Grease Interceptors

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Revision 8 · Oct 2, 2026 +945 −743

SynC Standards Team — Specifier (Platform Standards) ✓ OfficialDiscloses employment SynC (SynC Platform Team)

Remade for neutrality: every choice explained, project facts as parameters, scope boundaries linked both ways

Showing changes from Rev 7 to Rev 8 in Grease Interceptors.

−---

−title: Grease Interceptors

−category: Plumbing

−toc_depth: 3

−description: >

− When to use: Grease interceptors and grease-removal devices that pretreat fats, oils, and grease (FOG) bearing wastewater from food-service establishments before it discharges to the sanitary building drain or public sewer. Covers hydromechanical grease interceptors (HGI) — point-of-use under-fixture units and larger flow-rated units rated per PDI G101 and ASME A112.14.3 — automatic grease removal devices (GRD) per ASME A112.14.4, and gravity grease interceptors (GGI) — large in-ground or exterior precast concrete vaults sized by liquid volume and retention time. Addresses interceptor type selection, flow-rate and volume sizing methods, flow control fittings and air intake, trapping and venting, materials, accessible covers and maintenance access, sample and monitoring ports, the connection of grease-laden fixtures, and the operations and pump-out maintenance program. Applicable to commercial kitchens, restaurants, cafeterias, institutional food service, commissaries, bakeries, and similar food-service establishments.

− Not intended for: Sanitary drain, waste, and vent piping upstream and downstream of the interceptor (see [[sync/sanitary-waste-and-vent-piping]]); plumbing fixtures, three-compartment sinks, pre-rinse units, and commercial dishwashers themselves (see [[sync/plumbing-fixtures]] and the food-service equipment scope); oil/water separators serving vehicle repair, fueling, or industrial process areas requiring petroleum-hydrocarbon separation; sand, lint, plaster, or solids interceptors; chemical, acid-neutralization, or laboratory-waste pretreatment; storm-water treatment devices; the exterior building sewer and public sewer connection (separate civil or site utility scope); and grease-laden exhaust hood and duct systems (mechanical scope).

−---

−

−# Scope {toc}

−

−## This standard covers the selection, sizing, materials, construction, installation, testing, and operation of grease interceptors and grease-removal devices that pretreat fats, oils, and grease (FOG) bearing wastewater from food-service establishments before that wastewater enters the sanitary building drain or the public sewer. {note}

−## The scope encompasses both principal device families: hydromechanical grease interceptors (HGI), including point-of-use units installed under or adjacent to a fixture and larger flow-rated units, automatic grease removal devices (GRD) that mechanically skim and remove accumulated grease, and gravity grease interceptors (GGI), which are large in-ground or exterior precast concrete vaults that separate grease and solids by quiescent retention. {note}

−

−## Interceptor type, size, location, and the fixtures connected to it are [[drawing: as indicated on the plumbing floor plans, the food-service equipment plan, and the grease waste schedule]]. {note}

−

−## Grease interceptors exist to keep congealed FOG out of the sanitary sewer; FOG discharged from a commercial kitchen cools in the drain and sewer, congeals on pipe walls, and accumulates until it restricts or blocks the line, causing sanitary sewer overflows that are both an environmental violation and a public-health hazard, which is why the local sewer authority or pretreatment program frequently dictates the type, size, location, and maintenance of the interceptor through a FOG control ordinance. {note}

−

−## The Contractor and the Engineer of Record shall treat the local FOG ordinance as a governing document that may impose requirements more stringent than the adopted plumbing code.

−

−## The Contractor and the Engineer of Record shall confirm the local FOG ordinance requirements before the interceptor type and size are finalized.

−

−## The Contractor shall coordinate the grease waste and vent piping, traps, and the connection to the sanitary building drain with [[sync/sanitary-waste-and-vent-piping]], and shall coordinate the fixtures and food-service equipment that discharge to the interceptor with [[sync/plumbing-fixtures]] and the food-service equipment scope.

−

−## This standard does not cover oil/water separators for petroleum hydrocarbons, sand or solids interceptors, chemical or acid-neutralization pretreatment, or the exterior building sewer beyond the point of connection.

−

−## Where an interceptor is required to also remove settleable solids, as with a combination grease-and-solids interceptor, the solids-handling requirements of this standard apply only to the extent they support grease separation performance.

−

−# Referenced Standards {toc}

−

−## Materials, equipment, sizing, and installation shall comply with the latest adopted edition of the following standards, codes, and the governing local FOG control ordinance, unless a specific year is cited elsewhere in the contract documents.

−

−| Standard | Title |

−|----------|-------|

−| IPC | International Plumbing Code (Chapter 10 — Traps, Interceptors, and Separators) |

−| UPC | Uniform Plumbing Code (Chapter 10 — Traps and Interceptors; Appendix H — Recommended Procedures for Sizing Gravity Grease Interceptors) |

−| Local FOG ordinance | Sewer authority / pretreatment program Fats, Oils, and Grease control ordinance for the jurisdiction |

−| PDI G101 | Testing and Rating Procedure for Hydromechanical Grease Interceptors with Appendix of Sizing and Installation Data (Plumbing and Drainage Institute) |

−| ASME A112.14.3 | Grease Interceptors (hydromechanical, Types A through D by flow control and connection method) |

−| ASME A112.14.4 | Grease Removal Devices (automatic grease removal devices, GRD) |

−| ASME A112.14.6 | FOG (Fats, Oils, and Greases) Disposal Systems |

−| CSA B481 | Grease Interceptors (test and rating procedure, harmonized with PDI G101 / ASME A112.14.3) |

−| ASTM C1613 | Standard Specification for Precast Concrete Grease Interceptor Tanks |

−| ASTM C890 | Standard Practice for Minimum Structural Design Loading for Monolithic or Sectional Precast Concrete Water and Wastewater Structures |

−| ASTM C913 | Standard Specification for Precast Concrete Water and Wastewater Structures |

−| ASTM C443 | Standard Specification for Joints for Concrete Pipe and Manholes, Using Rubber Gaskets |

−| ASTM A48 | Standard Specification for Gray Iron Castings (interceptor covers and frames) |

−| ASTM A536 | Standard Specification for Ductile Iron Castings (traffic-rated covers and frames) |

−| NSF/ANSI 14 | Plastics Piping System Components and Related Materials (plastic interceptor bodies and components) |

−| ASME A112.6.3 | Floor and Trench Drains (referenced for floor-set interceptor and drain coordination) |

−

−## Where the contract documents, a referenced standard, the adopted plumbing code, or the local sewer authority impose conflicting requirements, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.

−

−## On any matter the local FOG control ordinance addresses directly, the ordinance governs.

−

−## Where the project is located in a jurisdiction that has adopted the Uniform Plumbing Code rather than the International Plumbing Code, references to IPC chapter and section numbers shall be understood to refer to the equivalent UPC provisions.

−

−## The Contractor shall confirm the adopted plumbing code edition and obtain the current FOG control ordinance and any interceptor sizing and installation guidelines published by the sewer authority prior to submitting the plumbing permit application.

−

−# Submittals {toc}

−

−## Action Submittals {toc}

−

−### Contractor shall submit the following for the Engineer's review and comment, and for the sewer authority's approval where the FOG ordinance requires it, prior to fabrication, procurement, or installation.

−

−- Sizing calculations for the interceptor, identifying the sizing method used (IPC fixture/DFU method, UPC fixture or drainage-fixture-unit method, PDI G101 flow-rate method, or the local FOG ordinance method), the fixtures and appliances connected to the interceptor, the computed flow rate or required liquid volume, and the selected unit's rated flow rate and grease capacity

−- Product data for the grease interceptor or grease removal device, identifying the manufacturer, model, material, rated flow rate (GPM), rated grease storage capacity (lb), the applicable PDI G101 / ASME A112.14.3 type (A, B, C, or D) or ASME A112.14.4 GRD designation, the certification listing, dimensions, inlet and outlet connection sizes and invert elevations, and weight

−- Product data for the external flow control fitting and air intake, including the orifice size matched to the rated flow and the air-intake vent configuration, where a flow-controlled (Type A or Type B) hydromechanical interceptor is used

−- Shop drawings for gravity grease interceptors, including the tank dimensions, compartment configuration and baffle arrangement, liquid volume, inlet and outlet invert elevations, access manhole and riser locations, structural design loading per ASTM C890, reinforcement, and the buoyancy / anti-flotation calculation where high groundwater is present

−- Product data for access covers and frames, including the load rating (pedestrian, light-duty, or traffic-rated H-20 / HS-20), gasketing, and the gas-tight and odor-tight sealing method

−- Product data and location for the sample / monitoring port where required by the FOG ordinance, including the construction that allows the sewer authority to obtain a representative effluent sample downstream of the interceptor

−- A maintenance and operations plan describing the proposed pump-out and cleaning frequency, the basis for that frequency (the 25 percent rule or the ordinance-mandated maximum interval), the licensed waste hauler arrangement, and the recordkeeping method

−

−```datasheet

−label: Action Submittals Required

−type: checkbox

−options:

− - "Interceptor sizing calculations with method identified"

− - "Grease interceptor / GRD product data with flow and grease-capacity rating"

− - "External flow control and air intake product data"

− - "Gravity interceptor shop drawings (compartments, baffles, structural loading)"

− - "Access cover and frame product data with load rating"

− - "Sample / monitoring port product data and location"

− - "Maintenance and pump-out operations plan"

− - "Sewer authority / FOG program approval of type and size"

−default: "Interceptor sizing calculations with method identified"

−```

−

−### No interceptor shall be procured or installed until the corresponding submittals have been reviewed and returned, and until the sewer authority has approved the interceptor type and size where local approval is required.

−

−## Closeout Submittals {toc}

−

−### Contractor shall provide the following at substantial completion before the grease interceptor system is accepted.

−

−- As-built drawings showing the installed interceptor type, model, rated capacity, location, inlet and outlet invert elevations, the fixtures connected, the flow control and venting configuration, and the location of access covers and the sample port

−- Operation and maintenance data for the interceptor and, for automatic grease removal devices, the skimmer, heater, timer, and grease-collection container, including manufacturer cleaning and service instructions

−- The completed maintenance and pump-out operations plan, with the recommended baseline cleaning frequency and the recordkeeping forms or log to be maintained by the Owner

−- Field test reports for the watertightness test of gravity interceptors and the leak test of hydromechanical interceptors

−- Manufacturer warranty documentation for the interceptor body and, for GRDs, the mechanical and electrical components

−- Sewer authority discharge permit or pretreatment authorization documentation where the FOG ordinance requires the establishment to hold a permit

−

−```datasheet

−label: Closeout Submittals Required

−type: checkbox

−options:

− - "As-built drawings (type, model, capacity, inverts, fixtures, covers, sample port)"

− - "Operation and maintenance data (interceptor and GRD components)"

− - "Completed maintenance and pump-out operations plan with recordkeeping log"

− - "Field test reports (watertightness and leak tests)"

− - "Manufacturer warranty documentation"

− - "Sewer authority discharge permit / pretreatment authorization"

−default:

− - "As-built drawings (type, model, capacity, inverts, fixtures, covers, sample port)"

−```

−

−# Quality Assurance {toc}

−

−## Installer Qualifications {toc}

−

−### Grease interceptor piping and connections shall be installed by a licensed plumbing contractor and by journeymen or apprentice plumbers working under the direct supervision of a licensed journeyman.

−

−### Setting of exterior gravity grease interceptors — excavation, bedding, rigging of the precast tank, joint sealing, and backfill — shall be performed by personnel experienced in precast concrete structure installation, and the precast tank shall be set under the direction of personnel familiar with the manufacturer's rigging and joint-sealing requirements.

−

−### Automatic grease removal devices shall be installed and commissioned by personnel trained by the device manufacturer in the specific product line, because the skimmer, heater, and control timer require manufacturer setup.

−

−## Listing and Marking {toc}

−

−### Hydromechanical grease interceptors shall be tested, rated, and marked in accordance with PDI G101, ASME A112.14.3, or CSA B481, and shall bear a legible permanent marking indicating the rated flow rate in gallons per minute and the rated grease storage capacity in pounds.

−

−### Automatic grease removal devices shall be listed and marked to ASME A112.14.4.

−

−### Plastic interceptor bodies and components shall bear the NSF/ANSI 14 listing mark.

−

−### Precast concrete gravity interceptor tanks shall be manufactured by a plant certified for precast concrete production and shall be marked with the manufacturer's identification, the liquid volume, and the date of manufacture.

−

−### Interceptors that do not bear the required certification marking shall be rejected.

−

−## Sewer Authority Coordination {toc}

−

−### The Contractor shall coordinate with the local sewer authority or pretreatment program throughout the interceptor scope.

−

−### Where the FOG ordinance requires the sewer authority to approve the interceptor type and size, to inspect the installation before backfill or concealment, or to issue a discharge permit to the food-service establishment, the Contractor shall schedule those approvals and inspections.

