BS 4978:1988

Specifies 2 methods of grading softwood namely, visual and machine stress grading. Permissible limits of characteristics for: (a) 2 visual stress grades – General Structural (GS) and Special Structural (SS); (b) 3 laminating grades – LA, LB and LC. Requirements for machine stress grades; Machine General Structural (MGS), Machine Special Structural (MSS), M50 and M75 and Strength Classes are specified. Also includes performance requirements for machines which grade softwood.