Performance of copper naphthenate-treated hardwoods
H M Barnes, T L Amburgey, H M Freeman, J A Brient
Copper naphthenate (CuNap) is a historically proven, commercially produced and industry utilized preservative for many wooden commodities including poles, fence posts, lumber, timber and wood shakes/shingles. Historically, most wood preservatives are tested using the sapwood of softwood species like pine (Pinus spp.) and or Douglas-fir (Pseudosuga menziesii) and even though the railroads of the world have commercially utilized hardwoods for their load carrying capacities, not many preservative evaluations are performed on hardwood species. This paper examines the efficacy of CuNap in hardwoods. Previously unpublished data on copper naphthenate-treated hardwoods comparing to P2 creosote in a high hazard test site are given as well as the recent results from the timber bridge testing program where CuNap is being evaluated in seven hardwood species plus southern pine. The test data presented in this paper support the potential commercial uses of CuNap to treat hardwoods and provide good to excellent service life for those treated members.