Structural Composite Lumber & Glued Laminated Timber

1. Structural Composite Lumber & Glued Laminated Timber • Awareness Guide • Ray O’Brocki, CBO • Manager - Fire Service Relations • American Wood Council

2. Purpose of this guide • The purpose of this awareness guide is to provide the fire service with information on the types and properties of Structural Composite Lumber (SCL) and Glued Laminated Timber (Glulam), how the products are manufactured, and how they are used in residential construction.

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8. Learning Objectives • Upon completion, participants will be better able to identify: • Identify the types and applications of structural composite lumber (SCL) • Structural Composite Lumber • Be able to identify Glued Laminated Timber (Glulam) and its applications • Glued laminated Timber • Identify methods for the manufacture of SCL and Glulam • Manufacture • What to look for when visiting a residential construction site and examining the framing • Site Visits 1 3 2 4

9. Structural Composite Lumber (SCL) • Rectangular shape • Superior strength, stiffness, and consistency • Manufacturing • smaller logs • sort the pieces • apply adhesive • reassemble • Popularity • long and wide dimensions • without warp Parallel Strand Lumber and Laminated Veneer Lumber

10. Types of structural composite lumber • Laminated Veneer Lumber (LVL) • Parallel Strand Lumber (PSL) • Laminated Strand Lumber (LSL) • Oriented Strand Lumber (OSL) Laminated veneer lumber is placed into a metal hanger and supported by another LVL girder.

11. Laminated Veneer Lumber (LVL) • Applications • Beams • Lintels • Purlins • Truss Chords • Girders • Headers • Manufacture almost any length • Strength of solid timber, concrete and steel LVL headers are commonly used to span large openings, such as this window

12. Laminated Veneer Lumber (LVL) • LVL Manufacturing • Rotary peeling method • knife parallel to edge of a log spinning on a lathe • similar to removing paper towels from a roll • individual cut sheets called veneer • dried • glued • pressed together • Plywood is made by a similar process Laminated veneer lumber is available in a variety of widths and depths generally to match I-joist depths

13. Laminated Veneer Lumber (LVL)

14. Laminated Veneer Lumber (LVL) • Bay window headers support a small roof • LVL header supports floor joists above and exterior wall and roof • Lumber floor joist cavities filled with batt insulation • Multi-ply LVL girder bolted together at regular spaces

15. Laminated Strand Lumber (LSL) • Applications • Rim boards, millwork • Window, door and garage headers • Resembles Oriented Strand Board (OSB) • Made from long strands using stranding manufacturing process Laminated veneer headers are commonly used to span large opening, such as this window opening.

16. Laminated Strand Lumber (LSL) • Stranding • 3-inch to 12-inch slices • similar to grating a block of cheese • Strands dried in large rotary drum • Adhesive applied • Strands dropped into forming bin • Pressed together • thin and flat sheets like plywood • long and wide like sawn lumber

17. Laminated Strand Lumber (LSL)

18. Parallel Strand Lumber (PSL) • Structural applications • Beams • Columns • Headers • Lintels • Attractive appearance • Used where finished appearance is a factor • Manufactured using stranding method PSL is a high strength SCL product manufactured by gluing wood strands together under pressure

19. Parallel Strand Lumber (PSL)

20. Parallel Strand Lumber (PSL) • Fabricated from veneer slices • Combined with adhesive • Formed into large billets • Sawn into more useable dimensions • Voids result from random strand lay-up • Makes preservative treatment possible

21. Parallel Strand Lumber (PSL) PSL available in variety of shapes for use as columns and girders PSL supports I-joist floor assembly sheathed with OSB

22. GlueD Laminated Timber (Glulam) • Fabrication • nominal 1- to 2-inch thick KD lumber • laminated under controlled temperature and pressure • form large timber sections Glulam Girder

23. Glued Laminated Timber (GLULAM) • Straight or arched long-spans • Required strength/position of each lam • predetermined through engineering analysis • Tension and compression (outside) lams • higher-grade lumber • carry much of the bending load • Core lams equally important • resist horizontal shear stresses • Thermosetting adhesives • adhesives undergo irreversible chemical change when first heated under pressure Glulam Girder

24. Glued Laminated Timber (GLULAM) • Retains traditional look of wood along with engineered strength Glulam used in a roof truss

25. Fire Performance of SCL and GLULAM • Glulam and SCL, although composed of smaller pieces of wood that are adhered together, offer the same fire performance as sawn members of similar size because the adhesives used in their manufacture does not adversely affect fire performance.* *Malhotra, H. and Rogowski, F., “Fire Resistance of Laminated Timber Columns,” Proceedings of Symposium No. 3. Her Majesty’s Stationary Office, London 1970, pp. 16-51. Glulam Header Courtesy of APA-The Engineered Wood Association

26. Fire Performance of SCL and GLULAM • The fire performance of timber can be attributed to the charring effect of wood. As wood members are exposed to fire, an insulating char layer is formed that protects the core of the section. Beams and columns can be designed with a sufficient cross section to sustain the design loads for the required duration of fire exposure in the ASTM E 119 Test.* *”ASTM E 119-88 Standard Test Methods for Fire Tests of Building Construction and Materials,” in ATSM Test Standards, Philadelphia, PA, 1993, pp. 674-694. LVL and plywood construction Courtesy of APA-The Engineered Wood Association

27. What is the ASTM E 119 Test? • Intended to evaluate duration for which types of building elements contain a fire, and retain structural integrity during predetermined test fire • Pass/Fail Criteria based on peak temperature attained at back of test assembly or material • Whether test assembly or material distorts or collapses and allows hot gases to escape • Whether wall can withstand hose stream pressure Glulam beam floor Courtesy of APA-The Engineered Wood Association

28. Site visits • During construction • best time to see how SCL or glulam systems configured to carry loads • Large dimension members • floor or roof beams • headers over doors and windows • rim board around foundation edges • Wall framing studs SCL used as roof ridge beam

29. Site visits • Residential construction • built from ground up • Framing inspection • from roof down SCL used as header and blocking

30. Site visits • Load path continuity • most important structural characteristic common to all buildings/construction • route that loads follow to footings • gravity • live, snow, and water ponding • lateral loads • wind and earthquake SCL used as header and blocking

31. Site visits • Simple single-family dwellings • roof, ceiling and floor loads • collected through rafters or joists • rest on • exterior walls • interior beams • bearing walls SCL used as header and blocking