• Journal of the Korea Furniture Society
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• v.26 no.1
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• pp.22-30
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• 2015

In order to prevent decay, distortion, bending, twist on wood products such as wooden furnitures, variety of coating materials were developed and used so far. The coating materials for wood finishing can be synthesized by natural resource or petroleum. However, these coating materials can cause contamination of indoor air quality due to emission of volatile organic compounds (VOCs). In this study, commercialized coating materials for wood finishing such as varnish, coat, and stain were evaluated on emission characteristics of VOCs. Among the varnish, eco-friendly products had about 15~46% lower TVOC emission ($1,042{\mu}g/m^2h{\sim}3,257{\mu}g/m^2h$, respectively, than typical product ($7,100{\mu}g/m^2h$). Natural resource based coating material showed lowest TVOC emission level. However, one of natural resource based waterborne stain showed higher TVOC emission level because waterborne stain already contained higher amount of natural VOC. Oil-based stain might not be suitable for indoor use on interior wall and furniture due to exceed amount of TVOC. Based on results, natural resource based coat or waterborne stain are recommenced to use on wood products.

• Journal of Korean Society for Atmospheric Environment
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• v.3 no.1
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• pp.65-73
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• 1987

Indoor air pollution problems, in fact, have been neglected due to the unawareness of its seriousness and the lack of accumulated data. Recently, some movement of research and regulations, however, have been made for several indoor air pollutants. In this study, one of the carcinogenic polynuclear aromatic hyrocarbon, Benzo(a) pyrene in indoor airborne particulate, was measured and analyzed to estimate emission strength of BaP from an unvented kerosene heater and to know its level in indoor environment with use of a kerosene heater and a wood-burning fireplace. By the measurement of BaP level in a dark room with air exchange rate of app. 3.0, BaP emission strength of a kerosene heater (11,000Btu/hr) was estimated to be 326.6ng/hr (or 29.7 ng/$10^3$ Btu). With 4-hr operation a day of the kerosene heater in an apartment, the BaP level became 2.97ng/m$^3$ from 0.27ng/m$^3$ of background level. The operation of a wood-burning fireplace app. 2hr a day, on the other hand, increased the BaP level from 0.16ng/m$^3$ of background to 3.53ng/m$^3$. So proper ventilation must be considered seriously when unvented heating facilities are used in indoor environment.

• Journal of the Korean Wood Science and Technology
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• v.42 no.5
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• pp.615-623
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• 2014

Increases of public attention on healthy environment lead to the regulation of indoor air quality such as Clean Healthy House Construction Standard. This standard covers emission of total volatile organic compounds (TVOCs) (e.g., formaldehyde, benzene, and toluene), ventilation, and use of environmentally-friendly products or functional products. Moisture absorption and desorption abilities are a recommended functionality for improving indoor air quality. In this study, moisture absorption and desorption capacities of carbonized board from wood-based panels and other materials were determined by using UNT-HEAT-01 according to ISO 24358:2008. Pine had higher moisture absorption and desorption capacities ($49.0g/m^2$ and $35.3g/m^2$, respectively) than hinoki cypress, cement board, gypsum board, oriented strand board, and medium density fiberboard (MDF). The moisture absorption and desorption capacities differed considerably according to the wood species. After carbonization process at $400^{\circ}C$, the absorption and desorption ability of MDF increased to 38% and 60%, respectively. However, moisture absorption and desorption capacities decreased with increasing carbonization temperature, but they were still higher than original MDF. Therefore, it is suggested that carbonization below $600^{\circ}C$ can improve moisture absorption/desorption capacities.

• The Plant Pathology Journal
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• v.35 no.6
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• pp.674-683
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• 2019

Some species of the Trichoderma genus are reported as the major problem in oak wood mushroom production in Korea. In spite of economic loss by the fungi, scientific information on airborne Trichoderma species is not much available. To generate information for disease management development we analyzed airborne Trichoderma. A total of 1,063 fungal isolates were purely obtained from indoor air sampling of cultivation houses used for oak wood mushroom using sawdust media. Among the obtained isolates, 248 isolates were identified as Trichoderma fungi including T. harzianum, T. atroviride, T. citrinoviride, and T. pseudokoningii, by morphological and molecular analysis. T. harzianum was dominant among the four identified species. All the four Trichoderma species grew fast on solid nutrient media tested (potato dextrose agar [PDA], malt extract agar [MEA], Czapek's Dox + yeast extract agar [CYA] and cornmeal dextrose agar). Compact mycelia growth and mass spore production were better on PDA and CYA. In addition, T. harzianum and T. citrinoviride formed greenish and yellowish mycelium and spores on PDA and CYA. Greenish and yellowish pigment was saturated into PDA only by T. pseudokoningii. These four Trichoderma species could produce extracellular enzymes of sawdust substrate degradation such as β-glucosidase, avicelase, CM-cellulase, amylase, pectinase, xylanase, and protease. Their mycelia inhibited the growth of oak wood mushroom mycelia of two tested cultivars on dual culture assay. Among of eleven antifungal agents tested, benomyl was the best to inhibit the growth of the four Trichoderma species. Our results demonstrate that the airborne Trichoderma fungi need to be properly managed in the cultivation houses for safe mushroom production.