−

−### The Contractor shall not conceal or place into service any interceptor before the required authority inspection has been completed and released.

−

−### The Contractor shall notify the Engineer of Record if the sewer authority imposes any requirement that differs from the contract documents.

−

−# Interceptor Type Selection {toc}

−

−## The two principal interceptor families serve different scales and installation conditions. {note}

−

−## The grease interceptor type shall be specified, selected to match the facility's flow scale and installation conditions.

−

−```datasheet

−label: Interceptor Type

−type: radio

−options:

− - "Hydromechanical grease interceptor (HGI) — point-of-use or flow-rated, indoor"

− - "Automatic grease removal device (GRD) — powered skimmer, indoor"

− - "Gravity grease interceptor (GGI) — exterior in-ground precast vault"

−default: "Hydromechanical grease interceptor (HGI) — point-of-use or flow-rated, indoor"

−```

−

−## Hydromechanical grease interceptors (HGI) are compact, flow-rated devices that separate grease by buoyancy and baffling at relatively high flow velocity; they install at or near the point of use, indoors, and are rated by flow rate and grease capacity. {note}

−

−## Gravity grease interceptors (GGI) are large in-ground or exterior vaults that separate grease and solids by quiescent retention over a defined retention time; they are sized by liquid volume and serve an entire kitchen or multiple establishments. {note}

−

−## Automatic grease removal devices (GRD) are hydromechanical interceptors fitted with a powered skimmer that continuously or periodically removes accumulated grease into a collection container, reducing the manual cleaning burden. {note}

−

−## The selection between HGI and GGI is driven by the connected load, the available indoor space, the local FOG ordinance, and the sewer authority's preference; many jurisdictions mandate an exterior gravity interceptor of a minimum volume for any establishment with a commercial kitchen, and permit hydromechanical interceptors only for limited fixture counts or for tenant build-outs where an exterior vault is impractical. {note}

−

−## The Contractor shall confirm the permitted interceptor types with the sewer authority before selection.

−

−## Application Guidance {toc}

−

−### Hydromechanical interceptors are appropriate for tenant restaurants, coffee shops, single-fixture installations, and kitchens with a modest connected fixture count where an exterior vault is not required by the ordinance and where the unit can be located within reach for regular manual cleaning; they occupy little space and have a low first cost, but require frequent manual cleaning — often weekly — to maintain separation efficiency, because their small grease capacity fills quickly under restaurant loads. {note}

−

−### Gravity grease interceptors are appropriate for full-service commercial kitchens, cafeterias, institutional food service, commissaries, and any establishment for which the ordinance mandates an exterior vault; their large liquid volume provides long retention time and high grease and solids storage, which extends the cleaning interval to monthly or quarterly, but they require exterior space, are costly to install, and require pump-out by a licensed liquid-waste hauler. {note}

−

−### Automatic grease removal devices are appropriate where space is limited but a high cleaning frequency is undesirable, such as in high-volume kitchens where manual cleaning of a small hydromechanical unit would otherwise be required several times per week; their higher first cost and the maintenance of the powered skimmer are offset by reduced manual labor and more consistent effluent quality. {note}

−

−# Interceptor Sizing Method {toc}

−

−```datasheet

−label: Sizing Method

−type: select

−options:

− - "Local FOG ordinance method (governs where prescribed)"

− - "IPC fixture / drainage-fixture-unit method (Chapter 10)"

− - "UPC fixture-count or DFU method (Chapter 10)"

− - "UPC Appendix H method (gravity interceptor volume)"

− - "PDI G101 flow-rate method (hydromechanical)"

−default: "Local FOG ordinance method (governs where prescribed)"

−```

−

−## The interceptor shall be sized by the method required by the local FOG control ordinance.

−

−## Where the ordinance does not prescribe a method, the interceptor shall be sized by the method in the adopted plumbing code.

−

−## The Contractor shall not reduce the interceptor size below the size the ordinance or code requires, and shall submit the sizing calculation for review.

−

−## The hydromechanical unit shall be matched to the connected load, not arbitrarily enlarged.

−

−## Oversizing a hydromechanical interceptor degrades performance, because at flows well below the rated flow the unit loses the velocity and baffling action it relies on; gravity interceptors, by contrast, benefit from generous volume because retention time and storage both improve with size. {note}

−

−# Hydromechanical Interceptor Flow Rate and Grease Capacity {toc}

−

−```datasheet

−label: Hydromechanical Interceptor Rated Flow

−type: select

−unit: GPM

−drawing_ref: true

−options:

− - "4 GPM (single point-of-use fixture)"

− - "7 GPM"

− - "10 GPM"

− - "15 GPM"

− - "20 GPM"

− - "25 GPM"

− - "35 GPM"

− - "50 GPM"

− - "75 GPM"

− - "100 GPM"

−default: deferred

−```

−

−```datasheet

−label: Hydromechanical Grease Storage Capacity

−type: select

−unit: lb

−options:

− - "Minimum 2 lb per GPM of rated flow (rating-standard minimum)"

− - "Enhanced capacity (greater than 2 lb per GPM, extended cleaning interval)"

−default: "Minimum 2 lb per GPM of rated flow (rating-standard minimum)"

−```

−

−## Hydromechanical interceptors shall be rated by flow rate in gallons per minute (GPM) and by grease storage capacity in pounds (lb), determined by test in accordance with PDI G101 or ASME A112.14.3.

−

−## The rated flow shall equal or exceed the computed drainage flow rate from the connected fixtures, determined either from the fixture drain rate or from the drainage fixture unit load converted to GPM by the method in the adopted code.

−

−## Where the connected fixtures have no assigned drainage fixture unit value, the flow rate shall be computed from the known fixture discharge rate.

−

−## The grease storage capacity rating shall comply with the minimum ratio established by the rating standard, which requires not less than 2 pounds of grease storage capacity for each gallon per minute of rated flow.

−

−## The grease capacity determines how long the unit can operate between cleanings before separation efficiency falls; a 20 GPM unit therefore provides at least 40 lb of grease capacity, a 50 GPM unit at least 100 lb, and a higher grease capacity at a given flow rate extends the maintenance interval and is preferred where the cleaning interval is a concern. {note}

−

−# Gravity Interceptor Liquid Volume {toc}

−

−```datasheet

−label: Gravity Interceptor Liquid Volume

−type: select

−unit: gal

−drawing_ref: true

−options:

− - "500 gal"

− - "750 gal"

− - "1000 gal"

− - "1500 gal"

− - "2000 gal"

− - "3000 gal"

−default: deferred

−```

−

−```datasheet

−label: Gravity Interceptor Compartments

−type: radio

−options:

− - "Two compartments (standard minimum)"

− - "Three compartments (enhanced separation, where required by ordinance)"

−default: "Two compartments (standard minimum)"

−```

−

−## Gravity grease interceptors shall be sized by liquid volume to provide the retention time required by the adopted code or FOG ordinance.

−

−## The minimum liquid volume and the number of compartments shall not be less than the values required by the governing ordinance.

−

−## The minimum liquid volume of a gravity grease interceptor shall be not less than 500 gallons unless the governing ordinance permits a smaller vault.

−

−## Gravity interceptors shall have not fewer than two compartments separated by a baffle wall, with the inlet to the first compartment and the outlet from the second.

−

−## The Uniform Plumbing Code recognizes a 30-minute retention time, and the UPC Appendix H method and the National Precast Concrete Association sizing procedure compute the required liquid volume from the drainage fixture units or the known fixture flow rate multiplied by the retention time, with adjustments for the establishment type and operating hours; many ordinances establish a 750-gallon or 1000-gallon minimum for any commercial kitchen. {note}

−

−## The two-compartment arrangement allows grease to rise and solids to settle in the first compartment while the second compartment provides a quiescent zone that polishes the effluent before discharge. {note}

−

−# Hydromechanical Grease Interceptors {toc}

−

−## Body Construction, Material, and Location {toc}

−

−```datasheet

−label: Hydromechanical Interceptor Body Material

−type: radio

−options:

− - "Coated fabricated steel"

− - "Stainless steel (Type 304)"

− - "Polyethylene / polypropylene (NSF/ANSI 14 listed)"

− - "Cast iron"

−default: "Polyethylene / polypropylene (NSF/ANSI 14 listed)"

−```

−

−```datasheet

−label: Hydromechanical Interceptor Installation Location

−type: select

−options:

− - "On-floor, adjacent to fixture (above-floor)"

− - "Partially recessed / semi-recessed in floor"

− - "Flush-with-floor (in-floor, traffic-rated cover)"

− - "Suspended / under-counter"

−default: "On-floor, adjacent to fixture (above-floor)"

−```

−

−### Hydromechanical grease interceptors shall be of welded or molded one-piece construction with internal baffles that direct the incoming flow downward and force the wastewater to follow a path that promotes grease flotation and solids settling before the effluent leaves through the outlet.

−

−### The interceptor shall include a removable cover with a gas-tight and odor-tight seal, an integral or separate flow control, and internal air-relief or anti-siphon features as required by the design type.

−

−### The interceptor body shall be corrosion-resistant for the service life of the installation.

−

−### Polyethylene and polypropylene interceptors shall be NSF/ANSI 14 listed and rated for the installation location, including for in-floor or on-floor service as applicable.

−

−### Coated fabricated steel interceptors are the traditional under-fixture material and are economical, but the coating is the only corrosion barrier and is vulnerable to abrasion during cleaning; stainless steel resists corrosion and cleans well, and is preferred where the interceptor is exposed in a finished kitchen or where long life is required; polyethylene and polypropylene interceptors are corrosion-proof, lightweight, and dominate the current point-of-use and larger flow-rated market; cast iron is durable and heavy but is the least common modern choice for hydromechanical units. {note}

−

−## Flow Control Fitting and Air Intake {toc}

−

−```datasheet

−label: Flow Control and Air Intake Type (ASME A112.14.3 / PDI G101)

−type: radio

−options:

− - "Type A — external flow control with air intake (vent), directly connected"

− - "Type B — external flow control without air intake, directly connected"

− - "Type C — no external flow control, directly connected"

− - "Type D — no external flow control, indirectly connected"

−default: "Type A — external flow control with air intake (vent), directly connected"

−```

−

−### A flow-controlled hydromechanical interceptor (PDI G101 / ASME A112.14.3 Type A or Type B) shall be installed with an external flow control fitting on the inlet side, sized with an orifice matched to the interceptor's rated flow.

−

−### The flow control orifice shall match the rated flow of the interceptor.

−

−### The flow control limits the rate at which wastewater enters the interceptor so that the unit is never overwhelmed by a slug discharge that would carry grease through before it can separate; an unmatched or omitted flow control causes the interceptor to fail under peak fixture discharge. {note}

−

−### The air intake of a Type A flow control shall be vented to atmosphere or to the vent system, shall terminate above the flood-level rim of the highest connected fixture, and shall not be capped, plugged, or omitted.

−

−### The flow control type shall be the type the interceptor manufacturer specifies for the rated flow and the connection method used.

−

−### As wastewater accelerates through the flow-control orifice of a Type A interceptor it creates a negative pressure that draws air through the air intake, and that entrained air mixes with the wastewater and improves grease separation as the flow enters the interceptor; a Type A interceptor with a sealed or missing air intake does not perform to its rating. {note}

−

−## Automatic Grease Removal Devices {toc}

−

−```datasheet

−label: Automatic Grease Removal Device Skimming Control

−type: radio

−options:

− - "Programmable timer-initiated skimming cycle"

− - "Sensor-initiated skimming (grease-layer thickness sensing)"

−default: "Programmable timer-initiated skimming cycle"

−```

−

−### Where an automatic grease removal device (GRD) is specified, the device shall conform to ASME A112.14.4 and shall automatically remove free-floating grease from the interceptor into a collection container without user intervention except for periodic emptying of the container and routine service.

−

−### The GRD shall include a heating element to liquefy the accumulated grease layer, a powered skimmer or draw-off mechanism, a control timer that initiates the skimming cycle on a programmable schedule, and a removable grease-collection container.

−

−### The control system shall be supplied from a dedicated circuit coordinated with the electrical scope.

−

−### The grease-collection container shall be sized for the establishment's grease load and the desired emptying interval, and shall be readily accessible for removal and emptying by kitchen staff.

−

−### The Contractor shall set the skimming schedule during commissioning to match the establishment's operating hours so that skimming occurs after peak meal-service periods when the grease layer is thickest.

−

−# Gravity Grease Interceptors {toc}

−

−## Tank Construction {toc}

−

−```datasheet

−label: Gravity Interceptor Tank Material

−type: radio

−options:

− - "Precast concrete (ASTM C1613)"

− - "Fiberglass-reinforced plastic (FRP)"

− - "High-density polyethylene (HDPE)"

−default: "Precast concrete (ASTM C1613)"

−```

−

−### Gravity grease interceptors shall be precast concrete tanks conforming to ASTM C1613, designed for the imposed structural loads in accordance with ASTM C890 and manufactured in accordance with ASTM C913.

