Comparison results of visual and machine strength grading of Scots pine
sawn timber from the Silesian Forestry Region in Poland

Krzosek, S.; Burawska-Kupniewska, Izabela; Mankowski, Peter; Grześkiewicz, M.

doi:10.5604/01.3001.0013.7633

Cited by 7 publications

(6 citation statements)

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“…As expected, and other authors had concluded [28], in maritime pine and Scots pine, in addition to the better yield of the higher strength class, a decrease in the percentage of rejection was obtained for machine grading with respect to visual grading. Visual grading of maritime pine resulted in similar yields than that obtained by Vega et al [29] for this Even though the visual grading of the studied samples did not comply with the relationships between visual grade and strength class given by EN 1912:2012 [5] for these species, a comparison between machine and visual grading was made considering the theoretical strength classes.…”

Section: Machine Grading Vs Visual Gradingsupporting

confidence: 88%

Evaluation of Yield Improvements in Machine vs. Visual Strength Grading for Softwood Species

Moltini

Íñiguez

Cabrera³

et al. 2022

Forests

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The current national standard for strength grading in Spain is based on a visual classification, which, for softwood species with small cross-sections (with a thickness equa tol or less than 70 mm), establishes two different visual grades (ME-1 and ME-2). These grades are assigned to the strength classes C24 and C18, respectively, for maritime and radiata pines, and C27 and C18 for Scots pine, according to the European standard EN-1912:2012. The production of engineered wood products, such as glulam or cross-laminated timber is increasing worldwide. The machine grading of wood using non-destructive testing provides the industry with a more reliable, fast, and consistent method for grading. With this background in mind, this study presents the yield comparison of machine grading vs. visual grading for those three pine species from Spain. The machine settings were obtained according to the standard EN 14081-2:2019, providing several possible strength grade combinations. Results allow new possibilities for the industry and improve the structural yield of the studied timber, thus increasing the material optimization.

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Section: Machine Grading Vs Visual Gradingsupporting

confidence: 88%

Evaluation of Yield Improvements in Machine vs. Visual Strength Grading for Softwood Species

Moltini

Íñiguez

Cabrera³

et al. 2022

Forests

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show abstract

“…Glued laminated timber has typical features of a solid timber: light weight, good strength, elasticity, durability, easy processing, and a unique feature (i.e., is readily shaped cross-sections). Its cross-section has a layered structure, enabling the manufacturing of components with variable cross-sectional height as needed [ 11 , 12 , 13 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

The Usefulness of Pine Timber (Pinus sylvestris L.) for the Production of Structural Elements. Part I: Evaluation of the Quality of the Pine Timber in the Bending Test

et al. 2020

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The study assessed the quality of pine lumber by marking the modulus of elasticity in the horizontal system. The research material was a plank with the following dimensions: 137 mm wide × 39.50 mm thick × 3485 mm long. The pine wood was obtained by sawing timber in the form of logs with round cross sections and originating from the Forest Division Olesno (50°52′30″ N, 18°25′00″ E). Each long log was sawn to provide four logs of about 3.5 m, which were marked as butt-end logs (O), middle logs (S)—2 items, and top logs (W). The origin of the logs from the trunk (Pinus sylvestris L.) has a significant impact on the physical and mechanical properties of the wood from which they are made. Only butt-end logs (log type O) allows for the production of high-quality timber elements. The pine timber that was evaluated in this paper had a high density of about 570 kg/m3 and a high percentage of timber items were assigned to class C24 and higher (above 50%). The adopted horizontal model of evaluation of the modulus of elasticity gave similar results to those obtained in an evaluation according to the EN-408.

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“…Figures 5 and 6 show a clear, typical, and high variance of the parameter within a given strength grade. This variance can be reduced by a more careful selection of research material, as well as by sub-dividing strength grades into smaller sub-grades [31,32]. Another possibility consists of improving the sorting methods, especially by preparing models that would provide higher correlations between the physico-mechanical properties of timber and timber strength grades.…”

Section: Resultsmentioning

confidence: 99%

Quality and Bending Properties of Scots Pine (Pinus Sylvestris L.) Sawn Timber

Burawska-Kupniewska

Krzosek

Mankowski

et al. 2020

Forests

Self Cite

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The paper presents the partial research results of a mechanical properties study conducted on Scots pine from the Silesian Forestry Area in Poland. The scope of research included the visual strength grading of the timber according to the PN-D-94021:2013 standard, mechanical testing (according to EN 408:2012) and an attempt to assign visuals to the C strength classes. The EN 1912: 2012 standard assigns the visual sorting classes of individual wood species (according to national sorting standards) to the C strength classes introduced by the EN 338: 2018 standard. At the moment, this standard does not assign Polish visual sorting classes (KW, KS, and KG) to C strength classes. The obtained MOE (modulus of elasticity) and MOR (static bending strength) values were corrected according to the EN 384:2018 standard, and their characteristic values were later calculated. On this basis, we proposed a classification of the grading classes determined on the basis of PN-D-94021 into C classes described in EN 338:2018, which is necessary in the process of the transposition of Polish strength grades (KW, KS, KG, and Reject) and the qualification of them in line with EN 1912:2012. The calculated characteristic values of density, MOR and E0 (the modulus of elasticity parallel to the grain) allowed us to assign Polish visual grades KW, KS, and KG to C35, C30, and C20, respectively. The pine timber under research had high physical and mechanical parameters, which translated into high C classes to which the KW, KS, and KG timber categories were assigned.

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Comparison results of visual and machine strength grading of Scots pine sawn timber from the Silesian Forestry Region in Poland

Cited by 7 publications

References 0 publications

Evaluation of Yield Improvements in Machine vs. Visual Strength Grading for Softwood Species

Evaluation of Yield Improvements in Machine vs. Visual Strength Grading for Softwood Species

The Usefulness of Pine Timber (Pinus sylvestris L.) for the Production of Structural Elements. Part I: Evaluation of the Quality of the Pine Timber in the Bending Test

Quality and Bending Properties of Scots Pine (Pinus Sylvestris L.) Sawn Timber

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