Page 224 - Facility Piping Systems Handbook for Industrial, Commercial, and Healthcare Facilities

HEAT TRANSFER, INSULATION, AND FREEZE PROTECTION

5.8 CHAPTER FIVE

Mineral Fiber
Mineral fiber (ASTM C 553) insulation is a rigid material composed of rock and slag made
into fibers bound together with a heat-resistant inorganic binder. The typical k value is 0.28,
and the R value is 4.9. This material is very well suited for high temperature work.

Insulating Cement
Insulating cement is produced from fibrous and/or granular insulation and cement, then
mixed with water to form a plastic mass. Typical k values range between 0.65 and 0.95,
depending on the composition of the cement. They can be of either the hydraulic setting or
the air drying type. This material is best suited for irregular surfaces or as a finish for other
insulation applications. It can also be used in situations where space is at a premium and
some kind of insulation is required. Installation costs are very high.

JACKETS

In order to function more efficiently and extend service life, most insulation must be pro-
tected from damage and degradation by the application of an effective cover, or jacket
material. A jacket is defined as any material, except cements and paints, that can be used to
cover or protect insulation installed on a pipe or vessel. The choice of jacketing will depend
on its use, which can be divided into seven general functional categories:

1. Weather barriers are used to prevent the entry of liquid water into insulation and also
the entry of chemicals that would affect the inside or outside of the insulation. Materials
include plastic, aluminum, and stainless steel as well as weather barrier mastics.
2. Vapor barriers are used to reduce the entry of water vapor into the surface of the insula-
tion. In order to be effective, the vapor barrier must be completely sealed at every open-
ing. A vapor barrier is used on cold surfaces primarily for eliminating the possibility of
entrapped water vapor condensing on the pipe.
3. Mechanical abuse-resistant coverings are used to protect the underlying insulation from
mechanical damage due to abuse or accidental contact by personnel or equipment. The
compressive strength of the insulation used should be considered when selecting a
jacket. Metal products are most commonly used.
4. Corrosion- and fire-resistant coverings are used as part of a complete hazard resistance
system. Almost any type of jacket or mastic increases the fire rating. The most success-
ful corrosion jackets are plastic or stainless steel depending on the nature of the spill,
leak, or atmosphere expected. Some mastics are also useful.
5. The visual appearance of some jackets over piping in exposed areas is an important
feature in the selection of various coatings, finishes, cements, and covers. Since this
consideration must often be approved by an architect or client, he or she should be
consulted before final selection.
6. Jackets capable of being disinfected are used to present a smooth surface that will resist fun-
gal and bacterial growth. They must withstand cleaning with powerful detergents coupled
with steam and high-pressure water. This requires a jacket with high mechanical strength.
7. Plain jackets are used on hot services and in other cases when a jacket is desired for ease
of installation and appearance.
Jackets come in various forms and types, and can be divided into three general catego-
ries: rigid (plastic, aluminum, or stainless steel), membrane (glass cloth, coated papers,

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