−

−### The tank shall be watertight, with monolithic or sectional construction.

−

−### Sectional joints between the base, mid-section, and top shall be sealed with a preformed flexible joint sealant or a rubber gasket conforming to ASTM C443 to achieve a watertight, gas-tight joint.

−

−### The tank shall have a structural design rating appropriate to its location, accounting for the depth of cover, the groundwater condition, and any vehicular loading above the tank.

−

−### Precast concrete is the standard material for exterior in-ground gravity interceptors because of its mass, structural strength, resistance to flotation, and long service life; fiberglass-reinforced plastic and high-density polyethylene tanks are lighter, corrosion-proof, and may be selected where site access limits the weight that can be set or where soil chemistry is aggressive to concrete, but a lightweight tank requires an engineered anti-flotation design where groundwater can rise to the tank, because an empty lightweight tank will float. {note}

−

−## Structural Loading and Anti-Flotation {toc}

−

−```datasheet

−label: Gravity Interceptor Surface Loading

−type: radio

−options:

− - "Non-traffic (landscaped or pedestrian area)"

− - "Traffic-rated H-20 / HS-20 (driveway, parking, or drive lane)"

−default: "Non-traffic (landscaped or pedestrian area)"

−```

−

−### The tank and its access risers and covers shall be designed for the loads imposed by the depth of burial, the soil, the groundwater, and any traffic above the tank.

−

−### Where the interceptor is located under a driveway, parking area, or other area subject to vehicle traffic, the tank, risers, and covers shall be traffic-rated for AASHTO H-20 / HS-20 loading.

−

−### Where groundwater can rise above the tank base, the Contractor shall provide anti-flotation restraint — an extended base slab, anti-flotation ballast, or tie-downs — designed so that the empty tank does not float, in accordance with the shop drawing buoyancy calculation reviewed by the structural engineer of record.

−

−## Inlet and Outlet Configuration {toc}

−

−### The inlet and outlet of a gravity interceptor shall be fitted with sanitary tees or submerged elbows that direct the inlet flow downward below the floating grease layer and draw the outlet flow from below the grease layer, so that the floating grease is retained in the tank and only the clarified middle layer of wastewater discharges.

−

−### The inlet invert shall be set above the outlet invert by the amount the tank manufacturer specifies to establish the flow gradient through the tank.

−

−### The inlet and outlet inverts and the connecting piping slope shall be [[drawing: as indicated on the plumbing and civil drawings]].

−

−# Connection of Fixtures {toc}

−

−## Permitted Connections {toc}

−

−```datasheet

−label: Fixtures Connected to Interceptor

−type: checkbox

−drawing_ref: true

−options:

− - "Three-compartment / scullery sink"

− - "Pot and pan sink"

− - "Pre-rinse station"

− - "Wok range / kettle drains"

− - "Mop sink (kitchen cleanup)"

− - "Kitchen floor drains and floor sinks"

− - "Food-preparation equipment indirect drains"

−default: "Three-compartment / scullery sink"

−```

−

−### Only fixtures and appliances that discharge grease-laden wastewater shall be connected to the grease interceptor; these typically include pot and pan sinks, three-compartment scullery sinks, pre-rinse stations, wok ranges and kettle drains, mop sinks used for kitchen cleanup, floor drains and floor sinks in food-preparation and dishwashing areas, and the indirect drains from food-preparation equipment.

−

−### The fixtures connected to the interceptor are [[drawing: as indicated on the food-service equipment plan and the grease waste schedule]].

−

−## Prohibited Connections {toc}

−

−```datasheet

−label: Food-Waste Grinder Connection

−type: radio

−options:

− - "No food-waste grinder discharges to the interceptor"

− - "Grinder permitted by ordinance — discharges to interceptor with separate solids handling"

−default: "No food-waste grinder discharges to the interceptor"

−```

−

−```datasheet

−label: Commercial Dishwasher Connection

−type: radio

−options:

− - "Dishwasher bypasses interceptor (discharges to sanitary building drain)"

− - "Dishwasher discharges to interceptor (where required by ordinance)"

−default: "Dishwasher bypasses interceptor (discharges to sanitary building drain)"

−```

−

−### Sanitary waste from water closets, urinals, and other plumbing fixtures that carry human waste shall never be connected to a grease interceptor; sanitary sewage must bypass the interceptor and discharge directly to the building drain.

−

−### Stormwater, condensate, and other non-grease wastewater shall not be connected to the interceptor, because diluting flows reduce retention time and degrade separation.

−

−### Food-waste grinders (garbage disposers) shall not discharge to a grease interceptor unless the governing FOG ordinance and the adopted code specifically permit it.

−

−### Commercial dishwasher discharge shall be connected to the grease interceptor only where the governing ordinance permits it.

−

−### The Contractor shall confirm the treatment of food-waste grinders and dishwasher discharge with the sewer authority before connecting either to the interceptor.

−

−### Connecting sanitary waste to a grease interceptor is a code violation and renders the interceptor effluent septic; macerated food solids from a grinder overload the interceptor and many jurisdictions prohibit grinders ahead of an interceptor or require a separately sized solids interceptor, and some jurisdictions exclude dishwasher discharge because the high temperature and detergent emulsify grease and carry it through the interceptor, while others require it to be connected. {note}

−

−# Trapping and Venting {toc}

−

−## Fixture Trapping {toc}

−

−### Each fixture discharging to the grease interceptor shall be individually trapped and vented in accordance with the adopted plumbing code and [[sync/sanitary-waste-and-vent-piping]].

−

−### The interceptor is not a trap and shall not be relied upon to provide the trap seal for the connected fixtures.

−

−### Where a hydromechanical interceptor has an integral trap on its outlet, no additional trap shall be installed downstream that would create a double trap.

−

−### Where the interceptor does not have an integral trap, a trap shall be provided on the interceptor outlet as required by code.

−

−## Interceptor Venting {toc}

−

−```datasheet

−label: Interceptor Venting Configuration

−type: select

−drawing_ref: true

−options:

− - "Flow-control air intake vent plus downstream outlet vent (hydromechanical Type A)"

− - "Downstream outlet vent only (hydromechanical Type B / C)"

− - "Vented access risers (gravity interceptor)"

− - "Dedicated vent connection (gravity interceptor)"

−default: deferred

−```

−

−### The grease interceptor shall be vented in accordance with the adopted plumbing code.

−

−### A flow-controlled hydromechanical interceptor of Type A shall have its flow-control air intake vented as described in the flow control section.

−

−### The interceptor outlet shall be vented downstream so that the discharge does not siphon the interceptor or the connected fixture traps, and so that air can move freely through the interceptor as wastewater flows.

−

−### Gravity interceptors shall be vented through the access risers or a dedicated vent connection as the code and the tank manufacturer require, so that gases generated within the tank are relieved and the tank does not become pressurized or develop a vacuum during flow.

−

−# Access and Monitoring {toc}

−

−## Access Covers {toc}

−

−```datasheet

−label: Gravity Interceptor Access Cover Material

−type: radio

−options:

− - "Gray iron (ASTM A48) — non-traffic"

− - "Ductile iron (ASTM A536) — traffic-rated"

− - "Coated steel"

−default: "Ductile iron (ASTM A536) — traffic-rated"

−```

−

−```datasheet

−label: Access Riser / Manhole Clear Opening

−type: range

−unit: in

−options:

− min: 18

− max: 36

− setpoints: [18, 20, 24, 30, 36]

−default: 24

−```

−

−### Every grease interceptor shall be provided with access covers that permit complete inspection, cleaning, and pump-out of every compartment without removing permanent construction.

−

−### Hydromechanical interceptor covers shall seal gas-tight and odor-tight and shall be removable by hand or with simple tools for routine cleaning.

−

−### Gravity interceptor access manholes shall extend to finished grade with risers, shall be located over the inlet, the outlet, and each compartment, and shall be fitted with gas-tight, odor-tight covers.

−

−### Covers in traffic areas shall be traffic-rated to match the tank loading.

−

−### Access manholes and risers shall be sized to permit a cleaning hose and pump-out equipment to reach the bottom of each compartment.

−

−### The Contractor shall confirm that the access provided allows a liquid-waste hauler to fully evacuate and clean the tank.

−

−### Risers that are too small or covers that cannot be opened without special equipment defeat the maintenance program. {note}

−

−## Sample and Monitoring Port {toc}

−

−```datasheet

−label: Effluent Sample / Monitoring Port

−type: radio

−options:

− - "Required by FOG ordinance — provided downstream of interceptor outlet"

− - "Not required by ordinance"

−default: "Required by FOG ordinance — provided downstream of interceptor outlet"

−```

−

−### Where the FOG control ordinance requires the sewer authority to obtain effluent samples, a sample port or monitoring structure shall be provided on the interceptor outlet, downstream of the interceptor and upstream of the connection to the building drain or sewer, so that a representative sample of the treated effluent can be drawn.

−

−### The sample port shall be accessible to the sewer authority without entering the establishment and shall be located and constructed [[drawing: as indicated on the plumbing and civil drawings]] to suit the authority's requirements.

−

−# Installation {toc}

−

−## Hydromechanical Interceptor Installation {toc}

−

−### Hydromechanical interceptors shall be installed level on a firm, supporting surface in the location shown on the drawings, with adequate clearance around and above the unit for cover removal and manual cleaning.

−

−### The interceptor shall be installed so that the inlet and outlet inverts establish the correct flow direction and so that the flow control fitting is upstream of the inlet at the elevation the manufacturer specifies.

−

−### Under-fixture and on-floor units shall be located where the floor can be cleaned around them and where staff can reach the cover for the frequent cleaning these units require.

−

−### In-floor flush units shall be set with the cover flush with the finished floor and shall be sealed to the floor so that floor washdown does not enter the cover seam.

−

−## Gravity Interceptor Installation {toc}

−

−```datasheet

−label: Gravity Interceptor Bedding

−type: radio

−drawing_ref: "structural / geotechnical drawings"

−options:

− - "Compacted granular bedding on prepared subgrade"

− - "Concrete leveling slab beneath tank"

−default: "Compacted granular bedding on prepared subgrade"

−```

−

−### Exterior gravity interceptors shall be set on a compacted, level bedding of granular material prepared to the dimensions and bearing capacity required by the tank shop drawings and the geotechnical recommendations.

−

−### The excavation shall be dewatered as required so that the tank is set on dry, stable bedding.

−

−### The tank shall be rigged and set in accordance with the manufacturer's lifting instructions, and sectional joints shall be sealed before the inlet and outlet piping is connected.

−

−### Backfill shall be placed and compacted uniformly around the tank in lifts so that the tank is not displaced, and anti-flotation restraint shall be in place before backfilling where groundwater is a concern.

−

−### The interceptor shall be located the minimum distance from the building required by the code and the ordinance, accessible to a pump-out truck, and clear of building footings, other utilities, and the water service.

−

−## Piping Slope and Connection {toc}

−

−### The grease waste piping from the connected fixtures to the interceptor, and from the interceptor outlet to the building drain or sewer, shall be sloped and installed in accordance with [[sync/sanitary-waste-and-vent-piping]].

−

−### The Contractor shall maintain uniform slope without sags, because grease waste piping is especially sensitive to inadequate slope as cooling grease deposits in any low spot or flat run.

−

−### The piping material between the fixtures and the interceptor, and downstream of the interceptor, shall be as indicated on the drawings and compatible with grease-laden waste at the temperatures discharged by the connected fixtures.

−

−# Testing and Commissioning {toc}

−

−## Watertightness and Leak Testing {toc}

−

−```datasheet

−label: Gravity Interceptor Watertightness Test

−type: radio

−options:

− - "Fill-and-observe water test to outlet invert (per manufacturer / authority)"

− - "Vacuum test (where specified for the tank type)"

−default: "Fill-and-observe water test to outlet invert (per manufacturer / authority)"

−```

−

−### Gravity grease interceptor tanks shall be tested for watertightness before being placed in service and before backfill conceals the tank joints, by filling the tank with water to the outlet invert and observing for leakage over the test period required by the tank manufacturer and the sewer authority.

−

−### Any leakage at joints, penetrations, or the tank body shall be repaired and the tank re-tested.

−

−### Hydromechanical interceptors and grease removal devices shall be checked for leak-free connections at the inlet, outlet, cover, and flow control after installation.

−

−## Commissioning and Initial Fill {toc}

−

−### Before the establishment is placed into service, the interceptor shall be filled with clean water to the operating level so that the grease-flotation and effluent-draw geometry functions from the first discharge.

−

−### For automatic grease removal devices, the Contractor shall verify operation of the heater, skimmer, timer, and grease-collection mechanism, and shall set the skimming schedule for the establishment's operating hours during commissioning.

