disconnection and inspection.
3.7.10
High Purity Water Pipe
Joints for metal pipe shall be made up with a polytetrafluoroethylene tape
as recommended by the pipe manufacturer. Joints for polyethylene shall be
made with heat fusion or heat socket fusion. Joints for PVC pipe shall be
socket type made up using PVC cement. All plastic joints shall be in
accordance with manufacturer's instructions.
3.7.11
Dissimilar Pipe Materials
Connections between ferrous and non-ferrous pipe shall be made with
dielectric unions, flanges or dielectric waterways. Dielectric waterways
shall have temperature and pressure rating equal to or greater than that
specified for the connecting piping. Waterways shall have metal
connections on both ends suited to match connecting piping. Dielectric
waterways shall be internally lined with an insulator specifically designed
to prevent current flow between dissimilar metals. Dielectric flanges
shall meet the performance requirements described herein for dielectric
waterways. Connecting joints between plastic and metallic pipe shall be
made with transition fittings for this specific purpose.
3.8
CORROSION PROTECTION FOR PIPE AND FITTINGS
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NOTE: Specify polyethylene coating for cast iron
piping if installed at locations where soil
corrosion has been a problem and where electrical
resistivity of soil is less than 2,000 ohm-cm. For
additional guidance on cathodic protection for
underground ferrous piping, refer to National
Association of Corrosion Engineers RP0169 (Rev
1992). Designer shall indicate slopes of horizontal
waste lines on the drawings.
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Buried cast-iron soil piping shall be completely encased in polyethylene
tube or sheet in accordance with AWWA C105. Exterior surfaces of steel
pipe and fittings installed underground shall be coated with primer and
wrapped with tape during installation. Tape shall conform to AWWA C203and
primer shall be as recommended by the tape manufacturer. After thoroughly
cleaning piping of foreign matter, the pipe shall be primed and immediately
wrapped with tape, applied with a 50 percent overlap. Joints and fittings
shall be coated and wrapped with the same primer and tape after piping has
been tested in accordance with ICC IPC.
3.9
PIPE SLEEVES AND FLASHING
Pipe sleeves shall be furnished and set in their proper and permanent
location.
3.9.1
Sleeve Requirements
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NOTE: The designer will coordinate requirements for
clearances around sleeves with Section 15070A
SEISMIC PROTECTION FOR MECHANICAL EQUIPMENT.
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SECTION 15405A
Page 87
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