Lumber Grade-Marking History: 1916

1916 was a year that gave us a great many things for the first time, many of which our lives literally depend on today. On New Year’s Day, the British Royal Army Medical Corps carried out not only the first successful blood transfusion in history, but they did so using blood that had already been stored and cooled.

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Lumber Grade-Marking History: 1915

About the History of Lumber Grade Marking SPIB has been in the process of archiving some of its historical documents.  In that process, we discovered a rare and treasured story about the history of grade marking southern pine. It begins in 1883 and leads us up to 1940 when SPIB was created. W.D. Durland prepared […]

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Your Rules Writing Agency for Southern Pine

How was SPIB formed? The Southern Pine Association was formed in 1915 to provide a common set of grading standards for the industry. Prior to the formation of the SPA, each regional pine association published their own grading rules using different grades and sizes. With the advent of World War I, the Department of Commerce […]

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Density of Wood Blog

Density of Wood

What is density of lumber? In a general sense, density is defined as mass per unit of volume. For lumber, that could be given in units of pounds per cubic foot, or expressed as specific gravity (or relative density) where the density of the lumber is divided by the density of water (also in pounds […]

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Moisture content in lumber

What is moisture content of lumber? The amount of moisture in wood is often expressed as a percentage of the weight of the wood when the oven-drying method is used. When a tree is still growing, the tree may have more moisture in it than ovendry wood fiber, resulting in moisture contents greater than 100%. […]

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SPIB Resource Monitoring Program

In the early 1990’s, new lumber design values were approved for all major softwood lumber species in North America. This testing program was known as the “In-Grade Testing Program” because each piece of lumber tested was required to be precisely of the grade being tested. The design values were based on tests of full-size pieces […]

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Visually Graded Lumber vs. Machine Graded Lumber

Visually Graded Lumber vs. Machine Graded Lumber

There are different ways of determining the grade of dimension lumber. Historically, “visual” grading is performed where a person looks at all four sides of a piece of lumber and evaluates the characteristics present to determine which of several visual grades the piece belongs. This grader works on a grading chain and quickly evaluates each […]

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Shake and Splits, What’s the Difference?

In our previous BLOG,  Shakes Checks and Splits in Dimension Lumber, we discussed the differences between these three types of defects or characteristics found in dimension lumber. All three are commonly thought of as different types of “cracks” or, “splits” in the wood.  Each will have different limits in various grades depending on their effect on […]

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