−

−### An empty interceptor placed into service passes grease straight through until it fills. {note}

−

−## Functional Verification {toc}

−

−### After installation, the Contractor shall verify that the interceptor receives flow only from the permitted grease-bearing fixtures and that no sanitary waste, stormwater, or prohibited connection has been made.

−

−### The Contractor shall verify that the flow control fitting and air intake are installed and unobstructed on flow-controlled hydromechanical units, that the venting is connected, and that all access covers seal and open as intended.

−

−# Operation and Maintenance {toc}

−

−## Maintenance Program {toc}

−

−```datasheet

−label: Maintenance Trigger

−type: radio

−options:

− - "25 percent rule — clean when grease plus solids reach 25 percent of liquid depth"

− - "Fixed maximum interval per FOG ordinance"

− - "Whichever of the 25 percent rule or the ordinance interval occurs first"

−default: "Whichever of the 25 percent rule or the ordinance interval occurs first"

−```

−

−```datasheet

−label: Baseline Cleaning Interval

−type: select

−options:

− - "Weekly (small hydromechanical point-of-use unit)"

− - "Monthly (larger hydromechanical unit)"

− - "Quarterly / every 90 days (gravity interceptor)"

− - "Per FOG ordinance and 25 percent rule (verify in service)"

−default: "Per FOG ordinance and 25 percent rule (verify in service)"

−```

−

−### The Owner shall maintain the grease interceptor on a schedule that keeps it functioning within its rated separation efficiency and that complies with the FOG control ordinance.

−

−### Under the 25 percent rule, the interceptor shall be fully pumped out and cleaned whenever the combined thickness of the floating grease layer and the settled solids layer reaches 25 percent of the total liquid depth.

−

−### Where the ordinance imposes a maximum interval, that interval applies regardless of the measured accumulation, and whichever trigger occurs first governs.

−

−### The ordinance maximum interval is commonly 90 days for a gravity interceptor at a food-service establishment, and as frequently as weekly for a small hydromechanical unit. {note}

−

−## Full Pump-Out and Cleaning {toc}

−

−### Gravity grease interceptors shall be fully pumped out — all liquid, floating grease, and settled solids removed — by a licensed liquid-waste hauler, not merely skimmed of the surface grease.

−

−### The hauled waste shall be disposed of at a permitted facility and disposal records retained.

−

−### Hydromechanical interceptors shall be fully emptied and the baffles and interior cleaned at each service.

−

−### Automatic grease removal devices require periodic emptying of the grease-collection container and periodic full cleaning of the interceptor body in addition to the automatic skimming.

−

−### Partial skimming that leaves the wastewater and solids in the tank is not compliant cleaning and allows solids to accumulate and reduce capacity. {note}

−

−## Prohibited Additives {toc}

−

−### Chemical, enzyme, solvent, and bacterial additives intended to dissolve, emulsify, or digest grease shall not be used.

−

−### Maintenance shall consist of physical removal of the accumulated grease and solids, not chemical treatment.

−

−### Additives do not remove grease from the waste stream; they liquefy or suspend it so that it passes through the interceptor and congeals downstream in the sewer, defeating the purpose of the interceptor, and most FOG ordinances prohibit additives outright. {note}

−

−## Recordkeeping {toc}

−

−### The Owner shall maintain a maintenance log recording the date of each cleaning, the measured grease and solids accumulation at the time of cleaning, the volume of waste removed, the name of the licensed hauler, and the disposal location, and shall retain the records and manifests for the period the FOG ordinance requires.

−

−### The maintenance log shall be available for inspection by the sewer authority.

−

−### The Contractor shall furnish the initial log forms and the recommended baseline cleaning interval as part of the closeout documentation.

−

−# Identification and Labeling {toc}

−

−```datasheet

−label: Grease Interceptor Cover Marking

−type: radio

−options:

− - "Cover cast or permanently marked 'GREASE INTERCEPTOR'"

− - "Surface-applied marker / tag"

−default: "Cover cast or permanently marked 'GREASE INTERCEPTOR'"

−```

−

−## The grease interceptor and its access covers shall be identified so that maintenance personnel and the sewer authority can locate and identify the unit.

−

−## Exterior gravity interceptor covers shall be marked to indicate that the structure is a grease interceptor.

−

−## Interior grease waste piping shall be identified in accordance with [[sync/sanitary-waste-and-vent-piping]] and distinguished from sanitary waste piping so that the grease waste system is not inadvertently cross-connected to sanitary waste during future work.

−

−# Delivery, Storage, and Handling {toc}

−

−## Interceptors and grease removal devices shall be delivered in the manufacturer's packaging with rating and listing markings intact, and shall be inspected on delivery for damage to the body, covers, flow control, and connections.

−

−## Damaged units shall not be installed.

−

−## Plastic interceptors shall be stored out of direct sunlight, because ultraviolet exposure degrades the material.

−

−## Precast concrete tanks shall be handled with the manufacturer's lifting points and shall not be rolled, dropped, or set on point loads that could crack the tank.

−

−## Automatic grease removal devices contain electrical and mechanical components and shall be stored dry and protected from impact until installed.

−

−# Warranty {toc}

−

−```datasheet

−label: Installation Warranty Period

−type: select

−options:

− - "1 year from substantial completion"

− - "2 years from substantial completion"

−default: "1 year from substantial completion"

−```

−

−## The Contractor shall warrant all materials and installation covered by this standard against defects in workmanship and against leakage for the project warranty period following substantial completion.

−

−## The warranty shall cover the interceptor body, covers, flow control, connections, and, for gravity interceptors, the watertightness of the tank and joints.

−

−## Manufacturer warranties for the interceptor body and, for automatic grease removal devices, the heater, skimmer, motor, and controls shall be passed through to the Owner as part of the closeout documentation.

−

−## Where a manufacturer warranty extends beyond the Contractor's installation warranty period, the Contractor shall assign and transfer the manufacturer warranty to the Owner at closeout.

−

−## The warranty shall not limit or replace the Contractor's obligation to comply with all applicable code and FOG ordinance requirements and the requirements of this standard.

+---

+title: Grease Interceptors

+category: Plumbing

+description: >

+ When to use: Grease interceptors that pretreat the fats, oils, and grease carried by the drainage from commercial kitchens, cafeterias, commissaries, bakeries, and other food-service operations before that drainage reaches the sanitary building drain: hydromechanical grease interceptors rated under PDI G101 and ASME A112.14.3, automatic grease removal devices under ASME A112.14.4, and gravity grease interceptors of precast concrete, cast-in-place concrete, fiberglass, or polyethylene. Covers the interceptor types furnished, the sizing method and the inputs it needs, the flow control fitting and air intake, body and tank materials, structural loading and anti-flotation of buried tanks, inlet and outlet fittings, access risers and covers, venting, the effluent sampling point, which fixtures and appliances connect to the interceptor, the grease waste pipe material and slope between those fixtures and the interceptor, setting and testing, and the pump-out program the Owner carries after acceptance.

+ Not intended for: The sanitary drain, waste, and vent pipe, fittings, joints, hangers, cleanouts, traps, and field tests upstream of the fixture drain outlets and beyond the interceptor outlet fitting ([[sync/sanitary-waste-and-vent-piping]]); the three-compartment sinks, pre-rinse assemblies, warewashers, and cooking appliances that drain to the interceptor ([[sync/foodservice-equipment]]); hand sinks, mop basins, and other plumbing fixtures ([[sync/plumbing-fixtures]]); the floor drains and floor sinks that collect kitchen washdown ([[sync/trench-drains-and-interceptors]] and [[sync/plumbing-specialties]]); the ejector that lifts pretreated effluent to the building drain where gravity flow is not available ([[sync/sump-and-sewage-pumps]]); the building sewer and the site sanitary sewer beyond five feet outside the foundation wall ([[sync/sanitary-sewer-systems]]); excavation, bedding, backfill, and dewatering for a buried tank ([[sync/earthwork]] and [[sync/excavation-support-and-dewatering]]); oil and water separators for vehicle service, fueling, and industrial process areas; sand, lint, plaster, and solids interceptors not serving a grease interceptor; the hoods, ducts, and grease collection of the kitchen exhaust ([[sync/kitchen-exhaust-systems]]); and pipe markers on the grease waste pipe ([[sync/plumbing-piping-identification]]).

+---

+# Scope {toc}

+## This standard governs the selection, sizing basis, materials, setting, testing, and maintenance program of the grease interceptors that separate fats, oils, and grease from kitchen drainage before it enters the sanitary building drain. {note}

+## The scope begins at the drain outlet of each fixture and appliance that discharges to the interceptor and ends at the interceptor outlet fitting, or at the effluent sampling point where one is furnished beyond the outlet. Within those limits it covers the grease waste pipe material and slope, the flow control fitting and its air intake, the interceptor body or tank with its baffles, inlet and outlet fittings, risers, and covers, the vent connections the interceptor needs, and the sampling point. {note}

+## The following are outside this standard: {note}

+- Sanitary drain, waste, and vent pipe, fittings, joints, hangers, cleanouts, traps, and field tests upstream of the fixture drain outlets and beyond the interceptor outlet fitting

+- The sinks, warewashers, and cooking appliances that drain to the interceptor, and the hand sinks and mop basins that do not

+- The floor drains and floor sinks in the kitchen, which this standard connects or excludes but does not specify

+- The ejector that lifts pretreated effluent where the interceptor outlet cannot reach the building drain by gravity

+- The building sewer and the site sanitary sewer beyond five feet outside the foundation wall

+- Excavation, bedding, backfill, and dewatering for a buried tank

+- Oil and water separators serving vehicle service, fueling, and industrial process areas

+- Sand, lint, plaster, and solids interceptors that do not serve a grease interceptor

+- Kitchen exhaust hoods, grease ducts, and the grease collected from them

+## Grease leaves a kitchen as a warm liquid and arrives in the sewer as a solid: it cools on the way, congeals on the pipe wall, and builds up until the line blocks and sanitary sewage surfaces in a street or a basement. The interceptor is the one point where that grease can be held while it is still warm enough to float free of the water, and the sewer authority's pretreatment ordinance exists because every interceptor that is undersized, bypassed, or never pumped turns into a blockage that the authority pays to clear. {note}

+## The pretreatment ordinance of the sewer authority having jurisdiction shall be treated as a Contract Document for the interceptor work, and where it is more stringent than the adopted plumbing code or this standard, the ordinance shall govern.

+## The Contractor shall obtain the current pretreatment ordinance and any sizing, installation, and sampling guidance the sewer authority publishes before the interceptor submittals are prepared.

+## Interceptor locations shall be as indicated on [[drawing: the plumbing floor plans]].

+## Interceptor sizes are a project quantity: they follow from the fixtures and appliances connected, their drain rates, the hours and type of operation, and the method the ordinance or the adopted plumbing code prescribes, so this standard sets what each interceptor must be and leaves its rated flow or liquid volume to the drawings. {note}

+## The Contractor shall report to the Engineer of Record any interceptor size shown on the drawings that does not agree with the sizing calculation submitted under this standard, before the interceptor is procured.

+# Referenced Standards {toc}

+## Interceptors, fittings, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited.

+## Where the Contract Documents, the adopted plumbing code, the pretreatment ordinance, and the referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.

+| Standard | Title |

+|----------|-------|

+| IPC | International Plumbing Code (Chapter 10, Traps, Interceptors and Separators) |

+| UPC | Uniform Plumbing Code (Chapter 10, Traps and Interceptors) |

+| PDI G101 | Testing and Rating Procedure for Hydro Mechanical Grease Interceptors with Appendix of Installation and Maintenance |

+| ASME A112.14.3 | Hydromechanical Grease Interceptors |

+| ASME A112.14.4 | Grease Removal Devices |

+| ASME A112.14.6 | FOG (Fats, Oils, and Greases) Disposal Systems |

+| CSA B481 | Grease Interceptors |

+| IAPMO/ANSI Z1001 | Prefabricated Gravity Grease Interceptors |

+| ASTM C1613 | Precast Concrete Grease Interceptor Tanks |

+| ASTM C890 | Minimum Structural Design Loading for Monolithic or Sectional Precast Concrete Water and Wastewater Structures |

+| ASTM C913 | Precast Concrete Water and Wastewater Structures |

+| ASTM C443 | Joints for Concrete Pipe and Manholes, Using Rubber Gaskets |

+| ASTM C990 | Joints for Concrete Pipe, Manholes, and Precast Box Sections Using Preformed Flexible Joint Sealants |

+| ASTM A48/A48M | Gray Iron Castings |

+| ASTM A536 | Ductile Iron Castings |

+| AASHTO LRFD | AASHTO LRFD Bridge Design Specifications (vehicular design loading of buried structures and castings) |

+| NEMA 250 | Enclosures for Electrical Equipment (1000 Volts Maximum) |

+## Where the project is in a jurisdiction that has adopted the Uniform Plumbing Code, a reference in this standard to a provision of the International Plumbing Code shall be read as the corresponding provision of the Uniform Plumbing Code.

