Section 10.09 - Interceptors, Separators and Holding Tanks(1)Interceptors, Separators and Holding Tanks Required. Interceptors, separators and holding tanks shall be provided to prevent the discharge of oil, gasoline, grease, sand, and other substances that are harmful or hazardous to building drainage systems, public and private sewer systems, systems governed by the Department of Environmental Protection (DEP), sewage treatment plants, or other environmentally sensitive areas. No wastes other than those requiring treatment or separation shall be discharged into any interceptor, separator, or holding tank. (a)Separation or Containment of Gas, Oil, and Other Petroleum Distillates. Note: For purposes of 248 CMR 10.09, a motor vehicle shall be considered a self-propelled road vehicle, commonly wheeled, including but not limited to cars, buses, trucks, and tractors. 1.Required Locations. A separation or containment system shall be required for any building or structure containing:a. Motor vehicle parking, repair/maintenance, washing, and storage areas;b. Other spaces which are sufficiently large enough to allow access by motor vehicles. Exception. A separation or containment system shall not be required for:
i. Single family residential garages;ii. Multi-family, condominium, and apartment garages which are sufficiently small that they could only hold a maximum of six motor vehicles;iii. Buildings or structures whose floor is unfinished or paved such that the surface is sufficiently porous that any gas, oil, or other petroleum distillates would be absorbed by the surface prior to reaching any separation or containment systems;iv. Buildings or structures that are exclusively classified as a storage group pursuant to 780 CMR: The Massachusetts State Building Code which are sufficiently small that they could only hold a single motor vehicle and there is no other plumbing;v. Showrooms used for the purpose of selling used or new motor vehicles which are located within a structure classified by the Plumbing Code, 248 CMR 10.10(18): Table 1, as a mall (covered) or retail (mercantile) that is open to and used by the public; andvi. Installations where outside permanent bollards or other devices are spaced in front of entrances to the building or structure to prevent the entrance of a motor vehicle. Where permanent bollards are used, they shall be spaced no more than 48" apart.c.Sump Pumps/Drains Used in Elevator Pits. i. Discharge from gravity drains or pumps entering the sanitary or storm drainage system shall comply with the requirements of 248 CMR 10.00. Elevators utilizing hydraulic oil or other petroleum distillates which may be harmful to the sanitary of storm drainage system shall discharge through a properly sized oil/water separator installed in compliance with 248 CMR 10.09. ii. Piping shall discharge into the building sanitary system.Exception:
i. Piping may discharge into the building storm drainage system if permitted by any local ordinance, bylaw, rule, or regulation.ii. Product accepted pumps equipped with sensors which divert volatiles may be installed in lieu of a gas/oil separation system.2.Rules for Separation Systems. For use when connecting to a sewer system a. In general, one of the following separation systems must be utilized: i. A system meeting the design specifications outlined in 248 CMR 10.09: Example 2 or such other specifications approved by the Board;ii. A product accepted separation system;iii. A separation system designed by a Massachusetts professional engineer who prepares all plans and specifications and certifies in writing to the inspector that the installation complies with these plans and specifications; orb.Approvals of Other Agencies.i. Where specifically noted, the approval of other agencies may be required to complete the installation of a separation system, however, said approvals shall not be deemed to supersede the requirements for a plumbing permit as well as full inspection by the plumbing inspector of all components and connections of a separation system. If the approval of another agency would necessitate a violation of 248 CMR 10.00 must be followed unless a variance is granted by the Board.ii. Connection of a separation system to a sewer shall adhere to Massachusetts Department of Environmental Protection rules located at 314 CMR 7.00: Sewer System Connection and Extension Permit Program.iii. When in an area governed by the Massachusetts Water Resources Authority (MWRA), notice of the installation of a separation system must be made to the MWRA prior to the issuance of a plumbing