Modelling the Material Resistance of Wood—Part 1: Utilizing Durability Test Data Based on Different Reference Wood Species

Abstract

To evaluate the performance of new wood-based products, reference wood species with known performances are included in laboratory and field trials. However, different wood species vary in their durability performance, and there will also be a within-species variation. The primary aim of this paper was to compare the material resistance against decay fungi and moisture performance of three European reference wood species, i.e., Scots pine sapwood (Pinus sylvestris), Norway spruce (Picea abies), and European beech (Fagus sylvatica). Wood material was collected from 43 locations all over Europe and exposed to brown rot (Rhodonia placenta), white rot (Trametes versicolor) or soft rot fungi. In addition, five different moisture performance characteristics were analyzed. The main results were the two factors accounting for the wetting ability (kwa) and the inherent protective properties of wood (kinh), factors for conversion between Norway spruce vs. Scots pine sapwood or European beech for the three decay types and four moisture tests, and material resistance dose (DRd) per wood species. The data illustrate that the differences between the three European reference wood species were minor, both with regard to decay and moisture performance. The results also highlight the importance of defined boundaries for density and annual ring width when comparing materials within and between experiments. It was concluded that with the factors obtained, existing, and future test data, where only one or two of the mentioned reference species were used, can be transferred to models and prediction tools that use another of the reference species.

Modelling the Material Resistance of Wood—Part 2: Validation and Optimization of the Meyer-Veltrup Model

“…0%), and capillary water uptake (CWU) of end-grain surfaces. The test protocols are described in detail in Part 1 of this publication [83]. In each case, the reference wood species was Norway spruce (Picea abies).…”

“…This study enlarged the pool of datasets and also included results where Scots pine sapwood (Pinus sylvestris) and European beech (Fagus sylvatica) were used as reference species. Factors accounting for the relationship between the material resistance and its respective components for the three reference species were applied as described in Part 1 [83] of this publication. In addition to standard basidiomycete tests with brown and white rot fungi (e.g., EN 113-2 [7]) and soil contact soft rot tests under laboratory (e.g., ENV 807 [11]) and field conditions (e.g., EN 252 [10]), results from basidiomycete mini-block tests [84] were considered.…”

“…In addition to standard basidiomycete tests with brown and white rot fungi (e.g., EN 113-2 [7]) and soil contact soft rot tests under laboratory (e.g., ENV 807 [11]) and field conditions (e.g., EN 252 [10]), results from basidiomycete mini-block tests [84] were considered. Results from submersion and floating tests according to CEN/TS 16818 [85] were considered for calculating k wa factors in addition to the tests described in Part 1 [83].…”

Modelling the Material Resistance of Wood—Part 3: Relative Resistance in above- and in-Ground Situations—Results of a Global Survey

“…In Part 1 and 2 of this publication [9,10], we focus on the counterpart of the exposure dose, which is the resistance, expressed as resistance dose, D Rd . The latter is considered to be the product of a critical dose, D crit , and two factors considering the wetting ability of wood (k wa ) and its inherent durability (k inh ).…”

“…In particular, in standard tests (e.g., EN 113-2 [12], AWPA E7 [13]) reference species are the sapwood of different pine species (softwoods) or beech (hardwoods). In Part 1 of this publication [9], we performed comparative durability and moisture performance tests with Norway spruce, Scots pine sapwood (Pinus sylvestris), and European beech (Fagus sylvatica), and determined factors between the three species for the resistance against different rot types and for different kinds of moisture uptake and release. The latter allows us to utilize further data for: (1) improving and validating existing material resistance models (Part 2 of this publication [10]), and (2) generating a material resistance database for different wood species and treated timbers.…”