fabricated air handlers and reheat coils shall be constructed as follows:
Construct steam distribution (nonfreeze type) coils of cast semi-steel,
welded-steel, or copper headers, red brass or copper tubes, and copper or
aluminum fins mechanically bonded or soldered or helically wound to tubes.
Roll and bush, braze, or weld tubes into headers. Condensing tubes shall
be not less than 16 mm 5/8 inch outside diameter. Distributing tubes shall
be not less than 10 mm 3/8 inch outside diameter, with orifices to
discharge steam to condenser tubes and shall be held securely in position.
The maximum length of a single coil shall be limited to 120 times the
outside diameter of the tube. Coil casings and tube support sheets, with
collars of ample width, shall be not lighter than 16 gage 1.6129 mm thick
0.0635 inch thick galvanized steel, formed to provide structural strength.
When required, provide multiple tube supports to prevent tube sag. The
finned tube and header section shall float within the casing to allow free
expansion of tubing for coils subject to high pressure steam service.
Factory test coils at 1724 kPa (gage) 250 psig hydrostatic test pressure or
under water at 1724 kPa (gage) 250 psig air pressure. Coils shall be
suitable for 1379 kPa (gage) 200 psig steam working pressure. Test rate
coils in accordance with ARI 410.
PART 3
EXECUTION
3.1
INSTALLATION
Work material and equipment into a complete, convenient, and economical
system or systems; and provide apparatus, parts, materials, and accessories
which are necessary to accomplish this result.
3.1.1
Piping
Fabricate, assemble, weld, solder, braze, and install piping and pipe
system in accordance with ASME B31.1 and as further qualified herein.
Piping shall follow the general arrangement shown. Cut piping accurately
to measurements established, for the work shown, by the Contractor, and
work into place without springing or forcing, except where cold-springing
is indicated. Locate piping and equipment within buildings entirely out of
the way of lighting fixtures, conduit, and doors, windows, and other
openings. Run overhead piping in buildings in the most inconspicuous
positions. Provide adequate clearances from walls, ceilings, and floors to
permit the welding of joints; at least 150 mm 6 inches for pipe sizes 100 mm
4 inches and smaller, 250 mm 10 inches for pipe sizes larger than 100 mm 4
inches, and in corners provide sufficient clearance to permit the welder to
work between the pipe and one wall. Make provision for expansion and
contraction of pipe lines. Do not bury, conceal, or insulate piping until
it has been inspected, tested, and approved. Do not conceal piping in
walls, partitions, underground, or under the floor except as indicated.
Where pipe passes through building structure, do not conceal pipe joints,
but locate where they may be readily inspected and not weaken building
structure. Run insulated pipe as shown and as required with sufficient
clearance to permit application of insulation. Use flanged joints only
where necessary for normal maintenance and where required to match valves
and equipment. Gaskets, packing, and thread compounds shall be suitable
for the service. Apply joint compound or tape on male thread only. Use
long radius ells wherever possible to reduce pressure drops. Pipe bends
may be used in lieu of welding fittings where space permits. Pipe bends
shall have a uniform radius of at least five times the pipe diameter and
shall 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
SECTION 15183N
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