located so that any equipment within the housing can be removed for
cleaning or maintenance. Fan section of the housing shall be internally
insulated with not less than 40 mm 1-1/2 inches of fibrous glass insulation
of not less than 12 kg/cubic meter 3/4 pound/cubic foot density and maximum
K-factor of 0.26.
2.4.3.1
Heating Coil
Coil shall be of nonferrous alloy, free to expand and contract, and shall
be pitched for drainage. Coil shall be tested hydrostatically after
assembly of the unit and provided tight under a gauge pressure of 1.4 MPa
200 psig.
2.4.3.2
Fans and Drive
Fans shall be the multiblade centrifugal type, one to each air outlet,
mounted on a common shaft. Fans within any one unit shall be of the same
size. Fan units shall be installed on vibration isolators and shall be
completely isolated from the building structure. Bearings shall be ball,
roller, or taper type and shall be provided with lubrication fittings,
externally accessible at the drive side of the unit. Fans shall be
directly connected or indirectly connected to the driving motors through
V-belt drive. V-belt drive shall be rated for 150 percent of motor
capacity. Adjustable sheaves shall be provided to produce at least 20
percent fan speed adjustment. Sheaves shall be selected to produce
specified fan capacity at the midpoint of the adjustment.
2.4.3.3
Motor
Motor shall be provided with general purpose type enclosure.
Direct-connected motors shall operate at a speed not in excess of 1,200
rpm, and motors using V-belt drives shall operate at 1,750 rpm. Adjustable
base rails shall be provided for motors of V-belt driven fans.
2.4.3.4
Filters
**************************************************************************
NOTE: Where the number of filters required is too
small to justify the installation of washing tanks,
disposable filters will be specified and cleanable
filters will be deleted. Otherwise disposable will
be deleted. The requirement for washing and
charging tanks will be deleted if centralized
washing and charging facilities are available, and
the sentences in brackets will be deleted.
**************************************************************************
Filters and filter racks of the V- or flat-type arrangement shall be
provided. Filters shall be removable from one accessible side of the unit.
Filters shall be [[25 mm 1 inch] [50 mm 2 inches] thick replaceable
throw-away type, in accordance with ARI 850] [of cleanable type, in
accordance with ARI 850, 25 mm 1 inch thick, or the size required to suit
the application. Viscous adhesive shall be furnished in 19 L 5 gallon
containers in sufficient quantity for 12 cleaning operations; not less than
one quart shall be provided for each filter section. [One washing and
charging tank shall be provided for every 100-filter section or fraction
thereof. Each washing and charging unit shall accommodate [_____]
filters.]]
SECTION 15562A
Page 26
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