Scope of Work — Valve and Yard Hydrant Installation
EXHIBIT C
There are 21 yard hydrants and gate valves at the Nashua Wastewater Treatment Facility located
at 2 Sawmill Road that are in need of replacement. The yard hydrants are on the plant water
systems or chlorinated effluent from the treatment plant. The existing plant water system was
originally installed in 1972 and later expanded in 1988 and again in 2000. The original plant
water system is cast iron pipe and in the later year’s ductile iron pipe was used. The pipe
material is shown on the plans. As a result of the age of the installation of the system, many of
the yard hydrant and associated valves do not operate properly.
The plant water system consists of effluent water that is filtered and chlorinated. It is pressurized
to 125 psi by four pumps in the lower level of the pump building. It typically pumps between
200-300gpm depending on the water use.
This project will occur in the 2 phases. First is the installation of the gates valves on the plant
water system mains at locations as shown in the Proposed drawing. The following size valves
will be installed using live without having to turn off the plant water: 1 — 12” valve, 1 — 10”
valve and 2 — 6” valves. In addition, 3 — 3” valves will be installed using pipe freezing
techniques to isolate the pipe at the locations shown on the Proposed Drawing. Each valve
installation shall include a valve box size for the installation (refer to specifications). Two valve
keys shall be supplied to match a standard 2-inch square top nut and long enough to extend a
minimum or 3-feet above ground. The contractor shall have a test pit dug at to verify the outside
diameter at four locations to verify the pipe size prior to ordering the valves. The test pits should
be dug at the same location where the valve will be installed. The depth is assumed to be 5— 6
feet. It shall be backfilled when done unless the contractor is able to get the valve within a few
days of the dig. Alternatively, the test pit may be plated over if it completely covers the
excavation. New gate valves should be installed on lawn areas (when possible) to minimize
disturbance to paved roadways. The number of gate valves to be installed may be limited by
funding or constraints that may be encountered prior to installation.
The second phase of the project will involve the installation of the 21 yard hydrants, valve shut
offs and connection piping/fittings. One hydrant was dug up recently (location number 6 on the
Design Plan) and the main was determined to be 4” (OD — cast iron) with a 4x4”x2.5” (all OD
measurements) tee. Based on this information, the contractor shall leave the main tee in place,
cut off the pipe at an appropriate distance from the tee and connect with a coupling to new pipe,
gate valve, yard hydrant and associated fittings.
The contractor will supply all coupling, pipe sections, gate valve shut offs, and yard hydrants.
and hydrant, gravel (min. 1 c.f.) for weep hole at base of hydrant and thrust block along with
general installation. Min bury is 5.5 feet above piping. The yard hydrants shall be #2 Post, 5’-6”
bury, 3” MJ inlet, duel outlet nozzles1-1/2”, NTS, ductile iron riser with cast iron top, galvanized
steel operating rod, self-draining, nonfreezing. The gate valves shall be 3” RW gate valve MJ,
open left, C509 Mueller or equal. Fitting are to be 3” EBBA DI Megalug and 3” MJ Gasket &
Bolt Pack. Valve box shall be a 2-piece slide type top flange valve box, complete with
