(2) Fixture Traps.

1. (a) Separate Traps for Each Fixture.

   1. 1. Separate Trapping Required.

      1. a. Individual plumbing fixtures shall be separately trapped by a water seal trap placed as close as possible to the fixture outlet. Exception: To the separate trapping requirements are as follows:

         1. i. Fixtures having integral traps.
         2. ii. A combination plumbing fixture may be installed on one trap provided one compartment is not more than six inches deeper than the other and the waste outlets are not more than 30 inches apart.
         3. iii. One trap may be installed for not more than three single compartment sinks or lavatories, immediately adjacent to each other, and in the same room. The trap is to be centrally located when three such fixtures are installed. The center-to-center measurement of the waste outlets shall not exceed 30 inches apart.
         4. iv. The waste for a domestic dishwasher may be separately trapped, connected to the manufactured inlet side opening of a food waste disposer or connected between the outlet of the kitchen sink and the inlet of the trap using a "wye" fitting.
      2. b. The vertical distance from the fixture outlet to the trap weir shall not exceed 24 inches. See 10.08: Examples 1 and 2.

10.08: Example 1 - Vertical Distance from Fixture Outlet to Trap Weir

Lavatory

M aximum Dist ance from Fixhire Outlet to Trap Weir

Fixt ure Outlet /

24 Inches

Tra pWei1r

10.08: Example 2 - Vertical Distance from Fixture Outlet to Trap Weir

Floor Drain

Maximum Distance from Fixture Outlet to Trap Weir

' Fixtu re Outlet

.1. I

Tra p Weir

~

(b) Size of Fixture Traps.

1. 1. The size of the fixture trap shall be sufficient to drain the fixture rapidly and in no case less than outlined in 248 CMR 10.08: Table 1: Minimum Size of Fixture Traps.

2. 2. The fixture trap shall be the same pipe size as the drain into which it discharges.

   Table 1

   Minimum Size of Fixture Traps PLUMBING FIXTURE Trap Size in Inches

Bathtub (with or without overhead shower) 1½ Bidet 1½

Clothes washing machine connection 2 Combination sink and wash tray 1½ Combination sink and wash tray with food waste disposer unit 1½ Dental unit or cuspidor 1½ Dental Lavatory 1½ Drinking Water Station, with Drain 1¼ Dishwasher, commercial 2 Dishwasher, domestic 1½ Floor drain 2 Food waste disposer 1½ Kitchen sink, domestic, with food waste disposer unit 1½ Kitchen sink (two compartments) 1½ Kitchen sink, domestic 1½ Lavatory, common 1½ Lavatory (barber shop, beauty parlor or surgeon's) 1½ Lavatory, (multiple type) (wash fountain or wash sink) 1½ Laundry sink (one or two compartments) 1½ Shower stall 2 Sink (surgeon's) 1½ Sink (flushing rim type with flushometer valve) 3 Sink (service type with floor outlet trap standard) 3 Sink (service trap with P trap) 2 Sink, commercial (pot, scullery, or similar type) 2 Sink, commercial (with food disposer unit) 2

1. (c) Prohibited Traps. The following type traps are prohibited.

   1. 1. Traps which depend upon moving parts to maintain their seal.
   2. 2. Bell traps.
   3. 3. Crown vented traps.
   4. 4. Separate fixture traps which depend on interior partitions for their seal.
   5. 5. Full "S" traps.

2. (d) Design of Traps.

   1. 1. Fixture traps shall be self-scouring and shall have no interior partitions except where such traps are integral with the fixture.
   2. 2. Slip or ground joints that are part of a trap shall meet the requirements on 248 CMR 10.07(6).

   3. 3. Each fixture trap shall have an accessible cleanout plug of ample size that is protected by the water seal. Exception:

      1. a. Traps which are cast integrally or in combination with the fixture in which the trap seal is readily accessible or except when a portion of the trap is readily removable for cleaning purposes.
      2. b. Traps for floor outlet and similar fixtures including bathtubs and showers where a cleanout would not be accessible. A cleanout shall be installed in the nearest accessible location.

3. (e) Trap Seal. Each fixture trap shall have a liquid seal of not less than two inches and not more than four inches, except where for special conditions, a deeper seal may be required. See 10.08: Example 3. The protection of trap seals from siphonage, aspiration, momentum, oscillation, back pressure, evaporation, or capillary action shall be accomplished by the appropriate use of soil or waste stacks, vents, re-vents, dry vents, wet vents, loop vents, circuit, or continuous vents, or combinations thereof, installed in accordance with the requirements of 248 CMR 10.16, so that at no time shall the trap be subjected to a pressure differential of more than one inch of water.

