ResumenSe evaluaron propiedades físicas, mecánicas y estéticas de tableros estructurales comerciales contrachapados (plywood) y tableros de virutas orientadas (OSB). Estos estaban recubiertos con dos protectores superficiales comerciales para madera que no forman película, y se mantuvieron a la intemperie durante un año en campos de prueba, según norma ASTM D 1006:1973. Se determinó estadísticamente la pérdida de propiedades mecánicas y se evaluó cómo se ven influenciadas las propiedades físicas y estéticas por el tiempo de exposición. Las conclusiones principales fueron que la protección de los recubrimientos utilizados no fue efectiva, no se cumplió la expectativa, de que los no formadores de película protejan la superficie y que no se presenten los defectos típicos de agrietamiento, erosión y decoloración. No se observó diferencias cualitativas entre ambos protectores, por lo que no se justifica el mayor precio de uno de ellos. Palabras clave: propiedades de tableros, tableros de madera, durabilidad, protectores superficiales Effects of Superficial Protectors on the Properties of Wooden Boards after a Year of Exposure to the Environment AbstractPhysical, mechanical and aesthetic properties were evaluated on structural boards as plywood and oriented strand board (OSB). The boards were covered by two commercial superficial protectors for wood that do not form films, and were maintained outside with no other protection during one year, in test field, according to the ASTM norm D1006:1973. Loss of mechanical properties was statistically determined and the influence of exposure time on the physical and aesthetic properties were evaluated. The main conclusions were that the protection of the used coverings was not effective and the main hypothesis that the non-forming film protect the surface and that typical defects of cracking, erosion and discoloration do not appear, was not proved. It was not observed qualitative differences between both protectors, so the higher price of one of them is not justified.

In Chile there is a gap that needs to be filled in order to have a positive impact upon emergencies, particularly in emergency houses (EH) In this study were evaluated the properties of a prefabricated prototype based on a "Structural Insulated Panel" 64mm thick (SIP64), built by two OSB panels bonded with a two component polyurethane adhesive to a high density expanded polystyrene core. SIP64 was manufactured as a main element for construction of EH. The thermal insulation was evaluated by NCh 853:2007 and was equal to 1.41 [m*K/W] equivalent to a thermal transmittance to 0.71 [W/m*K]. In fire resistance (FR), the quality was determined by NCh 935/1.Of97. The FR was F15 class, minimum safety requirement for bearing vertical elements and non-supportive frame walls. It is feasible to use the SIP64 as the main element in the construction of EH. FONDEF D09I1058 project has developed Technical and Normative standards for wood shelter. As main products Manuals for Manufacturing, Installation, Technical Specifications and Regulations for EH were developed and are available online for free. ResumenEn este estudio se evaluaron las propiedades de un prototipo prefabricado basado en un "Panel Estructural Aislado" de 64 mm de espesor (SIP64), construido por dos paneles OSB unidos con un adhesivo de poliuretano de dos componentes a un núcleo de poliestireno expandido de alta densidad. SIP64 se fabricó como un elemento principal para la construcción de viviendas de emergencia (VE). El aislamiento térmico fue evaluado por NCh 853: 2007 y fue igual a 1,41 [m * K / W] equivalente a una transmitancia térmica de 0,71 [W/m*K]. En resistencia al fuego (RF), la calidad fue determinada por NCh 935 / 1.Of97. La RF fue F15, requisito de seguridad mínimo para los elementos verticales y tabiques no soportantes. Es posible utilizar el SIP64 como el elemento principal en la construcción de VE. El proyecto FONDEF D09I1058 ha desarrollado estándares técnicos y normativos para viviendas de emergencia de madera. Como principales productos fueron desarrollados: Manuales de Fabricación, Instalación, Especificaciones Técnicas y Reglamentos para VE y están disponibles en línea de forma gratuita.Palabras clave: Vivienda de emergencia, refugios, habitabilidad, asentamiento, normas técnicas y estándares para viviendas de emergencia. panel SIP, aislamiento térmico, resistencia al fuego.

