Rev. 13 November 1, 2016
Page | 48a. Install horizontal sections o f domestic water m ains above-ceiling in corridors.
b. Pipi ng “ de ad ends” shall be a voi de d to prevent water stagnation and con tamination.
c. All above-ceiling sections of branch lines shall be at least ¾” diameter to allow for future capacity
reductions due to possible scaling. Terminal runs in walls and to fixt ur es m ay, at t he design cons ultant’s
options be less t han ¾” diameter.
d. Provide i solation valves on all major b ranch lines. Ball valves shall b e ins talled on a ll lines 2” diameter and
less. Ball valves s ha ll be specified to be chemical resistant due to the c hemical t reatment now in us e in
several buildings.
e. Manual air vents shall be installed at the top of each ri ser.- Pressure Reducing Valve (PRV) assemblies
a. PRVs shall be either:
i. For si zes above 2” diameter, Watts U5B-Z3 (epoxy-coated with stainless steel and Viton upgrades) o r
Owner approved equal. (Carefully review the proposed si ze. Proper si zing of these P RVs typically
require a P RV smaller than the line si ze.) For sizes up to 3”, no low flow/bypass r egulators a re
required.
ii. For sizes up to and including 2”, Watts 25AUB, equal by Wilkins or Owner approved equal. No low
flow/bypass regulators are required.
b. PRVs shall be specified to be chemical resistant due to the chemical treatment now in use in several
buildings.
c. Install PRVs at locations that provide full access for maintenance. To ensure that full access is provided, the
Engineer shall:
i. Graphically show the reserved access space around all PRVs on the bid documents for each
project.
ii. Require, via the bid documents, that the Contractor shall prepare and submit coordination drawings
that show the access space for each PRV.
d. For all PRVs without integral unions, install flanges on both ends. For all PRVs with an integral union on one
end, install a flange on the other end.
e. Provide two ½” ports on each main downstream of the PRV to allow for future remote sensing of the water
pressure and temperature. Review with the Owner whether the actual sensing will be included within a given
project.
f. All PRV assemblies shall be provided with:
i. A valved bypass line, equal to line size but with a 2” diameter maximum.
ii. A dial type pressure gauge with a ball valve shut-off. - Backflow prevention
a. For protection of entire additions or wings, install a reduced pressure backflow preventer, such as
Watts 909 (with integral gate valves) or Owner approved equal.
b. For protection of pipe branches above 2”, install a Watts 709 unless the Owner authorizes otherwise.
c. For protection of pipe branches up to and including 2”, install a Watts 909 QT-S
unless the Owner authorizes otherwise.
d. All backflow preventers shall be fully accessible on both sides and on its bottom.
e. The backflow preventer shall be field tested and certified prior to use. Certification tags are available through
the UIHC Plumbing shop. - Water hammer control
a. Install only water hammer arrestors certified by the Plumbing Drainage Institute.
b. Field-built air chambers are not acceptable.