3.1.1
Excavating and Backfilling
Perform excavating and backfilling of pipe trenches as specified in Section
02300 EARTHWORK. Place pipe directly in trench bottom and cover with
minimum 75 mm 3 inches of sand to top of pipe. If trench bottom is rocky,
place pipe on a 75 mm 3 inch bed of sand and cover as above. Provide
remaining backfilling. Coordinate provision of utility warning and
identification tape with backfill operation. Bury utility warning and
identification tape with printed side up at a depth of 305 mm 12 inches
below the top surface of earth or the top surface of the subgrade under
pavements.
3.1.2
Piping
Cut pipe to actual dimensions and assemble to prevent residual stress.
[Provide supply connections entering the buildings as indicated.] Within
buildings, run piping parallel to structure lines and conceal in finished
spaces. Terminate each vertical supply pipe to burner or appliance with
tee, nipple and cap to form a sediment trap. To supply multiple items of
gas-burning equipment, provide manifold with inlet connections at both ends.
3.1.2.1
Cleanliness
Clean inside of pipe and fittings before installation. Blow lines clear
using 550 to 690 kPa (gage) 80 to 100 psig clean dry compressed air. Rap
steel lines sharply along entire pipe length before blowing clear. Cap or
plug pipe ends to maintain cleanliness throughout installation.
3.1.2.2
Aboveground Steel Piping
Determine and establish measurements for piping at the job site and
accurately cut pipe lengths accordingly. For 50 mm 2 inch diameter and
smaller, use threaded or socket-welded joints. For 65 mm 2 1/2 inch
diameter and larger, use flanged or butt-welded joints.
a.
Threaded Joints: Where possible use pipe with factory-cut
threads, otherwise cut pipe ends square, remove fins and burrs,
and cut taper pipe threads in accordance with ASME B1.20.1.
Provide threads smooth, clean, and full-cut. Apply anti-seize
paste or tape to male threads portion. Work piping into place
without springing or forcing. Backing off to permit alignment of
threaded joints will not be permitted. Engage threads so that not
more than three threads remain exposed. Use unions for
connections to [valves] [meters] for which a means of
disconnection is not otherwise provided.
b.
Welded Joints: Weld by the shielded metal-arc process, using
covered electrodes and in accordance with procedures established
and qualified in accordance with ASME B31.8.
c.
Flanged Joints: Use flanged joints for connecting welded joint
pipe and fittings to valves to provide for disconnection. Install
joints so that flange faces bear uniformly on gaskets. Engage
bolts so that there is complete threading through the nuts and
tighten so that bolts are uniformly stressed and equally torqued.
d.
Pipe Size Changes: Use reducing fittings for changes in pipe
size. Size changes made with bushings will not be accepted.
SECTION 15195N
Page 15
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