+# Submittals {toc}

+## Action Submittals {toc}

+### The Contractor shall submit the following for the Engineer of Record's review before any interceptor is procured:

+- The interceptor sizing calculation, stating the method used, each fixture and appliance connected to each interceptor with its drain rate or drainage fixture unit value, the operating hours and type of operation where the method uses them, the computed flow rate or liquid volume, and the rated flow or liquid volume of the unit proposed

+- Product data for each hydromechanical grease interceptor and grease removal device, identifying the rating standard, the certified flow rate and grease capacity, the flow control type, the body material, the dimensions, the inlet and outlet sizes and invert elevations, the cover and its load rating, and the empty and operating weights

+- Product data for each flow control fitting, identifying the orifice size and the rated flow it corresponds to, and the air intake arrangement

+- Shop drawings for each gravity grease interceptor, showing the tank dimensions, the liquid volume, the compartments and baffles, the inlet and outlet fittings and their invert elevations, the riser locations and sizes, the joint type, the reinforcement, and the design loading

+- Product data for access risers, frames, and covers, identifying the material, the clear opening, the load rating, and the gasket or seal

+- Product data for the sampling tee or sampling structure where one is furnished

+- Where a grease removal device is furnished, its electrical characteristics, the control enclosure rating, and the heater and skimmer ratings

+```datasheet

+label: Action Submittals Required

+type: checkbox

+options:

+ - "Sizing calculation with method and connected load"

+ - "Hydromechanical interceptor and GRD product data"

+ - "Flow control fitting product data"

+ - "Gravity interceptor shop drawings"

+ - "Riser, frame, and cover product data with load rating"

+ - "Sampling point product data"

+ - "GRD electrical and control data"

+```

+### No interceptor shall be procured until the action submittals covering it have been reviewed and returned.

+## Informational Submittals {toc}

+### The Contractor shall submit the following with, or before, the action submittals:

+- The anti-flotation calculation for each buried tank, comparing the empty weight of the tank and the restraint provided against the uplift at the groundwater elevation stated in this standard

+- The sewer authority's written approval of the interceptor type and size where the pretreatment ordinance requires that approval before installation

+- The precast plant certification for each precast concrete tank

+- The installer training records required under Quality Assurance

+```datasheet

+label: Informational Submittals Required

+type: checkbox

+options:

+ - "Anti-flotation calculation"

+ - "Sewer authority approval of type and size"

+ - "Precast plant certification"

+ - "Installer training records"

+```

+## Closeout Submittals {toc}

+### The Contractor shall submit the following before the interceptor work is accepted:

+- Record drawings showing each interceptor as installed, with its rated flow or liquid volume, the inlet and outlet invert elevations, the fixtures and appliances connected, the flow control and vent connections, and the location of each riser, cover, and sampling point

+- Signed test reports for the watertightness test of each gravity interceptor and the leak check of each hydromechanical interceptor and grease removal device

+- Operation and maintenance data for each interceptor, including the manufacturer's cleaning instructions and, for a grease removal device, the heater, skimmer, timer, and container service instructions

+- The maintenance plan required under Operation and Maintenance, with the pump-out log forms

+- Manufacturer warranties, assigned to the Owner

+- The discharge permit or pretreatment authorization issued to the establishment where the ordinance requires one

+```datasheet

+label: Closeout Submittals Required

+type: checkbox

+options:

+ - "Record drawings with inverts and connected fixtures"

+ - "Signed test reports"

+ - "Operation and maintenance data"

+ - "Maintenance plan and pump-out log forms"

+ - "Assigned manufacturer warranties"

+ - "Discharge permit or pretreatment authorization"

+```

+# Quality Assurance {toc}

+## Installer Qualifications {toc}

+### Interceptors and the grease waste pipe within this standard shall be installed by personnel holding the plumbing license the Authority Having Jurisdiction requires for that work.

+### A buried tank shall be set by a crew whose foreman has set tanks of the same material and joint type before, under the tank manufacturer's rigging and joint instructions.

+### A grease removal device shall be installed and started by personnel who have completed the device manufacturer's training on the product furnished, and the training record shall be on site before the device is started.

+### The grease removal device is the one item in this standard that combines a plumbing connection, an electrical connection, a heater, and a timed mechanism, and a crew that has not seen the product before sets the skim cycle wrong in a way that shows up as a full interceptor two weeks after turnover. {note}

+## Listing and Marking {toc}

+### Hydromechanical grease interceptors shall be tested, rated, and certified to PDI G101, ASME A112.14.3, or CSA B481, and shall bear a permanent marking giving the rated flow in gallons per minute and the rated grease capacity in pounds.

+### Grease removal devices shall be certified to ASME A112.14.4 and shall bear the rated flow and grease capacity marking, and their electrical components shall be listed by a nationally recognized testing laboratory.

+### Prefabricated gravity grease interceptors of fiberglass or polyethylene shall be certified to IAPMO/ANSI Z1001 and shall bear the liquid volume and the certification mark.

+### Precast concrete tanks shall be produced by a plant holding a current precast plant certification, and each tank shall bear the plant identification, the liquid volume, and the date of manufacture.

+### An interceptor that does not carry the required marking shall not be installed, and one that is installed shall be removed and replaced at the Contractor's expense.

+### The rated flow and grease capacity on the body are what the sewer authority's inspector reads against the sizing calculation years after the submittal is gone, and a unit without a certified rating cannot be shown to meet the ordinance at all. {note}

+## Sewer Authority Approvals and Hold Points {toc}

+### The Contractor shall give the Engineer of Record and the sewer authority's inspector not less than 48 hours' notice before each hold point listed below, and shall not proceed past a hold point until the inspection has been performed and released:

+- Buried tank set, joints sealed, and inlet and outlet fittings connected, before backfill

+- Watertightness test of each gravity interceptor, before backfill above the joints

+- Hydromechanical interceptor and flow control set and connected, before the unit is enclosed or the floor is finished over a recessed unit

+- Sampling point installed, before it is concealed

+### Work concealed before its hold point has been released shall be uncovered for inspection at the Contractor's expense, and the concealing construction shall be reinstated at the Contractor's expense.

+### The Contractor shall notify the Engineer of Record in writing of any requirement the sewer authority imposes that differs from the Contract Documents, before complying with it.

+# Interceptor Types and Sizing Basis {toc}

+## Interceptor Types Furnished {toc}

+### The interceptor types furnished on the project shall be as indicated in the datasheet.

+```datasheet

+label: Interceptor Types Furnished

+type: checkbox

+options:

+ - "Hydromechanical grease interceptor"

+ - "Automatic grease removal device"

+ - "Gravity grease interceptor"

+```

+### The interceptor type serving each fixture group shall be as indicated on [[drawing: the plumbing floor plans]].

+### A hydromechanical interceptor is a compact baffled vessel that separates grease at a controlled flow rate near the fixtures, is rated by flow and grease capacity, fits inside the kitchen or just below its floor, and fills quickly, so it is cleaned often; a gravity interceptor is a large tank, usually buried outside, that separates by holding the drainage still for a retention period, is rated by liquid volume, serves a whole kitchen or several tenants, and is pumped by a hauler on an interval of weeks or months; a grease removal device is a hydromechanical interceptor with a heater and a powered skimmer that draws the grease off into a container on a schedule, which trades a higher first cost and an electrical connection for a cleaning interval that does not depend on kitchen staff opening a cover. {note}

+### Many sewer authorities require a gravity interceptor of a minimum volume for any establishment with a commercial kitchen and admit hydromechanical units only for a limited connected load or a tenant space with no outdoor room for a tank, and others accept certified hydromechanical units at any size, so the type is settled with the authority before it is settled with the drawings. {note}

+### The Contractor shall confirm with the sewer authority that each interceptor type shown is acceptable for the establishment before the sizing calculation is submitted.

+## Sizing Method {toc}

+### Each interceptor shall be sized by the method indicated in the datasheet.

+```datasheet

+label: Interceptor Sizing Method

+type: select

+options:

+ - "Pretreatment ordinance method of the sewer authority"

+ - "PDI G101 flow rate method"

+ - "IPC drainage fixture unit method"

+ - "UPC Chapter 10 fixture method"

+ - "Meals-per-peak-hour formula of the local ordinance"

+ - "Retention time method from the measured or estimated peak flow"

+```

+### The methods differ in what they take as input and in what they produce: an ordinance method is whatever the authority publishes and is the one the authority will check against, so it governs wherever it exists; the PDI G101 method converts the drain rate of each connected fixture into a flow in gallons per minute and selects a hydromechanical unit whose rated flow is not less than it; the drainage fixture unit methods of the model codes read the connected load from the fixture unit tables and select either a rated flow or a liquid volume from a code table, which is how the current UPC sizes both unit types in Chapter 10; the meals-per-peak-hour formula multiplies the meals served in the peak hour by a waste flow per meal, a retention time, and a storage factor, survives mainly in local ordinances, and tends to produce a larger tank than a fixture unit method; and a retention time method multiplies the peak flow by a holding period and is the fallback where no table fits the establishment. {note}

+### Where the pretreatment ordinance prescribes a sizing method, that method shall be used regardless of the datasheet selection, and the datasheet selection shall apply only where the ordinance is silent.

+### The rated flow of a hydromechanical interceptor shall be not less than the flow the sizing calculation produces, and the liquid volume of a gravity interceptor shall be not less than the volume the sizing calculation produces.

+### A hydromechanical interceptor shall not be selected at a rated flow more than one size above the flow the sizing calculation produces unless the Engineer of Record directs otherwise in writing.

+### A hydromechanical interceptor separates grease by the turbulence and baffling it creates at its rated flow, and a unit rated far above the flow it actually receives runs quiet and lets grease pass with the water, so for that type a larger unit is not a safer one; a gravity interceptor improves with volume, because retention time and storage both grow with it. {note}

+## Connected Load and Grease Load {toc}

+### The sizing calculation shall list every fixture and appliance connected to each interceptor, with the drain outlet size, the drain rate or drainage fixture unit value, and the appliance capacity where the method uses it.

+### The drain rates and capacities of the warewashers, three-compartment sinks, pre-rinse assemblies, and cooking appliances connected to the interceptor shall be taken from the product data for those items specified in [[sync/foodservice-equipment]].

+### Where a fixture or appliance has no assigned drainage fixture unit value, its flow shall be taken as the drain rate of its outlet at the fixture's full capacity.

+### The sizing calculation shall state the number of meals or the hours of operation assumed wherever the method uses them, and the Engineer of Record shall confirm those assumptions with the Owner before the calculation is submitted.

+# Grease Waste Pipe Within This Standard {toc}

+## Extent of the Grease Waste Pipe {toc}

+### The grease waste pipe within this standard runs from the drain outlet of each connected fixture and appliance to the interceptor inlet fitting, and from the interceptor outlet fitting to the sampling point where one is furnished beyond the outlet.

+### The pipe standards, joints, hangers, cleanouts, traps, and field tests of that pipe shall be as specified in [[sync/sanitary-waste-and-vent-piping]] for the material selected here, and this standard sets only the material and the minimum slope.

+### Grease waste pipe carries water hotter than ordinary sanitary drainage, from warewashers at 150°F to 180°F and from pot sinks drained in bulk, and carries the grease that will set on any wall that is cool or any run that is flat, so its material and slope are decided here rather than inherited from the sanitary standard. {note}

+## Grease Waste Pipe Material {toc}

+### The material of the grease waste pipe within this standard shall be as indicated in the datasheet.

+```datasheet

+label: Grease Waste Pipe Material

+type: select

+options:

+ - "Hubless cast iron"

+ - "Hub-and-spigot cast iron"

+ - "PVC drain, waste, and vent pipe"

+ - "CPVC drain, waste, and vent pipe"

+ - "Polypropylene drainage pipe"

+ - "Stainless steel drainage pipe"

+```

+### Cast iron takes the warewasher discharge temperature without softening and holds its slope on the hangers, and its rough interior lets grease adhere, so it is cleaned more often; PVC costs least and is smooth inside, and it softens above about 140°F, so a warewasher or a sanitizing rinse that drains at 180°F deforms it at the first fitting; CPVC holds its shape to about 200°F at the price of a solvent cement and a primer of its own and a cost between PVC and cast iron; polypropylene is heat fused, smooth, and rated for the full warewasher temperature, and it needs an installer qualified for fusion; stainless steel resists both heat and the chlorides in sanitizer at the highest cost on the list. {note}

+### Where PVC is selected, the pipe serving a warewasher or any appliance that discharges above 140°F shall be CPVC, polypropylene, or cast iron from the appliance drain to the first fitting at least 10 ft downstream, unless the Contract Documents direct otherwise.

