Western Wood Products Association is one of the
largest associations of lumber manufacturers in the United States,
representing sawmills in the 12 western states and Alaska. The Association's
Quality Services Division supervises lumber grading by maintaining
a highly competent staff of lumber inspectors who regularly check
the quality of mill production, including visual grade requirements
of glued products and machine stress-rated lumber.
The Association's Grading Rules for Western
Lumber establishes standards of size and levels of quality
in conformance with the American Softwood Lumber Standard PS 20.
The Association is certified as a rules writing and inspection agency
by the Board of Review, American Lumber Standard Committee. The
Association is approved to provide mill supervisory services under
its rules and the rules of the West Coast Lumber Inspection Bureau,
the Redwood Inspection Service, the National Lumber Grades Authority
for Canadian Lumber and the NGR portion of the Southern Pine Inspection
Bureau Rules. In addition, WWPA is approved to supervise finger-jointed
and machine stress-rated lumber.
Interpreting Grade Marks
WWPA uses a set of marks to identify lumber graded
under its supervision. The grade marks are stamped on the lumber
and appear near the ends of the product:
Most grade stamps, except those for rough lumber
or heavy timbers, contain 5 basic elements:
WWPA certification mark
certifies Association Quality standards and is a registered trademark. Mill identification
name, brand, or assigned mill number. WWPA can be contacted to identify
an individual mill whenever necessary.
Grade name, number or abbreviation. Species identification
Indicates species by individual species or species combination.
Condition of seasoning
Indicates condition of seasoning at time of surfacing:
- MC-15, KD-15
15% maximum moisture content
- S-DRY, KD
19% maximum moisture content
over 19% moisture content (unseasoned)