lumber grade การใช้

The Canadian Lumber Standards Accreditation Board ( CLSAB ) monitors the quality of Canada's lumber grading and identification system.
The National Lumber Grades Authority ( NLGA ) is responsible for writing, interpreting and maintaining Canadian lumber grading rules and standards.
The National Lumber Grades Authority ( NLGA ) is responsible for writing, interpreting and maintaining Canadian lumber grading rules and standards.
From 1898 to 1932, the NHLA based its lumber grades on the number and size of visual imperfections in a given piece of lumber.
As the creators of North America's commonly used lumber grading system, the NHLA has involved itself heavily in the education and certification of lumber inspectors.