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Individual Highlight

Wood Adhesives at High Temperatures

Photo of Finger joint after failure showing smooth wood surfaces that could be easily refit together where the adhesive failed at low temperatures.Finger joint after failure showing smooth wood surfaces that could be easily refit together where the adhesive failed at low temperatures.Snapshot : Researchers examined the performance of finger-jointed lumber to understand how it performs in fire.

Principal Investigators(s) :
Rammer, Douglas R.Hasburgh, Laura, E.
Zelinka, Samuel L. 
Research Location : FPL
Research Station : Forest Products Laboratory (FPL)
Year : 2018
Highlight ID : 1492

Summary

The ability of assemblies to maintain their integrity when exposed to a standard fire exposure, measured in units of time, is referred to as the fire resistance rating. In the United States, the fire resistance rating is typically determined by exposing a loaded assembly to an ASTM E119 time-temperature curve. The performance of wood adhesives under elevated temperatures (fire scenarios) has been studied since the 1960s, yet there are some important gaps in our understanding of how wood adhesives in engineered lumber affect the fire resistance. A test method was developed to screen adhesive formulations for finger-jointed lumber. The goal was to develop a small-scale test that could be used to predict whether an adhesive would pass a full-scale ASTM E119 wall assembly test. The method involved loading a 38-mm-square finger-jointed sample in a four-point bending test inside an oven with a target sample temperature of 204°C. It was found that samples finger-jointed with melamine formaldehyde and phenol resorcinol formaldehyde adhesives had the same creep behavior as solid wood. One-component polyurethane and polyvinyl acetate adhesives could not maintain the load at the target temperature measured mid-depth of the sample, and several different types of creep behavior were observed prior to failure. This method showed that the creep performance of the one-component adhesives may be quite different than the performance from short term load deformation curves collected at high temperatures.

Forest Service Partners

External Partners

  • N/A
  • American Wood Council