(4) Discharge piping.
Discharge piping from a pitless unit shall meet the following requirements:
The discharge piping from the pitless unit shall be directed to a separate building located above grade where all of the applicable pump discharge piping appurtenances shall be installed in accordance with s. NR 811.37
and Figure No. 7 in the Appendix.
The discharge piping from the pump in the well to the above grade pump discharge piping shall remain pressurized at all times. No provisions for drain back of the discharge piping may be allowed. A shut-off valve shall not be installed in the buried portion of the pitless unit discharge piping unless approved by the department as part of a pump-to-waste installation.
The buried portion of a pitless unit discharge piping along with any joints or fittings shall be ductile iron, steel, or plastic piping meeting at minimum the AWWA pressure class 150 water main standards required under s. NR 811.69
. Plastic piping shall not be used in areas where soil or groundwater contamination may be present. Plastic piping shall be transitioned to metal piping within 12 inches above the floor of the building into which it will be directed, under par. (a)
, unless minimum schedule 80 PVC pipe is installed in the building as allowed under s. NR 811.28 (5) (b)
(5) Check valves.
A check valve shall be installed in the submersible pump discharge piping in the well immediately above the pump. A check valve shall not be installed in the buried pitless unit discharge piping. A check valve may not be installed in the above grade pump discharge piping unless preceded by the pump on and off controls, or one or more pressure tanks, or unless the department approves an alternate method to maintain positive pressure in the piping under all operating conditions.
Pitless units shall be factory assembled and pressure tested, full length units, with the make and model number having received individual department approval for use. The inside diameter of the pitless unit shall not be smaller than the inside diameter of the well casing pipe as required by s. NR 812.31 (2) (b)
The department may not approve installation of a pitless unit unless any temporary outer well casing is totally removed from the well during the well construction process. Pitless units shall be attached only to the protective grouted well casing, including wells constructed with gravel packed screens.
The top surface of the remaining well grout shall be no greater than one foot below the installation depth of the pitless unit, which is the well casing cut-off depth.
Pitless units shall be installed by a licensed pump installer. The installed pitless unit shall be tested and proven watertight under a pressure of not less than 14 psig. The pressure shall be maintained for a minimum of 30 minutes. Additionally, any leaks detected shall be sealed during the pressure test. The installer shall notify the department a minimum of 48 hours before performing the pressure testing so that a department employee may witness the test. A report on the results of the pressure testing, signed by a licensed pump installer, shall be submitted to the department before placing the well in service.
A certification by the licensed pump installer that installed the pitless unit confirming that the well was originally grouted to the ground surface and that the requirements of pars. (b)
were met, shall be submitted to the department along with the pressure testing report and a copy of the well construction report.
Backfilling of the excavation shall commence as soon as practical after the installation and a successful pressure test of the pitless unit.
For slab-on-grade enclosures, a below grade length of pump discharge piping from the pitless unit, sufficient to extend beyond the enclosure, shall be installed prior to backfilling of the excavation and construction of the concrete floor slab. The buried piping shall be temporarily capped in a sanitary manner unless the piping is immediately extended and connected to the remainder of the system. During the installation of the discharge piping, if the sampling faucet riser pipe is not installed within the well and pitless unit, a metal riser pipe shall be extended vertically from the below grade discharge piping to terminate at a height a minimum of 12 inches above the top of the future concrete floor. The riser pipe shall be fitted with a frost-proof, down-turned, metal, smooth-end sampling faucet or shall be temporarily capped.
NR 811.35 History
History: CR 09-073
: cr. Register November 2010 No. 659
, eff. 12-1-10; correction in (6) (intro.) made under s. 13.92 (4) (b) 7.
, Stats., Register November 2010 No. 659
Each well shall be vented to the atmosphere in accordance with the following requirements:
For wells without pitless units, a metal vent pipe shall be installed which terminates in a 24-mesh corrosion resistant screened “U" bend or mushroom cap at least 24 inches above the floor. The vent pipe diameter shall be a minimum of 2 inches for well casings 10 inches in diameter and larger. Vent piping shall be welded watertight to the side of the well casing a minimum of 4 inches above the floor and may extend through a concrete pump base or collar where one is present. Alternatively, vent piping may project watertight through a well seal or pump discharge head if the well seal or discharge head will facilitate the installation of the vent pipe.
