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^ty- <br />•i • <br />?■. <br />4v^^ <br />•l^v <br />'K'. <br />‘tJ <br />M <br />-?r'.. <br />; V- <br />}h- <br />,.. <br />nf!-V <br />'<r,r <br />'■:» '■ <br />..8;A <br />■’f*.rry‘^. <br />rr. <br />’-V <br />f .V .’v' <br />T‘'\„ <br />tr- <br />k <br />%,..iT ., I. <br />[‘1 ^ <br />''^''-X ‘.4- <br />?.;■ ^ <br />V>'( j* > <br />’•*'> I <br />’ -'(f <br />•r •:*:.• <br />' ■' / .r-f."' <br />v‘ ■, yrl’^;: <br />&i <br />: ■ :> ■r' <br />- ^'V. <br />Technical <br />August 4, <br />Page 2 <br />Information - Styrofoam Flotation <br />1992 <br />D. <br />E. <br />F. <br />3.Polyurethane. Requires precise manufacturing <br />practices and must be encased in watertight <br />containers if temperatures will be near or below <br />freezing. Easily eroded if not carefully <br />protected. If unprotected, high water absorption <br />would lead to loss of buoyancy. <br />4.Extruded polystyrene ("Blueboard"). Normally <br />used without encasement as it is not easily eroded <br />by the normal deteriorating elements. <br />5.Expanded polystyrene ("Beadboard"). Absorbs some <br />water. Easily eroded. Disintegrates when exposed <br />to gasoline. <br />The buoyancy characteristic of a given foam product is <br />related to its affinity to absorb water over time. <br />While quality of the individual beads may affect <br />absorption, the greatest factor is the percentage of <br />voids. Therefore, when specifying the foam product, <br />one should not only call for a certain density, but for <br />an upper limit on water absorption. <br />Hunt provides a suggested set of minimum specifications <br />for the quality of foam product and for the encasement <br />of the fo2un, suggests that all flotation within 100* of <br />a gas dispenser or supply line must be 100% impervious <br />to water and gasoline, and require replacement of any <br />floats when the foam is visible or particles of foam <br />appear on the water. <br />Muschell of United Design Associates provides a <br />floating pier specification used by the Michigan <br />Department of Natural Resources for state- <br />owned/sponsored mooring facility projects. He notes <br />that this specification requires enclosure of the <br />polystyrene and pages 10, 13 and 14 deal specifically <br />with the flotation units. <br />This specification requires use of closed cell <br />polystyrene cellular materials, either preformed or <br />cemented in place. The flotation material must be <br />fully encased in 20 gauge galvanized steel, 1/8 inch <br />t..xck aluminum, 1/5 inch thick medium density <br />polyethylene, 2 inch thick wood, or a combination of <br />these materials. Detailed specifications are given for <br />the grades of galvanized steel, aluminum, and <br />polyethylene. Also, the specification on the closed <br />cell polystyrene requires an average density of 1 pound <br />per cubic foot and a buoyancy factor of 59 pounds per <br />cubic foot. <br />•J <br />Afn..