piping and apparatus, and as indicated. Provide a union for each
connection having a screwed-end valve. [Provide unions or flanges not
farther apart than 30 meters 100 feet.] [Provide unions or flanges as
indicated.] Provide unions on piping under 50 mm 2 inches in diameter, and
provide flanges on piping 50 mm 2 inches and over in diameter. Install
dielectric unions or flanges between ferrous and non-ferrous piping,
equipment, and fittings; except that bronze valves and fittings may be used
without dielectric couplings for ferrous-to-ferrous or non-ferrous to
non-ferrous connections.
3.1.18
Painting of Piping and Equipment
Paint piping and equipment in accordance with Section 09900 PAINTS AND
COATINGS.
3.1.19
Identification of Piping
Identify piping in accordance with PFI ES 22. Use commercially
manufactured piping identification labels. Space identification marking on
runs not farther apart than 15 meters 50 feet. Provide two copies of the
piping identification code framed under glass and install where directed.
3.1.20
Warning and Identification Tape
Coordinate installation of utility warning and identification tape with
backfill operation. Provide tape above buried lines at a depth of 200 to
300 mm 8 to 12 inches below finish grade.
3.2
CLEANING SILVERBRAZED PIPING
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NOTE: All silverbrazed piping, including low
pressure systems, should be cleaned to preclude
corrosion from residual brazing flux.
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Clean silverbrazed piping to remove residual flux remaining in the system
after fabrication. Use one of the procedures below. The hot flush and hot
recirculating flush are preferred. Minimum flow rate through any part of
the system in liters per second gallons per minute shall be 0.0037 1.5
times the inside diameter of the pipe in mm inches. For any flushing
method used, the system shall be full of water so that joints are
completely submerged at all times.
3.2.1
Hot Flushing Method
Hot flush the system for one hour using heated fresh water.
No part of the
system shall go below 43 degrees C 110 degrees F.
3.2.2
Hot Recirculating Flush Method
Perform hot recirculating flush for one hour. Heat water during flushing
so that no part of the system falls below 43 degrees C 110 degrees F.
After completing the hot recirculating flush, flush the system with cold
fresh water for 15 minutes.
3.2.3
Cold Soak Method
Cold soak the system using fresh water at not less than 15.50 degrees C 60
SECTION 15211N
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