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Wood 120 – Lumber Volume

Wood 120 – Lumber Volume. Lab #1 - 2013. Lumber volume. In sawmilling, lumber is most often measured by the “board foot” or “fbm” (Foot Board Measure). . 1fbm =  1 foot x 1 foot  x 1 inch A thousand fbm is written “Mfbm” A million fbm is written as “MMfbm”. Log Scaling in Cubic.

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Wood 120 – Lumber Volume

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  1. Wood 120 – Lumber Volume Lab #1 - 2013

  2. Lumber volume • In sawmilling, lumber is most often measured by the “board foot” or “fbm” (Foot Board Measure).  1fbm =  1 foot x 1 foot  x 1 inch A thousand fbm is written “Mfbm” A million fbm is written as “MMfbm”

  3. Log Scaling in Cubic • Logs in BC are usually measure in cubic meters • Smalian’s Formula is the standard used in BC Robert Fürst – Wood 120

  4. Au Smalian’s Formula • Vol = h/2 (Ab + Au) • Where: • H = Height • Ab = cross section area at base • Au = cross section are at top • Area (Ab or Au)=(d² x 3.14)/4 h Ab Robert Fürst – Wood 120

  5. Excel Example Area (Ab or Au)=(d² x 3.14)/4 Robert Fürst – Wood 120

  6. Foot Board Measure 12 inches 12 inches 1 inch Board foot = 12 inches wide, 12 inches long, 1 inch thick = 1/12 ft3

  7. Largest sawmill production capacity600 MMfbm (Houston, BC) Average BC sawmill capacityapprox. 150-200 MMfbm Price of softwood lumber$250-275/Mfbm Price of hardwood lumbere.g. sugar maple $4/board foot

  8. Quick conversion factors • Millimeters to Inches multiply by 0.03937 • Inches to Millimeters multiply by 25.4 • Meters to Feet multiply by 3,281 • Feed to Meters multiply by 0.3048 • Square Meters to Square feet multiply by 10.764 • Square Feet to Square Meters multiply by 0.0929 • Cubic Meters to Board Footage multiply by 423.79 • Board footage to Cubic Meters multiply by 0.0023596 Robert Fürst – Wood 120

  9. Volume of lumber - Conversion • When calculating board footage from metric sizes, it is necessary to convert the metric size to imperial measure before you begin the calculation • Example: 10 pieces - 27mm thick - 105mm wide - 3 meter long • 1 mm = 0.039937 in, ; 1 meter = 3.281 ft. 10 pieces x 27 x 0.03937 x 105 x 0.03937 x 3 x 3.281 12 = 36 board feet Robert Fürst – Wood 120

  10. Lumber Recovery Factor (LRF) • Definition: LRF is how many board feet of green/rough sawn lumber are produced out of one cubic meter of wood. • The units of LRF are board feet per cubic meter. LRF typically ranges between 200 to 300 board feet per cubic meter.

  11. 318 296 275 254 FBM/m3 233 212 Recovery % 50 55 60 65 70 75 Lumber Recovery Factor (LRF) LRF depends on: Size of logs entering the mill Quality of log – defects, grade Equipment used in a mill

  12. British Columbia Sawmill Lumber Recovery Factors LeadingMills Average LRF (bf/m ) 3 271 BC Mills +17% 231 (BC MoF, 2005)

  13. Standard Thicknesses

  14. Target Thickness Minimum dimension required to achieve desired final size given unavoidable reductions in size during manufacture.

  15. Fibre Recovery - Percentage Finished lumber (kds4s)      47% Chips                                 34% Sawdust & chip fines           9% Shrinkage                            4% Shavings                              6% Robert Fürst – Wood 120

  16. Lab Assignment Sawing – LRF – Log Volume Robert Fürst – Wood 120

  17. Lab Tasks - Sawing • Calculate the log volume of the sample log (m3) • Make 2 horizontal reference cuts #1 #2 Robert Fürst – Wood 120

  18. Lab Task - Sawing • Rotate log 90°, cut reference cut, saw boards #4 #3 Robert Fürst – Wood 120

  19. Lab Task - Sawing • Cut the log into 2” thick boards Robert Fürst – Wood 120

  20. Lab Tasks - Sawing Wane • Rip each individual board to 4” wide components • Grade each board (No wane, no loose knots, no end splits longer than 2”, no center board) • Calculate the volume (in bf) of the 2/4 material recovered • Calculate the LRF in % Robert Fürst – Wood 120

  21. Document your Findings of the Lab • Write a brief report describing all of your findings of the lab and explain what caused the fairly low LRF. Please be specific! • Submit all of your calculations as required • Due date: • Group 1: 28th November 2013 • Group 2: 5th December 2013 • Please e-mail your report to Mr. Sheng Xie E-Mail: xiesheng@gmail.com Robert Fürst – Wood 120

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