Panel Grades for RV, Bus and Transport Equipment (APA)
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GDE,G210,Transport.0 4/21/00 9:58 AM Page 1 APA The Engineered Wood Association INDUSTRIAL USE GUIDE TRANSPORT EQUIPMENT GDE,G210,Transport.0 4/21/00 9:58 AM Page 2 APA The Engineered Wood Association DO THE RIGHT THING RIGHT™ Wood is good. It is the earth’s natural, energy efficient and renewable building material. Engineered wood is a better use of wood. It uses less wood to make more wood products. ORIZED BY APA IS PROHIBITED BY THE U.S. COPYRIGHT LAWS. THE U.S. IS PROHIBITED BY APA ORIZED BY That’s why using APA trademarked I-joists, glued laminated timbers, laminated veneer lumber, plywood and oriented strand board is the right thing to do. A few facts about wood. I We’re not running out of trees. One-third of the United States land base – 731 million acres – is covered by forests. About two-thirds of that 731 million acres is suitable for repeated planting and harvesting of timber. But only about half of the land suitable for growing timber is open to logging. Most of that harvestable acreage also is open to other uses, such as camping, hiking, hunting, etc. I We’re growing more wood every day. American landowners plant more than two billion trees every year. In addition, millions of trees seed naturally. The forest products industry, which comprises about 15 percent of forestland ownership, is responsible for 41 percent of replanted forest acreage. That works out to more than one billion trees a year, or about three million trees planted every day. This high rate of replanting accounts for the fact that each year, 27 percent more timber is grown than is harvested. I Manufacturing wood is energy Percent of Percent of efficient. Wood products made up Material Production Energy Use 47 percent of all industrial raw materials Wood 47 4 manufactured in the United States, yet consumed only 4 percent of the energy Steel 23 48 needed to manufacture all industrial raw Aluminum 2 8 materials, according to a 1987 study. I Good news for a healthy planet. For every ton of wood grown, a young forest produces 1.07 tons of oxygen and absorbs 1.47 tons of carbon dioxide. Wood. It’s the right product for the environment. NOTICE: • ALL RIGHTS RESERVED. • ANY COPYING, MODIFICATION, DISTRIBUTION OR OTHER USE OF THIS PUBLICATION OTHER THAN AS EXPRESSLY AUTH THAN AS EXPRESSLY OTHER USE OF THIS PUBLICATION DISTRIBUTION OR OTHER MODIFICATION, • ANY COPYING, • ALL RIGHTS RESERVED. The recommendations in this guide apply only to panels that bear the APA APA trademark. Only panels THE ENGINEERED WOOD ASSOCIATION bearing the APA trademark are subject to the Association’s quality RATED SHEATHING15/32 INCH 32/16 auditing program. SIZED FOR SPACING EXPOSURE 1 000 PS 1-95 C-D PRP-108 APA – THE ENGINEERED WOOD ASSOCIATION APA ©1997 GDE,G210,Transport.0 4/21/00 9:59 AM Page 3 CONTENTS PANEL TYPES AND PROPERTIES . .4 Conventional Plywood . .4 APA Performance- Rated Panels . .4 PA trademarked plywood has been FRP Plywood . .7 indispensable to transport equipment Metal Overlaid Plywood . .8 Foam Core Insulated Panels . .8 manufacture for nearly 50 years. It A TRUCK, TRAILER has earned a sterling reputation as a AND INTERMODAL CONTAINER BODIES . .9 lightweight, reliable and cost-efficient structural Panel Selection . .9 material. In trucks, trailers, intermodal contain- Framing . .9 ers, rail cars, pickup trucks and recreational Joints . .10 Walls . .14 vehicles of all kinds, plywood and other wood Doors . .17 structural panels represent the logical choice for Floors . .17 bodies, linings, interior cabinetry and numerous Roofs . .18 other applications. Cargo Restraint Devices . .18 FRP Plywood Fabrication and Repair . .18 This manual is for transport equipment design- Metal Overlaid ers, engineers and manufacturers. It covers APA Plywood Fabrication . .20 TRUCK, TRAILER AND trademarked wood structural panel grades and RAIL CAR LININGS . .21 properties, structurally overlaid panels, design Panel Selection . .21 criteria, fastener data and other key topics. Truck and Trailer Front-End Structures . .21 Panel Installation . .22 Since the design of transport equipment is an Cargo Restraint Devices . .22 intricate and evolving science, this publication RECREATIONAL VEHICLES AND BUSES . .26 does not present complete unit designs. It does, Panel Selection . .26 however, provide the most recent and accurate Floors . .27 criteria available on appropriate wood structural Walls . .28 panel design aspects. Final decision on suitable Roofs . .28 Framing . .29 performance level is left to the design engineer. Fasteners . .29 Adhesives . .31 FASTENERS . .31 Estimating Allowable Design Loads . .31 ADDITIONAL INFORMATION . .35 GDE,G210,Transport.0 4/21/00 9:59 AM Page 4 PANEL TYPES AND PROPERTIES Conventional Plywood Strength And Stiffness. Plywood manufactured under U.S. Product Standard PS 1 for Construction and