For wells with pitless units, a metal vent pipe shall be installed which terminates in a 24-mesh corrosion resistant screened “U" bend or mushroom cap at least 24 inches above the floor. The pitless unit vent area shall be equal to or greater than the area provided by a 2-inch diameter vent pipe for pitless units 10 inches in diameter or larger. Vent piping shall extend above or be incorporated into the top of the pitless unit or be welded watertight to the side of the pitless unit a minimum of 4 inches above the floor and may extend through a concrete pump base or collar where one is present.
NR 811.36 Note
Note: It is recommended that vent installations for pitless units be factory installed to prevent damage to the integrity of factory units and paint systems.
If the well is flowing, the vent shall terminate above the artesian water level or a suitable automatic valve shall be provided.
Provisions shall be made for measurement of static and pumping water levels in the completed well by the use of an electric depth gauge, pressure transducer or an air line attached to the pump column and an altitude gauge.
The installation shall be constructed to prevent entrance of foreign material.
Air lines may not be installed through vent pipes unless justified when modifications are being made to existing installations, the minimum 2-inch diameter vent pipe area is maintained where applicable, and the specific approval of the department is obtained.
NR 811.36 History
History: CR 09-073
: cr. Register November 2010 No. 659
, eff. 12-1-10.
Pump discharge lines.
Pump discharge lines shall meet the requirements of this section and as shown in Figure Nos. 8 and 9 in the Appendix.
(1) Buried lines.
Adequate positive pressure shall be maintained on all buried piping. Pump suction and discharge lines which are to be buried shall be designed so that the line is under a continuous pressure head which is higher than the elevation of the ground surface under all operating conditions. Lines where a positive pressure head which is higher than the elevation of the ground surface cannot be maintained may be installed if the lines are encased for their entire length in watertight pipe conduit or a tunnel. Buried suction lines which, under all operating conditions, are not under a positive pressure head which is higher than the elevation of the ground surface are not permitted.
(2) Above grade piping materials.
Above grade pump discharge line piping materials shall meet the requirements of s. NR 811.28 (5) (b)
(3) Location of appurtenances.
Pump discharge piping containing appurtenances such as valves, sampling faucets, water meters, and other equipment shall be located above the ground surface.
All wells and high-lift pump stations shall be provided with a means to pump to waste. This shall be a plugged tee or blind flange or a shut-off valve followed by a hose connection installed on the pump discharge piping inside the pump station. For municipal and subdivision water systems, a valve and hydrant may be installed outside the pump station on the buried pump discharge piping.
NR 811.37 Note
Note: It is recommended that pump-to-waste fittings installed inside the pump station be installed as close as possible to the well or pump head in order to minimize the piping and appurtenances that water to be wasted will be pumped through.
(5) Pump discharge piping appurtenances.
The following appurtenances shall be provided for pump discharge piping in addition to the means for pumping the well to waste required in sub. (4)
. Additional requirements for the installation of pump discharge piping and appurtenances for pitless unit installations are given in s. NR 811.35
(a) Air-vacuum relief valve.
For line-shaft vertical turbine pump discharge pipes, an air-vacuum relief valve shall be installed between the pump and the check valve. The discharge line from the relief valve shall face downward and terminate with a 24-mesh corrosion resistant screen, at least 24 inches above the floor. For well line-shaft vertical turbine pump discharge pipes that discharge directly to reservoirs, the air relief valve is not required but a vacuum relief valve and a check valve are required. The installation of an air-vacuum relief valve is not required for submersible pump installations where check valves are installed at the pump and above grade and there are no weep holes in the pump drop pipe unless entrained air in the well water or pressure surges are a concern and the installation of an air relief valve is necessary or required by the department.
(b) Sampling faucet.
All pump discharge piping shall contain one or more sampling faucets meeting the following requirements:
A water sampling faucet shall be installed and located upstream of any chemical addition or water treatment equipment to allow for the collection of raw water. If possible, the faucet shall be located prior to any above grade check valve.
If chemical addition, water treatment, or water storage is installed, a second entry point sampling faucet shall be installed as far downstream of the chemical injection, water treatment, or water storage as practical. If necessary to obtain a water sample representing finished water quality, a water service lateral shall be brought back into the building and fitted with a sampling faucet after being connected to the finished water main outside the building.
All sampling faucets shall be installed to terminate a minimum of 12 inches above the floor, have a down-turned smooth end spout, be constructed of metal, have a minimum spout diameter of 0.25 inches, be installed directly on the piping conveying the water whenever possible, and be located in an area accessible for sampling.
