This entry covers the Western Wood Products Association (WWPA), a trade association of western US softwood lumber manufacturers and an ALSC-accredited lumber grading agency.
Detailed Definition
The Western Wood Products Association (WWPA) represents softwood lumber manufacturers in the western United States. It writes the Western Lumber Grading Rules, is accredited by the American Lumber Standard Committee as a rules-writing and grading agency, and supervises grade stamps used by its member mills. Species it covers include Douglas fir-larch, hem-fir and ponderosa pine. Whether an agency runs an ISPM 15 wood packaging program should be checked on ALSC's current list.
What a WWPA grade stamp tells a pallet buyer
Lumber graded under WWPA rules carries a grade stamp showing the agency mark, the mill number, the species or species group, the grade and the moisture condition at the time of surfacing, such as S-DRY or KD. For pallet buyers this matters mainly when a specification calls for graded lumber, for example structural stringers in a heavy-duty design. Much pallet lumber is cut from low grades or cants and is not individually grade stamped.
Lumber grading and ISPM 15 are separate programs
Grading lumber and certifying wood packaging are different jobs. ALSC accredits agencies to write or apply lumber grading rules, and separately accredits inspection agencies under the US wood packaging material program that supports ISPM 15. Some agencies do both and others do only one. To confirm a pallet's ISPM 15 mark, read the facility number and agency identification on the mark and check the agency against ALSC's current list.
Western species in pallets
Western softwoods are common in pallets built in western states and in components shipped elsewhere. Douglas fir is relatively strong and stiff for a softwood, while hem-fir and pines are lighter. As with any species, design and grade decide capacity.
Related Glossary Terms
Frequently Asked Questions
Is WTPCA the same as WWPA?
No. The Western Wood Products Association is abbreviated WWPA, and that is the organization this entry describes. If WTPCA appears on a document about western lumber grading, check the grade stamp or certificate itself, which shows the agency's actual mark, and verify the agency's accreditation on the American Lumber Standard Committee website.
Does a grade stamp mean lumber is heat treated for ISPM 15?
No. A grade stamp shows the lumber's grade, species and moisture condition at the mill. Lumber stamped KD has been kiln dried, but kiln drying is not the same as ISPM 15 heat treatment, which requires a core temperature of at least 56 C for at least 30 continuous minutes under a monitored program. Only an ISPM 15 mark from an authorized facility shows that wood packaging meets the standard.