Industrial Plywood may be made from over 70 species of wood. These species are divided by strength and stiffness into five groups. Group 1 species are the strongest and stiffest, Group 2 the next strongest and stiffest, and so on. The group number in the APA trademark is part of the correct grade designation for the sanded panels commonly recommended and specified for transport lining and recreational vehicle applications. The strength of wood along the grain is many times greater than across the grain. By cross-laminating layers of veneer, plywood provides along-the- Table 2 provides concentrated load Table 3 documents plywood resistance to grain strength in both directions. Yet strength information for Group 1 forklift tine penetration, a major cause of relative to its strength, plywood is a sanded plywood thicknesses. truck liner damage. According to tests of relatively lightweight material and can Span length within the limits normally different thicknesses, face grain direction thus help minimize tare – an important associated with a plywood thickness has of a panel only slightly influences total consideration in all transport applica- minimal influence on concentrated load tine penetration resistance. The impact tions. The relative strength of plywood capacity. Loads applied to a free unsup- resistance of a bare 1/4-inch plywood lining panels is given in Table 1. ported edge may be 50 to 90 percent of panel can be doubled by substituting a Plywood also exhibits excellent the load shown for center panel loca- special 1/4-inch plywood liner panel stiffness, or resistance both to deflection tions. If applied by a four-inch disc, with 0.050-inch-thick (1.5 oz/sq ft) under uniform and concentrated loads loads may be 20 to 50 percent greater fiberglass mat face. Thicker plywood and to racking forces. This stiffness than those charted. with more glass increases penetration often permits plywood to be used with resistance proportionately. Plywood also can withstand repeated less framing or bracing than other impact without cracking or crumbling materials may require. APA Performance-Rated Panels because of its cross-laminated construc- Wood structural panels of compositions Plywood withstands heavy concentrated tion. Since it has no plane of cleavage, and configurations other than conven- loads because the cross-lamination it’s extremely resistant to splitting. tional all-veneer plywood are also avail- distributes stress over a wide area. able from APA member mills. These 4 GDE,G210,Transport.0 4/21/00 9:59 AM Page 5 TABLE 1 RELATIVE STRENGTH OF PLYWOOD LINING PANELS Face grain ⊥ to supports Face grain || to supports 660 390 530 230 360 110 100 20 160 30 1/4-inch 11/32-inch 15/32-inch 19/32-inch 23/32-inch Sanded Sanded Sanded Sanded Sanded Group 1 species are most commonly used as lining. Group 2 and 3 plywood is 73% as strong and Group 4 is 67% as strong. The table above is valid for comparing panels within any one species Group. panel products are manufactured according to APA performance standards TABLE 2 TABLE 3 that set strength, stiffness and durability CONCENTRATED-LOAD FORK TINE criteria for specific construction applica- STRENGTH – 2 INCH PENETRATION RESISTANCE LOADING DISC Round tip fork tine 1/2 in. x 5 in. tions. Panels include oriented strand Face Grain Across Supports penetrating Group 1 plywood on supports 16 in. o.c. board (OSB) and composites (reconsti- Ultimate tuted wood cores bonded between Load (lb) Energy to Penetrate 2800 veneer faces). (in.-lb) 2400 Abrasion Resistance. In truck lining 3200 2000 applications wood structural panels 2400 1600 provide a smooth surface with relatively 1600 1200 few joints, making it ideal for sliding and 800 Penetration 800 resistance skidding palletized and loose-loaded 0 400 freight. Snag-free panel surfaces reduce 1/4 3/8 1/2 5/8 3/4 0 Plywood Thickness (in.) costly damage to boxed and bagged 1/4 3/8 1/2 5/8 3/4 goods and possess high resistance to Plywood Thickness (in.) prolonged friction and abrasion. Group 1 Sanded For extra protection against fork tine 12 in. span 16 in. span damage, replaceable scuff panels are 16, 24 in. span often installed over the bottom two feet 24, 32 in. span 5 GDE,G210,Transport.0 4/21/00 9:59 AM Page 6 of a liner. Table 4 rates the surface scuff The ability of a material to retard heat resistance of typical plywood panels flow is termed thermal resistance (R). TABLE 4 used in lining applications. To establish The R values of several panel SURFACE SCUFF* a comparative scale, bare APA trade- thicknesses are given in Table 5. RESISTANCE RATING Panel Rating marked A-C Group 1 plywood has been The burn resistance requirements for given a rating of 100. Remember that Common plywood linings materials used in the occupant compart- Bare Group 1 plywood (A-C) 100 scuff panel performance depends upon ments of motor vehicles are specified in High density overlay Group 1 solid wood structural panel backing.