Journal of Environmental Engineering (Transactions of AIJ)
Online ISSN : 1881-817X
Print ISSN : 1348-0685
ISSN-L : 1348-0685
Volume 82, Issue 733
Displaying 1-11 of 11 articles from this issue
  • Predictability of quasi-fireproof performance of external wooden walls with rock-wool insulation
    Osamu ITOGE, Yuji HASEMI, Tsukasa TSUKIDATE, Hirotaka SUZUKI
    2017 Volume 82 Issue 733 Pages 183-193
    Published: 2017
    Released on J-STAGE: March 30, 2017
    JOURNAL FREE ACCESS
     This study aims to establish the rational prediction of the fire protection performance of insulated wooden walls to reduce the full-scale fire tests. Series of small-scale furnace tests are conducted on various types of wall constructions with rock-wool insulation, the most stable practical insulation material.
     The results of the fire tests and one-dimensional steady-state heat transfer calculation lead the following conclusion on the wooden insulated walls with rock-wool insulation.
     Without cavity, the calculation can almost reproduce the temperature profile in the wall as the disadvantageous situation that temperature becomes higher in. And the engineering problems, to grasp the heat balance in cavity and to build calculation model of it, are left.
     Fire protection performance is required flame insulation property, heat insulation property and non-damage ability in Japan's building standard act.
     Heat insulation property can be predicted by checking thermal resistance. If insulated walls have thermal resistance bigger than 1.70m2K/W when heated for 45 minutes, or 2.10m2K/W when heated for 60 minutes, heat insulation property can be secured enough.
     Heat insulation property is made a difference between when heated from indoor side and from outdoor side by cavity or the material which phase conversion happens in high temperature. In non-insulated wall, infilled insulated wall and additional insulated wall, heat insulation property become more disadvantageous when heated from indoor side than from outdoor side, with gypsum board as interior material. In addition, cavity acts on more advantageous against heat insulation property.
     The time when combustion begins in the pillars depend on thermal resistance of external protection layer when heated from outdoor side, and depend on how long gypsum board delays temperature rise at around 100 degrees Celsius when heated from indoor side. Non-damage ability becomes more disadvantageous when heated from indoor side than from outdoor side in non-insulated wall and all insulated wall with rock-wool even if any constructing method.
     The infilled insulation raises the back-surface temperature of the protection layer, also reduces the damage by protecting the side of the pillar. And the external insulation disturbs heat diffusion to the back side when heated from indoor side, also reduces the damage by protecting the front of the pillar when heated from outdoor side. Thus the infilled insulation and the external insulation have both advantageous factor and disadvantageous factor for non-damage ability. The combination of these factors can explain about non-damage ability in every constructing method of the insulated wall.
     In addition, It is clarified that non-damage ability can be predicted by checking the back-surface temperature of the protection layer. This point suggests potential predictability by calculation, because the one-dimensional steady-state heat transfer calculation can almost reproduce the temperature profile, without cavity.
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  • Relationship between wallpaper pattern type, Munsell value, illuminance, and the perception of volume, width, depth and height
    Keishi YOSHIDA, Masato SATO
    2017 Volume 82 Issue 733 Pages 195-204
    Published: 2017
    Released on J-STAGE: March 30, 2017
    JOURNAL FREE ACCESS
     This study was conducted to evaluate the effects of wallpaper pattern type, Munsell value, and illuminance on the perception of interior space. A series of psychological experiments were conducted to evaluate the four parameters: magnitude values of volume, width, depth, and height of interior space, using two types of one-tenth scale models of a room.
