3.2.4
Cutting Existing Pipe
Perform the initial cutting of the existing piping with a multiwheel pipe
cutter, using a nonflammable lubricant. After cutting, seal the interior
of the piping with a gas barrier plug in accordance with API BULL 2209.
The interior of the piping shall be purged with carbon dioxide or nitrogen
during welding process. The complete method of cutting, sealing, and
welding shall be approved in advance of the actual work.
3.2.5
Cleaning of Piping
Keep the interior and ends of new piping and existing piping affected by
the Contractor's operations thoroughly cleaned of water and foreign matter.
Keep piping systems clean during installation by means of plugs or other
approved methods. When work is not in progress, securely close open ends
of pipe and fittings to prevent entry of water and foreign matter. Inspect
piping before placing into position.
3.3
PIPE AND FITTINGS
Inspect, test, and approve piping before burying, covering, or concealing.
Provide fittings for changes in direction of piping and for connections.
Reducing branch connections in steel piping may be made with forged branch
outlet reducing fittings for branches two or more pipe sizes smaller than
mains. Branch outlet fittings shall be forged, flared for improved flow
where attached to the run, reinforced against external strains, and
designed to withstand full pipe bursting strength. Stab type connections
are prohibited. Jointing compound for pipe threads shall be
polytetraflouroethylene (PTFE) pipe thread paste or PTFE powder and oil.
Pipe nipples 150 mm 6 inches long and shorter shall be Schedule 80 pipe.
Make changes in piping sizes through tapered reducing pipe fittings.
3.3.1
Fittings and End Connections
Install threaded fittings and end connections for sizes less than 25 mm one
inch; threaded or socket-welding or buttwelding fittings and end
connections for sizes 25 to 50 mm one to 2 inches; threaded connections for
threaded valves, traps, strainers, and threaded connections to equipment;
buttwelding fittings and end connections for sizes 65 mm 2.5 inches and
larger; and flanged connections for flanged valves, traps, strainers, and
flanged connections to equipment.
3.3.2
Pipe Hangers and Supports
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NOTE: Drawings should show details and spacing of
pipe supports and include appropriate seismic zone
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Install additional hangers and supports for the concentrated loads in
piping between hangers and supports, such as for valves. Install ASTM A
36/A 36M miscellaneous steel shapes as required. [After installation of
piping under piers, coat pipe hangers and supports including rods, bolts,
nuts, and washers, with two coats of coal tar mastic applied a minimum
total dry film thickness of 0.80 mm 30 mils.] Support piping as follows:
_________________________________________________________________________
Nominal Pipe
One and
SECTION 15194N
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