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Durability tests of wood materials related to constructions in Björnlandet National Park The aim of the present study, primarily initiated by the Swedish Environmental Agency, is to study the durability of different wood materials related to and used in constructions in Björnlandet National Park in northern Sweden (63°97´N, 18°05´E), completed during 2014 and 2015. Of particular interest is to determine the durability properties in a scientific way of local materials used, such as mountain-grown Norway spruce and locally grown Scots pine and larch. The effect on the performance of charring and superficial wood-tar treatment is also studied. The study consists of a laboratory test according to ENV 807, a field trial according to EN 252 and a service trial on-site in the national park, including constructions such as load-bearing piles, ramps, foot-bridges and platforms. Results from the tests according to ENV 807 and EN 252 as well as the initial inspection of the constructions and components of different materials are presented in this report. During the initial inspection of the constructions on site, then in use for 1-2 years, no decay was found besides a small initial attack on one single pile of larch. The accelerated tests in laboratory and field have provided interesting information on the durability properties of the different materials and the ranking between them from a durability point of view which can be concluded as follows: • The local materials show moderate durability with marginal differences between the materials, with the exception of the spruce materials which show lower durability, comparable to the durability of pine sapwood. • Heartwood of locally grown pine and larch show basically equal durability properties. • Slow-grown wood will not enhance the durability properties. • Superficial treatment with wood-tar contributes so far to a somewhat increased durability. However, the primary positive effect is most certainly owing to the smell and appearance of wood treated with wood-tar, which in certain environments contributes to a positive perception. Charring does not add any value from a durability point of view. It is important that the results of the laboratory and field tests are interpreted with some care and common sense. The relatively extensive decay achieved with all materials but the preservative-treated wood does not necessarily mean that the constructions will be subject to early decay. With respect to the geographical location of Björnlandet National Park in the inland of northern Sweden, where the decay hazard in general is moderate, the local materials can thus be expected to have a reasonably long service. However, results from the tests indicate that efforts to select local materials/use "traditional" treatments most certainly will not result in longer service life than can be achieved with corresponding materials commercially available. Finally, it is pointed out that: • Avoiding moisture traps by correct design of components and constructions is vital for the service life when "traditional" local materials and treatments are used. • Preservative treatment will in general give critical wooden constructions a longer service life. The use of untreated wood involves more uncertainty with expected service life. Regular inspections and maintenance are therefore particularly important for constructions critical to personal safety (e.g. foot bridges, ramps) or infrastructure (e.g. bridges). • Urgent future objectives to complete are the inspections of the field trial until remaining stakes have been exposed for five years, and to follow up the service trial in Björnlandet National Park with inspections in 4-5 years, i.e. in 2022 or 2023 in order to confirm or reassess the preliminary conclusions.

Testing different materials exposed in jetties at Öresund - Progress report No. 3 This report contains results of the fourth inspection on the performance of different decking materials – preservative-treated wood, modified wood, natural durable wood, recycled plastics and wood-plastic composites (WPCs), available on the market and exposed in two jetties near the Øresund Bridge, south of central Malmö in Sweden. The objective of the test is to gather information relatively quickly on material performance with respect to appearance, durability and function of the tested materials. The test has, in spite of the relatively short exposure time, provided useful information on the properties of the different materials and their suitability for outdoor end-use situations exposed to wet conditions and attacks by wood-destroying organisms, but also withrespect to mechanical and aesthetic aspects. All wood materials have become greyish in short time, whereas the colour of the recycled plastics and composites still remains roughly the same as the original after exposure during four summers. All materials but the re-cycled plastics and composites have been more or less attacked by discolouring fungi and algae. No decay has been observed with the exception of minorincipient decay around screws in roble and Western Red Cedar. The mechanical properties vary considerably between the materials. Oak, robinia, bangkirai, azobé and Thermowood® have all shown tendencies of formation of cracks andsplinters, which may cause injuries in bare feet Denna rapport innehåller resultat från den fjärde besiktningen av olika trä-, plast- och kompositmaterial exponerade i två bryggor vid Sibbarps badplats vid Öresund strax norrom Øresundsbron. Tanken med att exponera materialen i denna miljö är att relativt snabbt får besked om vilka material som ser ut att klara sig bäst och uppfylla Malmö Stadsgatukontors krav på utseende, hållbarhet och funktion i en utsatt miljö. Försöket har, trots att det pågått under en förhållandevis kort tid, givit värdefull information om olika materials egenskaper och lämplighet för användning utomhus i utsatta miljöer med hänsyn till fuktpåverkan och angrepp av biologiska skadegörare menäven med hänsyn till mekaniska och utseendemässiga aspekter. Samtliga trämaterial har snabbt blivit gråa, medan plast- och kompositmaterialen ännuefter fyra somrars exponering i stort sett har kvar sin ursprungsfärg. Samtliga material utom plast och kompositer har i varierande grad angripits av missfärgandesvamp samt alger. Inga rötskador har observerats med undantag från små begynnande angrepp runt skruvskallar i två av trämaterialen. De mekaniska egenskaperna har visat sig skilja en hel del mellan materialen. Sprickbildning och uppfläkning av virkesytan, särskilt på kantsidor, kan i värsta fallorsaka skador på framför allt bara fötter.