     The “horizontal model” measured 24 mc in height and 45 cm in width and depth, the “vertical model, ” measured 45 cm in height, 24 cm in width, and 45 cm in depth. The wallpaper patterns used in these experiments were vertical stripe, horizontal stripe, square, wave, floral and arabesque. The figures of the patterns were printed in three achromatic colours, N8.5, N7, and N5. The ground of the patterns and the floor were printed in achromatic colour N9. The walls and floor of a reference model with no pattern were also printed in N9. The experiments were conducted in three illuminance conditions: 750 lx, 500 lx, and 300 lx. A magnitude estimation method was applied to evaluate the four parameters. The eighteen subjects (12 women and 6 men) were asked to look into each model by turns through a viewing aperture in the rear wall and to compare their four spatial parameters of the comparison model with those of the standard model. These experiments were conducted separately with horizontal and vertical models.
     The results showed that the effects of the wallpaper pattern type, Munsell value, and illuminance were obvious. However, these effects were different between horizontal and vertical models and were more remarkable in horizontal model. It is because vertical model was so extraordinary that the effects of wallpaper pattern type and Munsell value became blurred. On the other hand, some of the effects were common between horizontal and vertical models, and can be regarded as stable results. These results can be summarized as follows:
     · The existence of wallpaper pattern decreased the magnitude value of volume.
     · The effects of the Munsell value were obvious;, the lower the Munsell value, the lower the magnitude values of volume, width, and depth.
     · The effects of the pattern type were different between horizontal model and vertical model. The pattern type had similar effects on the magnitude values of volume and depth of horizontal model. The horizontal stripe and floral patterns had higher corresponding value than did other types. The vertical stripe and horizontal stripe patterns had opposite effects on the magnitude values of width and height of both models. The horizontal stripe pattern increased the magnitude value of width and decreased that of height, whereas the horizontal stripe pattern increased the magnitude value of height and decreased that of width.
     · Illuminance was found to affect only the magnitude value of volume of horizontal model; the lower the illuminance, the lower the magnitude value of volume.
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  • Keita YAMAZAKI, Masaya SAITO, Yuji SASAKI, Masanori SHUKUYA
    2017 Volume 82 Issue 733 Pages 205-214
    Published: 2017
    Released on J-STAGE: March 30, 2017
    JOURNAL FREE ACCESS
     This paper describes a method for estimating radiant temperature and its associated with radiant exergy within outdoor space, which is one of the key factors in micro-climatic design of park space in summer.
     Measurements of outdoor air temperature (To) and humidity, wind velocity (Va), globe temperature (Tg) and surface temperature (Tei) were carried out for one day during daytime of a hot summer day in August, 2015 at Sapporo Art Park. The radiant exergies emitted from outdoor ground, buildings, trees, grassy plane, water surface of the pond and sky, were evaluated for quantifying the radiant environmental characteristics outdoors. The globe temperatures measured were compared with those obtained theoretically using solar radiation (I), long-wavelength mean radiant temperature (Tmr-photo) taken from infra-red thermal image camera, To and Va. On the basis of the measured results together with the theoretical investigation, we discussed the “coolness” to be available from park space.
     In the open space at Sapporo on 1st day August, which was sunny with patchy clouds, the Tei of concrete pavement (CP) of plaza at the point S1, and S5, ranged from 43 to 50 °C. At the point S1 and S5, whose form factor (fi) of CP were larger than 0.3, the rate of warm radiant exergy (WX) were larger than 900 mW/m2 during daytime, those were much larger than the rate of cool radiant exergy (CX). This contributes to Tmr-photo being 1 to 3 °C higher than To. The WX caused by the absorption of short-wave length radiation at points in shadow at the plaza reached the peak 1.5 to 3 hours later after the peak of the MRT ranged from 50 to 60 °C due to direct I directly incident on the globe. This peak contributes to raising Tmr-photo and To by the addition of reflected I from the CP so that MRT remains higher than 40 °C even in shaded space.
     We confirmed the validity of MRT and Tg measured by small gray-colored ball by comparing with that calculated. The CX emitted from the sky can contribute to increase the emergence of “coolness” within the open space. We have confirmed, through this series of measurement and calculation, that the MRT and Tg in outdoor space where we are exposed directly to I and or where even in shaded areas the WX and Tmr-photo are high resulted by the surface of CP whose fi is higher than 0.3. Provided that a pond is or grassy plane are arranged, and trees are planted so that their canopies cast their shadows over the CP, this would result in decreasing the surface temperature and reflected solar radiation, and thereby the “coolness” may emerge with in the park space.
