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All potable water openings and outlets shall be protected against backflow in accordance with the following:
1. Openings and outlets shall be protected by an air gap between the opening and the fixture flood level rim as specified in Table 18-29-608.15.1. Openings and outlets equipped for hose connection shall be protected by means other than an air gap.
2. Openings and outlets shall be protected by a reduced pressure principle backflow preventer.
3. Openings and outlets shall be protected by a backflow preventer with an intermediate atmospheric vent.
4. Openings and outlets shall be protected by atmospheric-type vacuum breakers. The critical level of the vacuum breaker shall be set a minimum of 6 inches (150 mm) above the flood level rim of the fixture or device. Ball cocks shall be set in accordance with Section 425.3.1. Vacuum breakers shall not be installed under exhaust hoods or similar locations that will contain toxic fumes or vapors. Pipe-applied vacuum breakers shall be installed not less than 6 inches (150 mm) above the flood level rim of the fixture, receptor or device served.
5. All pull-out spout-type faucets shall be in compliance with CSA CAN/CSA-B 125 and have an integral vacuum breaker or vent to atmosphere in their design or shall require a dedicated deck- or wall-mounted vacuum breaker. Approved deck-mounted or equipment-mounted vacuum breakers and faucets with integral atmospheric or spill-proof vacuum breakers shall be installed in accordance with the manufacturer's instructions and the requirements for labeling with the critical level not less than, 1 inch (25 mm) above the flood level rim.
6. Sillcocks, hose bibbs, wall hydrants and other openings with a hose connection shall be protected by an atomospheric-type or pressure type vacuum breaker or a permanently attached hose connection vacuum breaker.
Exceptions:
1. This section shall not apply to water heater and boiler drain valves that are provided with hose connection threads and that are intended for only tank or vessel draining.
2. This section shall not apply to water supply valves intended for connection of clothes washing machines where backflow prevention is otherwise provided or is integral with the machine.
Fixture | Minimum Air Gap | |
Away from a wall a(inches) | Close to a wall (inches) | |
Lavatories and other fixtures with effective opening not greater than 1/2 inch in diameter | 1 | 1 1/2 |
Sink, laundry trays, gooseneck back faucets and other fixtures with effective openings not greater than 3/4 inch in diameter | 1 1/2 | 2 1/2 |
Over-rim bath fillers and other fixtures with effective openings not greater than 1 inch in diameter | 2 | 3 |
Drinking water fountains, single orifice not greater than 7/16 inch in diameter or multiple orifices with a total area of 0.150 square inch (area of circle 7/16 inch in diameter). | 1 | 1 1/2 |
Effective openings greater than 1 inch. | Two times the diameter of the effective opening. | Three times the diameter of the effective opening. |
For SI: 1 inch = 25.4 mm.
a Applicable where walls or obstructions are spaced from the nearest inside edge of the spout opening a distance greater than three times the diameter of the effective opening for a single wall, or a distance greater than four times the diameter of the effective opening for two intersecting walls.