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DESCRIPTION 1
Identify
natural-growth, manufacturing and seasoning defects in timbers 2
Demonstrate the
correct use of visual grading rules to grade timbers. 3
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LEARNING
TASKS |
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CONTENT |
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1. Identify natural-growth defects |
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•
Knots (All Types) •
Burls •
Holes (All Types) •
Pitch Streaks •
Pockets •
Inclusions (Bark Seams &
Pitch Seams) •
Shake (All Types) •
Sapwood •
Stains (All Types) •
Decay (All Types) •
Compression Wood / Reaction
Wood •
Spiral Grain (LH & RH) •
Wane •
Insect Attack •
Pith |
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2. Identify manufacturing defects |
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•
Falling Fractures •
Slope of Grain •
Picaroon Holes & Dog
Holes •
Skip, Chipped Grain &
Torn Grain, Knife Marks, Machine Bite & Machine Burn •
Saw Cuts (All Types) •
Handling Damage (Dogs,
Forklift, Chains, Road-Rash, Etc) |
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3. Identify seasoning defects |
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•
Checks & Splits •
Warp (Crook, Bow, Cup &
Twist / Wind) •
Internal Checking (Collapse,
Case-Hardening & Honeycomb) |
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4. Demonstrate visual grading |
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•
Timber •
Beams & Stringers •
Posts & Timbers •
Identify Characteristics
& Limiting Provisions for Various Grades •
Salvaged & Reclaimed
Timbers •
Re-grading Timbers After
Joinery & Finished Lengths •
Shop-Culling &
Down-Grading Timbers During Designation for Framing |
Practical:41
i)
Given a current and appropriate
set of standard grading rules, learners will visually grade and correctly mark
a selection of 10 timbers with their appropriate grades. 42
ii)
As above, learners will
visually grade and correctly mark a selection of 10 salvaged / reclaimed
timbers with their appropriate grades. 43
DESCRIPTION 44
Identify standard grading rules. 45
Identify design values for timbers. 46
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LEARNING
TASKS |
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CONTENT |
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1. Identify grading standards |
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•
US •
American Lumber Standards
Committee (ALSC) •
American Softwood Lumber
Standard PS 20 •
Standard Grading Rules for
Northeasetern Lumber, Northeast Lumber Manufacturers Association (NeLMA) •
Standard Grading Rules,
Northern Softwood Lumber Bureau (NSLB) •
Standard Specifications for
Grades of Californian Redwood Lumber, Redwood Inspection Service (RIS) •
Standard Grading Rules for
Southern Pine, Southern Pine Inspection Bureau (SPIB) •
Standard Grading Rules for
West Coast Timber, West Coast Lumber Inspection Bureau (WCLIB) •
Western Lumber Grading Rules,
Western Wood Products Association (WWPA) •
Standard Grading Rules for
Canadian Lumber, National Lumber Grades Authority (NLGA) •
National Hardwood Lumber
Association (NHLA) |
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2. Identify design values. |
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•
National Design Specification
for Wood Construction (NDS) •
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Theory:64
i)
Given a sample timber species
and project location, learners will identify the appropriate standard grading
rules that can be used to satisfy local codes. 65
ii)
Using the example given above,
learners will use the NDS to identify the correct design values that should be
used (for structural engineering) for various grades of the sample timbers. 66
Practical:67
iii)
Given a timber of unknown
species and grade, learners will test the piece with measured loads to
determine the Modulus of Elasticity of that timber. 68