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Southern Pine In-Grade Testing. Fall 2011 Status. Prior to the SPA, various regional pine associations published their own grading rules. In some cases, different grades applied to the various states which produced Southern Pine.

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Prior to the SPA, various regional pine associations published their own grading rules. In some cases, different grades applied to the various states which produced Southern Pine.

The SPIB has published 13 grading rules since 1941. The current rule is the 2002 edition. Grading rules are intended to provide a “level playing field” for the producers and consumers of lumber products.

determination of design values
Determination of Design Values
  • A standard practice in accordance with ASTM D1990
  • ASTM D 1990 is a consensus standard
  • USDA Forest Service FPL is the referee for application of D1990
  • Design value determination is a calculation process that typically uses a model with known characteristics
  • An example of model use involves interpolation and extrapolation based on a characteristic value from consolidated data.
  • D1990 intent is to derive conservative values for the species group
  • A review and reassessment of values is required if there is cause to believe a significant change has occurred in the resource.
resource monitoring program
Resource Monitoring Program
  • In 1994 the SPIB, with assistance from the FPL, initiated a resource monitoring program to track possible changes that may occur in modulus of elasticity of No. 2 dimension lumber, over time.
  • Process is multi-stage sampling
  • Data collected using a Metriguard 340 E-computer
brief timeline
Brief Timeline
  • Summer 2010 – Need for additional testing
    • Building Components Research
    • Large Lumber Manufacturer
  • Test Plan approved by ALSC BOR
  • 2x4 #2
  • Fall 2010 – Gathered Samples
  • Winter/Spring 2011 - Testing
sampling continued
Sampling (continued)
  • Mills randomly selected within regions by FPL
  • Minimum of 10 pieces per property from sampled mills.
  • No more than 20 pieces per property from any one mill
  • Approx. 750 pieces tested for Bending by SPIB
  • Approx. 750 pieces tested for Tension by TP
observations
Observations
  • Very good consistency between data collected at each agency
  • Very similar percentages in each type of data sort
    • i.e. percent of pieces dense on one end, with pith, etc.
  • E data very similar
    • E-Computer averages similar between labs
    • Edge E averages similar between labs
how representative
How Representative?
  • The 17 pieces that set the 5th percentile came from 13 different mills in 9 different producing regions.
density
Density
  • Fewer rings per inch and lower percent summerwood
  • A field review of all widths and grades indicates coarse grain exists throughout all dimension products
  • Knots and slope of grain trump density in strength effects
astm d1990 size model
ASTM D1990 Size Model
  • A Full Matrix for IGT includes:
    • Minimum of 2 grades per size
    • Minimum of 3 widths
  • Grade Model is driven by the lowest strength pieces.
    • All widths are adjusted to 2x8-12 size
    • Lowest strength pieces from all widths fall to the bottom
    • Design values are taken from the 2x8-12 and interpolated to the grades/widths not sampled.
  • Observed data requires action
actions to date
Actions To Date
  • Data from initial testing submitted to the ALSC Board of Review
    • Testing on 2x4 No.2 verified by USDA-FPL. SPIB approach is conservative and reasonable.
    • Currently Under Public Comment
  • Full in-grade plan developed
  • Joint Timber Products / SPIB Full IGT Sample Selection In-Progress
  • Anticipate completion in 2012