permit.3.Rules for Containment Systems. When not connecting to a sewer system: a. When in an area governed by the Department of Environmental Protection, (DEP) notice of the installation of a containment system must be made to the DEP prior to the issuance of a plumbing permit.b. For smaller installations involving a maximum of two vehicle bays, a pump connected to a double wall tank, both of which are rated by the manufacturer to hold volatile chemicals, meeting the following requirements. See 10.09: Example 1.i. The tank must hold a minimum of sixty gallons per vehicle;ii. The tank must be equipped with a liquid sensor to detect leaks; andiv. The tank must be vented through a roof.c. Piping for containment tanks shall comply with the following requirements: i. The minimum inlet pipe size shall be four inch.ii. The vent shall not be less than two inch and shall returned to the inside of the building and extend independently through the roof.iii. Prior to being put into service, the tank and related piping shall be tested.iv. Piping materials shall be limited to extra heavy, service weight and nu-hub. 10.09: Example 1 - Containment for Smaller Installations
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4.Vents for Floor and Trough Drains. The vents for floor/trough drains that convey waste from all gas, oil and other petroleum distillate separation or containment systems shall be independent of the sanitary DWV systems. Vents for these floor/trough drains may connect to the chamber vent of the separator or other containment system no less than six inches above the flood level rim of the floor/trough drain fixture. See 248 CMR (2)(g)3. for exception to trap requirements in open parking garages.5.Design & Sizing of Separators. Where separators are required, they shall have a minimum volume of six cubic feet for the first 100 square feet of area drained, plus one cubic foot for each additional 100 square feet of area drained. In areas covered by 248 CMR 10.09 which may encounter excessive flow, separators shall be sized in accordance with manufacturers specifications. a.Pre-cast or Built-in-place Separators. See 10.09: Example 2. i. Shall be located outside of a building wherever possible and equipped with an access cover having a minimum diameter of 24 inches. Exception: For separators which are installed inside a building, the access cover must be sealed tight.
ii. The minimum inlet pipe shall be four inch and the outlet shall be equal to or greater than the inlet.iii. The invert of the inlet pipe shall be no less than four inches above the water line.iv. The chamber vent shall be four inch in size and located as close as possible to the top of the tank.v. The chamber and outlet vents shall be four inch in size, returned to the inside of the building and extend independently through the roof.vi. All venting associated with the installation of a gas/oil separator shall be labelled.vii. Access ladder steps shall be non-corrosive and spaced eighteen inches apart.viii. All pre-cast separators shall meet or exceed the ASTM C-478 standard of 4,000 PSI ix. Joint sections shall use butyl rubber joint sealant per ASTM C-990 standard.x. All separator pipe penetrations shall be sealed using hydraulic cement or butyl rubber sealant per ASTM C-990 standard.xi. All separators shall have a minimum liquid water seal depth of three feet.xii. The distance from the outlet pipe to the base of the tank shall be a minimum of two foot six inches.xiii. All piping penetrations on a pre-cast or built-in-place separator shall be sealed with hydraulic cement.xiv. Prior to being put into service, the separator shall be filled with water and tested.xv. Piping materials shall be limited to extra heavy, service weight and nu-hub cast iron.xvi. Sizing of separator shall be in accordance with 248 CMR 10.09: Table 10.09.xvii. Discharge from storm separators may be connected directly to the building storm drain or storm sewer.xviii. Discharge from sanitary separators may be connected directly to the building sanitary drain or sanitary sewer. 10.09: Example 2 - Pre-cast
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Inlet | A | B |
4" | 3'-0" | 2'-6" | 3'-6" |
5" | 5'-0" 3'-6" 3'-0" | 4'-0" 3'-0" 2'-6" | 3'-6" 4'-0" 4'-6" |
6" | 5-'0" 4'-0" 3'-6" | 4'-6" 3'-6" 3'-0" | 4'-0" 4'-6" 5'-0" |
8" | 6'-0" 4'-6" 4'-0" 3'-6" | 5'-0" 4'-0" 3'-6" 3'-0" | 5'-0" 5'-6" 6'-0" 6'-6" |
(b)Grease Interceptors and Grease Removal Devices.1.General Requirements. Note: For purposes of 248 CMR 10.09, Grease Interceptors and Grease Removal Devices shall be considered "interceptors".