+### Transitions between materials shall be made with a coupling or fitting listed for the two materials joined.

+## Grease Waste Pipe Slope {toc}

+### Horizontal grease waste pipe within this standard shall be installed at a slope not less than that indicated in the datasheet.

+```datasheet

+label: Minimum Grease Waste Pipe Slope

+type: range

+unit: in/ft

+min: 0.125

+max: 0.5

+setpoints: [0.125, 0.25, 0.5]

+default: 0.25

+```

+### The adopted codes permit 1/8 in/ft on pipe 3 in. and larger, and grease waste is the drainage that most often blocks at that slope, because the velocity at 1/8 in/ft lets cooling grease settle before it reaches the interceptor; 1/4 in/ft is what most grease waste is laid at, and 1/2 in/ft is chosen for a short run where the ceiling allows it and the kitchen above has a history of blockages. {note}

+### Grease waste pipe shall be installed without sags, and a run found holding water between the fixture and the interceptor when the line is empty shall be rehung at the Contractor's expense.

+# Fixture and Appliance Connections {toc}

+## Fixtures Discharging to the Interceptor {toc}

+### The fixtures and appliances that discharge to each interceptor shall be as indicated on [[drawing: the food-service equipment plan]].

+### Every fixture and appliance that receives grease in use, including pot and pan sinks, three-compartment sinks, pre-rinse assemblies, wok ranges, kettle and tilting skillet drains, rotisserie and combination oven drains, and the floor drains and floor sinks in the cooking and warewashing areas, shall discharge to a grease interceptor unless the pretreatment ordinance or the Contract Documents exempt it.

+### Each appliance that discharges to the interceptor through an indirect waste shall discharge through an air gap to a floor sink or a receptor, and the floor sink or receptor shall drain to the interceptor.

+### Each fixture discharging to the interceptor shall be trapped and vented under [[sync/sanitary-waste-and-vent-piping]], and the interceptor shall not serve as the trap for any fixture unless the interceptor is certified as providing a trap seal and the adopted plumbing code permits it.

+## Warewashing Discharge {toc}

+### The connection of commercial warewashers to the interceptor shall be as indicated in the datasheet.

+```datasheet

+label: Warewasher Connection

+type: radio

+options:

+ - "Warewashers discharge to the grease interceptor"

+ - "Warewashers bypass the grease interceptor"

+```

+### Warewasher discharge is the one connection on which the model codes and the ordinances disagree with each other: a hot, detergent-laden discharge emulsifies the grease in a hydromechanical interceptor and carries it through, so some authorities exclude it, while others require it connected because a warewasher sends more grease to the sewer than any sink and a gravity tank holds the discharge long enough to cool and separate. {note}

+### The Contractor shall confirm the warewasher connection with the sewer authority before the warewasher drain is roughed in, and shall report to the Engineer of Record any direction that differs from the datasheet selection.

+## Food Waste Grinders {toc}

+### The connection of food waste grinders shall be as indicated in the datasheet.

+```datasheet

+label: Food Waste Grinder Connection

+type: radio

+options:

+ - "No food waste grinder discharges to the grease interceptor"

+ - "Grinders discharge through a solids interceptor to the grease interceptor"

+ - "Grinders discharge directly to the grease interceptor"

+default: "No food waste grinder discharges to the grease interceptor"

+```

+### Ground food solids settle in the first compartment of an interceptor and fill it faster than grease does, which is why most ordinances keep grinders off the interceptor entirely; a solids interceptor ahead of the grease interceptor catches the solids where they can be emptied separately and is the arrangement authorities accept where a grinder has to drain somewhere; a direct connection is permitted by a few authorities for a gravity tank sized with the grinder load included, and it shortens the pump-out interval. {note}

+### Where no grinder discharges to the interceptor, a food waste grinder shall discharge to the sanitary drain, bypassing the interceptor, only where the pretreatment ordinance permits a grinder at all.

+## Prohibited Connections {toc}

+### Water closets, urinals, and any fixture that receives human waste shall not be connected to a grease interceptor.

+### Storm drainage, condensate, cooling water, and the brine and backwash discharge of water treatment equipment shall not be connected to a grease interceptor, and the drain receiving them shall be specified in [[sync/sanitary-waste-and-vent-piping]].

+### Hand sinks, mop basins, and toilet room fixtures shall bypass the interceptor unless the pretreatment ordinance requires them connected.

+### Sanitary sewage turns the interceptor septic and makes its pump-out a hazardous job, and every gallon of clean water that enters an interceptor shortens the retention time and pushes grease out with it, which is why the connection list is a short one. {note}

+# Hydromechanical Grease Interceptors {toc}

+## Rated Flow and Grease Capacity {toc}

+### Requirements in this section apply where hydromechanical grease interceptors are furnished.

+### The rated flow of each hydromechanical interceptor shall be as indicated in the datasheet.

+```datasheet

+label: Hydromechanical Interceptor Rated Flow

+type: range

+unit: gpm

+drawing_ref: "the plumbing equipment schedule"

+min: 4

+max: 500

+setpoints: [4, 7, 10, 15, 20, 25, 35, 50, 75, 100, 150, 200, 250, 300, 500]

+default: deferred

+```

+### The rated grease capacity of each hydromechanical interceptor, in pounds per gallon per minute of rated flow, shall be not less than the ratio indicated in the datasheet.

+```datasheet

+label: Minimum Grease Capacity per gpm of Rated Flow

+type: range

+unit: lb/gpm

+min: 2

+max: 25

+step: 1

+default: 2

+```

+### The rating standards certify a unit at not less than 2 lb of grease capacity for each gallon per minute of rated flow, and that is the capacity of a steel unit cleaned weekly; molded units are commonly certified at several times that floor, and the extra capacity is bought for one reason, which is a longer interval between cleanings at the same rated flow. {note}

+### Each hydromechanical interceptor shall be certified at its rated flow and grease capacity by the rating standard named under Listing and Marking, and a unit shall not be re-rated in the field by changing its flow control orifice.

+## Flow Control and Air Intake {toc}

+### The flow control arrangement of each hydromechanical interceptor shall be as indicated in the datasheet.

+```datasheet

+label: Hydromechanical Interceptor Flow Control Type

+type: radio

+options:

+ - "Type A"

+ - "Type B"

+ - "Type C"

+ - "Type D"

+```

+### The ASME A112.14.3 types describe where the flow is controlled: a Type A unit has an external flow control fitting with an air intake, so the orifice meters the flow and the air drawn in behind it breaks the grease out of the water as it enters; a Type B unit has the external flow control without the air intake and relies on the baffles alone; a Type C unit has no external flow control and is directly connected; and a Type D unit has no external flow control and is indirectly connected, so the fixture discharge reaches it through an air gap. {note}

+### Where a Type A or Type B unit is furnished, the flow control fitting shall be installed on the inlet side of the interceptor with an orifice sized for the rated flow of the unit it serves, and shall be the fitting the interceptor manufacturer certifies with that unit.

+### Where a Type A unit is furnished, the air intake shall be vented to the open air or connected to the vent system, shall terminate not less than 6 in. above the flood level rim of the highest fixture served, and shall not be capped, plugged, valved, or reduced.

+### A flow control fitting with a cleanout shall be accessible without removing the interceptor cover or any permanent construction.

+### A flow-controlled interceptor fails in one of two ways, both at the fitting: an orifice larger than the rating lets a sink dump pass through the unit faster than grease can rise, and an air intake that was capped because it smelled leaves the orifice with nothing to draw, so the unit passes grease at a fraction of its rated flow. {note}

+## Hydromechanical Interceptor Body Material {toc}

+### The body material of each hydromechanical interceptor shall be as indicated in the datasheet.

+```datasheet

+label: Hydromechanical Interceptor Body Material

+type: select

+options:

+ - "Molded thermoplastic (polyethylene or polypropylene)"

+ - "Coated fabricated steel"

+ - "Stainless steel"

+ - "Fiberglass-reinforced plastic"

+default: "Molded thermoplastic (polyethylene or polypropylene)"

+```

+### A molded body cannot corrode, weighs little, is certified at the high grease capacities, and is what most units sold today are made of; a coated steel body is the traditional under-sink unit at the lowest first cost, and its coating is the only barrier between the steel and the drainage, so it is scraped through within a few years of cleaning; a stainless steel body is cleaned with the kitchen and lasts as long as the building, at several times the cost of steel; a fiberglass body is molded to the large sizes and resists heat better than polyethylene, at a cost above thermoplastic. {note}

+### Where stainless steel is selected, the grade shall be as indicated in the datasheet.

+```datasheet

+label: Stainless Steel Interceptor Grade

+type: radio

+options:

+ - "Type 304"

+ - "Type 316"

+default: "Type 304"

+```

+### Type 316 carries molybdenum, which resists the chloride pitting that a sanitizer-laden discharge starts in Type 304, so it is chosen where the warewasher drains to the unit or the kitchen sanitizes with chlorine; Type 304 costs less and serves where the discharge is sink water. {note}

+### Where coated fabricated steel is selected, the coating shall be applied to every interior and exterior surface, and the body shall be furnished with a bolted cover and a replaceable gasket.

+### Every hydromechanical interceptor shall have internal baffles that direct the inlet flow downward and route it through the body before it reaches the outlet, and the baffles shall be removable for cleaning without tools or with the tool the manufacturer furnishes.

+### Every hydromechanical interceptor shall have an outlet fitting that draws from below the grease layer, and the outlet shall not be a plain opening in the end wall at the liquid surface.

+## Hydromechanical Interceptor Setting and Cover {toc}

+### The setting of each hydromechanical interceptor relative to the finished floor shall be as indicated in the datasheet.

+```datasheet

+label: Hydromechanical Interceptor Setting

+type: select

+options:

+ - "On the floor beside the fixture"

+ - "Partially recessed in the floor"

+ - "Recessed flush with the finished floor"

+ - "Below the floor with extension risers"

+```

+### An on-floor unit is the cheapest to install and the easiest to clean, takes up floor the kitchen wanted, and needs the fixture drain high enough to fall to it; a partially recessed unit buys inlet height at the cost of a pit; a flush unit disappears into the floor and needs a cover rated for whatever rolls over it and a seal that keeps mop water out of the seam; a unit below the floor with risers serves fixtures whose drains are at floor level and puts every cleaning at the end of a riser, which is why its risers are sized for a vacuum hose. {note}

+### The cover load rating of each hydromechanical interceptor shall be as indicated in the datasheet.

+```datasheet

+label: Hydromechanical Interceptor Cover Load Rating

+type: select

+options:

+ - "Not load rated (on-floor unit)"

+ - "Pedestrian traffic"

+ - "Pallet jack and forklift traffic"

+ - "Vehicular traffic"

+```

+### A cover set in a floor carries whatever the kitchen rolls over it, and a pedestrian cover under a loaded pallet jack cracks at the first pass; the vehicular rating is for a unit recessed in a loading dock or a drive-through lane, and an on-floor unit is never walked on, so its cover carries no rating. {note}

+### A cover set in the floor shall be rated for not less than the load the datasheet indicates, shall seat flush with the finished floor, and shall be sealed to the body with a gasket that keeps floor washdown out of the interceptor.

+### Every hydromechanical interceptor cover shall seal gas-tight and shall be removable by one person for cleaning with the tools the manufacturer furnishes.

+### Extension risers on a unit below the floor shall be of the manufacturer's design for that body, shall have a clear opening not less than the body opening they extend, and shall be sealed to the body and to each other.

+# Automatic Grease Removal Devices {toc}

+## Skimming Control {toc}

+### Requirements in this section apply where automatic grease removal devices are furnished.

+### Each grease removal device shall conform to ASME A112.14.4, shall be certified at its rated flow and grease capacity, and shall meet every requirement of this standard for a hydromechanical grease interceptor of the same rated flow.

+### The skimming control of each grease removal device shall be as indicated in the datasheet.

+```datasheet

+label: Grease Removal Device Skimming Control

+type: radio

+options:

+ - "Timer-initiated skim cycle"

+ - "Sensor-initiated skim cycle"

+default: "Timer-initiated skim cycle"

+```

+### A timer runs the skim cycle at set hours whether or not grease has accumulated, which is simple, cheap, and set once at startup to follow the meal periods; a sensor reads the thickness of the grease layer and skims when it reaches a setpoint, which matches the cycle to the actual load and adds a probe that is cleaned with the unit. {note}

+### Each grease removal device shall have a heating element that liquefies the grease layer before the skim cycle, a powered skimmer or draw-off that moves the grease to a collection container outside the body, and a container that can be removed and emptied by kitchen staff without tools.

+### The collection container shall be sized for not less than the grease the sizing calculation predicts between emptyings at the interval the Owner's maintenance plan states, and shall be located where it can be lifted out without reaching over the interceptor.

