Understanding of the winter environment dry solid wood floor and the gap shrinkage coefficient.

<p align="center"> </ p> <p> solid wood flooring produced in the course of the gap is mainly due to a dry environment, or wood shrinkage caused. .Solid wood floor in the north is the main problem facing our country. .The size of the gap between the floor and the floor of the wood shrinkage factor, the moisture content of the floor, the use of the environment and the equilibrium moisture content is closely related to the width of the floor. .National standards for the solid wood flooring (GB/T15036-2001) provides solid wood flooring in the rate of 7% moisture content of the local equilibrium moisture content, which means that the moisture content of factory floor that they meet the above requirements, indicating that the moisture content of the product is qualified .If we do not take into account other factors, there might have problems. .In order to reduce and eliminate the floor in the installation and use problems, the state issued a "wood flooring, acceptance and use of standardized GB/T20238-2006", the standard in the September 15, 2006 into effect. .The standard process of drafting a large collection of relevant information on the floor of complaints, heard in full on the basis of the opinions of the relevant provisions of the development, taking into account the various aspects (products, production and distribution business and consumer) interests. .Provided in the standard environment for consumers to use the relative humidity of 40% to 80%. .Under the conditions of the warranty period, the proper use of solid wood flooring should be less than or equal to the gap 2mm. .We explore the above parameters the width of solid wood flooring, floor shrinkage coefficient and shrinkage resulting from the relationship between the gap. .</ P> <P> <P> <p align="center"> </ p> <p> First, the moisture content of wood flooring north of the range under the "wood flooring, acceptance and use of standardized GB/T20238- .2006 ", consumers use the environmental relative humidity of 40% to 80%. .Also gives the consumer environment, the relative humidity of 40% bottom line, this time the environmental features of the standard requirements. .Such conditions for normal use, the gap in the floor of the warranty period, if exceeded, in line with the warranty conditions, the related parties should bear the warranty obligations. .According to the requirements of northern winter heating, the room temperature should reach about 20 ℃, look-up table 1, the air relative humidity of 40% and room temperature of 20 ℃, the floor of the equilibrium moisture content was 8%, indicating that the heating of the floor of the north .The bottom line for the water content of about 8%. .Northern moisture content limit should be for the local equilibrium moisture content, measured according to our northern summer (6 to 9 month rainy season) the floor of the equilibrium moisture content 12% ~ 13%. .Year, changes in northern floor moisture content (max - min) is about 5%, if you have dry winter, humidity (relative humidity of the indoor air of 30% or less), the year the floor moisture content may vary .even more. .The water content changes every year, alternating. .So, every winter produces relatively large gap. .Excessive use of the environment situation of the user aside, the normal range of moisture content changes the floor for about 5%. .So we need to look at the floor when the moisture content of 5% reduction of drying shrinkage is more than 2mm. .We installed the floor in the floor when the moisture content may not in the greatest state in the region, but should be based on the actual floor moisture content and equilibrium moisture content of each region to determine a reasonable reserve gap (the relevant thematic issues will be discussed later), ensure .the floor is not the wettest season of drum kits, the floor should not be a gap between articles, this time in the floor of the water was still the largest state. .Therefore, we should put the maximum moisture content of the region as a basis for consideration. .</ P> <p align="center"> </ p> <p> Second, the floor gap shrinkage coefficient and the relationship between the wood floor of the shrinkage coefficient of solid wood flooring reflects the changes in the moisture content of the importance of dimensional stability .indicators. .Shrinkage coefficient of wood cut in a different direction with the timber there is a clear difference. .Shrinkage coefficient string cutting diameter greater than the cut material. .Changes in water content under the same circumstances, the maximum string cutting wood shrinkage, if a path string cut timber and cut wood on the floor adjacent to install the gap may not excessive, when the two criteria of the strings adjacent to cut wood flooring .Installing it is very likely exceeded the gap. .In fact, the two criteria of the strings cut wood flooring installation is often encountered in the adjacent, then the floor of the drying shrinkage is the gap between the floor. .So we put the focus on strings cut wood flooring on the drying shrinkage is greater than 2mm. .Flooring manufacturers buy floor at the stock, should first understand the expansion and shrinkage of wood properties. .Some in the book can be found related. .Such as Wood commonly used in China in the "Wood Science" can basically be found in our calculation based on the shrinkage coefficient of wood flooring in the relevant areas and predict the shrinkage of the situation. .The vast majority of imported timber can also be found in the book. .Should be noted that more accurate data on domestic materials and imported materials because of different origin, the same species different teaching materials, it is recommended or re-measured data is more reliable. .The greater the shrinkage coefficient of wood with moisture content the greater the deformation. .Under the same conditions, the wider the floor the greater the deformation. .Northern China in summer (rainy season) and winter heating period, the floor moisture content range is about 5%, in this context, if the width of the floor of 125mm, the floor of the wood shrinkage factor of 0.33, the floor drying shrinkage .will be more than 2mm. .Elected by wood shrinkage coefficient greater than 0.45, the width of 92mm to the floor of the drying shrinkage than 2mm. .The analysis is solid wood flooring to the production and distribution units to pass a message to the special climatic conditions in the north, the floor of the shrinkage cracks exceeding (wood flooring, acceptance and use of standardized GB/T20238-2006) is not only the floor moisture content .caused by excessive, unreasonable or floor size selection can lead to unreasonable excessive shrinkage cracks. .For example, sales of wood flooring in the Northeast, 13% moisture content (moisture content consistent with GB/T15036-2001), the floor of the width of 125mm, the floor material shrinkage coefficient of string cut to 0.39, heating in winter the indoor environment when the user .temperature 20 ℃, indoor humidity is 40% (humidity found GB/T20238-2006 requirements), look-up table 1 we have: the floor of the equilibrium moisture content was 8%. .Rate of installation of the moisture content of the floor 13% to 8%, 5% moisture content changes. .Shrinkage coefficient according to the floor and the floor of the width of the look-up table 2, the floor of the drying shrinkage is 2.44mm (more than 2mm), according to GB/T20238-2006 requirements, the floor of the gap more than 2mm should be maintained. .As can be seen from this example, the product is qualified, the consumer is also in line with environmental requirements, the floor of the gap exceeds the standard requirements. .The problem is that the original selection of unreasonable or excessive width of the floor caused. .Also the above conditions, if we put the width of the floor into a 92mm, the floor of the drying shrinkage is 1.79mm (less than 2mm), does not require maintenance. .Also the above conditions, the width of the floor remains unchanged 125mm, if the user's ambient humidity to 55% (with a humidifier humidification), the floor rate of 11% equilibrium moisture content, water content of the floor rate of 13% of installation .dropped to 11% moisture content changes of 2% floor, the floor of the drying shrinkage is 0.98mm, consistent with GB/T20238-2006 requirements. .</ P> <p> III, the conclusion from the above analysis we can draw the following conclusions: 1, the width of solid wood flooring wood species used should be based on chord cut materials to determine the shrinkage coefficient, the shrinkage factor can be made relatively large species .narrow floor. .2, in northern China using solid wood flooring, 125mm width of the local board when the strings cut wood materials used in the shrinkage factor should be less than 0.33. .92mm width of the floor selection, the wood shrinkage coefficient string cut material should be less than 0.42. .3, an appropriate increase in the relative humidity of the environment can be used to reduce the gap resulting shrinkage of the floor. .Distributor shall provide consumers with the purchase of the floor of the use of environmental requirements </ p>.