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.

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

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

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 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) 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 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

MOR / UTS

Char Size 2x8-12' Char Size 2x8-12'

MOR Tolerance

Limit % of #2

UTS Tolerance Limit % of #2

Subset n TL OS MOR TL 2x4 Fb n TL OS UTS TL 2x4 Ft

Required 409 17 1781 1048 69.8% 410 18 1105 650 78.8%

Filler 334 14 1384 814 54.3% 341 14 768 452 54.8%

All 743 33 1599 940 62.7% 751 34 892 525 63.6%

How Representative?

The 17 pieces that set the 5th percentile came from 13 different mills in 9 different producing regions.

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

Example of Knots in Tested Material

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 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