a. Interceptors shall not be considered traps unless they meet the requirements of 248 CMR 10.08(2)(e)b. Interceptors shall be required to receive discharge from all fixtures and equipment which may produce grease-laden waste wherever food is prepared, or in other establishments where grease may be introduced into the sanitary drainage system.c. Only gravity interceptors, hydromechanical and engineered systems which have been tested and approved to the applicable standards shall be allowed.d. Grease removal is not required in dwellings or for fixtures which convey human waste.e. In unsewered areas refer to 310 CMR 15.00: The State Environmental Code, Title 5: Standard Requirements for the Siting, Construction, Inspection, Upgrade and Expansion of On-site Sewage Treatment and Disposal Systems and for the Transport and Disposal of Septage relative to grease removal at installations from which large quantities of grease can be expected to discharge.2.Interceptors Installed Inside of Buildings. a. Properly sized interceptors may be installed on individual fixture waste branches or form multiple fixtures. See 10.09: Example 3.b. A vent shall be installed downstream of all interceptors c. Individual fixtures to be protected by interceptors shall include, but not be limited to: ii. scullery sinks. Exception: Multiple Bay scullery sinks in patron areas for the purpose of serving alcohol, soda or other similar carbonated type beverages.iii. floor drains and floor sinks; Note: See248 CMR 10.09(1)(b)2.e.;iv. automatic dishwashers regardless of temperature;vi. soup kettles or similar devices;ix. automatic hood wash units.d. Waste branches for individual or multiple fixtures protected by interceptors may be sized equal to the inlet connection of the properly sized interceptor.e.Floor Drain, Floor Sink and Dishwasher Exception. Individual or multiple floor drains, floor sinks and commercial dish washing machines which may encounter grease shall be allowed to conduct grease directly to an outside grease trap or interceptor. Individual or multiple fixtures. conducting grease to an outside grease trap or interceptor shall be considered a dedicated system.
f. Interceptors shall be located not more than 25 feet of the most remote fixture being served. Exception: When an exterior grease interceptor or trap is installed within 25 feet of the most remote fixture being served; an inside interceptor shall not be required. 10.09: Example 3 - For Individual or Multiple Fixtures
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3.Food Waste Disposers and Pre-rinse Sinks.a. A dishwasher pre rinse sink not equipped with a food waste disposer that conveys the waste discharge to a dish washing machine drain shall discharge through an interceptor and be a minimum diameter of two-inch. The total developed length of the horizontal waste drain from the dishwasher pre-rinse sink outlet to the weir of the dish washing machine trap shall not exceed eight feet. See 10.09: Example 4.b. The waste discharge from a commercial food waste disposer shall not discharge into the sanitary drainage system through an interceptor. See 10.09: Example 5.c. Dishwasher pre-rinse sinks equipped with food waste disposer shall be discharged in accordance with 248 CMR 10.10(4)(b). 10.09: Example 4 - Pre-rinse Sinks and Dishwashers
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10.09 Example 5 - Pre-Rinse Sinks with Disposers
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4.Sizing, Testing and Design. Interceptors shall be sized, tested, and designed in accordance with PDI-G101, PDI-G102, ASME A112.14.3, ASME A112.14.4, ASME A112.14.6 ANSI Z1001 or CSA B481 standards. The Board may authorize the use of alternate design interceptors in accordance with 248 CMR 3.04: Product, Design, and Testing Standards.5.Capacity. Interceptors shall have a capacity of not less than two pounds of grease for each gallon-per-minute (GPM) of flow.6.Flow Control Device. a. Hydromechanical and Grease Removal Devices shall be equipped with flow control devices. A flow control device may be equipped with a vented (air intake) or be of an integral non-vented design. Integral non-vented flow control device shall be placed in accordance with manufacturers' installation instructions. A flow control device is required to be installed between the fixture and the interceptor in accordance with manufacturers' instructions.b. When installing an interceptor with an external flow control, the vent for the flow control shall be connected to the buildings sanitary venting system. The flow control vent shall not be considered a fixture vent.7.Water Cooled Interceptors/Separators. Water- cooled interceptors/separators are prohibited.8.Interceptors Not Required. a. Interceptors are not required for residential buildings, structures, dwellings, dwelling units or any private residence. Exception: Interceptors shall be required in buildings deemed residential that incorporate commercial cooking accommodations.
