Section 10.12 - Indirect Waste Piping(1)Indirect Wastes Required. (a)Food and Beverage Handling Establishments. 1. Food and beverage handling establishments engaged in the storage, preparation, selling, serving, processing, or in any manner the handling of food shall provide indirect waste piping for refrigerators, refrigerator coils, walk-in freezers or coolers, ice compartments, ice making machines, steam kettles, steam tables, potato peelers, egg boilers, coffee urns, coffee, soda and beverage trays and all similar types of equipment.2. In establishments which serve soda and alcohol, individual sink compartments which store ice shall discharge independently into a floor drain or floor sink.3. Dishwashing pre-rinse sinks installed in combination with a commercial dishwasher, pot sinks, scullery sinks, hand washing sinks and similar shall not be indirectly wasted and shall be directly connected to the sanitary drainage system.4. Single compartment sinks or individual compartments of multi-bay sinks for culinary or produce shall be individually discharged into a properly vented floor sink or floor drain. These compartments shall be properly labeled for produce preparation using a laminated sign with letters two inches in height that reads: "This Compartment ONLY Is Designated for Produce Preparation." See 10.12: Example 110.12: Example 1 - Culinary Sink
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5. All indirect waste shall discharge either through an air gap or air-break into a properly trapped and vented receptor. See 10.12, Example 4. An air gap shall be required if the indirect waste pipe is under vacuum.6.Vacuum Systems for Food Service Facilities. a. Vacuum drainage systems shall be installed in accordance with the equipment manufacturer's installation instructions or be designed by a Massachusetts professional engineer, regardless of discipline.b. Plastic pipe and fittings shall be allowed within ten feet of the equipment or above the equipment being served prior to transitioning to commercial materials. See 10.12: Example 2. 10.12: Example 2 - Plastic with Vacuum Systems
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(b)Connections from Water Distribution System. Indirect waste connections shall be provided for drains, overflows, or relief lines from the water distribution system by means of an air gap.(c)Sterilizers. Appliances, devices, or apparatus such as stills, sterilizers, and similar equipment requiring waste connections and used for sterile materials shall be indirectly connected by means of an air gap.(d)Drips or Drainage Outlets. Appliances, devices, or apparatus which have drips or drainage outlets may be indirectly discharged into an open receptacle through either an air gap or air-break.(e)Clear Water Wastes. 1. All clear water waste shall be cooled to a temperature no greater than 150 °F prior to discharging into the storm or sanitary drainage system.2. Expansion tanks, fire sprinkler systems, air conditioning equipment, drip, or overflow pans, or similar devices that waste clear water only, shall discharge into the building storm drainage system through an indirect waste by means of an air gap or air-break. The flood level rim of the indirect fixture shall be a minimum of two inches above floor level. See 10.12: Example 3.3. When clear water waste is discharged into a storm system through a vented trap, the vent for that trap shall be labeled "storm vent". Labels shall be: a. At a minimum of every ten feet: b. At all changes of direction:c. On each side of a penetration through a partition, wall, ceiling, or roof. Exceptions:i. Clear water waste may discharge to sanitary systems in cities and towns with written authorization from the authority having jurisdiction whose system will be accepting the discharge.ii. The waste discharge from safe waste pans serving water heaters, storage tanks and boilers may discharge to a properly trapped and vented fixture to the sanitary drainage system.iii. Clear water condensate waste that is produced in cumulative amounts of 12.5 gallons per hour or 300 gallons per day or less in buildings by air conditioning equipment, air compressor blow-down discharge (free of petroleum hydrocarbons) or other similar apparatus or appliances may be discharged to the sanitary drainage system. The clear water waste requirement is not withstanding any local ordinance, by-law, rule, or regulation to the contrary. Example 3 -Clear Water Waste Discharge
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(f)Safe Waste Pan. 1. Safe waste pans shall be installed under water heaters, storage tanks or boilers that have a storage capacity of six gallons or more and installed in a position elevated above any occupied space.2. Safe waste pans shall be piped indirectly to properly trapped and vented fixtures or to a point within 12 inches of the lowest floor level. See 10.12: Example 4, Drawing 1 for single heater installation and Drawing 2 for multiple heater installations. Exception: When installing a replacement water heater, storage tank or boiler, an acceptable alternate method may be to install a product accepted automatic water heater shut off device and a safe waste pan without the related drain piping. If this method is used, the water heater temperature and pressure relief valve shall discharge into the water heater safe waste pan. See 10.12: Example 4, Drawing 3.
