木门甲醛释放量的无损检测方法

Non-destructive testing methods for examination of formaldehyde emission from wooden doors

研究了可广泛普及的适用于木门甲醛释放量检测的无损检测方法。对比分析3种有害物质释放量无损检测方法测试过程及计算模型构建原理,构建2种木门有害物质释放量无损检测方法计算模型——无损检测法(直测法)、无损检测法(换算法)。采用5 m~3气候箱以中密度纤维板模拟木门承载率范围制备试样,使用直测法、换算法2种模型进行甲醛释放量检测,采用目前主流的木门甲醛释放量检测方法——1 m~3气候箱法检测实际甲醛释放量,对甲醛释放进行传质理论分析。结果表明:换算法所测甲醛释放量与产品实际甲醛释放量会发生偏离,产品实际甲醛释放量越大,换算法检测结果偏离越大;直测法与1 m~3气候箱法检测条件等效,使用直测法无损检测木门甲醛释放量真实、准确。相较于甲醛释放速率,以舱内甲醛浓度作为甲醛释放量评价指标较合理。木门甲醛释放量无损检测应选用无损检测法(直测法),即木门整体放入气候箱,以试验承载率与标准承载率(1 m~2/m~3)的比值设定试验时的空气交换率进行试验,所测舱内甲醛浓度即为木门甲醛释放量。无损检测法是对木门整体进行检测,采用无损检测法检测20扇木门甲醛释放量,部分检测数据与1 m~3气候箱法检测数据有较大差异,木门边部释放的甲醛不容忽视。

The widely applicable non-destructive testing(NDT) methods for detecting formaldehyde emission from wooden doors were studied.The testing process and calculation model construction principles of three non-destructive testing methods for harmful substance release were compared and analyzed,and two calculation models for non-destructive testing methods for detecting harmful substance release in wooden doors-NDT(direct measurement method) and NDT(conversion method) were developed.Medium density fiberboards were used to simulate the bearing capacity range of wooden doors to prepare samples for formaldehyde emission testing in a climate box with a size of 5 m~3,and the direct measurement and conversion methods were used to detect formaldehyde emissions.The current mainstream method for detecting the formaldehyde emission from wooden doors,i.e.,1 m~3 climate box method,was adopted for detecting actual formaldehyde emissions,and the mass transfer theory analysis was conducted on examining the formaldehyde release.The results showed that the data tested by conversion method would deviate from the actual formaldehyde emission of the product.The larger the actual formaldehyde emission of the product was,the greater the deviation of the conversion method detection results was.The direct measurement method is equivalent to the 1 m~3 climate box method in the detection conditions,and the non-destructive testing of formaldehyde emission from wooden doors using the direct measurement method was true and accurate.Compared with the release rate of formaldehyde emission,it was more reasonable to use the concentration of formaldehyde emission in the cabin as an evaluation indicator for the release amount of formaldehyde.The non-destructive testing method(direct measurement method) is able to be used for the examination of formaldehyde emission from wooden doors,that is,the wooden door should be placed in a climate box as a whole,the ratio of the testing bearing capacity to standard bearing capacity(1 m~2/m~3) should be set as the air exchange rate,and the concentration of formaldehyde in the measured cabin is the amount of formaldehyde released from the wooden door.In this study,the non-destructive testing method was used to test the entire wooden door,the formaldehyde emissions of 20 wooden doors were tested with the non-destructive testing method,and some of the testing data have significant differences with the testing data of the 1 m~3 climate box method,which showed that the formaldehyde released from the edges of wooden doors cannot be ignored.Using the NDT(direct measurement method) to detect the formaldehyde emission of wooden doors could not only improve the authenti-city of the testing data,but also avoid the waste of a large number of wooden door products caused by destructive testing and save wood resources.