7.4.5.

(1) Except as provided in Sentences (2) and (3) and Article 7.4.5.2., every fixture shall be protected by a separate trap.

(2) One trap may protect,

(a) all the trays or compartments of a two or three compartment sink,

(b) a two or three compartment laundry tray, or

(c) two similar type single compartment fixtures located in the same room.

(3) One trap may serve a group of floor drains and hub drains, a group of shower drains, a group of washing machines or a group of laboratory sinks if the fixtures,

(a) are in the same room, and

(b) are not located where they can receive food or other organic matter.

(4) Reserved.

(5) A grease interceptor shall not serve as a fixture trap and each fixture discharging through the interceptor shall be trapped and vented.

(6) Where a domestic dishwashing machine equipped with a drainage pump discharges through a direct connection into the fixture outlet pipe of an adjacent kitchen sink or disposal unit, the pump discharge line shall,

(a) rise as high as possible to just under the counter, and

(b) connect,

(i) on the inlet side of the sink trap by means of a Y fitting, or

(ii) to the disposal unit.

(1) Where a storm drainage system is connected to a public combined sewer, a trap shall be installed between any opening in the system and the drain or sewer, except that no trap is required if the opening is the upper end of a leader that terminates,

(a) at a roof that is used only for weather protection, and

(b) not less than 1 000 mm above or not less than 3.5 m in any other direction from any air inlet, openable window or door, and

(c) not less than 1 800 mm from a property line.

(1) Except as permitted in Sentence (2), no foundation drain or subsoil drainage pipe shall connect to a sanitary drainage system.

(2) Where a storm drainage system is not available or soil conditions prevent drainage to a culvert or dry well, a foundation drain or subsoil drainage pipe may connect to a sanitary drainage system.

(3) Where a subsoil drainage pipe may be connected to a sanitary drainage system, the connection shall be made on the upstream side of a trap with a cleanout or a trapped sump.

(1) Where a building trap is installed it shall,

(a) be provided with a cleanout fitting on the upstream side of and directly over the trap,

(b) be located upstream of the building cleanout, and

(c) be located,

(i) inside the building as close as practical to the place where the building drain leaves the building, or

(ii) outside the building in a manhole.

(1) Provision shall be made for maintaining the trap seal of a floor drain or a hub drain by the use of a trap seal primer, by using the drain as a receptacle for an indirectly connected drinking fountain, or by equally effective means.

(2) Where a mechanical device is installed to furnish water to a trap, the pipe or tube conveying water from the device to the trap shall be at least 3/8 in. inside diameter.