2.4.3.5
Duct Connections
Outside air intake shall be provided with aluminum, copper, or galvanized
steel rain louvers with [13 mm 1/2 inch mesh, 18 gauge galvanized wire
screen] [and] [16 by 18 mesh] [copper] [aluminum] [insect screen]. Intake
box shall be constructed of not less than 0.91 mm (20 gauge) 20 gauge
galvanized steel. Dissimilar metal shall be separated from galvanized
steel by plastic membrane. Discharge ductwork, diffusers, registers, and
grilles shall be as specified in Section 15895 AIR SUPPLY, DISTRIBUTION,
VENTILATION, AND EXHAUST SYSTEM.
2.4.3.6
Dampers
Dampers shall be galvanized steel, opposed-blade type with ball bearings.
Mixing dampers for outside and return air shall be provided as one assembly
in a mixing box.
2.5
SYSTEM ACCESSORIES
2.5.1
Foundations and Anchorage
Foundations and anchorage for pumping units and for other heating equipment
shall be in accordance with the manufacturer's requirements.
2.5.2
Pressure Gauges and Thermometers
Gauges shall be provided for piping as indicated. Gauges shall comply with
ASME B40.100 and thermometers shall comply with ASME PTC 19.3. A
thermometer and pressure gauge shall be provided on the steam supply and
return mains. Thermometers shall be separable socket type.
2.5.3
Vacuum Relief Valve
An approved vacuum relief valve shall be installed where indicated. On
shutoff of steam supply and condensing of steam, the vacuum relief valve
shall automatically admit air to the system.
2.5.4
Safety Valves
Pop safety valves shall be provided on the low side of each pressure
reducing valve. The valves shall be set to open automatically and to
relieve steam at 35 kPa 5 psi in excess of the setting of the reducing
valve, or as indicated. Safety valves shall conform to the requirements of
ASME BPVC SEC VIII D1 and shall be installed as indicated.
2.5.5
Drains
A drain connection with 25 mm 1 inch gate valve or 19 mm 3/4 inch hose bib
shall be installed at the lowest point in the return main. In addition,
threaded drain connections with threaded cap or plug shall be installed
wherever required for thorough draining of the steam system.
2.6
PIPING AND ACCESSORIES
2.6.1
Pipe and Fittings
2.6.1.1
Steam Piping and Fittings
Piping shall be black steel, conforming to ASTM A 53/A 53M, Grade A.
SECTION 15562A
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