c. Fixtures used for culinary purposes. See248 CMR 10.12(1)(a)3.9.Treatment Agents and Chemicals. Unless accepted by the Board, chemicals, liquids or agents of any type used for the primary purpose of emulsification and separation of grease that by formula allow grease to be transferred or conveyed from the trap or interceptor to the drainage system are prohibited.10.Maintenance.a. Grease and accumulated solids shall be removed from traps and interceptors and disposed of in accordance with applicable Federal, State and Local health code requirements by the owner or his/her agent. Federal, State and Local laws, regulations and by-laws may require monitoring and registration of installed traps and interceptors.b. The local board of health official(s) or similar authority having jurisdiction may require other methods or programs to monitor maintenance of grease traps and interceptors.11.Procedures for Sizing Grease Interceptors.a.Recommended Procedures and Formulas for Installing Grease Traps and Interceptors. As a rule, it is recommended that traps and interceptors be sized in accordance with the formulas indicated in 248 CMR 10.09: Tables 1 through 2. It is favorable policy to size the interceptor so that its rated capacity is never less than forty percent of the individual fixture capacity in gallons. Example below: The actual fixture capacity is 59.8 Gal. and 40% of this is 23.9 Gal.
248 CMR 10.09: Table 1: Recommended Procedure for Sizing Interceptors Inside Buildings
Example (Single Compartment)
STEP 1. Determine the cubic content of the fixture by multiplying length x width x depth, (per compartment) | A sink 48" long by 24" width by 12" deep. Cubic content 48" x 24" x 12" = 13,824 cu. in. or Cubic contents 4' x 2' x 1' x 7.5 Gals. = 60 Gals. |
STEP 2. Determine the total capacity in gallons. 1 gallon = 231 cubic inches | Contents in Gallons 13,824 = 59.8 Gals. 231 |
STEP 3. Determine actual drainage load. The fixture is normally filled to approximately 75% of the capacity with water. The items being washed displace about 25% of the fixture content, thus the actual drainage load = 75% of fixture capacity. | Actual Drainage Load .75 x 59.8 Gals. = 44.9 Gals |
STEP 4. Determine the flow rate and drainage period. In general, good practices dictate a one-minute drainage period, however where conditions permit, a two-minute period is acceptable. Drainage period is the actual time required to completely empty the fixture. | Calculate flow rate for one-minute period. Flow rate 44.9 Gals.1/min. = 44.9 G.P.M. For two-minute period Flow rate .9 Gal./2min. = 22.5 G.P.M. |
STEP 5. Select the interceptor which corresponds to the flow rate calculated. Note: Select larger size when flow rate falls between two sizes listed. |
NOTE: The example above is representative of acceptable method(s) when purchasing an interceptor based on the total fixture flow rate capacity in gallons. When purchasing an interceptor based on grease retention pounds only, multiply the total gallon flow rate capacity of the fixture by two.
248 CMR 10.09: Table 2:
CAPACITY OF INTERCEPTORS
Total Flow Through Rating (G.P.M.) | Grease Trap/Interceptor Retention Capacity (lbs.) |
4 | 8 |
6 | 12 |
7 | 14 |
9 | 18 |
10 | 20 |
12 | 24 |
14 | 28 |
15 | 30 |
18 | 36 |
20 | 40 |
25 | 50 |
35 | 70 |
50 | 100 |
75 | 150 |
100 | 200 |
Note: For total flow through ratings (G.P.M) more than 100, double the flow through rating to determine the proper grease retention capacity in pounds.
12.Grease Interceptors or Traps Installed Outside of the Buildings. a.General Requirements. When other authorities or agencies require the installation of an outside grease interceptor/trap, the entire installation within the property line shall comply with 248 CMR 10.03. Where required, the design of said systems shall be specified by the authority or agency requiring the installation, however, said requirements shall not be deemed to supersede the requirements of 248 CMR 10.00.b. This installation shall require a chamber vent which shall: i. be piped to the inside of the building in compliance with 248 CMR 10.16; andii. shall be not less than four-inch minimum pipe diameter;iii. The chamber vent may connect into the buildings sanitary venting system.(c)Special Use Interceptors and Separators. 1.General Requirements. Individual fixture traps shall be installed when special use interceptors or separators are connected to the drainage system which do not meet the requirements of 248 CMR 10.08(2)(d) and (e).2. Commercial establishments which need to be protected by special use interceptors and separators shall include, but not be limited to:e. Other facilities where products that are harmful or hazardous and may enter the building drainage system.3. Special use interceptors shall be:a. designed and located as to be readily accessible for cleaning; andb. have a wire or sand basket capable of preventing the passage of sand or solids likely to cause a stoppage into the drainage system.4. Sand interceptors shall have a water seal of not less than six inches.Amended by Mass Register Issue 1331, eff. 1/27/2017.Amended by Mass Register Issue 1510, eff. 12/8/2023.