3. The Minimum size waste pipe shall be one inch. See 10.12: Example 4, Table for Sizing Safe Waste Pans.4. Where floor drains and other acceptable points of indirect discharge are installed on the same floor level, no safe waste shall be required.5. Safe waste pans shall be at least two inches deep and have a minimum clearance of two inches around the base of the appliance being served.6. Materials for the Discharge Piping of Safe Waste Pans. Materials shall comply with materials covered under 248 CMR 10.06 relating to commercial and residential installations. 10.12 Drawing 1
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10.12 Drawing 2
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10.12 Drawing 3
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10.12 Drawing 4
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Table for Sizing Safe Waste Pan Mains
Relief Valve Size | Number of Heaters or Storage Tanks |
2 | 3 | 4 or More |
3/4" | 1-1/4" | 1-1/4" | 1-1/2" |
1" | 1-1/4" | 1-1/2" | 1-1/2" |
1-1/4" | 1-1/2" | 1-1/2" | 2" |
1-1/2" | 2" | 2" | 2" |
2" | 2" | 2" | 2" |
(2)Air Gap or Air-break Required. All indirect waste piping shall discharge into the building sanitary or storm drainage system through an air gap or air-break, as stated in 248 CMR 10.12(1)(a)5., and in no instance shall the indirect waste be trapped ahead of the air gap or air-break. (a)Methods of Providing an Air Gap. The air gap between the indirect waste and the building sanitary or storm drainage system shall be at least twice the effective diameter of the drain served and shall be provided by one of the following methods: See 10.12: Example 5, Drawing 1.1.To a Receptor. Extend the indirect waste pipe to an open, accessible individual waste sink, floor drain or another fixture which is properly trapped and vented.2.To the Inlet Side of Trap. Provide an air gap in the drain connection on the inlet side of the trap which receives the waste from the indirect waste.(b)Methods of Providing an Air-break. When an air-break is required between the indirect waste and the building sanitary or storm drainage system, the distance to which the outlet of the indirect waste pipe extends below the flood level rim of the receptacle into which it is discharging shall be prescribed in 248 CMR 10.12. See 10.12: Example 5, Drawing 2. 10.12: Example 5 - Use of Air-Gap and Air Break
Drawing 1: Use of Air Gap for Indirect Waste with a Floor Sink
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Drawing 2: Use of Air-Break for Indirect Waste with a Floor Sink
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(3)Receptors or Sumps. (a)Installation. Indirect waste receptors and sumps serving indirect waste pipes shall not be installed in toilet facilities or in any location that is an inaccessible or unventilated space such as a closet, storeroom, or crawl space.(b)Size of Receptor. The pipe size serving a receptor shall be a minimum of one size larger than the largest indirect waste it serves.(c)Cleanout Location. If the indirect waste receptor is set below floor level, it shall be equipped with a running trap adjacent thereto with the trap cleanout brought level with the floor.(d)Strainers and Baskets. Every indirect waste receptor shall be equipped with a readily removable metal basket over which all indirect waste pipes shall discharge, or the indirect waste receptor outlet shall be equipped with a beehive strainer not less than four inches in height.(e)Splashing to be Prevented. All plumbing receptors receiving the discharge of indirect waste pipes, shall be of a design and capacity to prevent splashing or flooding of the adjacent area.(f)Domestic or Culinary Fixture Prohibited as Receptors. No plumbing fixture which is used for domestic or culinary purposes shall be used to receive the discharge of an indirect waste pipe, except that in a residence a kitchen sink is acceptable for use as a receptor for dishwashers and portable clothes washing machines provided the kitchen sink drain in a minimum of two inch.(4)Condenser Sumps. No steam condenser waste pipe shall directly connect to any part of a sanitary or storm drainage system, nor shall any water above 150 °F be discharged into any part of a sanitary or storm drainage system.(5)Installation of Indirect Waste Piping. (a)Accessibility. Indirect waste piping shall be installed to enable ready access for flushing, cleaning, or replacement.(b)Sizing. Any fixture or piece of equipment to be indirectly wasted that has a waste outlet smaller than 1¼ in diameter shall be connected to an indirect waste pipe one size larger than said outlet.(c)Indirect Waste Piping.1.Individual Indirect Waste. An indirect waste which connects to one waste outlet and extends to the receiver shall be classified as an Individual Indirect Waste.2.Indirect Waste Branch. An indirect waste which connects to one waste outlet and extends to either an indirect waste main or an indirect waste branch main shall be classified as an Indirect Waste Branch.3.Indirect Waste Main. An indirect waste which connects to more than one waste outlet and extends to the receiver shall be classified as an Indirect Waste Main.4.Indirect Waste Branch Main. A branch from an indirect waste main which connects to more than one waste outlet shall be classified as an Indirect Waste Branch Main.(d)Traps.1. A trap shall not be installed on an indirect waste main or on an indirect waste branch main.2. A trap may be installed on any indirect waste branch or individual indirect waste where it is necessary or desirable to prevent the flow of air from inside the indirect waste piping through the indirect waste branch.(e)Air Circulation Through Indirect Waste Piping.1. Provision shall be made so that air can circulate freely through an individual waste, waste main or a waste branch main.2. When a waste branch is trapped a properly sized vent shall be installed.3. An indirect waste stack receiving the discharge from fixtures on two or more floors shall be extended to the outer air as required for a stack vent.(6)Multiple Occupancy. (a) When a system of indirect waste piping serves buildings or premises having more than one tenant occupancy, it shall be designated as a "Central Indirect Waste System" and connection to it from separate tenant occupancies shall be designated as "Separate Indirect Waste Systems."(b) Separate indirect waste systems shall be connected to "Central Indirect Waste Systems" as follows:1. The indirect waste branch to a separate occupancy shall be trapped, and this trap shall serve as a secondary indirect waste receiver for the separate indirect waste system.2. The indirect waste branch to a separate occupancy may be from a horizontal indirect waste main or branch main, or from an indirect waste stack.(c)Secondary Indirect Waste Receivers.1. Traps serving secondary indirect waste receivers shall be protected from siphonage by adequate individual battery of stack vents.2. Vents on indirect waste piping systems shall not be connected to the vents of any other piping system but shall be extended separately to the outer air as required for stack vents.Amended by Mass Register Issue 1331, eff. 1/27/2017.Amended by Mass Register Issue 1510, eff. 12/8/2023.