• Journal of the Korean Wood Science and Technology
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• v.49 no.2
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• pp.122-133
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• 2021

The radon gas from nature mainly considers a cause of radon problems, and it is closely affect human life cycle. Korean yellow residual soil, Hwangtoh, widely used as a building material, is considered to be one of major sources of indoor radon. However, there have, as yet, been no studies about radon from Hwangtoh in mass market brands. Here, we investigated the indoor radon concentrations and exhalation rates in four Hwangtohs from different brand names and regional features. The Closed Chamber Method (CCM) conducted by a Continuous Radon Monitor (CRM) has been used for the rates of radon exhalation. Based on equations of previous references, the indoor radon concentrations were deducted. As a result, the radon surface exhalation rates resulted in the 1.4208 to 3.0293 Bq·㎡·h-1 range. Significant differences were found among Hwangtohs according to production regions. Materials with higher radon concentration required a longer time to reach a quasi-steady state in a given environment, in other words, the number of half-life cycles increased from a set starting point. The experimentally identified Hwangtohs demonstrated its safety for construction purposes. There exists, so far, a possibility to exert influence radon emanation due to unidentified factors. Therefore, it is necessary to corroborate with more research by increasing the number of Hwangtohs, considering the other references reported high radon exhalation rates. In addition, it is highly recommended that the radon exhalation rates should be measured for all building materials for preventing human health before the material usage.

• Journal of the Korean Society of Combustion
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• v.22 no.2
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• pp.9-18
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• 2017

In this study, we measured that fire characteristics of four wood species using indoor finish materials. Wooden specimens were treated with fire retardant chemicals such as diammonium phosphate and potassium carbonate. The wooden specimens are Larix kaempferi, Pinus koraiensis, Cryptomeria japonica, and Chamaecyparis obtusa, which are used for indoor finish. The heat release rate (HRR) values of fire retardant treated woods were confirmed lower than that of untreated woods. For specific details, the HRR values of vacuum impregnated specimens for Pinus koraiensis and Cryptomeria japonica were measured lower than coatings. However, those of Larix kaempferi and Chamaecyparis obtusa showed the opposite effect to it. Total heat release rate values of all wooden specimens, vacuum impregnated were lower than coated specimens.

• Journal of the Korean Wood Science and Technology
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• v.44 no.3
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• pp.440-448
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• 2016

As recent buildings become more air tight, the natural ventilation rate is significantly reduced and it leads to difficulty in removing accumulated moisture in buildings. Hot and humid weather in summer and the large amount of moisture caused by indoor activity are the major factors of moisture problem in Korea. The hygrothermal behavior of building environment has to be considered carefully to reduce condensation risk and mold growth potential, and comfortable indoor environment. In this study, we evaluated hygrothermal behavior of Standard Wood-frame Structure published in the Korea Rural Community Corporation Using WUFI simulation program. The results indicated that the total water contents of wood wall measured in 2014 was lower than wood wall in 2010. As a result of evaluation by separating the farming and fishing areas, Moisture problems in fishing area became larger. The walls had a significant impact on the relative humidity than the temperature each areas. Furthermore, excessive water content problem of the wood-based material was reduced in the wall that could be applied in the fishing villages by changing the outdoor finishing materials. And Mold growth risk on the interior materials could be removed through the different setting of the indoor temperature during summertime.

• Journal of Conservation Science
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• v.38 no.1
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• pp.72-79
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• 2022

A paulownia wood has been widely used with various advantages as its low weight, permeability, convenient workability and aesthetic patterns for a long time. However, the related empirical researches and simultaneous evaluations of functionality are insufficient compared with acid-free archival boxes for now. In this study, the indoor and outdoor temperature and relative humidity control and heat release rate were evaluated under the controlled and uncontrolled circumstance in 2018. The paulownia wood storage box showed superior control effect of relative humidity than the acid-free archival box in constantly uncontrolled environment. Also, the possibility of the flame diffusion from the surface of the materials was higher for the paulownia materials, and the acid-free archival box showed more dangerous patterns in the early stages of the fire.

• Journal of the Korean Wood Science and Technology
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• v.40 no.2
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• pp.101-109
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• 2012

Wood composites are a hygroscopic material and have ability to exchange its moisture content with air. This study investigated the formaldehyde emission and moisture content change of four wood composites (particleboard (PB), medium density fiberboard (MDF), high density fiberboard (HDF), laminated HDF (L-HDF)) as a function of bake-out temperature and time. The composites were baked out for 1, 3, 5, 7, 10, 14, 21, and 28 days at temperatures of $20{\pm}2$, $35{\pm}2$, and $50{\pm}2^{\circ}C$ in a dry oven. The moisture content change was used to determine the emission bake-out of the composites. Best bake-out time results were obtained with after 7 days all composites. Formaldehyde emission values of composites decreased with decreasing moisture content for both temperatures. The formaldehyde emission results of bake-out temperature 35 and $50^{\circ}C$ showed a similar tendency.

• Journal of the Korean Wood Science and Technology
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• v.44 no.2
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• pp.264-273
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• 2016

The insulation of a building envelope influences the hygrothermal performance as well as the thermal performance of the building. While most of Korean wood frame houses have an interior insulation system, the exterior insulation system with high thermal performance has recently been applied. While it can be effective in energy savings for better insulation performance, without consideration of the moisture, condensation and mould growth can occur. Therefore, in this study, hygrothermal behaviour, water content, and mould growth were analyzed using hygrothermal simulation of an exterior wall of a wood frame house with which the interior insulation and exterior insulation systems were applied. The wall layer included Wall A (Interior insulation) and Wall B (Exterior insulation). The U-values were identified as 0.173 and $0.157W/m^2K$, respectively. The total water content and OSB absolute water content of Wall A were confirmed to be higher than those of Wall B, but the absolute water content did not exceed the reference value of 20%. The moisture content of the two walls was determined to be stable in the selected areas. However, mould growth risk analysis confirmed that both Wall A and Wall B were at risk of mould growth. It was confirmed that as the indoor setting temperature decreased, the mould index and growth rate in the same area increased. Therefore, the mould growth risk was affected more by indoor and outdoor climate conditions than by the position of the insulation. Consequently, the thermal performance of Wall B was superior to that of Wall A but the hygrothermal performances were confirmed to be similar.