Service life prediction of wood treated with wax emulsions and copper amine based solutions exposed in third use class

V raziskavi smo preučevali življenjsko dobo lesa, izpostavljenega na prostem, v tretjem razredu izpostavitve, z dvoslojnim testom. V prvem delu raziskave smo naravnim razmeram izpostavili vzorce smrekovine, impregnirane z vodnimi emulzijami montana in polietilenskih voskov v kombinaciji z borovimi spojinami. V drugem delu testa pa smo testirali vzorce, zaščitene z baker-etanolaminskim pripravkom na vodni osnovi (Silvanolin) in posameznimi sestavinami tega pripravka. Za primerjavo smo izpostavili tudi nezaščitene vzorce smrekovine, macesnovine, bukovine in hrastovine. Skozi celotno obdobje izpostavitve smo spremljali klimatske podatke pod vzorci in na vremenski postaji. Rezultati kažejo, da impregnacija z emulzijami voskov in pripravki na osnovi bakra podaljšuje življenjsko dobo lesa, a je zaščita s pripravki na osnovi bakrovih spojin boljša. Odpornost lesa, zaščitenega z emulzijami voskov in baker etanolaminskimi pripravki, je odvisna od koncentracije emulzije/ raztopine in kakovosti lesa. Na podlagi spremljanja vlažnosti in temperature lesa smo ugotovili, da se v lesu ustvarjajo ustreznejše vlažnostne razmere za razvoj gliv, kot bi sklepali iz meritev temperature in vlažnosti zraka.In our research, service life of wood exposed outdoor in the third use class, determined with double layer test, was investigated. In the first part of the investigation, Norway spruce wood specimens were impregnated with montan and polyethylene water based wax emulsion in combination with boron compounds. In the second part of the research, Norway spruce wood samples were impregnated with a copper-ethanolamine (Silvanolin) water based solution and aqueous solutions of individual components. For comparison, untreated Norway spruce, larch, beech and oak wood specimens were exposed as well. During exposition time, climate data under specimens and at weather station were recorded. The results showed that impregnation with wax emulsions and copper based solutions prolongs service life of wood, but protection with copper-ethanolamine solutions is considerably better. Resistance of wood, preserved with wax emulsions and copper-ethanolamine solutions, was influencedby concentration of emulsions/solutions and wood quality. The parallel measurements of wood moisture content and wood temperature clearly showed that there were more suitable conditions in wood for development and growth of fungi than indicated by air temperature and relative air humidity measurements

Minimal fungicidal and fungistatic concentrations of boron compounds for wood remediation

V raziskavi smo določili minimalno fungicidno mejno vrednost borove kisline inbakrovega sulfata pentahidrata za tri glive rjave (Gloeophyllum trabeum, Serpula lacrymans in Antrodia vaillantii) in tri glive bele trohnobe (Trametesversicolor, Pleurotus ostreatus in Hypoxylon fragiforme). Kurativno učinkovitost smo določali tako, da smo okužene smrekove in bukove lesne vzorce za 10 min potopili v vodno raztopino bakrovih oziroma borovih učinkovin. Zatem smo jih postavili na sterilno hranilno gojišče in opazovali preraščnje. Rezultati kazejo, da so borove učinkovine boljsi fungicidi kot bakrove spojine. Minimalna inhibitorna koncentracija borove kisline v lesu za kurativno zaščito je približno petkrat višja od mejne inhibitorne koncentracije za preventivno zaščito.Minimal remedial fungicidal concentrations of boric acid and copper sulphate pentahydrate for three brown (Gloeophyllum trabeum, Serpula lacrymans and Antrodia vaillantii) and three white rot (Trametes versicolor, Pleurotus ostreatus and Hypoxylon fragiforme) fungi were determined. Remedial efficacy was determined on infested spruce and beech wood specimens, which were immersed into selected copper- or boron-based preservative solutions for ten minutes. The treated specimens were transferred to nutrient medium and fungal growth was monitored. The results showed that boron compounds where better fungicides than the copper ones. Furthermore, minimal remedial boron fungicidal concentration is approximately five times higher, than the preventive minimal inhibitory concentration

Influence of PVA emulsion on leaching of boron and copper from wood and efficacy on wood decay fungi

