Page 89 - Vessel Sanitation Program 2018 Operations Manual

VSP 2018 Operations Manual

BACKFLOW PREVENTION DEVICES must be installed when
AIR GAPS are impractical or when water under pressure is
required. Provide an AIR GAP for the atmospheric vent of all
BACKFLOW PREVENTION DEVICES.

A mechanical BACKFLOW PREVENTION DEVICE must have
an atmospheric vent.

5.7.1.2.2 2X Diameter (08)
AIR GAPS must be at least twice the diameter of the delivery
fixture opening and a minimum of 25 millimeters (1 inch).

5.7.1.2.3 Flood-Level Rim (08)
An ATMOSPHERIC VACUUM BREAKER must be installed at
least 150 millimeters (6 inches) above the flood-level rim of the
fixtures.

5.7.1.2.4 After Valve (08)
An ATMOSPHERIC VACUUM BREAKER must be installed
only in the supply line on the discharge side of the last control
valve.

5.7.1.2.5 Continuous Pressure (08)
A CONTINUOUS PRESSURE-type BACKFLOW
PREVENTION DEVICE must be installed when a valve is located
downstream from the BACKFLOW PREVENTION DEVICE.

5.7.1.2.6 Backflow Prevention Devices (08)
BACKFLOW PREVENTION DEVICES must be provided on all
fixtures using POTABLE WATER and that have submerged inlets.

5.7.1.2.7 Vacuum Toilets (08)
An ATMOSPHERIC VACUUM BREAKER must be installed on a
POTABLE WATER supply connected to a vacuum toilet system.
An ATMOSPHERIC VACUUM BREAKER must be located on
the discharge side of the last control valve (flushing device).

5.7.1.2.8 Diversion Valves (08)
Lines to divert POTABLE WATER to other systems by valves or
interchangeable pipe fittings must have an AIR GAP after the
valve.

5.0 Potable Water; 60