+### The Contractor shall set the skim schedule at startup to follow the establishment's meal periods, so that each cycle runs after the period in which the grease layer forms, and shall record the schedule in the operation and maintenance data.

+## Grease Removal Device Electrical and Control Enclosure {toc}

+### The electrical connection of each grease removal device shall be made from a dedicated circuit, and the Contractor shall coordinate the circuit, the disconnect, and the receptacle or junction box with the electrical work before the device is set.

+### The control enclosure rating of each grease removal device shall be as indicated in the datasheet.

+```datasheet

+label: Grease Removal Device Control Enclosure Rating

+type: select

+options:

+ - "NEMA Type 1"

+ - "NEMA Type 12"

+ - "NEMA Type 4"

+ - "NEMA Type 4X"

+default: "NEMA Type 1"

+```

+### Type 1 keeps fingers out of a control in a dry indoor room; Type 12 adds a gasket against the dust and dripping of a mechanical room; Type 4 seals against a directed hose; and Type 4X does the same in a corrosion-resistant body for a sanitizer-washed kitchen or an outdoor location. {note}

+### Where the control enclosure is in a location that is hosed down or washed with sanitizer, the enclosure shall be rated NEMA Type 4X.

+### Where the control enclosure is outdoors, the enclosure shall be rated NEMA Type 4 or Type 4X.

+# Gravity Grease Interceptors {toc}

+## Liquid Volume and Compartments {toc}

+### Requirements in this section apply where gravity grease interceptors are furnished.

+### The liquid volume of each gravity grease interceptor shall be as indicated in the datasheet.

+```datasheet

+label: Gravity Interceptor Liquid Volume

+type: range

+unit: gal

+drawing_ref: "the plumbing equipment schedule"

+min: 300

+max: 10000

+setpoints: [300, 500, 750, 1000, 1250, 1500, 2000, 2500, 3000, 4000, 5000, 6000, 8000, 10000]

+default: deferred

+```

+### Where the pretreatment ordinance or the adopted plumbing code sets a minimum liquid volume for a gravity interceptor, the volume furnished shall be not less than that minimum regardless of the sizing calculation.

+### The number of compartments in each gravity grease interceptor shall be as indicated in the datasheet.

+```datasheet

+label: Gravity Interceptor Compartments

+type: radio

+options:

+ - "One compartment"

+ - "Two compartments"

+ - "Three compartments"

+default: "Two compartments"

+```

+### A single compartment holds the grease and the solids in one chamber, is what the smallest prefabricated tanks offer, and sends solids to the outlet whenever the tank is surged; two compartments put the grease and solids in the first and leave the second as a still zone that polishes the effluent, which is the arrangement the model codes and most ordinances assume; a third compartment extends the still zone for an authority that sets an effluent limit the second compartment does not meet, at the cost of a longer tank and another riser. {note}

+### Where the tank has more than one compartment, the first compartment shall hold not less than two thirds of the liquid volume, and the compartments shall be connected by a baffle wall with openings that pass flow below the grease layer and above the settled solids.

+### The inlet shall enter the first compartment and the outlet shall leave the last compartment.

+## Gravity Interceptor Tank Material {toc}

+### The tank material of each gravity grease interceptor shall be as indicated in the datasheet.

+```datasheet

+label: Gravity Interceptor Tank Material

+type: select

+options:

+ - "Precast concrete"

+ - "Cast-in-place concrete"

+ - "Fiberglass-reinforced plastic"

+ - "Polyethylene"

+default: "Precast concrete"

+```

+### Precast concrete has the mass to stay down in groundwater, the wall to carry a drive lane, and a plant that has cast the same tank a hundred times, and it needs a crane and a road the crane can reach; cast-in-place concrete is built where a crane cannot set a tank or where the tank is larger than any truck carries, and it is watertight only if the waterstops and the joints are made right; fiberglass and polyethylene tanks are set by hand or a small machine, cannot corrode in a sulfide-rich tank, and float the moment they are pumped empty in wet ground, so they are specified with the anti-flotation provision built into the design rather than added. {note}

+### Precast concrete tanks shall conform to ASTM C1613, shall be designed under ASTM C890 for the loading this standard indicates, and shall be produced under ASTM C913.

+### Joints between precast sections shall be sealed with a preformed flexible sealant conforming to ASTM C990 or a rubber gasket conforming to ASTM C443, and the joint shall be watertight and gas-tight.

+### Cast-in-place concrete tanks shall be designed by the structural engineer of record for the loading this standard indicates, with a waterstop at every construction joint and an interior coating or liner the Engineer of Record approves for sewage service.

+### Fiberglass and polyethylene tanks shall conform to IAPMO/ANSI Z1001 and shall be installed with the bedding, backfill, and restraint the tank manufacturer publishes for the burial depth and the groundwater condition.

+### The interior of a concrete tank above the liquid line shall be protected against hydrogen sulfide attack by a coating or liner where the pretreatment ordinance requires it or where the tank serves an establishment whose pump-out interval exceeds 90 days.

+### A gravity tank that is pumped seldom goes septic between pump-outs, and the hydrogen sulfide that forms in the headspace becomes sulfuric acid on the concrete above the water line, which is how a thirty-year tank is eaten through in ten. {note}

+## Gravity Interceptor Structural Loading {toc}

+### The surface loading each gravity grease interceptor, its risers, and its covers are designed for shall be as indicated in the datasheet.

+```datasheet

+label: Gravity Interceptor Surface Loading

+type: select

+derived: "the surface use above the tank shown on the civil site plan"

+options:

+ - "Non-traffic"

+ - "Pedestrian and light vehicle"

+ - "AASHTO HS-20 highway loading"

+ - "AASHTO HS-25 highway loading"

+default: derived

+```

+### A tank in a lawn or a planting bed carries soil and nothing else; a tank under a walk or a service drive carries a delivery van and the hauler's truck that pumps it, which is the load most often forgotten; HS-20 is the rating for a tank under a parking lot or a fire lane, and HS-25 is specified where the authority or the fire code official requires it for the apparatus. {note}

+### The tank, its risers, and its frames and covers shall be designed for the soil load at the burial depth shown, the groundwater at the elevation this standard states, and the surface loading indicated in the datasheet, and the loading shall be stated on the shop drawings.

+### A tank in any area that a vehicle can reach, including the area the pump-out truck uses, shall be designed for not less than HS-20 loading unless the Contract Documents direct otherwise.

+## Anti-Flotation {toc}

+### The anti-flotation provision of each gravity grease interceptor shall be as indicated in the datasheet.

+```datasheet

+label: Gravity Interceptor Anti-Flotation Provision

+type: select

+derived: "[[parameter: seasonal-high-groundwater-elevation]] relative to the tank base and the empty weight of the tank"

+options:

+ - "None"

+ - "Extended base slab"

+ - "Concrete ballast collar"

+ - "Anchor straps to deadman anchors"

+default: derived

+```

+### A tank is pumped empty on every service, and an empty tank below groundwater is a boat: a heavy concrete tank in dry ground needs nothing, an extended base slab holds a concrete tank down with the weight of the soil on its lip, a ballast collar adds mass where the base cannot be widened, and straps to deadman anchors are what hold a fiberglass or polyethylene tank that has no mass of its own. {note}

+### The anti-flotation calculation shall show a factor of safety of not less than 1.25 against uplift with the tank empty and the groundwater at [[parameter: seasonal-high-groundwater-elevation]], neglecting the weight of the tank contents and the friction of the backfill on the tank walls.

+### Where the calculation shows that the empty tank is not held down by its own weight and the soil on its base, the restraint selected in the datasheet shall be furnished and shall be in place before the tank is backfilled.

+## Inlet and Outlet Fittings {toc}

+### The inlet of each gravity grease interceptor shall be a sanitary tee or a drop pipe that directs the flow downward into the first compartment below the grease layer, and the outlet shall be a sanitary tee or an elbow that draws from below the grease layer and above the settled solids in the last compartment.

+### The inlet and outlet fittings shall be the size of the pipe they connect, shall extend not less than 12 in. below the liquid level, and shall be removable from the riser above them for cleaning.

+### The inlet invert shall be set above the outlet invert by the difference the tank manufacturer publishes for the tank furnished, and not less than 2 in.

+### The inlet and outlet invert elevations of each gravity grease interceptor shall be as indicated on [[drawing: the plumbing site plan]].

+### Pipe connections through the tank wall shall be made with a resilient connector cast into the wall or a boot sealed to a cored opening, and shall allow the pipe to deflect without cracking the wall or the pipe.

+### Where the tank is set outdoors, the inlet and outlet pipe and the tank top shall be below [[parameter: frost-depth]], or the pipe shall be insulated and the tank top covered so that the inlet and outlet fittings do not freeze.

+## Access Risers and Covers {toc}

+### Each gravity grease interceptor shall have a riser to finished grade over the inlet fitting, over the outlet fitting, and over each compartment, and the risers shall be sealed to the tank and to each other.

+### The clear opening of each riser shall be not less than that indicated in the datasheet.

+```datasheet

+label: Gravity Interceptor Riser Clear Opening

+type: range

+unit: in

+min: 18

+max: 36

+setpoints: [18, 20, 24, 30, 36]

+default: 24

+```

+### The hauler's hose, a squeegee, and a worker's shoulders all have to pass the riser opening, and the riser over the inlet also has to pass the inlet tee when it is lifted out for cleaning; 24 in. is the opening those jobs are done through on most tanks, and the larger openings are specified where the tank is deep enough that a worker enters it. {note}

+### The frame and cover material of each gravity grease interceptor shall be as indicated in the datasheet.

+```datasheet

+label: Gravity Interceptor Frame and Cover Material

+type: select

+options:

+ - "Gray iron"

+ - "Ductile iron"

+ - "Fiber-reinforced polymer composite"

+ - "Steel checker plate"

+```

+### Gray iron is the ordinary manhole casting, heavy enough to stay put and brittle under the impact of a truck wheel at the edge; ductile iron takes that impact and is the casting a traffic rating usually calls for; a composite cover is light enough for a kitchen worker to lift and does not corrode or conduct, and it is bolted down where the rating requires it; a steel plate cover is fabricated to an odd opening and is the one that rusts. {note}

+### Gray iron frames and covers shall conform to ASTM A48/A48M and ductile iron frames and covers to ASTM A536, and each frame and cover shall be rated for the surface loading indicated in the datasheet.

+### Covers shall be gas-tight, shall be gasketed where the pretreatment ordinance or the tank location requires an odor-tight cover, and shall be bolted or locked where the tank is in an area the public can reach.

+### Covers shall be set flush with finished grade, or with the finished floor where the tank is indoors, and shall be located so that the pump-out truck can park within hose reach of every riser.

+# Interceptor Venting {toc}

+## Each grease interceptor shall be vented in accordance with the adopted plumbing code, and the vent connections shall be made under [[sync/sanitary-waste-and-vent-piping]] at the points this standard requires.

+## The outlet of each interceptor shall be vented so that the discharge cannot siphon the interceptor or the traps of the fixtures it serves.

+## The air intake of a Type A flow control shall be vented as required under Flow Control and Air Intake.

+## Each gravity grease interceptor shall be vented through the inlet and outlet pipe or through a dedicated vent so that gas generated in the tank is relieved and the tank is neither pressurized nor placed under vacuum as it fills and drains.

+## An interceptor without an outlet vent is a trap with a long tailpiece: a full sink dumped into it siphons the liquid out through the outlet, drops the grease layer onto the baffles, and leaves the kitchen smelling of the tank until it refills. {note}

+# Effluent Sampling {toc}

+## The effluent sampling provision of each interceptor shall be as indicated in the datasheet.

+```datasheet

+label: Effluent Sampling Provision

+type: radio

+options:

+ - "None"

+ - "Sampling tee within the outlet riser"

+ - "Separate sampling manhole beyond the outlet"

+```

+## A sampling tee in the outlet riser costs a fitting and gives the inspector a sample at the tank, which some authorities accept and others do not because the sample is drawn above the tank's own turbulence; a separate manhole on the outlet pipe gives a sample of the settled effluent and a place to measure flow, at the cost of a structure and a riser, and is what most authorities with a numerical effluent limit require; no provision is furnished where the authority does not sample. {note}

+## Where a sampling provision is furnished, it shall be located beyond the interceptor outlet and ahead of any connection from another drain, so that the sample drawn is the interceptor effluent alone.

+## Where a sampling provision is furnished, it shall be accessible to the sewer authority's inspector from outside the establishment without entering the kitchen, and its location shall be as indicated on [[drawing: the plumbing site plan]].

+# Installation {toc}

+## Hydromechanical Interceptor and Grease Removal Device Setting {toc}

+### Each hydromechanical interceptor and grease removal device shall be set level on a surface that carries its operating weight, at the location shown, with clearance above the cover for its removal and clearance on the service side for the baffles to be lifted out.

+### A unit set on the floor shall be located where the floor around it can be cleaned and where the cover can be reached by the staff who clean it, and not under a fixture or a counter that has to be moved to open it.