Borove spojine učinkovito delujejo proti glivam razkrojevalkam, a se na žalost v vlažnem okolju izpirajo iz lesa. Z namenom doseči čim boljšo vezavo v les, smo borovo kislino, boraks in bakrov(II) sulfat pentahidrat kombinirali s polivinil acetatno (PVA) emulzijo. Z izbranimi pripravki smo impregnirali vzorce smreke (Picea abies) in jih izpostavili trem različnim glivam razkrojevalkam lesa (Antrodia vaillantii, Gloeophyllum trabeum in Trametes versicolor) po postopku mini blok. Del impregniranih vzorcev smo izpirali v skladu s standardom SIST EN 1250-2. Ugotovili smo, da dodatek PVA-emulzije rahlo izboljša vezavo borovih in bakrovih ionov v les. Smrekovina, impregnirana s pripravki z najnižjo koncentracijo borovih učinkovin (cB = 0,1 %), je odporna na vse testne glive, medtem ko je les, zaščiten z raztopinami na osnovi bakra, dobro zaščiten pred glivama Gloeophyllum trabeum in Trametes versicolor in neustrezno zaščiten pred glivo Antrodia vaillantii. Dodatek emulzije PVA že sam po sebi nekoliko zavre delovanje gliv in izboljša delovanje bakrovih in borovih učinkovin.Boron compounds are very effective fungicides, but they leach from wood in wet environments, unfortunately. In order to improve boron fixation, boric acid, borax and copper(II) sulphate were combined with polyvinyl acetate emulsion (PVA). Selected preservative solutions were chosen for impregnation of Norway spruce wood specimens (Picea abies). Wood blocks were exposed to three wood decay fungi Antrodia vaillantii, Gloeophyllum trabeum and Trametes versicolor according to the mini block procedure. Part of impregnated specimens was leached according to the EN 1250-2 procedure. The results showed that addition of PVA emulsion slightly improves copper and boron fixation. Spruce wood impregnated with the lowest concentration of boron based solutions (cB = 0.1%) was found resistant against tested fungi. In contrast, wood blocks impregnated with copper were sufficiently protected against G. trabeum and T. versicolor but not against A. vaillantii. Furthermore, PVA itself has a negative impact on fungal growth, and it improves performance of boron and copper based aqueous solutions

Utjecaj polietilenske i oksidirane polietilenske voštane emulzije na dinamiku ispiranja borne kiseline iz impregnirane smrekovine

Boron biocides belong to the most frequently used ingredients of commercial wood preservatives. They are very effective fungicides and insecticides, but they do not react with wood and thus leach from it in wet applications. This fact signifi cantly limits use of boron compounds in the field of wood preservation. In order to reduce leaching of boric acid, the emulsion of polyethylene (WE1) and an emulsion of oxidized polyethylene (WE6) wax were combined with boric acid (cB = 0.1 % or 0.5 % of boron). Spruce wood specimens were vacuum impregnated and afterwards leached according to the prCEN/TS 15119-1, EN 1250-2 and EN 84 procedures. The results showed that the boron leaching is predominantly infl uenced by moisture content of wood during leaching, and furthermore by the concentration gradient (frequency of water replacement). The fact that the prCEN/TS 15119-1 leaching procedure is less severe than other two methods is also refl ected in the results. The results of the EN 84 and ENV 1250 test are comparable, while the results of the prCEN/TS 15119-1 testing are not in line with the other two methods. Considerable portions of boron are leached from wood in the first leaching cycles, already. WE6 wax emulsion (oxidized polyethylene wax emulsion) in combination with heat treatment reduces boron leaching to a certain extent. On the other hand, impregnation of wood with WE1 (polyethylene wax emulsion) does not reduce it and it even enhances it.Biocidi bora pripadaju najčešće upotrebljavanim sastojcima komercijalnih zaštitinih sredstava za drvo. Vrlo su učinkovita zaštita od gljiva i insekata, no ne vežu se s drvom i stoga su skloni ispiranju iz drva, posebno kada se takvo drvo primjenjuje u vlažnim uvjetima. Ta činjenica znatno ograničava upotrebu spojeva bora na području zaštite drva. U nastojanju da se smanji ispiranje borne kiseline, polietilenska emulzija (WE1) i oksidirana polietilenska voštana emulzija (WE6) kombinirane su s bornom kiselinom (cB = 0,1 ili 0,5 % bora). Uzorci smrekovine vakuumski su impregnirani i nakon toga ispirani prema procedurama opisanim u prCEN/TS 15119-1, EN 1250-2 i EN 84. Rezultati su pokazali da na ispiranje bora najviše utječe sadržaj vode u drvu tijekom ispiranja, a zatim gradijent koncentracije (frekvencija zamjene vode). Činjenica da je testiranje ispiranja prema proceduri prCEN/TS 15119-1 manje strogo od druge dvije metode odražava se i na rezultate ispitivanja. Rezultati ispitivanja prema procedurama EN 84 i ENV 1250 usporedivi su, dok se rezultati prema proceduri testiranja prCEN/TS 15119-1 ne mogu usporediti s rezultatima dobivenim drugim dvjema metodama. Znatan dio bora iz impregniranog drva ispire se već u prvom ciklusu ispiranja. WE6 emulzija (oksidirana polietilenska voštana emulzija) u kombinaciji s termičkom obradom donekle smanjuje ispiranje bora. Nasuprot tome, impregnacija drva s WE1 (polietilenskom emulzijom) ne smanjuje već, naprotiv, pojačava ispiranje bora

