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9.7 Pressure and Leakage Tests of Water Mains
and fixture outlet protection. Follow up to ensure that
state authorities and members of the local press and
radio attend the meeting.
the recommended devices are installed and tested on
both an initial basis and a periodic basis consistent
3. Place written notices of the pending cross-connection
with the cross-connection control ordinance.
control program in the local newspaper and have the
local radio station make announcements about the
The surveys should be conducted by personnel experi-
program as a public service notice.
4. Send employees who will administer the program
or owners’ representatives should be questioned as to what
to a course, or courses, on backflow tester certifica-
the water is being used for in the facility and what haz-
tion, backflow survey courses, backflow device repair
ards the operations may present to the water system (both
courses, and so on.
within the facility and to the water distribution system) in the
5. Equip the water authority with a backflow device
event that a backsiphonage or backpressure condition were
test kit. enced in commercial and industrial processes. The owners
to exist concurrent with a nonprotected cross-connection. In
the event that experienced survey personnel are not available
6. Conduct meeting(s) with the local plumbing inspec-
within the water authority to conduct the survey, considera-
tion people, building inspectors, and licensed
tion should be given to having a consulting firm perform the
plumbers in the area who will be active in the inspec-
survey on behalf of the water department.
tion, installation, and repair of backflow devices.
Inform them of the intent of the program and the part
that they can play in the successful implementation
of the program. 9.7 PRESSURE AND LEAKAGE TESTS OF
WATER MAINS
7. Prior to initiating a survey of the established commer-
cial and industrial installations, prepare a list of these All external contaminations of water mains should be pre-
establishments from existing records, then prioritize vented. Contaminants entering the water mains through leaks
the degree of hazard that they present to the water are other types of cross-connections. Section 6.9.10 discusses
system: plating plants, hospitals, car wash facilities, the required separation of water mains from sources of con-
industrial metal finishing and fabrication, mortuaries, tamination. Even with proper separation of water mains from
and so on. These will be the initial facilities inspected pollution sources, all water mains must still pass the required
for cross-connections; inspection of less hazardous pressure and leakage tests to ensure that public health is pro-
installations follows. tected. It is required to maintain a pressure of at least 20 psi
8. Ensure that any new construction plans are reviewed (140 kPa) at ground level at all points in the water distribution
by the water authority to assess the degree of haz- system under all conditions of flow. Unfortunately accidents
ard and ensure that the proper backflow preventer do happen due to human errors or unforeseen events. For
is installed concurrent with the potential degree of instance, more than one major fire or major pipe leaks or other
hazard that the facility presents. unanticipated high water demands might draw the hydraulic
grade line down to a point that a negative pressure (vacuum)
9. Establish a residential backflow protection program
might be created at some service connections. This negative
that will automatically ensure that a residential dual
pressure could potentially cause backflow from a contam-
check backflow device is installed automatically at
inated source of water, if the pipe leaks. This section dis-
every new residence.
cusses how the pressure and leakage tests can be conducted
10. As water meters are repaired or replaced at resi-
to prevent any possible backflow from a contaminated source
dences, ensure that a residential dual check backflow
of water.
preventer is set with the new or reworked water meter.
Be sure to have the owner address thermal expansion
provisions.
9.7.1 Preparation for Pressure and Leakage Tests
11. Prepare a listing of all testable backflow devices in the
community and ensure that they are tested by certified Pressure and leakage tests are usually conducted after the
test personnel at the time intervals consistent with the trench has been partially backfilled for a new pipeline. Same
local cross-connection control ordinance. tests can also be conducted frequently after an old pipeline
is being suspected of leakage.
12. Prepare and submit testing documentation of back-
For a new pipeline installation, the pipe joints are often
flow devices to the state authority responsible for
left uncovered until after the tests are completed. Each valved
monitoring these data.
section of the water main is filled slowly with water, with air
13. Survey all commercial and industrial facilities and in the pipe being slowly released through corporation stops
require appropriate backflow protection based on the and hydrants. Corporation stop (or corporation cock) is a
containment philosophy and/or internal protection water service shutoff valve located at the street water main,