   10.08: Example 3 - Minimum Liquid Trap Seal

   Minimum 2" to 4" Trap Sea l

4. (f) Trap Setting and Protection. Traps shall be set level with respect to their water seals and wherever necessary, shall be protected from freezing.

5. (g) Building and Running Traps.

   1. 1. Building and running traps shall not be installed unless in the opinion of the Inspector they are deemed necessary. Exception: Where a trap in compliance with 248 CMR 10.08(2)(d) may be subject to freezing temperatures, a running trap may be installed in an area not subject to freezing but as close as possible to the fixture it serves.
   2. 2. Each building trap when installed shall be provided with an accessible cleanout and with a relieving vent or fresh air intake which need not be larger than ½ the diameer of the drain to which it connects.

   3. 3. Open Parking Garages. Parking garages containing openings in exterior walls on two or more sides of each level of not less than 20% of the total perimeter wall space on that level.

      1. a. Installation of traps for floors drains which are located on the open level(s) shall not be required.

      2. b. A running trap shall be installed on the sanitary drain prior to entering the separation or containment system as required in 248 CMR 10.09(1)(a) and equipped with:

         1. i. an accessible cleanout;
         2. ii. a vent four-inch in size run independently through the roof.
      3. c. Stacks shall be installed in intervals not exceeding 60 feet and in accordance with 248 CMR 10.16(3)(a).
6. (h) Acid Resistant Trap. Where a vitrified-clay or other brittle ware, acid-resistant trap is installed underground, it shall be embedded in concrete extending six inches beyond the bottom and sides of the trap.

(3) Drainage Pipe Cleanouts.

1. (a) Location: Cleanouts shall be placed no more than 50 feet apart in all horizontal drainage piping and branch drain piping which is four-inch in diameter or less. On horizontal piping which is over four inch in diameter, cleanouts shall not be more than 100 feet apart. See 10.08: Example 4.

10.08: Example 4 - Maximum Cleanout Distance on Horizontal Drain

Over Fou r-inch Diameter Pipe - Maximum of One Hund red Feet

Four-inch Diamet er Pipe or Less - Maximum of Fift y Feet

1. (b) Cleanout plugs shall meet the following requirements.

   1. 1. Shall be composed of brass or plastic.
   2. 2. Shall meet the latest testing standards.
   3. 3. Shall have raised or countersunk square or hexagon heads.
   4. 4. If a tripping hazard may exist, only a countersunk head shall be used.
   5. 5. Plastic cleanout plugs shall be of the same material to which it connects.

2. (c) Underground Drainage. Cleanouts, when installed on underground drainage piping, shall be:

   1. 1. extended vertically to or above the finished grade level; or
   2. 2. extended to an accessible location immediately outside the building. See 10.08: Example 9.

3. (d) Change of Direction. Accessible cleanouts shall be installed:

   1. 1. at each change of direction of the building drain; or
   2. 2. at each change of direction of horizontal waste or soil lines and branch lines, that are greater than 45E.

4. (e) Concealed Piping. Cleanouts on concealed piping shall be extended through and terminate flush with the finished wall or floor. Cleanouts located in floors, walls, pits, and chases may be left in the wall or floor provided an access panel of sufficient size to allow removal of the cleanout plug and proper cleaning of the system. See 10.08: Example 5.

   10.08: Example 5

Concealed Cleanout in Floor Concealed Cleanout in Wall

Floor Cleanout Access Panel

Clea nout Access Plat e

(f) Base of Stacks. A cleanout shall be provided at or near the base of each vertical storm water conductor, waste, or soil stack. See 10.08: Example 6.

10.08: Example 6 - Cleanout at the Base of a Stack

Cleanout

M

BaseofStack Floor Level

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1. (g) Building Drain at Foundation Wall.

   1. 1. There shall be a clean-out installed on the building drain so located as to provide accessibility in direct line through the building drain to building sewer.
   2. 2. If necessary, a pit or manhole shall be provided.
   3. 3. Piping configuration shall be installed as diagramed in 10.08: Example 7 and in compliance with 10.06: Table 1 and consistent with the materials being installed.
   4. 4. An additional full-sized cleanout may be installed outside of the building but not more than five feet beyond the foundation wall.