Efficiency of visual strength grading of timber with respect to origin, species, cross section, and grading rules: a critical evaluation of the common standards
-
Peter Stapel
and
Jan-Willem G. van de Kuilen
Abstract
Strength grading is essential for the efficient use of structural timber. Although international standards exist for machine strength grading, visual grading is still regulated based on national rules, which are expected to allow safe and economic grading results. Although there are large differences in the graded output because the species, the cross section, and the origin of the timber influence the results, some of these standards are considered to be applicable universally. The present article demonstrates how the chosen standards influence the grading results. Depending on the parameters, the yields or the mechanical properties are low compared with the declared values. The results also show the efficiency and applicability of different national standards for strength grading of timber from various origins. Furthermore, it is recommended to reconsider the existing limits for source areas and cross sections given in the standard EN 1912.
We like to thank Olaf Strehl and Andreas Gossler of HFM for programming the grading rule routines into the database and our student assistants for measuring tens of thousands of knots.
References
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©2014 by Walter de Gruyter Berlin Boston
Articles in the same Issue
- Masthead
- Masthead
- Review
- Mode of action of brown rot decay resistance in modified wood: a review
- Original Articles
- Photoyellowing of chemically modified chemithermomechanical pulps (CTMP) from Eucalyptus globulus under various atmospheres
- Selective purification of bleached spruce TMP process water by induced air flotation (IAF)
- Evaluation of the effects of compression combined with heat treatment by nanoindentation (NI) of poplar cell walls
- Measured temperature and moisture profiles during thermal modification of beech (Fagus sylvatica L.) and spruce (Picea abies L. Karst.) wood
- Modeling the influence of thermal modification on the electrical conductivity of wood
- Spruce fiber properties after high-temperature thermomechanical pulping (HT-TMP)
- Efficiency of visual strength grading of timber with respect to origin, species, cross section, and grading rules: a critical evaluation of the common standards
- Synthesis of alcohol-soluble phenol-formaldehyde resins from pyrolysis oil of Cunninghamia lanceolata wood and properties of molding plates made of resin-impregnated materials
- Enzymatic strategies to improve removal of hexenuronic acids and lignin from cellulosic fibers
- Phylogenetic analysis of major molds inhabiting woods. Part 4. Genus Alternaria
- Short Notes
- Comparison of hydrogenolysis with thioacidolysis for lignin structural analysis
- Detection of complex vascular system in bamboo node by X-ray μCT imaging technique
- Obituary
- Professor Gösta Brunow (1936–2013)
- Meetings
- Meetings
Articles in the same Issue
- Masthead
- Masthead
- Review
- Mode of action of brown rot decay resistance in modified wood: a review
- Original Articles
- Photoyellowing of chemically modified chemithermomechanical pulps (CTMP) from Eucalyptus globulus under various atmospheres
- Selective purification of bleached spruce TMP process water by induced air flotation (IAF)
- Evaluation of the effects of compression combined with heat treatment by nanoindentation (NI) of poplar cell walls
- Measured temperature and moisture profiles during thermal modification of beech (Fagus sylvatica L.) and spruce (Picea abies L. Karst.) wood
- Modeling the influence of thermal modification on the electrical conductivity of wood
- Spruce fiber properties after high-temperature thermomechanical pulping (HT-TMP)
- Efficiency of visual strength grading of timber with respect to origin, species, cross section, and grading rules: a critical evaluation of the common standards
- Synthesis of alcohol-soluble phenol-formaldehyde resins from pyrolysis oil of Cunninghamia lanceolata wood and properties of molding plates made of resin-impregnated materials
- Enzymatic strategies to improve removal of hexenuronic acids and lignin from cellulosic fibers
- Phylogenetic analysis of major molds inhabiting woods. Part 4. Genus Alternaria
- Short Notes
- Comparison of hydrogenolysis with thioacidolysis for lignin structural analysis
- Detection of complex vascular system in bamboo node by X-ray μCT imaging technique
- Obituary
- Professor Gösta Brunow (1936–2013)
- Meetings
- Meetings
