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Removable-reusable insulation has four basic parts: liner, insulation, outer jacket, and closure. Let's take a look at each of these, beginning with liners.
One of the first considerations in selecting a liner material is the hot (or cold) face temperature on which the insulation will be installed. Some viable materials, and an outline of their general limitations are listed as follows.
Silicone-Impregnated Cloth
This material is a very good selection for functional all-round general service. The matrix cloth is usually a glass fiber weave with a through-thickness impregnation of high-temperature silicone. This cloth is very flexible and easily handled. Upper temperature limitations for this material are in the range of 500 degrees fahrenheit (F) for continuous use, but above 500 degrees F can they take intermittent exposure of up to 700 degrees F for an accumulated time of about 100 hours.
Vermiculite-Coated Glass Fiber Cloth
This material can be used at temperatures up to 500 degrees F. However, one constraint is that in humid or wet environments, moisture and heat can deteriorate the base cloth. This should be considered when contemplating outdoor applications, or use on steam or hot water systems where the potential for leaks exist (at valve bonnets or pipe flanges, for example).
Aluminum Foil Laminated to Glass Cloth
This is material that may be used on low-temperature applications. It's reasonably flexible and low cost. The aluminum foil serves as a barrier to retard fluids entering the insulation layer from the inside. Its temperature limitation is about 200 degrees F. Above this temperature the lamination bond tends to break down due to adhesive degradation and the aluminum flakes.
Stainless Steel Foil Laminated to Glass Cloth
The foils used for this material are quite heavy (generally around 3 mils). Using this material provides a puncture-proof liner. However it can't be folded due to its lack of flexibility. It also can't be sewn. Construction of the finished product entails using "hog rings" to join it at the edges of the liner, to the outer jacket. This joining method has now become virtually obsolete in manufacturing quality removable-reusable insulations.
Silica Cloth
Woven silica cloth is used as a liner for very high temperature applications (up to 1,800 degrees F). Its main limitation is that it's difficult to work with and frays easily.
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