling,
e. a bypass is available.
Each booster pumping station should contain not less than two pumps with capacities such that peak demand can be satisfied with the largest pump out of service.
All booster pumping stations should contain a totalizer meter.
In addition to the other requirements of this section, inline booster pumps shall be accessible for servicing and repairs.
Individual home booster pumps shall not be allowed for any individual service from the public water supply main.
All automatic stations should be provided with automatic signaling apparatus which will report when the station is out of service. All remote controlled stations shall be electrically operated and controlled and shall have signaling apparatus of proven performance. Installation of electrical equipment shall conform with the applicable state and local electrical codes and the National Electrical Code.
Pumps shall be adequately valved to permit satisfactory operation, maintenance and repair of the equipment. If foot valves are necessary, they shall have a net valve area of at least 2 1/2 times the area of the suction pipe and they shall be screened. Each pump shall have a positive-acting check valve on the discharge side between the pump and the shut-off valve.
In general, piping shall
a. be designed so that the friction losses will be minimized,
b. not be subject to contamination,
c. have watertight joints,
d. be protected against surge or water hammer and be provided with restraints where necessary,
e. be such that each pump has an individual suction line or that the lines shall be so manifolded that they will insure similar hydraulic and operating conditions.
a. shall have a standard pressure gauge on its discharge line,
b. shall have a compound gauge on its suction line,
c. shall have recording gauges in the larger stations,
d. should have a means for measuring the discharge.
The station should have indicating, totalizing, and recording metering of the total water pumped.
Water seals shall not be supplied with water of a lesser sanitary quality than that of the water being pumped. Where pumps are sealed with potable water and are pumping water of lesser sanitary quality the seal shall
a. be provided with a either an approved reduced pressure principle backflow preventer or a break tank open to atmospheric pressure,
b. where a break tank is provided, hav an air gap of at least six inches or two pipe diameters, whichever is greater, between the feeder line and the flood rim of the tank.
Pumps, their prime movers and accessories, shall be controlled in such a manner that they will operate at rated capacity without dangerous overload. Where two or more pumps are installed, provision shall be made for alternation. Provision shall be made to prevent energizing the motor in the event of a backspin cycle. Electrical controls shall be located above grade. Equipment shall be provided or other arrangements made to prevent surge pressures from activating controls which switch on pumps or activate other equipment outside the normal design cycle of operation.
To ensure continuous service when the primary power has been interrupted, a power supply shall be provided from at least two independent sources or a standby or an auxiliary source shall be provided. If standby power is provided by onsite generators or engines the fuel storage and fuel line must be designed to protect the water supply from contamination. Natural gas or bottled gas are the preferred fuels. (See Section 2.6).
When automatic pre-lubrication of pump bearings is necessary and an auxiliary direct drive power supply is provided, the pre-lubrication line shall be provided with a valved bypass around the automatic control so that the bearings can, if necessary, be lubricated manually before the pump is started or the pre-lubrication controls shall be wired to the auxiliary power supply.