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  • -Study on the conservation of a stone Buddha carved into a cliff at Motomachi PART1-
    Nobumitsu TAKATORI, Daisuke OGURA, Soichiro WAKIYA, Masaru ABUKU, Kyok ...
    2017 Volume 82 Issue 733 Pages 215-225
    Published: 2017
    Released on J-STAGE: March 30, 2017
    JOURNAL FREE ACCESS
     Motomachi Sekibutsu, which was registered as a national historic site in 1934, is the representative stone Buddha statue carved into the cliff in Oita city, Japan. It is always affected by the ground water through the cliff because it cannot be separated from the cliff, and thus there has been a great concern in its moisture-related problems such as salt damage and growth of bryophytes.
     As an onset to proposing a conservation environment that is the most appropriate to suppress the salt damage, this paper is dedicated to environmental measurement to obtain the essential data set and numerically quantifying influences of the heat and moisture behavior in the cliff on potential salt damages mainly at and near the surfaces of the main Buddha statue, which has been suffering from salt precipitation.
     Sodium sulfate (Na2SO4) is focused on in this paper as it is considered to have been the most problematic at this site. In discussions, we deal with two phenomena, (1) crystallization due to water evaporation and/or solubility changes and (2) thenardite-mirabilite cycles that are assumed to be dependent on the temperature and humidity.
     We analyze simultaneous heat and moisture transfer in the two-layered cliff that consists of soil and tuff, the latter of which includes the stone Buddha. Two steady state and two unsteady state analyses are carried and their results are compared, in order to quantify the influence of the room temperature, humidity, solar radiation and the rainfall. The main results are described below.
     1. As a result of the ground water level that is considered at about 1m below the ground level, a high water content is maintained deep in the cliff; the moisture content can get much lower due to evaporation at and near the surface of the stone.
     2. When the moisture content at the surface is low, significant vaporization of water occurs inside of the statue where the moisture content changes drastically.
     3. The moisture content inside of the statue fluctuates throughout the year. The moisture content near the surface is increasing from summer to autumn, and decreasing in the rainy season and from winter to spring.
     4. The direct solar radiation and a rapid absolute humidity decrease by opening the door of the shelter can accelerate vaporization of water in the stone near the surface, even when the moisture content is low at the surface.
     5. It is in autumn to winter that salt damage near the surface can be the most significant because of an overall decrease in solubility of Na2SO4 due to a low temperature, a local increase of solar radiation incident on the stone Buddha, and the rapid absolute humidity decrease by opening the door of the shelter.
     6. The phase change of Na2SO4 occurs at the shallow areas in the internal corner; in the external corner, it occurs not only at the shallow area but also deep in the stone.
     7. With the current shelter, at the knee in the external corner, thenardite precipitates in autumn to winter and dissolution of thenardite often occurs in winter to spring. Thus, a particular attention would be recommended to be paid to salt damage in these seasons.
     8. A high air-tightness and ventilation would lead to more frequent thenardite-mirabilite cycles.
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  • Part. 1 Investigation of high insulation and air tightness in detached houses using time series heat load simulation
    Mao SERIKAWA, Makoto SATOH, Tatsuo NAGAI, Takashi AKIMOTO
    2017 Volume 82 Issue 733 Pages 227-235
    Published: 2017
    Released on J-STAGE: March 30, 2017
    JOURNAL FREE ACCESS
     Since many of residential houses in Japan were built before 1980, they have very poor thermal insulation. With poor thermal insulation specification, these houses could consume much amount of energy for heating. In addition to that, indoor thermal environment in winter could be so poor especially in non-living rooms such as bathrooms. Low temperature in houses could cause occupants' higher blood pressure, heat shock, and many other diseases.
