plumbing appliances

Portable Dishwasher

Permanently Installed Dishwasher

If the dishwasher is located adjacent to a kitchen sink it is a common practice to install a tee and a shut-off valve off the pipe supplying hot water to the sink.

If the dishwasher is located away from the kitchen sink. It should have its own water supply equipped with its own shut-off valve.

Dishwashers are equipped with electronic solenoid valve that can cause water hammer.

Provisions shall be made to protect the water distribution system from the adverse effects of water hammer.


Water hammer is typically controlled by the installation of a mechanical device known as a Water Arrester.		A small coil of plastic (PEX) water pipe 3' to 5' long can be installed behind or under dishwasher. It can absorb the energy created by the shock wave surging through the pipe.

If the dishwasher is installed adjacent to a kitchen sink, the dishwasher may discharge through the sink trap.

Dishwasher Tailpiece

Dishwasher Adapter

When a single bowl sink is installed, the dishwasher may connect upstream of the trap by the use of either a dishwasher tailpiece, or a Y and a dishwasher adaptor installed.

When a double sink is to be installed, the dishwasher must connect upstream of the trap into the fixture outlet pipe on either vertical or the horizontal section.

When a dishwasher connects into the outlet pipe of a kitchen sink there is no additional load placed on the trap or the drainage system: "no load when connect to garbage grinder or domestic sink".

If the dishwasher is not located directly adjacent to a kitchen sink, a separate hot water and drainage connection must be provided for the dishwasher.

Note: if a separate trap is provided for a domestic dishwasher the fixture unit loading is 1/2 of a fixture unit. (See Table 7.4.9.3.).

Garbage Disposal Unit			Water and Ice Dispensing Refrigerators
	Garbage grinders discharge into either the fixture trap, or the fixture outlet piping of the sink.			have water supply piping of either 1/4" or 3/8" size. In common with dishwashers, these appliances also incorporate quick closing valves and some consideration needs to be taken to control water hammer.

If a washer is to be located on the second floor, it is advisable to install a floor drain to provide drainage in the event of a failed water supply hose, or a leak developing in the machine itself.

Unlike dishwashers, washing machines require both hot and cold water. The water service for each machine should be in the form of hose bibs whish connect to the hot and cold flexible supply hoses attached to the machine.

It is common to install in single family homes.

The drainage pipe from a domestic washing machine is usually a rubber hose of approximately 1-inch inside diameter. This pre-shaped hose connects into the washer box or hangs over the edge of the laundry tub.

Another drainage connection used in conjunction with a laundry tub, is to pipe in a standing waste for the drain hose. A standing waste is a 1 1/2" drainage pipe connected to the fixture outlet pipe and extended up the side of the laundry tub.

7.4.5.1.(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

are in the same room, and
are not located where they can receive food or other organic matter.

Note: ganged-trapped fixtures must drain into a running trap with a cleanout installed on the upstream side of the trap.

Table 7.4.9.3. does not list a fixture outlet pipe size for either a domestic or commercial clothes washers. However,

The four commercial clothes washers shown ganged trapped above will produce a maximum hydraulic load of eight fixture units. This would require a 3" running trap installed with a 1 1/2" vent.

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