2. INSULATION
MATERIALS AND PROPERTIES
2.2 GENERIC TYPES AND FORMS OF INSULATION
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Insulations will be discussed in this manual according
to their generic types and forms. The type indicates composition
(i.e. glass, plastic) and internal structure (i.e. cellular, fibrous). The
form
implies overall shape or application (i.e. board, blanket, pipe covering).
2.2.1 TYPES
1. Fibrous Insulation – composed of small diameter fibers
which finely divide the air space. The fibers may be perpendicular
or parallel to the surface being insulated, and they may or may not be
bonded
together. Silica, rock wool, slag wool and alumina silica fibers
are used. The most widely used insulations of this type are glass fiber
and
mineral wool. Glass fiber and mineral wool products usually have
their fibers bonded together with organic binders that supply the limited
structural
integrity of the products.
2. Cellular Insulation – composed of small individual
cells separated from each other. The cellular material may be glass
or foamed plastic such as polystyrene (closed cell), polyisocyanurate
and
elastomeric.
3. Granular Insulation – composed of small nodules which
may contain voids or hollow spaces. It is not considered a true
cellular material since gas can be transferred between the individual
spaces.
This type may be produced as a loose or pourable material, or combined
with a binder and fibers or undergo a chemical reaction to make
a rigid insulation. Examples of these insulations are calcium silicate,
expanded
vermiculite, perlite, cellulose, diatomaceous earth and expanded
polystyrene.
2.2.2 FORMS
Insulations are produced in a variety of forms suitable
for specific functions and applications. The combined form and type of
insulation determine its proper method of installation. The forms most
widely used are:
1.
Rigid boards, blocks, sheets, and pre-formed shapes such as pipe
insulation, curved segments, lagging etc. Cellular, granular, and fibrous
insulations are produced in these forms.
2. Flexible sheets and pre-formed shapes. Cellular and
fibrous insulations are produced in these forms.
3.
Flexible blankets. Fibrous insulations are produced in flexible
blankets.
4. Cements (insulating and finishing). Produced from
fibrous and granular insulations and cement, they may be of the hydraulic
setting or air drying type.
5. Foams. Poured or froth foam used to fill irregular
areas and voids. Spray used for flat surfaces.
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