Pressure-treatment has been recognized as a process that protects wood by extending its life indefinitely. That’s why building codes require wood for certain uses to be "treated" and why codes explicitly define "treated" to mean pressure treated.
International Building Code (IBC) sponsored by International Code Council
5203 Leesburg Pike, #600
Falls Church, VA 22041
Timber piling is in Section1808.1
Timber Piling Design Values
Allowable stresses for timber piling are published in the National Design Specification titled, “Timber Poles and Piles.” The following design values for pressure-treated timber piling meeting the requirements of ASTM D25 are often listed in building codes.
ASTM D25 are often listed in building codes.
|Modulus of elasticity
American Forest and Paper Associaton (AF&PA)
1111 19th Street, Suite 800, Washington, DC 20036
The American Wood Council of AF&PA publishes the National Design Specification which includes allowable design stresses for the wood products industry.
American Society for Testing and Materials (ASTM)
100 Barr Harbor Drive, West Conshohocken, PA 19428-2959
ASTM D25 Round Timber Piles
ASTM D2899 Establishing Design Stress for Round Timber Piles (from small clear specimens)
ASTM D7381 Establishing Design Stress for Round Timber Piles from Full Scale Tests
American Wood Protection Association
P. O. Box 388 Selma, AL 36702-0388
Develops standards for wood preservation. Piling standards are:
Lumber and Timber for Salt Water Use = Use Categories 5A, 5B, 5C (formerly C2)
Piles, Pressure Treat = Use Category 4C (formerly C3)
Wood for Highway Construction = Use Category 4A (formerly C14)
Material in Marine Construction, Pressure Treat = Use Categories 5A, 5B, %c (formerly C18)