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Interceptors, separators, neutralizers, dilution tanks, or other means shall be provided where required to prevent liquid wastes containing fats, oils, greases, flammable liquids, sand, solids, acid or alkaline waste, chemicals, or other harmful substances from entering a building drainage system, a public or private sewer, or sewage treatment plant or process. The determination of necessity shall be made by the plumbing subcode official in accordance with N.J.A.C. 5:23-3.3. See Figure 6.1.1
Figure 6.1.1
DIFFERENT TYPES OF INTERCEPTORS
The size and type of liquid waste treatment equipment shall be based on the maximum volume and rate of discharge of the plumbing fixtures and equipment being drained.
Only wastes from fixtures and equipment requiring treatment or separation shall be discharged into treatment equipment.
EXCEPTION: Non-grease discharges into grease interceptors that are permitted in Section 6.2.1.e.
The type, size, capacity, design, arrangement, construction, and installation of liquid waste treatment devices shall be as required by this Code.
Each application of a manufactured liquid waste treatment device employing pumps, filters, drums, collection plates, or other mechanical means of operation shall be certified by the manufacturer to provide effluent meeting the environmental requirements of the sewer or other approved point to which it discharges.
Liquid waste treatment equipment shall be so designed that they will not become air-bound if tight covers are used. Equipment shall be properly vented if loss of its trap seal is possible.
  1. Liquid waste treatment equipment shall be so installed that it is accessible for the removal of covers and the performance of necessary cleaning, servicing and maintenance.
  2. The need to use ladders or move bulky objects in order to service interceptors and other liquid waste treatment equipment shall constitute a violation of accessibility.
Connections to sewers or other points of discharge for the effluent from liquid waste treatment equipment shall be as permitted by the Authority Having Jurisdiction.
  1. Grease interceptors shall comply with the requirements Section 6.1.4.
  2. Grease interceptors include the following types:
    1. Hydromechanical grease interceptors (HGI)
    2. Grease removal devices (GRD)
    3. Gravity grease interceptors (GGI)
    4. FOG (fats, oils, and greases) disposal systems
  3. Grease interceptors shall be provided to receive the waste discharges from fixtures in food handling areas that introduce grease into the sanitary drainage system. Fixtures include, but are not limited to pot washing sinks, utensil soak sinks, pre-rinse sinks at dishwashers, wok range stations, drains from wash-down ventilation hoods, can washing drains, mop sinks, floor drains and floor sinks in areas around grease producing fixtures, and similar fixtures.
  4. Water closets, urinals, and other fixtures that discharge human waste shall not discharge through a grease interceptor.
  5. Non-grease drainage from handwashing sinks, lavatories, food preparation sinks, ice machines, ice bins, and similar fixtures shall be permitted to discharge through a grease interceptor along with grease producing fixtures.
  6. Ice machines, ice bins, food preparation sinks, and other food containing equipment shall drain indirectly through an air gap.
  1. Hydromechanical grease interceptors (HGI) shall comply with the performance, testing, and installation requirements of ASME A112.14.3, PDI G101 or CSA B481.
  2. HGI interceptors shall be sized according to Section 6.2.10 and retain not less than two pounds of grease for each gpm of rated flow.
  3. A calibrated, non-adjustable flow control device shall be provided on the inlet side of each HGI interceptor to prevent the waste flow (gpm) from exceeding the rated flow capacity of the interceptor. The flow control device shall be vented in accordance with Section 6.2.4.
  4. Where optional FOG level sensing and alarm devices are provided for PDI G101 HGI interceptors, they shall comply with PDI G102.
  1. Grease removal devices (GRD), which are hydromechanical grease interceptors, that are capable of automatically removing free-floating grease, fats, and oils from their waste discharge without intervention of the user except for maintenance, shall comply with ASME A112.14.4 or CSA B481.
  2. GRD interceptors shall be sized according to Section 6.2.10.
  3. A calibrated, non-adjustable flow control device shall be provided on the inlet side or within each GRD interceptor to prevent the waste flow (gpm) from exceeding the rated flow capacity of the interceptor. The flow control device shall be vented in accordance with Section 6.2.4.
  1. Outdoor underground gravity grease interceptors (GGI) serving commercial kitchens shall be sized and designed by a registered design professional who is licensed to practice in the particular jurisdiction.
  2. Gravity grease interceptors (GGI) shall comply with the requirements of Section 6.2.10.b and the Authority Having Jurisdiction, including materials of construction, arrangement, retention time, storage factor for floatable FOG and settled solids, and minimum size.
