The power behind quality wood

The National Grading Rule for dimension lumber was established nearly two decades ago to standardize softwood grades, sizes, design values, and species groupings. Its homogenous standards have greatly simplified the work of building inspectors, builders, remodelers, and even do-it-yourselfers.

But this was not always the case. In the early 1900s, improved transportation allowed a multitude of regional grades, products, sizes and species to pour into a national distribution system. The resulting product mix was diflicult to follow and stirred the lumber industry to establish order.

By April, 1924, the industry had approved its first set of voluntary product standards with guidance from the Department of Commerce. The voluntary standards are depend- ent on self-regulation.

That first effort also produced a Central Committee on Lumber Standards, later named the American Lumber Standards Committee (ALSC). Made up of softwood producers, retailers, wholesalers, engineers, architects, consumers, and government agency relpresentatives, it has continually refined the standards to meet changing conditions.

The current and most effective standard is Product Standard 20-70, or simply PS 20-70, in effect since September, 1970. Promulgated by the ALSC, it has produced numerous benefits for softwood lumber users, manufacturers, and related industries.

One of the more far-reaching effects of PS 20-70 is National Grading Rule for dimension lumber under five inches thick. In essence. this successfully condensed regional grades, sizes and design values to establish universal grade descriptions and names for dimension lumber.

This ensures end users that lumber conforms to clearly stated sizes and grades, regardless of source or manufacturer. Without surrendering product integrity, the rule simplified grading design, specification and use.

The standard set a precedent by defining dry lumber as that with a moisture content (MC) of l9o/o or less, the level at which decay organisms no longer function. Secondly, it was the level most uniformly adopted by various grading agencies. Thislevel was accepted by the Federal Housing Authority and numerous building codes.

The new standard required grade marks to show moisture content at time of surfacing: Surfaced Green