3.1.3.1
Fittings
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NOTE: Delete bending of medium and high pressure
pipe when not included in project.
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Use long radius ells where appropriate to reduce pressure drops. Pipe
bends in lieu of fittings may be used for low pressure piping where space
permits. Pipe bends shall have a uniform radius of at least five times the
pipe diameter and must be free from any appreciable flattening, wrinkling,
or thinning of the pipe. Mitering of pipe to form elbows, notching
straight runs to form full sized tees, or any similar construction shall
not be used. Make branch connections with welding tees, except factory
made forged welding branch outlets or nozzles having integral
reinforcements conforming to ASME B31.1 may be used.
3.1.3.2
Clearances for Welding
Provide clearances from walls, ceilings, and floors to permit the
installation of joints. The clearances shall be at least 150 mm 6 inches
for pipe sizes 100 mm 4 inches and less, 250 mm 10 inches for pipe sizes
over 100 mm 4 inches, and sufficient in corners. However, the specified
clearances shall not waive requirements for welders to be qualified for the
positions to be welded.
3.1.3.3
Cleaning and Flushing Procedures
Before jointing and erection of piping or tubing, thoroughly clean
interiors of pipe sections, tube, and components. In steel pipe, loosen
scale and other foreign matter by rapping sharply and expel by wire brush
and swab. Blow out both steel pipe and copper tube and components with
compressed air at 689 kPa (gage) 100 psig or more. Maintain cleanliness by
closure of pipe/tube openings with caps or plugs. Before making final
terminal connections, blow out complete system with compressed air at 689
kPa (gage) 100 psig or more.
3.1.3.4
Changes in Pipe Size
Use reducing fittings for changes in pipe size. The use of bushings will
not be permitted. In horizontal lines, 65 mm 2 1/2 inches and larger,
reducing fittings shall be of the eccentric type to maintain the bottom of
the lines in the same plane.
3.1.3.5
Drainage and Flexibility
Compressed air piping shall be free of unnecessary pockets and pitched
approximately 25 mm per 10 meters 3 inches per 100 feet in the direction of
flow to low points. Where pipes must be sloped so that condensate flows in
opposite direction to air flow, slope 50 mm per 10 meters 6 inches per 100
feet or greater. Provide flexibility by use of fittings, loops, and
offsets in piping. Install branches at top of a main to prevent carryover
of condensate and foreign matter.
3.1.4
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
SECTION 15211N
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