  3. Where drain piping and a gravity grease interceptor (GGI) are provided for the future installation of a commercial kitchen, the design plans shall indicate the maximum permitted future drainage load in either gallons per minute (excluding diversity) or drainage fixture units (DFU).
  4. Prefabricated gravity grease interceptors (GGI) shall comply with IAPMO/ANSI Z1001.
  5. Precast concrete grease interceptor tanks shall comply with ASTM C1613.
  1. FOG disposal systems shall be designed to:
    1. remove FOG from the effluent,
    2. retain the separated FOG,
    3. internally dispose of the retained FOG by means of mass and volume reduction by thermal, chemical, electrical, biological or other approved processes.
  2. FOG disposal systems based on hydromechanical grease interceptors shall have a minimum separation/retention efficiency in accordance with ASME A112.14.3 or PDI G101.
  3. FOG disposal systems based on gravity grease interceptors shall be designed in accordance with IAPMO/ANSI Z1001.
  4. FOG disposal systems shall comply with ASME A112.14.6 and be installed according to the manufacturer's instructions.
  1. Fixtures that discharge into a hydromechanical or GRD grease interceptor shall be trapped and vented between the fixture and the interceptor.
    EXCEPTION: A hydromechanical or GRD grease interceptor with the required flow control device shall be permitted to serve as a trap for an individual fixture if the developed length of the drain between the fixture and the interceptor does not exceed four feet horizontally and 30 inches vertically.
  2. Where one or more fixtures discharge into a hydromechanical or GRD grease interceptor, the required vented flow control device shall be installed in the drain line between the fixture(s) and the interceptor.
See Figures 6.2-A and 6.2-B
Figure 6.2 - A
A GREASE INTERCEPTOR SERVING A TRAPPED AND VENTED FIXTURE
Figure 6.2 - B
A GREASE INTERCEPTOR SERVING AS A FIXTURE TRAP
  1. Trapped fixtures draining to a grease interceptor shall be vented in accordance with the manufacturer's instructions for the grease interceptor and the applicable requirements of this Code.
  2. Where a grease interceptor is permitted to serve as the trap for a single fixture that does not have a trap, the air intake for the flow control device between the fixture and the grease interceptor shall be vented by a return bend that is open to the space at least 6 inches above the flood level rim of the fixture being drained. See Figure 6.2-B
  3. When the fixture connected to the grease interceptor has a separate vented trap, the air intake on the flow control device for the grease interceptor shall be connected to the vent piping system. See Figure 6.2-A
  1. Where food waste disposers discharge through an HGI hydromechanical or GRD grease removal grease interceptor, a solids separator shall be installed either in the drain line from the food waste disposer or upstream of the grease interceptor to prevent food waste particles from entering the grease interceptor.
  2. Solids separators shall not be required where (1) the GRD device includes a removable solids strainer basket, or (2) the food waste disposer discharges to a GGI gravity grease interceptor. See Figure 6.2.5
Figure 6.2.5
A FOOD WASTE DISPOSER WITH SOLIDS SEPARATOR AND GREASE INTERCEPTOR
  1. Commercial dishwashers shall be permitted to discharge through a grease interceptor. The size of the grease interceptor shall be determined by the GPM discharge rate of the dishwasher as indicated by its manufacturer.
  2. Where a commercial dishwasher does not discharge through a grease interceptor, it shall discharge downstream from any grease interceptors in the drainage system.
  3. Where necessary, the drainage rate from a commercial dishwasher shall be converted from gallons per minute (GPM) to drainage fixture units (DFU) in accordance with Section 11.4.2.
  1. GGI gravity grease interceptors shall not be located indoors. HGI hydromechanical and GRD grease removal interceptors may be installed indoors within buildings only when permitted by the Authority Having Jurisdiction.
  2. Where grease interceptors are remote from the fixtures served, the drain piping between the fixtures and the grease interceptor shall be as direct as possible and shall include provisions for periodic cleaning.
The installation of water-cooled grease interceptors is prohibited.
  1. The use of enzymes, emulsifiers, or similar chemicals in HGI hydromechanical, GRD grease removal, and GGI gravity interceptors is prohibited.
  2. Sinks or sink compartments used for sanitizing pots or other ware shall not be drained through a grease interceptor.
  1. Where hydromechanical grease interceptors (HGI) and grease removal devices (GRD) serve one or more individual fixtures, they shall be sized for the total drainage flow rate from the fixtures served in accordance with PDI G101, Table 6.2.10, or the manufacturer's instructions. All compartments of multi-compartment sinks shall be considered to drain simultaneously, except that sanitizing compartments shall not be drained through a grease interceptor.
