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南方松
调味要求
使南方松木作为建筑材料在结构上优越的品质之一是其调味要求。
厚度不超过 2 英寸的南方松木尺寸木材必须干燥至最大含水量 19%,以获得最佳尺寸稳定性。
这最大限度地减少了与生坯木材相关的收缩,并提供了长期稳定性。
分级规则将 2 英寸厚或更小的南方松木的水分含量限制在最高 19%。
如果指定为“KD”、“KD19”、“干”或“风干”,则最大值为 19%。
如果南方松木被指定为“KD15”(窑干)或“MC15”,则最大值为15%。
由认证等级标志标识的材料证明南方松木材是按照适当的调味要求生产的。
如果涉及修整木材,则在装运和修整时适用含水量限制。
当南方松木交付给买家时,它们也适用,除非运输时暴露在天气下。
在这些规则的限度范围内修整的木材对于大多数用途来说是足够稳定的,但如果修整后水分含量进一步降低或增加,则会出现有限的尺寸变化——收缩或膨胀。
正常的收缩或膨胀余量是水分含量每减少 4 个百分点,尺寸就会减少 1%。
Items (Nominal thickness) | Kiln-DriedKiln-Dried | Kiln-Dried |
---|---|---|
D and Better Grades 1" and 1-1/4" | Max. 12% on 90% of pieces 15% on remainder | 15% |
1-1/2", 1-3/4" and 2" Over 2", but not over 4" Over 4" | 15% | 18% |
15% | 19% | |
18% | 20% | |
Paneling | 12% | 12% |
Boards1 | 19% | 19% |
Dimension1,2 | 19% | 19% |
Decking3 | 19% | 19% |
Timbers2 | 20% | 23% |
* Lumber dressed at a moisture content within the limits of these rules is sufficiently stabilized for most uses, but limited size changes will occur from shrinkage or expansion if the moisture content is further reduced or increased after dressing. The normal shrinkage allowance is 1% reduction in size for each 4-point reduction in percentage of moisture content and same tolerance for any expansion. (1) KD15 or MC15 may be specified if desired. (2) Moisture content provisions must be specified for material 2-1/2" and thicker because seasoning is not mandatory for these sizes. (3) All thicknesses of roof decking should be specified at 15% maximum moisture content. |