Utjecaj polietilenske i oksidirane polietilenske voštane emulzije na dinamiku ispiranja borne kiseline iz impregnirane smrekovine

Boron biocides belong to the most frequently used ingredients of commercial wood preservatives. They are very effective fungicides and insecticides, but they do not react with wood and thus leach from it in wet applications. This fact signifi cantly limits use of boron compounds in the field of wood preservation. In order to reduce leaching of boric acid, the emulsion of polyethylene (WE1) and an emulsion of oxidized polyethylene (WE6) wax were combined with boric acid (cB = 0.1 % or 0.5 % of boron). Spruce wood specimens were vacuum impregnated and afterwards leached according to the prCEN/TS 15119-1, EN 1250-2 and EN 84 procedures. The results showed that the boron leaching is predominantly infl uenced by moisture content of wood during leaching, and furthermore by the concentration gradient (frequency of water replacement). The fact that the prCEN/TS 15119-1 leaching procedure is less severe than other two methods is also refl ected in the results. The results of the EN 84 and ENV 1250 test are comparable, while the results of the prCEN/TS 15119-1 testing are not in line with the other two methods. Considerable portions of boron are leached from wood in the first leaching cycles, already. WE6 wax emulsion (oxidized polyethylene wax emulsion) in combination with heat treatment reduces boron leaching to a certain extent. On the other hand, impregnation of wood with WE1 (polyethylene wax emulsion) does not reduce it and it even enhances it.Biocidi bora pripadaju najčešće upotrebljavanim sastojcima komercijalnih zaštitinih sredstava za drvo. Vrlo su učinkovita zaštita od gljiva i insekata, no ne vežu se s drvom i stoga su skloni ispiranju iz drva, posebno kada se takvo drvo primjenjuje u vlažnim uvjetima. Ta činjenica znatno ograničava upotrebu spojeva bora na području zaštite drva. U nastojanju da se smanji ispiranje borne kiseline, polietilenska emulzija (WE1) i oksidirana polietilenska voštana emulzija (WE6) kombinirane su s bornom kiselinom (cB = 0,1 ili 0,5 % bora). Uzorci smrekovine vakuumski su impregnirani i nakon toga ispirani prema procedurama opisanim u prCEN/TS 15119-1, EN 1250-2 i EN 84. Rezultati su pokazali da na ispiranje bora najviše utječe sadržaj vode u drvu tijekom ispiranja, a zatim gradijent koncentracije (frekvencija zamjene vode). Činjenica da je testiranje ispiranja prema proceduri prCEN/TS 15119-1 manje strogo od druge dvije metode odražava se i na rezultate ispitivanja. Rezultati ispitivanja prema procedurama EN 84 i ENV 1250 usporedivi su, dok se rezultati prema proceduri testiranja prCEN/TS 15119-1 ne mogu usporediti s rezultatima dobivenim drugim dvjema metodama. Znatan dio bora iz impregniranog drva ispire se već u prvom ciklusu ispiranja. WE6 emulzija (oksidirana polietilenska voštana emulzija) u kombinaciji s termičkom obradom donekle smanjuje ispiranje bora. Nasuprot tome, impregnacija drva s WE1 (polietilenskom emulzijom) ne smanjuje već, naprotiv, pojačava ispiranje bora