As part of the analysis of the technical criteria for emergency housing of Fondef project D09I1058, the acoustic behavior of three types of dwellings was measured: brick social housing, structural insulated panel (SIP) emergency housing and "mediagua" emergency housing. The acoustic reduction index (Rw) was measured in medium-density fiberboard (MDF), oriented strand board (OSB), plywood (Plywood), hard fiberboard (HB) and particle board (PB). PB and HB obtained Rw values of 20 dB, while MDF and Plywood obtained Rw values of 17 dB, and OSB obtained an Rw value of 19 dB, reflecting an additional positive characteristic of their structural properties that enables a lower cost for the manufacture of SIP emergency housing in compliance with the technical thermal mechanical regulations enforced by the General Ordinance of Urbanism and Construction (Ordenanza General de Urbanismo y Construcción, OGUC). To reduce costs, these dwellings were not designed to comply with acoustic regulations, but if they were evaluated for compliance, their result would fulfill the important criteria for a positive impact on acoustic insulation. NCh 432-10, according to OGUC, requires a minimum attenuation of 45 dB (Insttituto Nacional de Normalización, 2010a) in paired walls for social housing but not for emergency housing. The test was performed according to NCh 2785-2002 (Instituto Nacional de Normalizacion, 2002), using a sound-emitting speaker and a sound level meter, to obtain the attenuation of the paired wall. The social housing reached an attenuation of 42 dB, the SIP housing reached an attenuation of 39 dB, and the mediagua housing reached an attenuation of 6 dB, evidencing the precariousness of housing that is constructed from low-quality wood and that is poorly assembled, without air-and water-tightness, consequently affecting quality of life.

RESUMENAl saturar la pared celular de la madera con anhídrido acético, se reemplazan los grupos hidroxilos libres de las macromoléculas celulosa y hemicelulosa. Con ello se logra rellenar los espacios moleculares con grupos acetilo y así evitar que éstos reaccionen con las moléculas de agua o con los complejos enzimáticos de los hongos de pudrición. Así, se produce la muerte de los hongos por falta de alimento. Con esta modi cación química de la madera también se ha mejorado la estabilidad dimensional y la resistencia a agentes xilófagos. Bajo esta premisa, se evaluó el tratamiento químico de acetilación para la protección de madera de Pinus radiata D. Don. Se empleó una metodología en condiciones de laboratorio que permitió determinar el efecto de la acetilación sobre las propiedades de: contenido de humedad; densidad; absorción de agua; estabilidad dimensional y biodegradación por hongos en madera de Pinus radiata D. Don.Se trabajó con dos tiempos de inmersión en anhídrido acético y dos tiempos en autoclave logrando ganancias en peso que fueron desde 6 a 20%. Se mejoraron algunas propiedades de la madera del Pinus radiata D. Don, tales como: a) la resistencia a la degradación producto de la acción de hongos de pudrición café, dado que las pérdidas de peso en las maderas acetiladas fueron desde 1.38% a 17.43% en comparación con la madera control que alcanzó un 64.94%, con el mismo hongo; b) Con un hongo de pudrición blanca se obtuvieron valores de pérdida de peso en madera acetilada que fueron entre 2.96% y 9.12% en comparación con madera no acetilada que exhibió sólo 17.9%, tras cuatro meses de exposición. Además, se mejoraron las propiedades de estabilidad dimensional y absorción de agua.Palabras claves: Acetilación, degradación natural, estabilidad dimensional, Pinus radiata ABSTRACTWhen woody cell wall is saturated with acetic anhydride, the free hydroxyl groups present on cellulosic structures are replaced. us, the capillary spaces are lled with acetyl groups and this replacement avoids further reactions with water or enzymatic degradation provoked by rot fungi. So, the death of di erent fungi is produced by the lack of food. It has been observed too that this chemical modi cation has improved the dimensional stability and the resistance to xylophages agents. Under this premise, we conducted a research in order to test acetylation of Pinus radiata D. Don wood as a strategy for their protection. An experimental methodology was used under laboratory conditionsCiencia y tecnología, 14(1): 103-113, 2012 Maderas. U n i v e r s i d a d d e l B í o -B í o 104to determine the e ect of the acetylation on some properties such as: water content; density, water uptake; dimensional stability and biodegradation provoked by rot fungi in Pinus radiata D. Don.Two immersion times of pine wood on acetic anhydride and two times in autoclave were tested (30 and 60 minutes). us, observed weight gains ranged between 6 and 20%. We also noted the improvement of other properties such as: a) the resistance to the degradation provoke...