This is the second progress report on two field trials with fence posts at SP’s test site in Borås, Sweden. The tests started in 1997 and 2006. The aim of the tests was to comparethe performance of posts of “traditional” materials, such as untreated, fine-textured(narrow growth rings) Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) aswell as spruce posts with charred butt end or butt end immersed in a wood tar productwith preservative-treated posts, Nordic wood preservation class NTR A. Both trials were inspected in 2016 and the conclusions reported in the first progress reportwere further confirmed, namely Preservative-treated material, NTR class A, performs far better than untreated posts, irrespective of material, and posts of “traditional” material. Charred butt end has not improved the durability properties at all in this trial and was the same as for untreated material. The service life of the “traditional” materials was in general from a few years upto between 5 and 10 years. Favorable exposure conditions may give a somewhat longer service life. “Traditional” materials cannot be regarded as realistic alternatives topreservative-treated posts, NTR A class A, even with very low expectations onservice life and cost-effectiveness.

Updated 2012-09-03

VI. Congreso Nacional de Protección de la Madera

Report TVBK-3060, ISSN 0349-4969, ISBN 978-91-979543-0-3, Lund University, Division of Structural Engineering

Polsk version av 2004:15 Minska risken för missfärgande svampar på tryckimpregnerat virke.

Fransk version av 2004:15, Minska risken för missfärgande svampar på tryckimpregnerat virke.

Engelsk version av 2004:15, Minska risken för missfärgande svampar på tryckimpregnerat virke.

Rubricerat projekt har haft som mål att genom en översyn av kunskapsläget etablera en kunskapsbas som kan användas vid utformning av ansökningar till större forskningsprogram både på nationell och på europeisk nivå. Med utgångspunkt från det nya regelverk som styr hantering av byggprodukter kan man förvänta ett stort behov av bättre dokumenterade materialegenskaper. Utifrån den projektplan som finns i ansökan har omdisponeringar gjorts främst med anledning av att tidpunkter för ansökningar till forskningsprogram kom tidigt under projektets gång. Den tänkta pilotstudien fyllde inte den ursprungligen tänkta funktionen eftersom den inte kunde vara klar och kunna utgöra underlag för ansökningar. Fokus för projektet har därför varit utformning av tre större ansökningar varav två beviljats, inventering av lämpliga modeller för dimensionering för beständighet samt att identifiera forskningsbehov. Det av Södras forskningsstiftelse finansierade projektet har möjliggjort för SP och LTH att vara aktiva i sökandet av nya projekt – projekt som gör det möjligt att flytta fram träs position som ett modernt och tillförlitlig byggnadsmaterial. För SPs och LTHs del är beloppet för de beviljade projekten i storleksordningen 40 miljoner kronor under fem år. Det bidrag som Södras forskningsstiftelse gett till projektet har varit av avgörande betydelse för de möjligheter som nu finns att göra en genomgripande insats på området.

Tysk version av 2004:15, Minska risken för missfärgande svampar på tryckimpregnerat virke.

1994 infördes begränsningar för användning av träskyddsmedel baserade på krom- och arsenikföreningar. Detta har medfört att impregnerat trä för användning ovan mark på den svenska marknaden sedan dess nästan enbart produceras i klass AB med krom- och arsenikfria träskyddsmedel. I denna undersökning har krom- och arsenikfria träskyddsmedel som var kommersiellt tillgängliga 1995 provats i och ovan mark. I provningen ingår även som referens medel innehållande krom och arsenik samt obehandlad gran, kärnved av furu samt kärnved av lärk. Under en tioårsperiod har följande parametrar studerats:• beständigheten, det vill säga motståndskraften mot rötsvampar, i olika utomhusexponeringar• urlakning av aktiva ämnen• hur fästdon (spik och skruv) av olika material påverkas av korrosion.Under de första tre till fem åren undersöktes• i vilken utsträckning proverna angreps av missfärgande svampar (blånads- och mögelsvamp)• väderbeständigheten med avseende på hur provernas ursprungliga kulör förändrades med tiden.1997 utökades försöket med ytterligare ett medel, Scanimp KF, som endast impregnerats i dimensionen 22x95 mm och som ingår i försök i markkontakt samt vissa ovan markprovningar. Såväl målade som omålade prover ingår i försöket.I föreliggande rapport presenteras resultaten efter tio års exponering samt resultaten från tidigare avslutade försöksled. För Scanimp-impregnerade prover redovisas resultaten efter nio års exponering.