Srečanje ALUMNI kluba Oddelka za lesarstvo

Na Oddelku za lesarstvo smo imeli 16. 11. 2017 že 10. srečanje ALUMNI kluba. Srečanja se je udeležilo preko 120 udeležencev. Po zboru na oddelku, ogledu laboratorijev in kulturnem programu z nastopom zbora Barje, kjer pojeta 2 člana našega kluba, se je začel uradni program. Udeležence so nagovorili dekan Biotehniške fakultete prof. dr. Miha Humar, prodekan Oddelka za lesarstvo prof. dr. Milan Šernek, predsednik Društva lesarjev Slovenije doc. dr. Boštjan Lesar in vodja ALUMNI kluba prof. dr. Katarina Čufar. Letošnji sponzor srečanja je bilo družinsko podjetje SILVAAPIS d.o.o., ki ima kar štiri člane ALUMNI kluba. Silvana in Franc Šivic sta diplomanta 11. in 13. generacije gozdarjev / lesarjev, sin in hči Matjaž Šivic, univ. dipl. ing. les., mag. ekonomije in Alenka Šivic, univ. dipl. ing. les. pa sta diplomirala na univerzitetnem študiju lesarstva leta 1995 in 1997. Alenka Šivic je predstavila podjetje, kjer sta z bratom soustanovitelja in solastnika. Matjaž Šivic je predstavil svojo knjigo z naslovom The Golden Tree, ki je izšla v novembru 2017. Z nami je delil glavna sporočila knjige, kjer je opisal svojo strokovno pot in kako uspeti v poslu, povezanim z lesom. Na srečanju so se predstavile tudi generacije lesarjev, ki so diplomirali pred 40, 30, 20 in 10 leti. Generacijo 1977 je predstavil Bine Kladnik, univ. dipl. inž. les. Generacijo 1982-1987 je zastopalo kar 15 udeležencev, ki so obudili  spomin na dogodivščine, ki so jih doživeli kot študenti pred več kot 30 leti in predstavili svojo poklicno pot. Nato so se nam predstavile še skupine tistih, ki so diplomirali pred 20 in 10 leti. Društvo lesarjev Slovenije je podelilo priznanja prof. dr. Katarini Čufar, Tomažu Vilarju, univ. dipl. inž. les. in športnemu društvu »Buldožerji« Rudno. Tomaž Vilar je udeležence povabil na 7. veleslalom lesarjev, Borut Kričej pa je predstavil Društvo za zaščito lesa. Uradnemu delu je sledilo druženje ob pogostitvi. Tu so se našli stari prijatelji, sklepala so se nova poznanstva in posli, vse pa je potekalo v prijateljskem vzdušju, ki je zaščitni znak tovrstnih srečanj. Na različnih programih in stopnjah je študij doslej zaključilo 2057 diplomantov. Vsi so neformalno člani ALUMNI kluba in so dobrodošli na vseh aktivnostih. Vse, ki tega še niste storili, vabimo, da h klubu formalno pristopite in se včlanite v Društvo lesarjev Slovenije. ALUMNI klub namreč deluje kot sekcija Društva lesarjev Slovenije. Pristopnico najdete na spletni strani www.ditles.si. Srečanje je organizirala velika ekipa zaposlenih na Oddelku za lesarstvo. Veseli smo bili pohval in zadovoljstva udeležencev. Priprave na 11. srečanje, ki bo predvidoma v novembru 2018, so se že začele. Vabljeni že sedaj

Improvement of fire reaction and mould growth resistance of a new bio-based thermal insulation material

In the present paper, the performance of an innovative thermal insulation rigid board is evaluated in terms of fire behaviour and fungal resistance. The board is based on vegetal pith and a natural gum (corn pith and sodium alginate) and it is completely compostable. This new composite was developed in previous work. Here boric acid, aluminium hydroxide and ammonium polyphosphate are used as fire retardants and montan wax, acetic acid and lactic acid are used as water repellent and fungicides respectively. Interactions between these different treatments is investigated. Both flaming and smouldering combustion processes of the different formulations are evaluated by small-scale techniques which include pyrolysis microcalorimetry and thermogravimetric analysis. A medium-scale device is also designed in order to study the impact of the different additives to the smouldering kinetics. Fire behaviour tests show that good improvement is obtained, both in flaming and smouldering combustion when boric acid is added. Although smouldering is not avoided in any case, the addition of 8% of boric acid or aluminium hydroxide slows down the speed of combustion propagation. The effect of the different additives on the moisture content and mould growth at 97% RH and 27 °C is analysed. Under such severe conditions none of the additives is able to prevent mould growth, with the exception of boric acid. None or marginal mould growth was observed on samples containing 8% of boric acid although moisture content was higher than the other cases.Peer ReviewedPreprin

Service Life of Beech Wood in Outdoor Applications

Beech wood is amongst the most important wood species in Slovenia. The EU standard EN 350-2 classifies beech wood into the group of the least durable wood species. This is one of the most important reasons which limit the use of beech wood in outdoor applications. The majority of the data about beech wood durability is a result of laboratory tests as there were limited numbers of field tests performed. As the service life of wood significantly depends on the local climate conditions, this data cannot be simply copied from other countries. Therefore, field tests have been running at the field test site of the Department of Wood Science and Technology for several years now to determine comprehensive performance of most important Slovenian wood species including beech wood. Majority of the tests are performed in use class 3 applications (above ground, not covered). The first signs of decay on beech wood are visible after few months of exposure. Afterwards the decay proceeds and the samples are degraded between 4 and 6 years of exposure. The most important reasons for insufficient outdoor performance of beech wood are lack of biologically active extractives and low water exclusion efficacy. In order to elucidate this phenomenon moisture content was continuously monitored for 15 months. We believe that the field tests performed will lead us to the data which will enable better understanding of the phenomena of durability and improve durability of beech wood with state of the art modification solutions