     Energy consumption and health hazards in a model house were investigated using a heat load simulation tool in this research. The simulation tool were capable to show that annual heat load, energy consumption for HVAC, and room air temperatures of every five minutes in the house in several cases which differed thermal insulation performances. We confirmed that, in general, the higher insulation level of the model house were associated with the lower health hazards and reduce energy consumption for heating. We also indicated that effective heating methods enable to reduce health hazards with a small amount of additional energy.
     In Chapter 1, we referred to previous studies relating to this research. There are many research papers discussing topics, thermal insulation, thermal environment in houses, and health respectively, however, most of the preceding papers are not dealing with the topics integrally.
     In Chapter 2, we indicated that input condition for simulation case studies. We chose the model house plan for the simulation which met ‘Standards of Judgment for Residential Construction Clients’. The simulation conditions include not only various insulation performances, but also several heating methods such as heating sanitary space just before bathing time.
     In Chapter 3, we proposed an index that indicated health hazards. This index was provisional since the relationship between indoor temperature and occupant's health should be reconsidered by further actual health hazards study results.
     In Chapter 4, we showed results of the case studies. Indoor temperature with no insulation reached about 5°C in winter morning. The case that had enough insulation performance to meet the Japanese energy saving standard, the room temperature did not get below 10°C. In order to keep the room temperature above 15°C, insulation level needed to be as high as the German energy saving standard. However, the temperatures of non-heating rooms did not get higher in some cases which had implemented partial thermal insulation renovation of only at LDK (a living room, dining room and kitchen) or other rooms.
     Energy consumption for heating could reduce by high insulation level. Heating energy of no insulation house was more than twice as much as the house which had enough insulation level that met the Japanese energy saving standard. In order to reduce health hazards, heating non-heating rooms in short time was as effective as improvement of thermal insulation performance. By heating the sanitary space and bedroom, it enabled to improve the health hazard index with a small amount of additional energy.
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  • Thermal environment evaluation in office over cooling period with direct cooling system of internal heat gain Part 2
    Li WANG, Shinsuke KATO, Weirong ZHANG, Hyokeun HWANG, Taiki SATO, Kent ...
    2017 Volume 82 Issue 733 Pages 237-247
    Published: 2017
    Released on J-STAGE: March 30, 2017
    JOURNAL FREE ACCESS
     In previous study, indoor thermal environment in occupied zone of direct cooling system of internal heat gain was evaluated by taking the space distribution and time change into consideration. A method that is similar to quasi-coupling simulation of contribution ratio of indoor climate (CRI) and energy-network model was used to realize the calculation of predicted mean vote (PMV). However, the control and performance change of the HVAC system were not involved in previous evaluation, which cannot be ignored. In this study, the control and performance of the four components of the HVAC system, liquid cooling - heat recovery unit (HRU), active chilled beam (ACB), radiation partition (RP) and dry fan coil unit (DFCU) are modeled. Then, with considering control and performance change of the HVAC system, a basic case study is conducted to evaluate the spatial and temporal PMV distribution of occupants. Results showed that the indoor thermal comfort was affected obviously by the operation-controlled strategy of water distribution system of ACB. As well as previous results, the differences of PMV value were smaller and the comfortability rates were higher than those by conventional system.
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  • Eunsu LIM, Kazuhide ITO
    2017 Volume 82 Issue 733 Pages 249-256
    Published: 2017
    Released on J-STAGE: March 30, 2017
    JOURNAL FREE ACCESS
     The amount of contaminant re-circulated in a local domain implies the potential of the ventilation efficiency in a room. The returning probability (hereafter RP) of contaminant generated in a local domain and the net escape probability (NEP) of that will become useful information for understanding the mechanism of contaminant concentration distribution formed in a target room and for controlling Indoor Air Quality. Here we proposed the fundamental definitions of RP and NEP, and then discussed the potential relation with net escape velocity ((hereafter NEV, 2013 Lim et al.) concept. Further, the calculation results of RP, NEP and NEV distributions in simple 2D model room were demonstrated.