(c) Check valve or other type of automatically closing valve.
A check valve shall be provided except if prohibited at pitless unit installations under s. NR 811.35 (5)
. Where extreme surge pressures occur, slow opening valves, voltage ramped motors, or other means of surge protection shall be provided.
All municipal well pump discharge pipes, all other-than-municipal well pump discharge pipes with pumps discharging at a rate greater than or equal to 70 gallons per minute or if chemical addition is practiced, all groundwater reservoir high-lift pumps if chemical addition is practiced, and all surface water low-lift and high-lift combined pump discharge pipes shall be provided with water meters to determine the quantity of water discharged.
NR 811.37 Note
Note: It is recommended that an hour meter be installed for any pump motor where the pump discharge piping will not be provided with a water meter.
(g) Chemical injection tap.
A chemical injection tap allowing chemical injection, shall be provided and installed in accordance with s. NR 811.39 (2) (f)
NR 811.37 History
History: CR 09-073
: cr. Register November 2010 No. 659
, eff. 12-1-10.
This subchapter contains general requirements for the design and construction for chemical storage, handling, and addition facilities. Specific treatment design requirements are contained in subch. VII
. Specific operating requirements are contained in subch. I of ch. NR 810
. No chemicals may be applied to treat drinking water unless approved by the department. This requirement applies to first time application, temporary application, or when it is proposed to replace one chemical with another. The department shall be contacted prior to discontinuing the use of any chemical.
NR 811.38 History
History: CR 09-073
: cr. Register November 2010 No. 659
, eff. 12-1-10.
Number of feeders.
If chemical feed, such as chlorination, coagulation or other essential processes, is necessary to produce a water quality meeting the primary maximum contaminant levels, a minimum of 2 feeders shall be provided so that a standby unit or combination of units will be available to replace the largest unit during shut-downs. Spare parts shall be available for all feeders to replace parts which are subject to wear and damage.
(2) Design and capacity.
The design and capacity of chemical feed equipment shall meet all of the following requirements:
(a) Separate chemical feed systems.
Separate chemical feed systems shall be provided in accordance with the following requirements:
Separate disinfection chemical feed systems shall be provided if pre- and post- water treatment disinfection application points are installed.
Each chemical feed pump or gas feeder shall take suction from its own dedicated chemical solution tank or gas cylinders. The department may approve multiple chemical feed pumps or gas feeders for the same process application point taking suction from the same chemical solution tank or gas cylinders in the following situations:
Where multiple water sources are discharging to the same location. In this case, a means shall be provided for determining the flow from each individual water source.
Where multiple pumps are pumping from the same water source and discharging to the same location through a combined header pipe. In this case, a means shall be provided for measuring total flow.
For the situations in subd. 3. a.
, a single chemical feeder with a single feed point or multiple chemical feeders with multiple feed points may be used, provided the installation meets the other requirements of this subchapter.
NR 811.39 Note
Note: An example of subd. 3. a. would be multiple wells discharging to a single reservoir or water treatment plant. An example of subd. 3. b. would be multiple high-lift pumps taking suction from a single reservoir and discharging to a combined pump discharge pipe.
(b) Acceptable chemical feed pumps.
Positive displacement diaphragm metering pumps, peristaltic chemical feed pumps or other pumps, as approved by the department, shall be used to feed liquid chemicals. Pumps shall be sized to match or exceed maximum head conditions found at the point of injection.
(c) Chemical feeder settings.
Feeders shall be able to supply, at all times, the necessary amounts of chemical at an accurate rate, throughout the range of feed. All positive displacement diaphragm metering pumps shall be operated at a minimum speed setting of 12 strokes per minute. For positive displacement diaphragm metering pumps with an adjustable stroke length the pumps shall be operated at a minimum of 20 percent of the maximum stroke length. Peristaltic chemical feed pumps shall be operated at a minimum of 10 percent of the maximum feeder output for the given interior diameter of the feed tube installed. If these operating requirements cannot be met using stock chemical solution, dilution of the chemical shall be required.
(d) Flow paced chemical feed.
Automatic proportioning of chemical feed to rate of water flow shall be provided when water flow rates will vary. Chemical feed pumps shall be proportionally flow paced by a signal from a water meter when discharge rates from a well or service pump will be variable over the pump cycle. When applicable, this includes variable output control devices as required by s. NR 811.34 (5)
(e) Anti-siphon devices.
