地采暖用木质地板甲醛释放限量指标探讨

利用1 m3气候箱法测定地采暖用实木复合地板和浸渍纸层压木质地板在23、30、35℃条件下的甲醛释放量,结果表明:1)两种地采暖用木质地板的甲醛释放量均随着测试温度的升高而增加;2)按照GB18580-2017《室内装饰装修材料人造板及其制品中甲醛释放限量》方法,甲醛释放量检测结果不超过0.06mg/m3的样品,在30℃时的甲醛释放量也能达到标准限量要求。建议地采暖用木质地板的甲醛释放限量指标要求修订为≤0.06 mg/m3。     

实木复合地采暖地板运行工况下的甲醛和VOC释放浓度

【目的】研究实木复合地采暖地板在冬季运行工况下室内温湿度变化及其对地板甲醛和VOC释放浓度的影响,为地采暖地板使用过程中的室内环境质量控制以及相关地采暖用地板的质量检测标准提供参考依据。【方法】构建一个面积约36 m~2的多层实木复合地板辐射供暖系统,供暖末端采用低温热水地板辐射形式。研究供暖季不同运行工况下(包括不同室外温度、不同系统供水温度等)室内温度和湿度分布以及实木复合地采暖地板中甲醛和VOC等有机污染物释放浓度的变化情况,分析地板辐射供暖系统的供热温度分布,探索多层实木复合地采暖地板甲醛和VOC的释放规律及相关影响因素。【结果】在40℃恒定水温地板辐射供暖条件下,室内平均初始温度为14.6℃,甲醛和VOC初始浓度分别为0.01和0.50 mg·m~(-3),随着持续供暖,室内温度逐渐升高,50 h后室内温度上升为20.3℃,甲醛和VOC释放浓度分别为0.04和0.70 mg·m~(-3),运行第20天甲醛和VOC释放浓度达到峰值,分别为0.05和0.86 mg·m~(-3)。在供暖温度上升至50℃时,50 h后室内平均温度为24.2℃,甲醛和VOC释放峰值浓度分别上升为0.11和1.01 mg·m~(-3),在试验供暖周期结束时浓度分别为0.03和0.72 mg·m~(-3)。甲醛和VOC释放浓度与室外温度和室内相对湿度具有一定正相关性,但其波动幅度较小。【结论】多层实木复合地采暖地板的甲醛和VOC释放与室内温湿度都具有正相关性,且受系统运行工况和室外环境的影响;当供暖系统运行温度较高时,在密闭的室内容易造成空气中甲醛等有机污染物含量超标,需进行开窗通风。本研究结果可用于指导实木复合地板采暖系统的使用以及地采暖用地板甲醛和VOC释放限量标准的补充。     

地采暖运行工况下木质地板甲醛释放量的变化分析

为研究地采暖环境下木质地板在居室环境中释放甲醛的规律,在地采暖试验房间内分别全屋铺设3种木质地板(三层实木复合地板、多层实木复合地板和浸渍纸层压木质地板,1 m³气候箱法检测其甲醛释放量分别为0.083、0.025和0.080 mg/m³),采用酚试剂分光光度法,在地采暖设施关闭与运行工况下分别测试空气中甲醛质量浓度,以分析木质地板甲醛释放量的变化。结果表明：1)室内全屋铺设木质地板后,按GB 50325—2020《民用建筑工程室内环境污染控制规程》规定在门窗关闭1 h后测试,地采暖设施关闭、运行工况下空气中甲醛质量浓度(含本底值)范围分别为0.025～0.033、0.023～0.043 mg/m³,符合GB 50325—2020对Ⅰ类民用建筑室内环境甲醛浓度≤0.07 mg/m³的限量要求;按GB/T 18883—2022《室内空气质量标准》规定,门窗关闭12 h后,地采暖设施关闭、运行工况下空气中甲醛浓度(含本底值)范围分别为0.025～0.039、0.018～0.060 mg/m^3<...     

一个不容忽视的问题——实木复合地板甲醛释放量的相关标准及检测方法

(一) 实木复合地板也叫工程地板,分为多层实木复合地板和三层实木复合地板.美国是多层地板主要消费区,而欧洲则更多地采用三层实木复合地板.由于中国是这两种地板的主要出口国家,所以在中国这两种都有一定的市场份额.多层地板、三层实木复合地板等人造板产品,目前绝大多数使用改性脲醛树脂胶生产.这类产品存在甲醛释放量的问题,为此各个国家和地区纷纷制定了严格的法律法规来限制相关产品中的甲醛释放.     

