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A comparative analysis of pine and beech wood classification according to Polish and EU norms

Barszcz A., Michalec K., Wąsik R.

Drewno : prace naukowe, doniesienia, komunikaty

2014

vol. 57, nr 193

135--145

Investigations were carried out at timber storage sites (depots) on large-sized pine (110 pieces) and beech (130 pieces) wood from three forest districts within the territory of the Regional Directorates of the State Forests (RDSF) of Łódź, Lublin and Kraków. As a result of a comparison of both classification systems, it was proved that in the case of pine wood classified according to EU norms, the shares of the number of pieces and volume in classes B and C decreased, whereas they increased in class D when compared with Polish classification. Analogically, in the case of beech wood, a decrease in the share of the number of pieces and volume in classes A, B and D, and an increase in class C were recorded. Among the most common defects that influence the classification of both sorts of wood, open and burl knots as well as curvatures are recognised, while in the case of beech wood, shakes and galls (disease T stains) are encountered. The results of the classification determined differences in the wood value. According to the pricelists for wood standing in forest districts where the raw wood under investigation originated, it was established that the value of the pine wood classified according to the EU norm decreased by ca. 7.6% when compared with the value estimated using the Polish norm. The value of the beech wood was nearly identical in both cases, which was mainly due to the higher share of wood of class C and lower share of class D upon applying the EU standards, in comparison with the Polish classification system.

Badania kolektorów słonecznych według europejskiej normy EN 12975

Danielewicz J., Szulgowska-Zgrzywa M., Jadwiszczak P.

Ciepłownictwo, Ogrzewnictwo, Wentylacja

2005

R. 36, nr 6

18-24

Przedstawiono zagadnienia poruszane w normie EN 12975. Omówiono metody wyznaczania wydajności kolektorów słonecznych. Przybliżono: zalecany przez normę model matematyczny kolektora, warunki oraz procedurę prowadzenia testów oraz sposoby estymacji poszukiwanych parametrów. Przedstawiono również fragment wyników badań oraz opis nowo otwartego stanowiska badawczego Katedry Klimatyzacji i Ciepłownictwa Politechniki Wrocławskiej, umożliwiającego wyznaczanie parametrów kolektorów słonecznych w warunkach zewnętrznych według zaleceń normy.

The problems of the EN 12975 Standard dealing with methods of determining solar collector capacity are presented. The mathematical model recommended in the Standard, conditions and test procedures are given, as well as estimation methods concerning parameters of interest. Part of the results achieved is included. Description of a recently opened research stand, in the Department of Air Conditioning and Heat Engineering of Wroclaw Polytechnic, is also given. The stand enables the determining of solar collector parameters according to the Standard in outdoor conditions.