020-12 Wyo. Code R. § 12-12

Current through April 27, 2019

Section 12-12 - Pumping Facilities

(a) Total dynamic head. The total dynamic head rating of pumping units shall be based on pipe friction, pressure losses from piping entrances, exits, appurtenances (bends, valves, etc.), and static head at the design flow.

(b) Location.

(i) The pumping station shall be elevated or protected to a minimum of 3 feet above the 100-year flood elevation, or 3 feet above the highest recorded flood elevation, whichever is higher.

(ii) The station shall be accessible to operating personnel at all times, and during all weather.

(iii) The site around the station shall be graded to lead surface drainage away from the station.

(iv) The station shall have security installed to prevent vandalism and entrance by unauthorized persons or animals.

(c) Pumping stations - raw and finished water.

(i) They shall have outward opening doors.

(ii) They shall have a floor elevation or a main level entry of at least 6 inches above finished grade. All floors shall slope at least 2-1/2 inches in every 10 feet to a suitable drain. Pumps shall have an outlet for drainage from pump glands without discharging onto the floor.

(iii) They shall have any underground structures waterproofed.

(d) Wetwells. Finished water wetwells shall be covered. All vents shall be turned down and screened. Finished water wetwells shall be located above the groundwater table and the top of the walls from the wetwell shall be at least 18 inches above finished grade.

(e) Equipment servicing. Pump stations shall be provided with craneways, hoist beams, eyebolts, or other facilities for servicing or removing pumps, motors or other heavy equipment. They shall be rated for not less than 50 percent more than the weight of the heaviest single item to be lifted. Openings in floors and roofs shall be provided as needed for removal of heavy or bulky equipment.

(f) Stairways and ladders. Stairways or ladders shall be provided between all floors, and in pits or compartments which must be entered. They shall have handrails on both sides, and treads of non-slip material. The Wyoming Occupational Health and Safety Rules and Regulations shall be complied with.

(g) Heating. Provisions shall be made for heating to maintain a minimum temperature of 40° F (4° C) if not typically occupied and 50° F (10° C) if occupied.

(h) Ventilation. All accessible pumping station areas shall be ventilated. Ventilation may be continuous or intermittent. If intermittent, ventilation in areas normally visited by operating personnel shall be started automatically at not greater than 30 minute intervals. Permanently installed drywell ventilation shall provide at least 6 air changes per hour if continuous, and 12 air changes per hour if intermittent. Intermittent ventilating equipment shall ensure starting upon entry of operating personnel. Wetwells shall be designed to permit the use of portable blowers that will exhaust the space and continue to supply fresh air during access periods.

(i) Dehumidification. In below ground pumping stations, a means for dehumidification shall be provided. The facilities shall be sized to maintain the dewpoint at least 2 below the coldest anticipated temperature of water to be conveyed in the pipes.

(j) Lighting. Lighting levels shall be sufficient to permit safe operation and maintenance of all equipment within the pumping stations, but not less than 30 foot candles. All areas shall be lit in such a manner that the failure of 1 lighting fixture or lamp will not cause the area to be completely dark.

(k) Sanitary and other conveniences. All pumping stations that are manned for four or more hours per day shall be provided with potable water, lavatory and toilet facilities. Wastes shall be discharged to the sanitary sewer or to an on-site waste treatment system.

(l) Pumps. At least two pumping units shall be provided. With the largest pump out of service, the remaining pump or pumps shall be capable of providing the maximum pumping rate of the system.

(m) Suction lift. Pumps shall be selected so that the net positive suction head required at maximum flow (NPSHR) is less than the net positive suction head available (NPSHA) minus 4 feet (1.2 m) based on the hydraulic conditions and altitude of the pumping station. If this condition is not met, then priming shall be provided.

Priming water must not be of lesser sanitary quality than that of the water being pumped. Vacuum priming may be used.

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.

(n) Surge control. Piping systems shall be designed to withstand the maximum possible surge (water hammer) from the pumping station, or adequate surge control provided to protect the piping. Pressure relief valves are not acceptable surge control.

(o) Booster pumps.

(i) Booster pumps shall not produce a pressure less than 5 psi in suction lines. Where the suction line has service connections, booster pump intake pressure shall be at least 35 psi (138 kPa) when the pump is in normal operation and shall be provided with a low pressure cutoff switch if the suction line pressure is a minimum of 20 psi (69 kPa).

(ii) Automatic or remote control devices shall have a range between the start and cutoff pressure which will prevent cycling of more than 1 start every 15 minutes.

(iii) In-line booster pumps shall be accessible for servicing and repairs. The access opening and vault shall be large enough to remove the pump.

(iv) Individual home booster pumps shall not be allowed for any individual service from the public water supply main.

(p) Automatic and remote controlled stations. Conditions that may affect continuous delivery of water shall be alarmed at an attended location.

(q) Appurtenances.

(i) Valves.
- (A) All pumps except submersibles shall have a suction and discharge valve to permit satisfactory operation, maintenance and repair of the equipment. Submersible pumps shall have a check valve and discharge valve to permit satisfactory operation, maintenance and repair of the equipment.
- (B) 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.
- (C) Each pump shall have an individual suction line or the lines shall be so manifolded that they will ensure similar hydraulic and operating conditions.
- (D) Check. All pumps shall be provided with a check valve located between the pump and the discharge shutoff valve, except where arranged so that backflow is not possible under normal operating conditions.
- (E) Air release. Air release valves shall be provided where the pipe crown is dropped in elevation.

(ii) Gauges. Each pump shall have a standard pressure gauge on its discharge line. Each pump shall have a compound gauge on its suction line, except wet pit type pumps.

(iii) Water seals. 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 be supplied from a break tank open to atmospheric pressure. The tank shall have an air gap of at least 6 inches (0.15 m) or 2 pipe diameters, whichever is greater, between the feeder line and the spill line of the tank.

(iv) Controls. Pumps, their prime movers and accessories, shall be controlled in such a manner that they will operate at rated capacity without overload. Provision shall be made to prevent energizing the motor in the event of a backspin cycle. Electrical controls shall be located above grade.

020-12 Wyo. Code R. § 12-12