248 CMR, § 10.08

Current through Register 1533, October 25, 2024

Section 10.08 - Traps and Cleanouts

(1)General Requirements. Fixture traps shall be of standard design, weight and in compliance with 248 CMR 10.06(2)(c) and (d). Exposed traps made of copper alloy tubing shall be a minimum of 17 gauge.

(2)Fixture Traps.

(a)Separate Traps for Each Fixture.

1.Separate Trapping Required.

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:

i. Fixtures having integral traps.

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.

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.

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.

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

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

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(b)Size of Fixture Traps.

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. 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)	11/2
Bidet	11/2
Clothes washing machine connection	2
Combination sink and wash tray	11/2
Combination sink and wash tray with food waste disposer unit	11/2
Dental unit or cuspidor	11/2
Dental Lavatory	11/2
Drinking Water Station, with Drain	11/4
Dishwasher, commercial	2
Dishwasher, domestic	11/2
Floor drain	2
Food waste disposer	11/2
Kitchen sink, domestic, with food waste disposer unit	11/2
Kitchen sink (two compartments)	11/2
Kitchen sink, domestic	11/2
Lavatory, common	11/2
Lavatory (barber shop, beauty parlor or surgeon's)	11/2
Lavatory, (multiple type) (wash fountain or wash sink)	11/2
Laundry sink (one or two compartments)	11/2
Shower stall	2
Sink (surgeon's)	11/2
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

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

1. Traps which depend upon moving parts to maintain their seal.

2. Bell traps.

3. Crown vented traps.

4. Separate fixture traps which depend on interior partitions for their seal.

5. Full "S" traps.

(d)Design of Traps.

1. Fixture traps shall be self-scouring and shall have no interior partitions except where such traps are integral with the fixture.

2. Slip or ground joints that are part of a trap shall meet the requirements on 248 CMR 10.07(6).

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

Exception:

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.

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.

(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

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

(g)Building and Running Traps.

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. 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 1/2 the diameer of the drain to which it connects.

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.

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

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:

i. an accessible cleanout;

ii. a vent four-inch in size run independently through the roof.

c. Stacks shall be installed in intervals not exceeding 60 feet and in accordance with 248 CMR 10.16(3)(a).

(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.

(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

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(b) Cleanout plugs shall meet the following requirements.

1. Shall be composed of brass or plastic.

2. Shall meet the latest testing standards.

3. Shall have raised or countersunk square or hexagon heads.

4. If a tripping hazard may exist, only a countersunk head shall be used.

5. Plastic cleanout plugs shall be of the same material to which it connects.

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

1. extended vertically to or above the finished grade level; or

2. extended to an accessible location immediately outside the building. See 10.08: Example 9.

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

1. at each change of direction of the building drain; or

2. at each change of direction of horizontal waste or soil lines and branch lines, that are greater than 45 °.

(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

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Concealed Cleanout in Wall

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(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

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(g)Building Drain at Foundation Wall.

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. If necessary, a pit or manhole shall be provided.

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. An additional full-sized cleanout may be installed outside of the building but not more than five feet beyond the foundation wall.

10.08: Example 7 - Piping Configurations of Building Drains at Foundation Wall

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(h)Inaccessible Cleanouts. For buildings with concrete floors (slabs) or with less than 36 inches of crawl space under the floor, or where a cleanout is not easily accessible, the cleanout for the building drain may be installed outside of the building but not more than five feet beyond the foundation wall.

10.08: Examples 8 and 9

10.08: Example 8

Inaccessible Cleanout at The Base of A Stack

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10.08: Example 9

Building Drain Cleanout Installed Outside

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(i)Direction of Flow. Every cleanout shall be installed so that the cleanout opens in the direction of the flow of the drainage line or at right angles thereto.

(j)Cleanout Size: Cleanouts shall be of the same nominal size as the pipes up to four inches and not less than four inches for larger piping.

(k)Cleanout Clearances. See 10.08: Example 10.

1.Large Pipe - 18 Inch Clearance: Cleanouts on three inch or larger pipes shall be so installed that there is a clearance of not less than 18 inches for the purpose of clearing stoppages.

2.Small Pipe - 12 Inch Clearance: Cleanouts smaller than three inches shall be so installed that there is a 12-inch clearance for the purpose of clearing stoppages.

10.08: Example 10 - Cleanout Clearances

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(l)Cleanouts Shall Be Kept Uncovered and Accessible.

1. Cleanout plugs shall not be covered with cement, plaster, or any other permanent finishing material.

2. Where it is necessary to conceal a cleanout plug, a covering plate or access door shall be provided which will allow ready access to the plug for removal. See 10.08: Example 5.

(m)Cleanout Equivalent: The cleanout equivalent may be satisfied by one of the following methods:

1. a fixture trap that incorporate a union connection;

2. a fixture with an integral trap; or

3. roof drain covers that are readily removable without disturbing concealed rough piping.

(n)Connections to Cleanouts Prohibited. Cleanout openings shall not be used for the installation of any new or additional plumbing except where another end-cleanout of equal access and capacity is provided.

(o)Manholes for Large Pipes.

1. For underground and "dedicated system" piping that is over ten inches in diameter and is outside a building, manholes shall be provided and located at every change of size in diameter, alignment grade or elevation and at intervals of not more than 350 feet except when the total developed length of the drain is less than 150 feet, cleanouts may be installed at 75 intervals.