  2. Gravity interceptors for commercial kitchens shall be sized based on the inlet pipe flowing half-full according to Appendix K, a 30-minute retention time, and an additional 25% storage factor for floatable FOG and settled solids, or as required by the Adopting Agency.
    Table 6.2.10
    FIXTURE DRAINAGE FLOW RATES FOR SIZING HYDROMECHANICAL GREASE INTERCEPTORS (HGI) AND GREASE REMOVAL DEVICES (GRD)
    FIXTURE FLOW
    1-1/4" Sink Drain Outlet (each) 7.5 GPM
    1-1/2" Sink Drain Outlet (each) 15 GPM
    2" Sink Drain Outlet (each) 22.5 GPM
    Floor Drain without Indirect Waste 0 GPM
    Floor Drain or Floor Sink with Indirect Waste (1)
    Commercial Dishwasher (2)
    NOTES FOR TABLE 6.2.10
    1. The GPM drain load shall be the total indirect waste flow in GPM.
    2. The GPM drain load for a commercial dishwasher shall be not less than the manufacturer's peak drain flow rate with a full tank.
Grease interceptors shall not be required in individual dwelling units or any private living quarters.
A combination system of HGI hydromechanical, GRD grease removal, and GGI gravity grease interceptors may be permitted if necessary to meet any separation needs of the Authority Having Jurisdiction when space or existing physical constraints of existing buildings necessitates such installations.
  1. Liquid waste containing grease, oil, solvents, or flammable liquids shall not be directly discharged into any sanitary sewer, storm sewer, or other point of disposal. Such contaminants shall be removed by an appropriate separator.
  2. Sand interceptors and oil separators shall be provided wherever floors, pits or surface areas subject to accumulation of grease or oil from service or repair operations are drained or washed into a drainage system. Such locations include, but are not limited to, car or truck washing facilities, engine cleaning facilities, and similar operations. The drainage or effluent from the interceptors and separators in such locations shall be connected to the sanitary sewer.
  3. Drains shall not be required in service or repair garages that employ dry absorbent cleaning methods; however, if any drains are located in such areas, they shall discharge to the sanitary sewer through a sand interceptor and oil interceptor.
  4. Drains shall not be required in parking garages unless the garage, or portions thereof, has provisions for either washing vehicles or rinsing the floor. Where such cleaning facilities are provided, the area subject to waste drainage shall be provided with one or more floor drains, complete with sand interceptor and oil interceptor, and the effluent from the oil separator shall be connected to the sanitary sewer. Any storm water shall be drained separately and directly to the storm sewer.
  5. Where parking garages without provisions for vehicle washing or floor rinsing require storm water drainage, drains shall be permitted to connect to the storm sewer without a sand interceptor and oil separator. Such drainage, including rainwater, melting snow and ice, or rainwater runoff from vehicles, shall not be connected to the sanitary sewer.
  6. Where oil separators include a waste holding tank, it shall not be used to store or contain any other waste oil (e.g., motor oil) or hazardous fluid.
  1. Where oil separators are required in garages and service stations, they shall have a minimum volume of six cubic feet for the first 100 square feet of area drained, plus one cubic foot for each additional 100 square feet of area drained. Oil separators in other applications shall be sized according to the manufacturers rated flow.
  2. Field-fabricated oil separators shall have a depth of not less than two feet below the invert of the discharge outlet. The outlet opening shall have a water seal depth of not less than 18 inches.
  3. Manufactured oil separators shall be sized according to gallons per minute of rated flow. They shall include a flow control device and adjustable oil draw-off.
  4. Oil separators shall have a 3-inch minimum discharge line and a 2-inch minimum vent to atmosphere. The discharge line shall have a full-size cleanout extended to grade or otherwise be accessible.
  5. The oil draw-off or overflow piping from oil separators shall be connected to an approved waste oil tank that is installed and permitted according to the environmental requirements of the Authority Having Jurisdiction. The waste oil from the separator shall flow by gravity or may be pumped to a higher elevation by an automatic pump. Pumps shall be adequately sized, explosion-proof, and accessible. Waste oil tanks shall have a 2-inch minimum pump-out connection and a 1-1/2 inch minimum vent to atmosphere.
  6. Where oil separators are subject to backflow from a sewer or other point of disposal, their discharge line shall include a backwater valve, installed in accordance with Section 5.5.