+### A unit set in or below the floor shall be set so that the cover finishes flush with the finished floor, and the opening around it shall be sealed to the floor finish so that washdown does not enter the pit.

+### The flow control fitting shall be installed at the elevation and the distance from the inlet the interceptor manufacturer publishes, and the air intake shall be run before the fixture connection is made.

+### The connection between the fixture drain and the interceptor inlet shall be made so that the inlet invert is at or below the elevation the manufacturer publishes for the fixture outlet it serves, and the inlet and outlet shall not be reversed.

+## Gravity Interceptor Setting {toc}

+### The excavation, bedding, backfill, and dewatering for each buried tank shall be performed under [[sync/earthwork]] and [[sync/excavation-support-and-dewatering]], to the dimensions, bearing, and bedding the tank shop drawings require.

+### The tank shall be set on a bedding that is level in both directions, and the Contractor shall verify the bedding elevation against the inlet and outlet inverts shown before the tank is lifted.

+### The tank shall be rigged and set by the lifting points the manufacturer provides, and a tank that has been dropped, set on a point, or cracked in setting shall be rejected and replaced at the Contractor's expense.

+### Sectional joints shall be cleaned, primed where the sealant manufacturer requires it, and sealed before the next section is set, and the sealant shall be continuous around the full joint.

+### The inlet and outlet pipe shall be connected, the watertightness test performed and released, and the anti-flotation restraint placed before any backfill is placed above the base of the tank.

+### Backfill shall be placed in lifts on all sides of the tank together so that the tank is not pushed off its bedding, and the risers shall be braced until the backfill reaches the cover frame.

+### Each buried tank shall be located outside the building at a distance from the foundation that the adopted plumbing code and the pretreatment ordinance require, clear of the water service and other utilities, and where the pump-out truck can reach every riser.

+### Where a gravity tank is located inside the building because the site gives it no other place, it shall be set in a vault with risers to the finished floor, vented to the open air, and located where the hauler's hose can reach it through a door or a hatch, and the location shall be as indicated on [[drawing: the plumbing floor plans]].

+# Testing and Commissioning {toc}

+## Gravity Interceptor Watertightness Test {toc}

+### Each gravity grease interceptor shall be tested for watertightness after the tank is set and the inlet and outlet pipe are connected, and before backfill is placed above the joints, by the method indicated in the datasheet.

+```datasheet

+label: Gravity Interceptor Watertightness Test Method

+type: radio

+options:

+ - "Hydrostatic test"

+ - "Vacuum test"

+default: "Hydrostatic test"

+```

+### A hydrostatic test fills the tank and shows a leak as a wet joint and a falling level, and it needs water on site and a day for the concrete to soak before the reading means anything; a vacuum test pulls the air out of the sealed tank and reads a leak on a gauge in minutes with no water, and it needs the risers and openings plugged against the vacuum and a tank the manufacturer rates for it. {note}

+### For a hydrostatic test, the tank shall be filled with water to the outlet invert, allowed to stand for 24 hours, refilled to the outlet invert, and held for not less than 1 hour with no visible leakage and no measurable drop in level.

+### For a vacuum test, every opening shall be sealed, the tank shall be evacuated to 4 in. of mercury, and the vacuum shall be held for not less than 5 minutes with a loss of not more than 1 in. of mercury.

+### A tank that leaks or loses level or vacuum shall be repaired by resealing the joint or replacing the section, and shall be retested by the same method until it passes, at the Contractor's expense.

+### The test shall be witnessed by the Engineer of Record's representative and, where the pretreatment ordinance requires it, by the sewer authority's inspector, and a test not witnessed shall be repeated.

+## Hydromechanical Interceptor Leak Check {toc}

+### Each hydromechanical interceptor and grease removal device shall be filled with water to its operating level after the connections are made, and the inlet, outlet, flow control, air intake, and cover shall be checked for leakage with the unit full and with the connected fixtures discharging at their full rate.

+### A unit that leaks at any connection or at the cover shall be resealed and rechecked, and a unit that leaks through its body shall be replaced at the Contractor's expense.

+## Commissioning and Initial Fill {toc}

+### Each interceptor shall be filled with clean water to its operating level before the establishment begins operating, and shall not be placed in service empty.

+### An empty interceptor passes the first week's grease straight to the sewer, because the outlet draws from the bottom of a vessel that has no water in it for the grease to float on. {note}

+### Where a grease removal device is furnished, the Contractor shall verify at startup that the heater reaches its setpoint, the skimmer runs through a complete cycle, the container receives the skimmed grease, and the timer or sensor initiates the cycle as set, and shall record the results in the test report.

+### The Contractor shall verify before acceptance that every fixture and appliance assigned to each interceptor discharges to it, that no prohibited connection has been made, and that the flow control, air intake, vents, and sampling provision are installed and open.

+# Operation and Maintenance {toc}

+## Pump-Out Trigger {toc}

+### The basis on which each interceptor is pumped out shall be as indicated in the datasheet.

+```datasheet

+label: Pump-Out Trigger

+type: radio

+options:

+ - "Accumulated grease and solids reach 25 percent of the liquid depth"

+ - "Fixed maximum interval set by the pretreatment ordinance"

+ - "Whichever of the 25 percent depth and the ordinance interval occurs first"

+default: "Whichever of the 25 percent depth and the ordinance interval occurs first"

+```

+### The 25 percent rule pumps the tank when its working volume is actually used up, so it matches the service to the load and needs someone to measure the layers; a fixed interval needs no measurement and is what an authority can audit from a hauler's manifest, and it pumps a lightly loaded tank too often and a heavily loaded one too late; most ordinances state both and enforce whichever comes first. {note}

+### The baseline interval between pump-outs stated in the maintenance plan shall be not more than that indicated in the datasheet.

+```datasheet

+label: Baseline Pump-Out Interval

+type: range

+unit: days

+min: 7

+max: 180

+setpoints: [7, 14, 30, 60, 90, 180]

+```

+### A small steel unit under a sink is cleaned weekly because it holds a few days of grease, a large molded unit monthly, and a gravity tank quarterly, and the interval written into the plan is a starting point that the first year's measurements shorten or lengthen. {note}

+### The Contractor shall prepare a maintenance plan for the Owner stating, for each interceptor, the pump-out trigger, the baseline interval, the measurement method for the grease and solids layers, the hauler arrangement, and the records to be kept, and shall deliver it with the closeout submittals.

+### The Owner shall pump out each interceptor on the trigger the maintenance plan states after acceptance, and shall keep the records the pretreatment ordinance requires.

+## Pump-Out and Cleaning {toc}

+### A gravity grease interceptor shall be pumped out by removing the entire contents, grease, water, and solids together, by a hauler licensed for grease waste, and shall not be skimmed of its grease alone or decanted back into the tank.

+### A hydromechanical interceptor shall be emptied completely at each cleaning, and its baffles, walls, and outlet fitting shall be scraped and the flow control fitting cleared.

+### A grease removal device shall have its container emptied at the interval the maintenance plan states and shall be cleaned as a hydromechanical interceptor at the interval the plan states for its body.

+### Pumped waste shall be disposed of at a facility permitted to receive it, and the hauler's manifest shall be retained with the maintenance log.

+### Skimming the grease and leaving the water and solids behind is the service that costs least and does least: the solids stay, the working volume keeps shrinking, and the tank that was pumped on schedule still overflows grease to the sewer. {note}

+## Chemical and Biological Additives {toc}

+### The use of additives in each interceptor shall be as indicated in the datasheet.

+```datasheet

+label: Interceptor Additive Policy

+type: radio

+options:

+ - "No additives"

+ - "Biological additives permitted where the sewer authority approves the product"

+default: "No additives"

+```

+### Where no additives are selected, no enzyme, solvent, emulsifier, or bacterial product shall be added to an interceptor, and cleaning shall be by removal of the grease and solids alone.

+### Where biological additives are selected, only a product the sewer authority has approved in writing shall be used, and the additive shall not replace the pump-out the maintenance plan requires.

+### Enzymes and solvents do not remove grease; they liquefy or emulsify it so that it leaves the interceptor with the water and sets in the sewer where the interceptor was supposed to keep it from, which is why most ordinances ban them; bacterial products digest some grease in a tank that is held long enough, and a few authorities permit them as a supplement to pumping. {note}

+## Maintenance Records {toc}

+### The Owner shall keep a log for each interceptor recording the date of each pump-out or cleaning, the measured depth of the grease and solids layers before cleaning, the volume removed, the hauler and the disposal facility, and any repair, and shall retain the log and the manifests for the period the pretreatment ordinance requires.

+### The log shall be kept at the establishment and shall be produced for the sewer authority's inspector on request.

+### The Contractor shall furnish the log forms and the first year's baseline interval with the maintenance plan.

+# Identification {toc}

+## The cover of each gravity grease interceptor and of each hydromechanical interceptor set in the floor shall carry the legend GREASE INTERCEPTOR by the method indicated in the datasheet.

+```datasheet

+label: Interceptor Cover Legend Method

+type: radio

+options:

+ - "Legend cast into the cover"

+ - "Engraved plate fastened to the cover or frame"

+default: "Legend cast into the cover"

+```

+## An on-floor hydromechanical interceptor shall bear a permanent label on its cover identifying it as a grease interceptor and giving its rated flow and grease capacity.

+## The grease waste pipe within this standard shall be marked as grease waste, distinct from the sanitary waste marking, under [[sync/plumbing-piping-identification]].

+## Ten years after turnover, the cover legend is what stops a paving crew from burying the risers and a plumber from tying a toilet room into the grease line, and the pipe marking is what tells the next tenant's plumber which drain the new fryer goes to. {note}

+# Delivery, Storage, and Handling {toc}

+## Interceptors, flow control fittings, risers, and covers shall be delivered in the manufacturer's packaging with the rating marks legible and intact, and shall be inspected on receipt for cracks, dents, damaged coatings, and missing baffles, gaskets, or covers.

+## Damaged units shall be rejected and removed from the site, and shall not be repaired for use.

+## Thermoplastic and fiberglass interceptors and tanks shall be stored out of direct sunlight and off the ground, and shall not be stacked or loaded.

+## Precast concrete tanks shall be stored on level dunnage at the points the manufacturer designates and shall be lifted only by the lifting inserts cast for that purpose.

+## Grease removal devices shall be stored indoors, dry, and upright, with the control enclosure and the heater protected from impact until the device is set.

+# Warranty {toc}

+## Installation Warranty {toc}

+### The installation warranty period shall be as indicated in the datasheet.

+```datasheet

+label: Installation Warranty Period

+type: range

+unit: years

+min: 1

+max: 5

+setpoints: [1, 2, 3, 5]

+default: 1

+```

+### The Contractor shall warrant the interceptor installation, including the interceptor or tank and its setting, the joints, the flow control and vents, the risers and covers, the sampling provision, and the grease waste pipe within this standard, against defects in materials and workmanship and against leakage for the period selected in the datasheet, beginning at substantial completion.

+### The installation warranty shall cover the labor and materials to correct a defect, the excavation and restoration needed to reach a buried tank, and the repair of finishes and contents damaged by leakage from a defective installation.

+### Where a warranted defect is corrected, the corrected work shall carry a fresh warranty for the full selected period from the date of correction, or the remainder of the original period, whichever ends later.

+### The warranty shall not cover a blockage or an overflow caused by the Owner's failure to pump out the interceptor on the trigger the maintenance plan states, and where the parties disagree whether a failure originates in the installation or in the maintenance, the Engineer of Record shall make the initial determination.

+## Manufacturer Warranty Pass-Through {toc}

+### The Contractor shall obtain and transfer to the Owner the manufacturer warranty for each interceptor, tank, flow control fitting, and cover, and for the heater, skimmer, motor, and controls of each grease removal device.

+# Spare Parts {toc}

+## The Contractor shall deliver the following spare parts to the Owner at substantial completion, packaged and labeled by interceptor:

+- One cover gasket for each hydromechanical interceptor and grease removal device

+- One flow control cleanout cap and gasket for each flow control fitting furnished

+- One grease collection container for each grease removal device

+- One skimmer wiper or draw-off seal set for each grease removal device, where the manufacturer lists it as a service part

+- One frame gasket for each gasketed cover on a gravity interceptor

+```datasheet

+label: Spare Parts Inventory

+type: checkbox

+options:

+ - "Hydromechanical interceptor cover gaskets"

+ - "Flow control cleanout caps and gaskets"

+ - "Grease removal device collection containers"

+ - "Grease removal device skimmer service parts"

+ - "Gravity interceptor cover frame gaskets"

+```

+## The gasket is the part that is lost: it comes off with the cover at every cleaning, is set aside on a wet floor, and is not found at reassembly, and a cover closed without it lets the kitchen smell the interceptor until the gasket is replaced. {note}

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