     We have already reported the definition and calculation procedure of NEV. NEV is defined for control volume of CFD (C.V.) and is calculated based on the net flux, difference between transport out of and into the C.V. NEP is defined as the probability that is exhausted directly through exhaust outlet and does not re-circulate to the target local domain (here, C.V.) again. If the RP, to target local domain is assumed to be constant, is calculated by the summation of geometric series of returning frequency to the target local domain. The sum of NEP and RP equals ‘1.0’ and the NEP must be (1-α).
     In this study, the NEV and NEP distributions were analyzed in 2D simple model room. The size of indoor model is 10L0×10L0 (L0: size of inlet) with a dimensionless scale. We set up the dimensionless wind velocity Uin 1.0 [-] at inlet. For calculating the NEP and NEV in a C.V., contaminant was assumed to be generated in C.V. and this meant that the same numbers of CFD calculations with the number of C.V. within the target room were required.
     As a result, the supplied jet from the inlet opening flowed into the room along the floor and reached the sidewall opposite the supply inlet. Flow bifurcation was observed in front of the exhaust outlet and a large circulating flow and one-pass flow from the supply opening to the exhaust outlet were formed. A stagnant region was formed at the center of the room. The slight differences between air velocity vector and NEV that were calculated by net flux removed/diluted contaminant from the target C.V. was confirmed.
     NEP became ‘1.0’ at the vicinity of exhaust outlet because the contaminant in the target C.V. was directly exhausted through exhaust outlet and would not be returned. It means that RP denotes ‘0’. NEP at the vicinity of inlet was ‘0.94’ because most of contaminant in the target C.V. was transported from inlet to exhaust outlet with little re-circulation. NEP became high at the center, stagnant region, in the room. In this region, the contaminant concentration was high and the driving force of contaminant transportation depended on diffusion than convection. And then diffused contaminant from stagnant region in room did not return to the original C.V.
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  • Study on the relationship between indoor air environment and the incidence of influenza in schools
    Go IWASHITA
    2017 Volume 82 Issue 733 Pages 257-264
    Published: 2017
    Released on J-STAGE: March 30, 2017
    JOURNAL FREE ACCESS
     A deteriorated indoor climate is commonly related to increases in sick building syndrome symptoms, respiratory illnesses, sick leave, reduced comfort and losses in productivity. In schools, sick leave might to be a significant index of productivity. Elementary schools are thought to be amplifiers for infections in influenza in communities. In School Health and Safety Act, children are told to stay home in case of an epidemic of influenza. Therefore the indoor air environment should be controlled for avoiding an epidemic of influenza. The humidity ratio had been reported to be a critical factor for infection of influenza. However the relationship between the really measured indoor thermal factors and the incidence of influenza is rarely investigated. Then the room temperature and relative humidity are continuously measured in twelve classrooms in a public elementary school in Tokyo. And the period of analysis was set as 3 winter seasons from 2005/2006 to 2007/2008.
     The average values of the room temperature per every winter season in all classrooms were met the School Environmental Sanitary Standard. On the other hand, the average values of indoor relative humidity were not met the standard in some classrooms and lower than the standard value.
     The high correlation coefficients were not obtained in the relationship between the average values of indoor thermal factors, i.e., air temperature, relative humidity, and humidity ratio per every winter season in each classroom, and the number of absence on account of flu. Although the tendency was found that the lower the humidity, the greater the number of absence on account of flu, the correlation coefficient was low and not significant.
     Focusing on the indoor climatic data when the absence of flu was occurred, the highest correlation coefficient was observed at 0.984 in the relationship between the daily average indoor temperature of two days before the absence and the probability of flu. The second highest correlation coefficient was observed in the relationship between the daily average indoor room relative humidity of one day before the absence and the probability of flu.