  7. Where oil separators are installed in parking garages and other areas where the waste flow will include sand, dirt or similar solids, a sand interceptor shall be provided upstream from the oil separator. Sand interceptors shall comply with Section 6.4.
  8. Oil interceptors, waste oil tanks, oil pump-out connections, backwater valves and atmospheric vent piping shall be permanently identified by suitable labels or markings.
The atmospheric vents from oil separators and their waste holding tanks shall be separate from other plumbing system vents and shall be extended to an approved location at least 12 feet above grade or the surrounding area.
A combination oil separator and sand interceptor meeting the functional requirements of Sections 6.3 and 6.4 shall be permitted to be installed.
  1. A sand interceptor shall be installed upstream from an oil separator if required in Section 6.3.2.g.
  2. A sand interceptor shall be provided downstream from any drain whose discharge may contain sand, sediment, or similar matter on a continuing basis that would tend to settle and obstruct the piping in the drainage system. Multiple floor drains shall be permitted to discharge through one sand interceptor.
  1. Sand interceptors shall be constructed of concrete, brick, fabricated coated steel, or other watertight material, and shall be internally baffled to provide an inlet section for the accumulation of sediment and a separate outlet section.
  2. The outlet pipe of a sand interceptor shall be the same size as the drain served.
    EXCEPTION: If serving an oil separator, the outlet from the sand interceptor shall be the same size as the inlet to the oil separator.
  3. The inlet baffle shall have two top skimming openings, each the same size as the outlet pipe and at the same invert as the outlet opening. The openings in the baffle shall be offset to prevent straight-line flow through the interceptor from any of its inlets to its outlet.
  4. The inlet to the interceptor shall be at the same elevation as, or higher than, the outlet. The bottom of the inlet section shall be at least 24 inches below the invert of the outlet pipe.
  5. The bottom of the inlet section shall be at least two feet wide and two feet long for flow rates up to 20 gallons per minute. The bottom of the inlet section shall be increased by one square foot for each 5 gpm of flow or fraction thereof over 20 gpm. The bottom of the outlet section shall be not less than 50% of the area of the bottom of the inlet section.
  6. A solid removable cover shall cover the outlet section. An open grating suitable for the traffic in the area in which it is located shall cover the inlet section. Covers shall be set flush with the finished floor.
When a sand interceptor is used separately without also discharging through an oil separator, its outlet pipe shall be turned down inside the separator below the water level to provide a six-inch minimum water seal. A cleanout shall be provided for the outlet line.
Alternate designs for construction of, or baffling in, sand interceptors shall comply with the intent of this Code and be submitted to the Authority Having Jurisdiction for approval in accordance with N.J.A.C. 5:23-3.3.
  1. Solids interceptors shall be provided where necessary to prevent harmful solid materials from entering the drainage system on a continuing basis. Such harmful materials include, but are not limited to, aquarium gravel, barium, ceramic chips, clay, cotton, denture grindings, dental silver, fish scales, gauze, glass particles, hair, jewels, lint, metal grindings, plaster, plastic grindings, precious metal chips, sediment, small stones, and solid food particles.
  2. Solids interceptors shall separate solids by gravity, trapping them in a removable bucket or strainer.
  3. Solids interceptors shall be sized according to their drain pipe size or by the required flow rate.
  4. Drum trap solids interceptors shall comply with Section 5.3.7.
  1. Neutralizing or dilution tanks shall be provided where necessary to prevent acidic or alkaline waste from entering the building drainage system. Such waste shall be neutralized or diluted to levels that are safe for the piping in the drainage and sewer systems.
  2. Vents for neutralizing or dilution tanks shall be constructed of acid-resistant piping and shall be independent from sanitary system vents.
Commercial laundries shall be equipped with one or more lint interceptors having wire baskets or similar devices, removable for cleaning, that will prevent passage into the drainage system of solids 1/2 inch or larger in size, strings, rags, buttons, lint, and other materials that would be detrimental to the drainage system.
Bottling plants shall discharge their process wastes into a solids separator that will retain broken glass and other solids, before discharging liquid wastes into the drainage system.
Drains in slaughtering rooms and dressing rooms shall be equipped with separators or interceptors, approved by the Authority Having Jurisdiction, that will prevent the discharge into the drainage system of feathers, entrails, and other waste materials that are likely to clog the drainage system.
Shampoo sinks in barbershops, beauty parlors, and other grooming facilities shall have hair interceptors installed in lieu of regular traps.
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