3024 Chapter 24 



gypsum, and steel decking less frequently used. Fergus et al. (1977) found that 

 most new buildings in the non-residential market are typically one- and two- 

 story, flat-roofed structures with multi-ply, built-up roof coverings. Most of the 

 buildings have concrete floors, steel framing bents on 20-foot centers, decking 

 systems over purlins spaced 5 feet on centers, and metal-clad siding materials. 

 Typically, ribbed metal roof decks are mechanically fastened or spotwelded to 

 metal purlins. 



MATERIAL SELECTION 



Fergus et al. (1977) concluded that roof deck material should have structural 

 integrity, be light in weight, stable, durable, easily fastened, simple, compatible 

 with other systems, cheap, and resistant to fire, heat flow, sound transmission, 

 and vibration. 



The major wood-base roof deck materials that have been used in the commer- 

 cial and industrial roof deck market include solid and laminated timber decking, 

 tongue-and-groove structural-grade plywood, cementitious composite utilizing 

 wood fibers, and reconstituted wood fiberboards. 



Fergus et al. (1977) proposed a study to develop a structural particleboard roof 

 deck material for the commercial-industrial building market. 



TARGET SPECIFICATIONS 



Based on the Fergus et al. (1977) market analysis, and some preliminary 

 experimentation. Hunt et al. (1978) concluded that a 1-1/8-inch-thick, three- 

 layer particleboard roof deck could be made of red oak sp. that would have 

 density about equal to that of the parent wood, i.e. , the compaction ratio could 

 be near unity. To be competitive, they set the following target specifications: 



Statistic Face layers Core layers 



Species Red oak sp. Red oak sp. 



Thickness, inch 0. 1875 (each) 0.75 



Density 44 Ib/cu ft 40.5 Ib/cu ft 



Flake type Disk Ring 



Flake length, inches 3 2 



Flake thickness, inch 0.010 0.045 



Liquid phenolic resin 



solids, percent 5 6 



Wax content 1 1 



Flake arrangement Aligned Random 



MOE, psi 1 ,500,000 (parallel), 390,000 



500,000 (perpendicular) 



Hunt et al. (1978) found that this panel (fig. 24-48) could be cured at 350°F with 

 closed press time of about 10 minutes (fig. 24-49). 



