5.18 Plumbing Systems
Domestic Water Service Pressure Maintenance.
Distribution water pressure shall provide fixture,
equipment, and outlet required pressures at the
hydraulically most demanding (generally the
Water conservation shall be a requirement of all plumbing
topmost/highest and most remote) outlet. Required outlet
systems. Use water-saving plumbing fixtures.
pressure shall be minimum requirements of code, or
higher requirements of the fixture, equipment, or outlet
Domestic Water Supply Systems
demand as identified by the manufacturer or warrantee.
Domestic Cold Water Service. Domestic potable cold
Distribution water pressures shall not exceed system
water service shall consist of a pressurized piping
material, piping, and device rated maximum working
distribution system incorporating an independent
pressures, or maximum pressures at the fixture,
(separate) service pipe from the tap at the exterior utility
equipment, or outlet as required by code. The A/E shall
service water main to the water meter and backflow
schedule and specify pressure regulating valves or valve
preventer equipment inside the building.
stations where pressures at maximum working pressure
(High HGL, plus booster pump shut-off pressure for
Water service meters shall be located inside the building,
boosted systems) may exceed code maximum, or
utilizing meters (generally) furnished by the water utility
manufacturer/warranty maximum operating pressures
purveyor, to maintain security and supervision within the
(generally lower than code maximums. Pilot operated
security perimeter. Exterior water meter crocks or vaults
pressure reducing valves (or valve stations) with
shall not be permitted. Water meters shall be remote
expansion by-pass (for domestic hot water) shall be
reading type with transponder signal transmitted by
utilized to regulate supply water pressures within
telephone line. Irrigation systems, and similar water
distribution zones. Individual outlets may utilize pressure
supply/make-up systems that do not discharge to the
reducing valves compliant with code requirements and as
sanitary sewer, shall be sub-metered (remote read) for
recommended by the outlet use manufacturer. Pressure
utility billing rate deduction of sanitary service not
reducing valves shall be specified to operate at peak flow
utilized. The water service shall have a code and water
within the entire range of Low HGL and maximum
purveyor compliant reduced pressure zone backflow
working pressure of the system (High HGL, plus pump
prevention device immediately downstream of the service
shut-off head for pressure boosted systems).
water meter(s) prior to all other connections and
branches. Maintain manufacturer and water purveyor
A packaged and third party tested triplex (three pump)
required access and service clearances for meters and
booster pumping system or duplex (two pump) with
backflow preventers.
120-170 gallon hydropneumatic storage pressure tank,
shall be utilized where water flow test and water purveyor
Internal distribution shall consist of a piping system that
low hydraulic grade line (Low HGL) water pressures do
supplies domestic potable cold water to all plumbing
not provide required pressure demands at peak draw.
fixtures, plumbing equipment, water heaters, mechanical
Water pressure boosting shall generally be provided only
make-up, and cold water equipment/system demands.
159
MECHANICAL
ENGINEERING
5.18
Plumbing Systems
Revised March 2005 PBS-P100
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