This standard provides procedures for quality control and inspection at wood preserving plants of residential and commercial products, including but not limited to lumber, timbers, and certain pressure treated wood composites such as plywood, glue laminated timber, cross laminated timber, mechanically fastened timber, and structural composite lumber. These products are generally treated without a written specification from the end user and are generally supplied through retail lumber dealers and home centers to consumers and contractors for use in residential and commercial construction. This standard contains minimum requirements for the treating plant quality control and inspection agencies to monitor the treating plant and process, sample treated products and determine conformance to the applicable portions of Standards U1 and T1.