1. Hazards to Firefighters from Engineered Wood Products
MFRI Drill of the Month – October 2017

2. Engineered Wood Products are taking the Building Industry by storm
Some obvious advantages:
light weight
equal or better load bearing
capacity
environmental friendliness

3. BUT, there are some serious concerns when FIRE enters the equation!

4. Laminated Veneer Lumber (LVL)
Basically a beam made of plywood
Dimensionally stable with no splitting or warping
Because of construction it can be longer than conventional solid beams
Very high strength

5. Parallel Strand Lumber (PSL)
Laminating veneer that is clipped into long strands
High bending strength
All strands parallel to the long axis of the lumber
Used for beams, headers and columns

6. Laminated Strand Lumber (LSL)
Similar to PSL
Utilizes wood flakes instead of long strands
Not as strong as LVL or PSL
Pressed into large mats or billets, then cut to size
Used for studs and millwork

8. Oriented Strand Lumber and Board (OSL & OSB)
Flakes of wood pressed together to make a sheet or lumber
Virtually the same as LSL
Used for flooring, decking, studs and millwork

10. Glulam
Laminating layers of solid wood to make a larger component
Heavy beam similar to older heavy beams, but made from smaller pieces
Used to make arches and exposed beams
Does not quickly degrade in heat

11. Everyday Uses in Construction
Glulam ridge with Composite I-beam rafters

12. LVL beam with composite I-beam floor joists

13. PSL beams with conventional sawed lumber joists and OSB flooring

14. Composite I-beams. This model has web and flanges made of engineered lumber. Flanges can also be of conventional sawed lumber and webs can be of plywood

15. Wood trusses with OSB decking
Wood trusses with OSB decking. This model is made of sawed lumber, but we are now seeing them made completely of engineered wood members.

16. Engineered wood studs

17. An example of all engineered wood construction
Studs, Headers, Beams, Sheathing, Flooring—
ALL ENGINEERED WOOD!

18. And It’s Not Just Single-family Homes
Condominiums

19. Multi-family Apartments

20. Combination Commercial and Apartments

21. Large Multi-Family

22. The List Goes On . . .
On a side note, notice the lack of apparatus access!

23. Implications to the Firefighter
Open trusses and I-beams provide more
voids for fire spread
 Softer woods burn faster and more intensely
Large open areas in current designs provide
a ready oxygen source
 Exterior siding materials melt easily and
expose sheathing to heat
Engineered products lack mass and burn
quicker

24. Underwriters Laboratory Tests
12 fire furnace tests of various construction assemblies
Measured time to collapse
Fires simulated typical fully-involved contents fire utilizing
ASTM E 199 criteria
1000°F at five minutes ° F at 60 minutes

26. Note: the two firefighters are mannikins placed for the test
12-inch wood I-beam floor without ceiling below
Note: the two firefighters are mannikins placed for the test
Collapse time = 6 minutes and 3 seconds!!

27. Note the extreme deflection of the floor
The center web of the I-beam is completely burned through

28. Typical gusset plate teeth are less than one inch
Metal gusset plates are 18 gauge or 1/20 of an inch thick!

29. Metal teeth conduct heat into the wood fibers causing rapid failure

30. Failure of OSB sheathing causes loss of support and shingles collapse into opening

31. OSB flooring completely destroyed between floor joists

32. Notice that the temperature on the surface is only 85° F (1200 ° F+ below) just prior to the floor collapse!

35. How Should This Affect Your Next Response?
Keep These in Mind:
There may be no warning of imminent collapse. Flooring and roofing materials may insulate sufficiently so the surface temperature may give no indication of the heat and damage below
Due to the quick deterioration of the engineered materials, there is no margin of safety. Some elements have failed in as little as six minutes in test situations.
Much new residential construction has the same fuel load as commercial structures of the past

36. Thermal Imaging Cameras DO NOT provide an adequate indication of weakened structures and imminent collapse
Fire Codes are minimal or non-existent for Type II and Type V construction in regard to fire resistant floor, roof and exterior assemblies
Due to the high fuel loads, you are likely to need additional manpower and high water flows
High GPM flows may also weaken the structure as most designs do not have a built-in safety factor

37. The average response time in the U.S. is just over 10 minutes
Many lightweight structural elements may be near, or have already failed before the first units arrival
EVALUATE RISK VERSUS BENEFIT
In many cases, the safest recourse is a defensive exterior attack

38. Type V Construction approximately 15 minutes elapsed time

39. These materials have been called “solidified gasoline” by Fire Chief Steve Lohr, Hagerstown, Maryland, formerly Chief of Mongomery County, Maryland.

40. We cannot fight fires like we have done in the past—it’s going to get firefighters injured or killed
Tactics need to keep up with the quickly-changing construction industry

41. REMEMBER—
EVERYONE GOES HOME!