Pine (Pinus sylvestris) and spruce (Picea abies) of Swedish origin has been heat-treated according to a process intended for above-ground end-uses. Tests have been carried out in order to study and evaluate the durability of the heat-treated material against decay and discolouring micro-organisms as well as technical and other properties, such as bending strength, stiffness, delamination of glulam, withdrawal load for fasteners and chemical emissions. The tests have shown that the bending strength has been reduced by approximately 50 % whereas the stiffness has been much less affected. Thus, the use of heat-treated wood where the strength is a decisive property should be carefully considered. There is an indication that the withdrawal load for fasteners for heat-treated wood is lower than for untreated wood. Gluing of heat-treated wood needs particular consideration, and PVAc adhesives seems to be unsuitable for gluing heat-treated wood. Chemical emissions (VOCs) were very low and will not be any major problem, providing proper conditioning is carried out after treatment. Heat-treated wood seems to be less susceptible to attack by discolouring micro-organisms than untreated wood. The decay tests in the laboratory and in the field have not yet given an unambiguous answer concerning the performance in various end-uses. However, the use of heat-treated wood in ground contact should be avoided.

Wood is traditionally used in indoor as well as outdoor applications. However, wood is easily attacked by wood degrading micro-organisms in damp situations and the service life is heavily affected by construction design, choice of wood species and wood treatment. For most constructions there is an expected service life. The expectations concerning wooden constructions and what kind of wood is chosen to fulfil the expectations is not very well known. To increase the knowledge about professionals’ as well as house owners’ expectations of the service life of outdoor wooden constructions an inquiry was carried out. In addition a literature survey was made. According to the literature survey there are requirements of service life for all building materials, including wood, following the European Construction Products Directive, CPD. All materials permanently included in a construction shall have a declaration of service life. Standards and standardized products become more and more important. For the DIY builder there is very little written about durability of wood. In principle, he only learns that a well designed wooden construction will last for a long time. The inquiry showed that many private house owners expect wood to last for long time even in outdoor conditions. About 25 % thought that a service life between 10 and 20 years was sufficient while more than 40 % wanted the constructions to last for more than 40 years. The professional builders require service lives of load-bearing wooden constructions according to the CPD. For non-structural constructions the majority of the professionals found 30 years an acceptable service life.

Since 1994 there are restrictions in Sweden on the use of chromium and arsenic containing wood preservatives. These preservatives are now in principle allowed for use in ground contact and water only. The use of chromium and arsenic free preservatives has increased and dominates the Swedish market for commodities above ground (Nordic wood preservation class AB). As the knowledge of the performance of these preservatives is limited, a field trial was set up in order to get more information about the durability in ground and above ground, discolouration by staining fungi, leaching, weathering and corrosion on fasteners in contact with the treated wood. Samples were treated according to class AB in commercial treating plants with the following preservatives: Basilit Bauholz KVD, Impralit KDS, Kemwood ACQ 1900, Tanalith E, Wolmanit CX-S and Wolmanit CX-8. Untreated spruce and heartwood of pine and larch were also included in the trial. In addition to testing according to EN 252 and ENV 12037 (lap-joint), both somewhat modified, testing was also carried out according to methods specially designed for this trial. After five years exposure the results show that: · No treated samples exposed above ground have yet been attacked and very few untreated samples only have been severely attacked by wood destroying fungi. There is thus some concern that the methods used, and in particular the lap-joint method, are not suitable for above ground testing in temperate climates. · The tests in ground indicate that with increasing copper content in the treated wood the better is the performance. · Heartwood of larch performs better than heartwood of pine in the in ground tests. On contrary, heartwood of pine shows better decay resistance than heartwood of larch in the above ground tests. · All samples are more or less attacked by bluestain fungi. Untreated samples are severely attacked. · Stainless steel has the best performance against corrosion. Wood treated with Kemwood ACQ 1900 and Wolmanit CX-8 seems to accelerate the corrosion of most other fastener materials. · The leaching of the chromium and arsenic free preservatives seems to be substantial whereas the leaching from CCA-treated references is little or moderate. For wood preservatives containing copper and an organic active ingredient, copper seems to be less susceptible to leaching then the organic component for which not only leaching but also chemical decomposition may take place.

NORDTEST Projekt Nr 1315-96