低毒脲醛树脂胶接实木复合地板的性能研究

从实际应用出发,在不同热压温度、不同固化剂用量条件下,对三聚氰胺改性低毒脲醛树脂胶接实木复合地板的物理力学性能、甲醛释放量进行了研究。试验结果表明,采用3%三聚氰胺改性合成的低毒脲醛树脂用于实木复合地板胶接,在热压温度为85℃条件下,使用复合固化体系,各项物理力学性能均达到GB/T18103-2000要求,穿孔萃取法测得甲醛释放量小于3mg/100g。热压温度和固化剂用量对实木复合地板的静曲强度和弹性模量影响不明显。随着热压温度升高,甲醛释放量逐渐减少,随固化剂用量变化其甲醛释放量亦有所不同。     

地采暖环境模拟舱的研制

为了准确地检测地采暖环境下木质地板的甲醛释放量,研制一种模拟地采暖环境的模拟舱。主要介绍该地采暖环境模拟舱的结构组成和工作原理,以及运行测试结果。结果表明,该模拟舱的温度及相对湿度波动范围都在1 m~3气候箱法允许范围内,地板上下表面存在温度梯度,可模拟真实的地面辐射供暖情况。应用模拟舱对浸渍纸层压木质地板和多层实木复合地板的甲醛释放检测值,高于常规1 m~3气候箱法检测值,且低于气候箱整体加热方式下的检测值,能更真实地反映地采暖用木质地板的甲醛释放情况。     

添加阻燃剂对三层实木复合地板生产工艺的影响

以三层实木复合地板为对象,探讨阻燃剂对其生产工艺的影响,结果表明:芯板、背板浸渍阻燃剂时,单板的增重率随着浸渍时间的延长而增加,当浸渍时间超过30 min后,增重率增加不明显;随着阻燃剂施加量增加氧指数增大,含水率、静曲强度随着施加量增加而降低;含水率、静曲强度、甲醛释放量和氧指数随着涂胶量的增加而增大;热压温度和热压时间对含水率、静曲强度、甲醛释放量和氧指数影响不明显。最佳热压工艺条件为:阻燃剂施加量8%,涂胶量360g·m-2,热压温度120℃,热压时间12 min。     

地板基材用桦木胶合板在生产上易出现的问题与对策

目前,地热取暖方式逐渐普及并成为一种时尚,但以前的纯实木地板在这种地面上铺装时会出现干缩变形等问题而无法应用,取而代之地是复合地板。目前中低档复合地板是以高密度纤维板为基材覆以三聚氰胺耐磨浸渍纸制成,由于这种基材是以脲醛树脂为粘合剂,所以板材的耐水性能较差,并且甲醛释放量相对较高(通常为0.5mg/L左右),对室内空气质量有一定的影响。中高档复合地板是以酚醛桦木胶合板或以实木为基材,覆以实木薄板(5mm厚)或1mm厚纹理优美的旋切或刨切单板制成的实木复合地板。这种地板外观好,弹性和隔热性能优良,甲醛释放量很低(小于0.3mg/L…     

3层实木复合地板VOC释放及快速检测

【目的】为了降低人造板挥发性有机化合物(VOC)的检测成本、增强可靠性,提高产品环保水平和工作效率,提出一种新型的VOC快速检测方法。【方法】以3层实木复合地板为研究对象,建立单因素试验方案,合理搭配各环境条件,快速采样装置与气质联用仪结合使用,对其在不同温度、相对湿度和空气交换率与负荷因子之比条件下释放的VOC进行检测和分析,一方面探索3层实木复合地板释放VOC的主要成分及释放规律,另一方面分析各环境因素对3层实木复合地板释放的VOC达到稳定期时浓度的影响。根据板材VOC的释放规律,确定快速释放法在最佳环境条件下得到的VOC量值,同时,利用传统气候箱法表征板材自然衰减过程中VOC释放量值,将2种方法测得数据进行对比,分析快速检测法与传统气候箱法的相关性。【结果】芳香烃和酯类是3层实木复合地板的主要挥发性有机释放物,除了部分烷烃、烯烃和醛酮类化合物外,板材还释放少量的醚、醇和酸类化合物。在测试期间,酯类和芳香烃类化合物的质量浓度变化趋势明显。温度和相对湿度增加会使平衡时的TVOC释放量增大,但当温度越高,湿度对平衡条件下TVOC的释放量影响越小。空气交换率与负荷因子之比越小,处于稳定散发阶段的实木复合地板释放的TVOC浓度值越大。【结论】快速检测法和传统气候箱法测得3层实木复合地板TVOC释放水平趋势基本一致,并且检测物相同。随着时间的延长,TVOC的释放量逐渐下降至稳定趋势。3层实木复合地板释放的主要挥发物酯类和芳香烃类来源于板材表面加工过程中使用涂料的有机溶剂,建议选择环保型涂料。温湿度的协同作用影响3层实木复合地板VOC释放量,高温高湿条件对3层实木复合地板中VOC的释放量有显著影响。而且,空气交换率与负荷因子之比对高温高湿条件下3层实木复合地板释放的TVOC量影响较大。快速检测法VOC释放速率快于传统气候箱法,且该方法性能可靠,可用于人造板材挥发性有机化合物的快速检测,便于企业有针对性地解决生产过程中出现的问题,提高产品质量。     

不同温度条件下浸渍纸层压木质地板的甲醛释放量研究

现今,我国没有专门针对地采暖地板的相关标准。国标 GB 18580—2001 中只对常温条件下 （20 ℃或 23 ℃）地板的甲醛释放量有明确规定,而对于地采暖条件下（30~40 ℃）地板甲醛释放限量值 没有可供参考的科学值。又因为甲醛检测方法不同和测试结果的表征方式不同,使得测试结果可比性差。 试验采用 3 种测试方法,分别对同种地采暖地板样品进甲醛放量的测试,分析在不同溫度条件下甲醛释 放量的变化规律,为测试方法的改进和发展提出合理化建议。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.