Grading - An Introduction
The grading rules for American hardwood lumber were established over 100 years ago by the newly formed National Hardwood Lumber Association (NHLA). Today the NHLA has over 2000 members worldwide, and the NHLA rules are still the national standard for the US hardwood industry and form the basis for grading of export lumber.
Wood is a natural material and by its very nature may contain different characteristics and defects that need to be understood and allowed for in any given application. The grading of sawn wood into categories as it is processed helps to determine to a large extent the value and potential use possible or each board of sawn lumber.
The NHLA grading rules provide both the buyer and seller with a consistent language to use in specifying hardwood lumber transactions. Although the NHLA grading rules are targeted for the US marketplace, a reasonable knowledge is essential for buyers worldwide in order to attain their expected degree of quality. The grade of lumber purchased by a manufacturer will determine both the cost and waste factor that is achieved. Because the grades are based on the percentage of clear wood in the board, many of the beautiful, natural characteristics found in hardwoods are not considered in calculating the clear yield.
Hardwood lumber is usually graded on the basis of the size and number of cuttings (pieces) that can be obtained from a board when it is cut up and used in the manufacture of a hardwood product. The NHLA rules were designed with the furniture trade in mind to provide a measurable percentage of clear, defect-free wood for each grade. The upper grades provide the user with long clear pieces, while the Common grades are designed to be re-sawn into shorter clear pieces.
The upper grades, which will include FAS, FAS-One-Face (FAS/1F) and Selects, are most suitable for long clear mouldings, joinery products such as door frames, architectural interiors; and furniture applications, which require a heavy percentage of long wide cuttings.
The Common grades, primarily Number 1 Common (No. 1C) and Number 2A Common (No. 2AC), are likely to be most suitable for the kitchen cabinet industry, most furniture parts, and plank and strip flooring. Worth noting is the fact that once re-sawn, the cuttings obtained from the Common grades will be the same clear wood as the upper grades but in smaller (shorter and/or narrower) cuttings. The grade name simply designates the percentage of clear wood in the board, not the overall appearance.
The American hardwood temperate forest resource is the largest of its kind anywhere in the world, with a significant history of sustainability. Exploring the Common grades, where possible, is invaluable in achieving the most value both in lumber cost and yield. These efforts will also help to ensure the sustainability of the resource for generations.
AHEC Europe would like to thank the NHLA for their collaboration in producing this section.