     The significant high correlation was seen in the relationship between the probability of flu and the daily average outdoor air temperature of the absence day obtained from the meteorological data. The significant high correlation was also found in the relationship between the probability of flu and the daily average outdoor humidity ratio of one day before the absence.
     A multiple regression analysis was conducted with the probability of flu as a objective variable. The explanatory variables were indoor and outdoor climatic factors. As a result of the analysis, the room temperature of two days before the absence was merely a significant factor (p<0.05). A time-series analysis for indoor/outdoor climate especially a few days before the absence could be useful for understanding the infection of flu.
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  • Tatsunori ITO, Satoru IIZUKA, Yingli XUAN, Masato MIYATA, Kaede WATANA ...
    2017 Volume 82 Issue 733 Pages 265-272
    Published: 2017
    Released on J-STAGE: March 30, 2017
    JOURNAL FREE ACCESS
     Vietnam (Socialist Republic of Viet Nam) is a rapidly developing country. The recent growth rates of the economy and population are about 6.0 % and 1.1 %, respectively. Under such a social situation, the sprawls of urban areas are progressing and many city master plans have been proposed in Vietnam. Recently, a city master plan was proposed for Vinh city, the capital of Nghe An Province, located in the north-central part of Vietnam. The proposed city master plan targets the year of 2030 with a population of 900,000 and the total planning area covers an area of approximately 250 km2.
     In this study, future projections of the thermal environment in the urban districts in Vinh city for a month of June (hottest month) in the 2030s were performed by introducing the proposed city master plan. The future projections were carried out using a regional atmospheric model, the Weather Research and Forecasting (WRF) model, combined with a pseudo global warming method. The effect of the introduction of the proposed city master plan on the future thermal environment (air temperature and heat stress index) in the urban districts was quantitatively examined by comparing with the present land use case. Moreover, two modified city master plans by changing the arrangement (northern or southern concentration) of the new urban districts were introduced, and the effects of the modifications on the future thermal environment in the urban districts were also investigated.
     The space-averaged (over the whole urban district) and monthly-averaged (during June in the 2030s) temperature difference between the cases with and without the introduction of the proposed city master plan is 0.25 °C. This is considerably smaller than the temperature increase by the global warming in the 2030s projected in this study (1.74 °C). However, the small temperature difference cannot be negligible considering the fact that the increase in the global average surface temperature over the period from 1880 to 2012 was 0.85 °C. Therefore, active actions to mitigate the temperature increase due to the introduction of the proposed city master plan will be necessary.
     In the case with the northern or southern concentration of the new urban districts in the proposed city master plan, the space-averaged and monthly-averaged (during June in the 2030s) temperature in the northern or southern new urban districts is higher than that in the original city master plan. From the viewpoint of thermal environment, the original city master plan, in which the new urban districts are decentralized in both northern and southern parts of the planning area, is better than the two modified plans (northern or southern concentration of the new urban districts).
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  • Gen AOKI, Shin-ichi TANABE, Toshimasa ITAYA
    2017 Volume 82 Issue 733 Pages 273-279
    Published: 2017
    Released on J-STAGE: March 30, 2017
    JOURNAL FREE ACCESS
     The purpose of this research is to evaluate the economic value of certification of green buildings based on j-reit (Japan Real Estate Investment Trust) owned office buildings. In the recent years, assessment systems for the environmental performance of buildings are being widely used in Japan. Some analyses were conducted in Japan to investigate whether green building certificates have a positive influence on the contract rent. However we need to investigate profits and expenses of the real estate rent to clearly explain the economic benefits of green buildings.
     In this research, we analyze the office building annual data in Japan which was disclosed by J-REIT. Operating benefits and utilities costs of 657 buildings in January 2014 - December 2014 was analyzed. Regarding the objective office, the total leased area is under 50000 m2 and each building was divided into green building certified or Non-certified. Subject green building certifications are Tokyo Top-Level Business Facility and CASBEE (Comprehensive Assessment System for Built Environment Efficiency).