Chemical feed pumps shall be provided with anti-siphon devices meeting the following requirements:
All electronic positive displacement diaphragm metering pumps shall be provided with a spring-opposed diaphragm type anti-siphon device or a spring opposed diaphragm type anti-siphon and back pressure valve device installed in the discharge piping of the chemical feed pump. The anti-siphon and back pressure functions may be part of a common device or separate devices. Any back pressure valve shall be set to open at a pressure greater than the maximum pressure in the piping or facilities into which the chemical feed pump will discharge. When a back pressure valve is installed on the discharge piping of a chemical feed pump, it shall be preceded by a pressure relief valve and a pressure gauge or other department approved means to verify that the back pressure valve is operating satisfactory.
Digitally controlled diaphragm metering pumps shall be provided with a spring opposed diaphragm type anti-siphon and back pressure valve device installed in the discharge piping of the chemical feed pump in accordance with the requirements of subd. 1.
Peristaltic chemical feed pumps shall be provided with a back pressure valve device installed in the discharge piping of the chemical feed pump in accordance with the requirements of subd. 1.
The department may be contacted to request approval of an equivalent anti-siphon device or equivalent means of providing anti-siphon protection if the installation of the anti-siphon devices as required in subds. 1.
is not practical given the properties of the chemical to be fed. Adequate justification shall be provided to the department for the request.
Chemical solutions shall be prevented from being siphoned into the water supply. Anti siphon protection shall be provided by discharging chemicals at points of positive pressure and by providing anti-siphon devices in accordance with par. (e)
, or through a suitable air gap or other effective means approved by the department. A point of continuous positive pressure shall be assured on the system side of the last shut-off valve. If a second shut-off valve is provided downstream of the primary shut-off valve, the point of injection may be between the 2 shut-off valves.
All chemicals shall be fed downstream of the check valve. Strong acids and bases such as fluorosilicic acid and sodium hydroxide shall be fed downstream of both the check valve and the shut-off valve.
NR 811.39 Note
Note: It is recommended that all chemicals be fed downstream of both the check valve and the shutoff valve.
If chemical feeding is at a location without continuous positive pressure, one of the following installation requirements shall be met to prevent siphoning of chemical solutions:
A suitable air gap shall be provided which is at a higher elevation than the chemical solution tank.
A dual head feeder with a small break tank located higher than the chemical solution tank shall be provided.
A chemical feed pump discharging without any air gap or break box may be approved by the department on a case-by-case basis if the installation is provided with a spring opposed diaphragm type anti-siphon and back pressure valve device. The back pressure valve shall be installed as close as possible to the point of chemical addition. The spring opposed diaphragm type anti-siphon and back pressure valve device shall be installed in accordance with the requirements of par. (e) 1.
(g) Makeup water lines.
The makeup water supply lines to chemical feed tanks shall be protected from contamination by chemical solutions either by equipping the supply line with backflow or backsiphonage prevention devices, or by providing an air gap between the supply line and the top of the solution tank.
(h) Chemical resistance.
Materials and surfaces coming in contact with chemicals shall be resistant to the aggressiveness of the chemical solution.
(i) Dry chemical feeders.
Dry chemical feeders shall meet the following requirements:
Provide effective dissolving and mixing of the chemical in the solution pot and provide gravity feed from solution pots, if possible.
Completely enclose chemicals to prevent emission of dust to the operating room.
(j) Direct sewer connections prohibited.
No direct connection shall be made between any sanitary or storm sewer and a drain or overflow from any feeder or solution chamber or tank.
Chemical feed equipment shall meet the following requirements:
Be located near points of application to minimize length of feed lines.
Be readily accessible for servicing or repair and observation of operation.
Be located and have protective containment curbs so that chemicals from equipment failure, spillage, or accidental drainage may not enter the water in conduits, treatment, or storage basins.
Be located within a containment basin capable of receiving accidental spills, drainage, or overflows without an uncontrolled discharge outside of the containment basin. A common containment basin may be provided for each group of compatible chemicals. At minimum, the containment basin shall be sized to contain the volume of the largest tank that could fail. Chemical containment basins shall not be provided with floor drains. Trapped and vented floor drains discharging to sanitary sewers, holding tanks or the ground surface in accordance with s. NR 811.25 (1) (h)
may be installed for chemical rooms outside of containment basins. Chemical feed pumps shall be located within the containment basin. Piping shall be designed to minimize or contain chemical spills in the event of pipe ruptures.
Be located above grade, except if this requirement is waived by the department.