Pages: 7 Published: Jan 2012
SEALANTS ARE PRODUCTS INSTALLED INTO AN opening to prevent the intrusion of air, water, dust, heat, cold, and other materials such as gases, e.g., radon. The liquid-applied sealant is installed into the opening by gun or knife. It is then expected to function even though the space (joint) it occupies is stressed because of movement of the joint to which the sealant is applied due to expansion and/or contraction due to temperature changes, thereby placing significant strain upon the adhesive forces that bond the sealant to the substrate to which it is attached. The sealant is also expected to function regardless of whether it is applied to a horizontal opening or a vertical one or whether it is applied to a building facade subject to rapid expansion and contraction or to a plaza or deck where it is subject to puncture by spiked heels. The opening, or gap, into which a liquid-applied sealant is installed is usually called a joint. The sides of the joint (substrates) may be made of similar or dissimilar materials, generally varying in width from 0.250 to 2.00 in. (0.64 to 5.08 cm) with the depth of the installed sealant usually about one half the width. When required, sealant backing (preformed joint fillers) made of materials such as open or closed cell rubber or polyurethane foam are installed to control the joint depth. Primers are sometimes used to improve adhesion of the sealant to the substrate. Typical building materials that sealants are used with are glass, steel, concrete, mortar, granite, marble, aluminum, various painted or coated surfaces, or wood. When the sealant is installed into the joint, the surfaces the sealant contacts must be clean, dry, sound, and free of contaminants or loose particles to provide an opportunity for the sealant to perform as intended .
Paper ID: MNL12245M
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