As used in this chapter, unless the context
or subject matter otherwise requires, the following terms shall have
the following meanings:
ACCEPTABLE DEVICES
Those devices or assemblies found to be acceptable for containment
control in New York State in accordance with Department of Health
requirements.
[Amended at time of adoption of Code (see Ch. 1, General
Provisions, Art. I)]
AESTHETICALLY OBJECTIONABLE FACILITY
One in which substances are present which, if introduced
into the public water supply system, could be a nuisance to other
water customers but would not adversely affect human health. Typical
examples of such substances are food-grade dyes, hot water, stagnant
water from fire lines in which no chemical additives are used, etc.
AIR GAP SEPARATION
The unobstructed vertical distance through the free atmosphere between the lowest opening from any pipe or faucet supplying water to a tank, plumbing fixture or other device and the flood level rim of the receptacle. The differential distance shall be at least double the diameter (D) of the supply pipe. In no case shall the air gap be less than one inch. (See
Figure 24-1.)
APPROVED CHECK VALVE
A check valve that seats readily and completely. It must
be carefully machined to have free-moving parts and assured watertightness.
The face of the closure element and valve seat must be of bronze composition
or other noncorrodible material which will seat tightly under all
prevailing conditions of field use. Pins and bushings shall be of
bronze or other noncorrodible, nonsticking material, machined for
easy, dependable operation. The closure element, e.g., clapper, shall
be internally weighted or otherwise internally equipped to promote
rapid and positive closure in all sizes where this feature is obtainable.
AUXILIARY SUPPLY
Any water supply on or available to the premises other than
the approved public water supply.
BACKFLOW
A flow condition induced by a differential in pressure that
causes the flow of water or other liquids and/or gases into the distribution
pipes of a public water supply from any source other than its intended
source.
BACKPRESSURE
The resulting backflow of contaminated, polluted or otherwise unacceptable quality water from a plumbing fixture or other customer source(s) into a public water supply system due to a greater pressure within the customer's water system. (See
Figure 24-2.)
BACKSIPHONAGE
The backflow of contaminated or polluted water or water of questionable quality from a plumbing fixture or other customer source(s) into a public water supply system main due to a temporary negative or subatmospheric pressure within the public water supply system. (See
Figure 24-3.)
CERTIFIED BACKFLOW PREVENTION DEVICE TESTER
A person who is examined annually by the water purveyor and
found competent for the testing of backflow prevention devices. He
or she shall be provided with an appropriate identification card which
must be renewed annually. Failure to perform his or her duties competently
and conscientiously will result in prompt withdrawal of his or her
certification.
CONTAINMENT
Cross-connection control which isolates the customer's entire
facility from the public water system so as to provide the protection
necessary to prevent contamination of the public water supply in the
event of backflow from the customer's facility.
CONTAMINATION
The presence in water of a substance that tends to degrade
its quality.
CROSS-CONNECTION
A physical connection through which a water supply could
be contaminated.
CUSTOMER
A water user served by a public water system.
CUSTOMER'S WATER SYSTEM
The piping used to convey water supplied by a public water
supply system throughout a customer's facility.
DEGREE OF HAZARD
Whether a facility is rated as hazardous, aesthetically objectionable
or nonhazardous.
DOUBLE CHECK VALVE (DCV) ASSEMBLY, ACCEPTABLE
Two single, independently acting check valves, including tightly closing shutoff valves located at each end of the assembly and suitable connections for testing the watertightness of each check valve. This device must be approved as a complete assembly. (See
Figure 24-4.)
HAZARDOUS FACILITY
One in which substances may be present which, if introduced
into the public water system, would or may endanger or have an adverse
effect on the health of other water customers. Typical examples include
laboratories, sewage treatment plants, chemical plants, hospitals
and mortuaries.
INTERCONNECTION
A joining of two independently operated public water supply
distribution systems.
NONHAZARDOUS FACILITY
One which does not require the installation of an acceptable
backflow prevention device.
PLUMBING CONTROL
Prevention and elimination of cross-connections within the
customer's water system by enforcement of building or plumbing codes.
PUBLIC WATER SUPPLY SYSTEM
A supplier of water system, including the source, treatment
works, transmission mains, distribution system and storage facilities
serving the public.
REDUCED PRESSURE ZONE (RPZ) DEVICE, ACCEPTABLE
A minimum of two independently acting check valves, together with an automatically operated pressure differential relief valve located between the two check valves. During normal flow and at the cessation of normal flow, the pressure between these two checks shall be less than the upstream (supply) pressure. In case of leakage of either check valve, the differential relief valve, by discharging to the atmosphere, shall operate to maintain the pressure between the checks at less than the supply pressure. The unit must include tightly closing shutoff valves located at each end of the device, and each device shall be fitted with properly located test cocks. This device must be approved as a complete assembly. (See
Figure 24-5.)
SUPPLEMENTARY SUPPLY
Any water source or system, other than the public water supply,
that is available within the water customer's facility.
WATER SUPERVISOR
The consumer or a person on the premises charged with the
responsibility of complete knowledge and understanding of the water
supply piping within the premises and for maintaining the consumer's
water system free from cross-connections and other sanitary defects,
as required by regulations and laws.
The protective device required shall depend
on the degree of hazard as tabulated below:
A. At the service connection on any premises on which
there is an auxiliary water supply, the public water supply system
shall be protected by an air gap separation or an approved reduced
pressure principle backflow prevention device.
B. At the service connection to any premises on which
a substance that would be objectionable (but not hazardous to health
if introduced into the public water supply) is handled so as to constitute
a cross-connection, the public water supply shall be protected by
an approved double check valve assembly.
C. At the service connection to any premises on which
a substance of unusual toxic concentration or danger to health is
or may be handled, but not under pressure, the public water supply
shall be protected by an air gap separation or an approved reduced
pressure principle backflow prevention device. This device shall be
located as close as practicable to the property line, and all piping
between the water meter and receiving tanks shall be entirely visible.
D. At the service connection to any premises on which
any material dangerous to health or toxic substance in toxic concentration
is or may be handled under pressure, the public water supply shall
be protected by an air gap separation. The air gap shall be located
as close as practicable to the property line, and all piping between
the property line and receiving tanks shall be entirely visible. If
these conditions cannot reasonably be met, the public water supply
shall be protected with an approved reduced pressure principle backflow
prevention device, provided that the alternative is acceptable to
the Director of Public Works.
E. At the service connection to any sewage treatment
plant or sewage pumping station, the public water supply shall be
protected by an air gap separation. The air gap shall be located as
close as practicable to the property line, and all piping between
the water meter and receiving tanks shall be entirely visible. If
these conditions cannot be reasonably met, the public water supply
shall be protected with an approved reduced pressure principle backflow
prevention device.
F. At the service connection to any premises not covered by Subsections
A through
E above, the public water supply shall be protected with an approved single check valve assembly.