As part of the Fondef D09I1058 project, an emergency housing solution was developed and five prototypes constructed. The prototypes solved mechanical, thermal, water tightness and airtightness problems common to emergency housing, achieving a minimum durability of five years. Emergency housing does not fall under the jurisdiction of permanent housing codes, hence, there are no requirements that these houses must meet. A first step towards establishing minimum requirements is the evaluation of the current emergency housing solutions. This paper presents the structural evaluation of these prototypes. The prototypes were fabricated with "structural insulated panels" (SIPs), which provide structural strength and thermal insulation, for four thermal zones of the country. All the prototypes presented adequate structural performance. Out of all the locations considered, only two houses presented minor strength problems in the roof structure, but almost satisfied the requirements indicated by the codes for permanent social housing. In the case of the floor diaphragms, only one prototype fell short 97.5% of the required strength, which was considered acceptable this emergency housing. For the walls, laboratory tests, performed applying lateral and out-of-plane loads on the panels that compose the prototypes, established that they could withstand the design earthquake loads and wind loads.

In Chile the amounts of wood sawdust, shavings, and chips available is around 2.72 million, 340 thousand, and 4.25 million m3/year, respectively, and about 30% of this material is employed in the manufacture of particleboards. Two types of particleboards were made from wood residues as moisture-resistant particleboards, and the main goal was to meet the requirements for P3 moisture resistance according to the European Standard EN 312. Five mats of each type were pressed without stops in a 30 cm diameter electrically heated hot press at 180°C for 3.5 min. Target board density was 680 kg/m3 (T1) and 720 kg/m3 (T2), mat moisture was 10%, resin dosage applied was 6%, and board thickness was 15 mm for both boards (0.5 x 0.5 m). Samples were designated as T1 and T2, on which both physical and mechanical tests were conducted. Density, moisture content, thickness swelling, and water absorption were measured. Mechanical tests included internal bond before and after cyclic test, as well as fire retardancy. The analysis of the high resolution images allowed us to ensure that there was no gap between the veneer and the particleboard; therefore it can be concluded that there was no adherence loss. Results for all tests showed that both boards met all the P3 standards for moisture resistant non-structural board for use in humid conditions.

Six treatments (one control and five decoration coatings) were applied to radiata pine wood treated with micronized copper azole for outdoor use at a rate of 3,08 kg/m 3 retention. One decoration coating was applied prior to impregnation, prestain and two decoration coatings were applied in a mixture with the micronized copper azole preservative Black Cylinder and Red Cylinder.The following two varnishes were tested: a water-based varnish and a solvent-based varnish. Additionally, untreated radiata pine specimens were tested as a reference. The changes in the gloss and color of these five decorative coatings were evaluated after undergoing natural aging tests for three months and accelerated aging trials during exposure to ultra-violet radiation of 340 nm for 500 hours. In the accelerated aging trials treatments, changes in gloss and color showed the lowest variations in treatment trials prestain and Black Cylinder and the highest variations in treatment trial Red Cylinder. In the aging tests trials, changes in gloss and color showed the lowest variations in treatment trials prestain and Black Cylinder. The costs of each decorative coating were assessed in terms of performance according to timber volume coated. The lowest cost of the three decoration treatments was prestain, with a value of 16 US$/m 3 , followed by Black Cylinder with a value of 24 US$/m 3 . Compared with the alternative siding products available in the market, such as fiber cement and vinyl siding, colored wood treated with prestain is competitive with vinyl siding, with 58% lower costs than fiber-cement.

Toda vivienda debiese cumplir con estándares de seguridad, confort y durabilidad, aún más cuando debido al cambio climático los desastres tienden a ocurrir con mayor frecuencia. En Chile, los estándares de construcción se encuentran en la Ordenanza General de Urbanismo y Construcción (OGUC), cuya actualización incluirá elementos de gestión de riesgo para disminuir la vulnerabilidad. En este estudio, se evaluaron estándares mecánicos, térmicos, de aislación térmica y al fuego en 5 zonas térmicas. Esta información permitió la creación de manuales de construcción, instalación y especificaciones técnicas, y un proyecto de ley que regula los estándares de viviendas de emergencia y asentamientos transitorios. Esta experiencia permitió un análisis crítico del cumplimiento de estándares para viviendas sociales y edificaciones en madera, los que no consideraban, por ejemplo, opacidad y toxicidad del humo, aislantes térmicos y acústicos, resistencia al fuego, persevantes menos dañinos o recubrimientos sustentables. La existencia de disposiciones normativas en la ordenanza (OGUC) no implica que en la practica se cumplan los estándares de eficiencia energética, resistencia sísmica y al fuego simultáneamente en viviendas que además, en muchos casos, no cuentan con recepción final de obra. Estos análisis de discriminación multi-criterio ayudarán a la toma decisiones de diseño en construcción en madera.