Insulation Facilities (Energy Engineering)

Insulation Facilities (Energy Engineering)

Insulation: Facilities (Energy Engineering)

Abstract

In this entry, insulation materials and techniques are described in detail. The advantages and disadvantages of the most popular materials and their manufacturing processes are discussed. Information concerning new and emerging techniques and materials is also included. The concept of a building envelope is explained and descriptions of each major building component, such as floors, ceilings and walls, are illustrated in detail.

The proper installation methods for each major type of insulation are explained in both the text and in illustrations. These methods are repeated for the different types of wall construction, frame, masonry, and insulated concrete. The concept of a radiant barrier is also explained, along with related installation instructions.

INTRODUCTION

Insulation is rated in terms of thermal resistance, called R-value, which indicates the resistance to heat flow. Although insulation can slow all types of heat flow—conduction, convection, and radiation—its greatest impact is on conduction.

The higher the R-value is, the greater the insulation effectiveness is.[1,2] The /lvalue of thermal insulation depends on the type of material, the thickness, and the density. When calculating the R-value of a multilayered installation, the /^-values of the individual layers are added.

The effectiveness of an insulated wall or ceiling also depends on how and where the insulation is installed. For example, compressed insulation will not give its full rated R-value. The overall R-value of a wall or ceiling will also be somewhat different from the R-value of the insulation itself because some heat flows around the insulation through the studs and joists thermal bridging. With careful design, this short-circuiting can be reduced.

The key to an effective insulation system is proper installation of quality insulation products. A building should have a continuous layer of insulation around the entire building envelope (Fig. 1). Studies show that improper installation can cut performance by 30% or more.

INSULATION MATERIALS

The wide variety of insulation materials makes it difficult to determine which products and techniques are the most cost effective (Table 1). Whatever product is chosen, install it per the manufacturers specifications.

Here are short descriptions of a few of the insulation products available today:

• Fiberglass insulation products come in batt. roll, and loose-fill form, as well as a semirigid board material. Many manufacturers use recycled glass in the production process of fiberglass building insulation, with most using between 20 and 30% recycled glass in their product. Fiberglass is used for insulating virtually every building component—from walls to attics to ductwork.

• The term mineral wool refers to both slag wool and rock wool. Slag wool is manufactured from industrial waste product. It is primarily (

75%) produced from iron ore blast furnace slag, a by-product of smelting. Rock wool is fireproof and produced from natural rocks—basalt primarily—under high heat. Mineral wool insulation is available as a loose-fill product, batts, semirigid, or rigid board. Usage of this product has decreased as more and more building codes require active sprinklering of buildings.

Insulation Facilities (Energy Engineering)

• Cellulose insulation, primarily made from post-consumer recycled newsprint with up to 20% ammonium sulfate and/or borate flame retardants, is installed in loose-fill, wall-spray (damp), dense-pack, and stabilized forms. Because of its high density, cellulose can help reduce air leaks in wall cavities, but air sealing other areas of air infiltration, such as under wall plates and band joists, must be performed to obtain an effective air barrier. However, given certain conditions and applications, cellulose may hold moisture.

• Molded expanded polystyrene (MEPS), often known as beadboard, is a foam product made from molded beads of plastic. MEPS is used in several alternative building products discussed in this chapter, including insulated concrete forms and structural insulated panels (SIPs).

Fig. 1 Building envelope insulation.

• Extruded polystyrene (XPS), also a foam product in rigid board form, is a homogenous polystyrene produced primarily by three manufacturers with characteristic colors of blue, pink, and green.

• Polyisocyanurate, foil-faced rigid board, is insulating foam with one of the highest available R-values per inch.

• Closed-cell, high-density spray polyurethane is used both for cavity insulation and as insulating roofing materials [often referred to as spray polyurethane foam (SPF)]. It has structural properties, good adhesive properties, and good compressive strength.

Table 1 Comparison of insulating materials


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