     The net operating incomes of Top-Level Business Facility or CASBEE certified office buildings over 10000 m2 of total building area are bigger than that of not certified office buildings. The utilities costs of Top-Level Business Facility certified office buildings are the same as that of not certified office buildings, but the utilities cost of CASBEE certified office buildings is bigger than that of not certified office buildings. The net operating incomes of CASBEE certified office buildings over 3000 m2 and less than 10000 m2 of total building area are bigger than that of not certified office buildings. The utilities costs of CASBEE certified office buildings over 3000 m2 and less than 10000 m2 are the same as that of not certified office buildings. The net operating incomes of expired CASBEE certified office buildings over 10000 m2 of total building area are bigger than that of not certified office buildings. The utilities costs of expired CASBEE certified office buildings are the same as that of not certified office buildings. Using these results, the environmental performance of Top-Level Business Facility certified office buildings over 10000 m2 of total building area and expired CASBEE certified office buildings over 10000 m2 of the area, CASBEE certified office buildings over 3000 m2 and less than 10000 m2 of the area may be high in the value of the real estate.
     The utilities costs of buildings are not always related to the energy consumption, because an energy source, a type of contract and a contract fee are different in each building. In this survey, the primary energy consumption of CASBEE real estate buildings is correlated with the utilities cost of the buildings. The objective buildings do not install the regional air-conditioning.
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  • Demonstration in 4 areas of the Japanese Alps
    Fuka NISHITANI, Yohei SOEHARA, Yoshiharu ASANO, Kazuhiro IWAI, Yoshiak ...
    2017 Volume 82 Issue 733 Pages 281-288
    Published: 2017
    Released on J-STAGE: March 30, 2017
    JOURNAL FREE ACCESS
     Japan has rich forest resources, however, these resources have not been effectively utilized. It is therefore necessary to promote the utilization of forest resources in order to maintain multiple functions of forests and to sustainably manage the forests.
     The enactment of “The Act on the Promotion of the Utilization of Wood in Public Buildings” and widespread popularity of pre-cut wood has resulted in a growing demand for quality wood. Therefore, in order to promote the use of domestic timber, it is necessary to distribute timber whose qualities such as area of production and strength have been revealed. For that reason, it is necessary to develop a wood traceability system.
     The wood traceability system was tested in 8 areas in Japan, and the method and effectiveness of the system were clarified. However, due to its low cost-effectiveness, the wood traceability system has not been widely used.
     In this study, in order to improve the method of the wood traceability system, we conducted tests in 4 areas; Neba Village and Shinano Town in Nagano Prefecture, Kamo City in Niigata Prefecture and Takayama City in Gifu Prefecture. Furthermore, we conducted hearing survey at each distribution process in order to extract the necessary information about the wood. From the tests, we verified that the electronic tag labels are useful in wood traceability, because there is no need to replace the tag in the process of producing timber. In addition, through the hearing survey, we obtained the necessary information about the wood that is required by forestry cooperatives N and H, lumber market H, and sawmill N.
     The forestry cooperatives required accurate information on amount of forest resources such as a diameter at breast height, tree height, and forest management history. It is advisable to grasp such information by linking it with the geographical information. The lumber market required information on the tree species, owner of the timber, legality of the timber, and area of production when receiving the timber and , tip-end diameters, length, blemish on the timber, bending on the timber when shipping the timber. The saw-mills required information on tree species, tip-end diameters, length, blemishes, bending, and production areas when receiving timber logs. The information required by the saw-mills before shipping timber included; timber dimensions, moisture content, strength, area of production, and aesthetics on the timber surface. The necessary information required when dealing with traceability is mostly on the area of production and legality of timber.
     We considered a simple method of the wood traceability system based on the results obtained from the tests and hearing survey. Adopting the method of managing the timber in batches and tracking the wood from the lumber market to the intermediate lumber yard makes the wood traceability system simple and reduces the workload. Therefore, adopting the simple method would facilitate the proof of origin and legality of the timber.
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