Session 28 ic2011 barnes

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Session 28 ic2011 barnes

  1. 1. Session 28: It’s not Just Rot: Towards Holistic Evaluation of Wood Product Durability Ground Contact Performance ofCreosote Amended with Chlorothalonil: Can we Reduce Retentions? H. M. Barnes, M. G. Sanders, G. B. Lindsey, and T. L. Amburgey Forest Products Laboratory
  2. 2. Background Creosote supply Reduction of impact (92-192 kg/m3) BMPs Chlorothalonil highly effective  Ag crops, paints, mold & sapstain  Broad spectrum, low mammalian toxicity  Combined with insecticides, antioxidants  Removed from AWPA BoS, 2004, lack of use
  3. 3. ObjectivesThis study asks: To what extent can creosote retentions be reduced by the addition of chlorothalonil?
  4. 4. Materials & Methods Wood  All sap southern pine  19 x 19 x 1120 mm (r x t x l)  Cut into matched halves Preservatives  P2 Creosote  Chlorothalonil  Both met AWPA 2003 specs
  5. 5. Sample Treatment Treated full cell at room temperature 91 kPa vacuum for 30 min Introduction of preservative under vacuum Pressure increased to 1034 kPa in 5 minutes Held for 60 min Vent to atmospheric, drain, remove samples, wipe & weigh 102 mm retain cut from end
  6. 6. Sample Exposure & Evaluation  Matched samples placed in Dorman (AWPA Hazard Dorman = silty clay loam Zone 4) & Saucier (AWPA Hazard Zone 5) test plots at depth of 230 mm  Rows 0.75 m apartSaucier = loamy sand
  7. 7.  Evaluated annually for decay and termite attack
  8. 8. AWPA (2003) visual grading scale for rating decay and termite attack Decay Rating TermitesSound; suspicion of decay 10 Sound; 1-2 small nibblespermitted permittedTrace decay to 3% of cross 9 Slight feeding to 3% of crosssection sectionDecay from 3-10% of cross 8 Attack from 3-10% of crosssection sectionDecay from 10-30% of cross 7 Attack from 10-30% of crosssection sectionDecay from 30-50% of cross 6 Attack from 30-50% of crosssection sectionDecay from 50-75% of cross 4 Attack from 50-75% of crosssection sectionFailure (>75% of cross section) 0 Failure (>75% of cross section)
  9. 9. Data Evaluation Approach 1:Dose response curves CTL after 6 years of exposure
  10. 10. •Approach 2: Depreciation curves
  11. 11.  Curves were fitted Time to score of 70 (t70) was calculated for comparison purposes
  12. 12. • Fitted curves constructed to give a dose-response curve over time
  13. 13. Organism Response Decay was more severe than termite attack in both test plots Decay was generally greater at the Dorman site than Saucier Termite attack was generally greater at the Saucier site compared to Dorman
  14. 14. Test Plot Response
  15. 15. Impact of CTL addition
  16. 16. What does the study show? At P2 retentions lower than the AWPA minimum (<92 kg/m3), the addition of CTL improves the performance even for the lowest CTL addition rates For P2 retentions >92 kg/m3, significant improvement is seen only for the highest CTL addition rate
  17. 17. So, can we reduce creosoteloadings and get equivalent orbetter performance by adding CTL? YES, . . . . . but, Will we?
  18. 18. Future research papers will report on Different species including:  Red oak (Quercus rubra)  Sweetgum (Liquidambar styraciflua)
  19. 19. Thank you----Any questions?????

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