3.2
INSULATION INSTALLATION
Apply insulation in order to permit access doors, inspection doors,
flanges, sampling portals and other special features to be opened, or
removed for inspection or maintenance, without disturbing insulation.
Provide boxouts around code stamping symbols and nameplates. Install
double thickness insulation with joints of the two layers staggered. Fill
cracks, voids, and depressions in layers of insulation with suitable
insulating cements before application of another layer of insulation or
jacket application. Provide expansion joints in insulation as required to
allow for thermal expansion movements which might cause cracks or tears in
the insulation. Install insulation between and over stiffeners in such a
manner that stiffeners are completely insulated. Install additional
insulation or casing spacers between stiffeners so that a level surface is
achieved. The intent of this insulating procedure is to prevent a direct
metal path between the collector inside and ambient air. Securely wire
insulation and lace in place using No. 14 dead soft Type 302 stainless
steel wire conforming to ASTM A 580/A 580M.
3.2.1
Block and Mineral Fiberboard Insulation Installation
Hold block and mineral fiberboard insulation in place with insulation lugs
spaced on not greater than 300 to 460 mm 12 to 18 inch centers. Lugs shall
be stud-type welded in place. Reinforce blocks on exterior face with
expanded metal, if necessary, to prevent sagging or cutting of insulation
by lacing wire. Securely wire block and mineral fiberboard insulation of
specified thickness in place over entire surface by means of wire threaded
through lugs both ways, pulled tight with ends of wire loops twisted
together with pliers, bent over, and carefully pressed into surface of
insulation.
3.2.2
Mineral Fiber Blanket Insulation
Hold mineral fiber blanket insulation in place with speed washers and
impaling pins spaced on centers not exceeding 300 mm 12 inches. Provide
mineral fiber blanket insulation with expanded metal reinforcement on the
outer surface and wire mesh or expanded metal on the inner surface.
Tightly butt sections of blankets, jam together, and securely tie for
maximum sealing at joints and edges. Take care in applying speed washers
so that designed thickness of insulation is not reduced when washers are
installed.
3.3
CASING INSTALLATION
3.3.1
Structural Steel Grid System
Install casings on an aluminized structural steel grid system of subgirts.
Provide subgirts of sufficient size, gage, and depth to provide adequate
support and a smooth exterior surface. Subgirts shall be welded to
equipment and structural support surfaces. Subgirts shall be of sufficient
depth to provide for application of full thickness of insulation over the
stiffeners, access doors, flanges, ribs, and other surfaces having uneven
contours to provide a smooth finished surface. Subgirts on vertical and
bottom surfaces shall be at a maximum spacing of 1.22 meters 4 feeton
centers. Subgirts on top surfaces shall be at a maximum spacing of 610 mm
2 feet on centers. Design so as to transmit an external 114 kg 250 pound
walking load from aluminum casing to structural steel grid system without
compression of insulation material.
SECTION 15861N
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