Flooring is graded according to appearance. There is no nationally or internationally accepted standard applicable to all flooring manufacture, in the way the NHLA rules apply to hardwood lumber production. Therefore grades and quality standards tend to be set by individual producers based on customer requirements.
However, flooring standards do exist and are adhered to by specific groups of producers. For example, the National Oak Flooring Manufacturers Association (NOFMA), which represents most of the major producers of hardwood flooring in the USA, publishes and enforces hardwood flooring standards for its members who produce strip flooring, and most producers of solid hardwood flooring incorporate the basic principles upon which these rules are structured. The NOFMA rules also cover other species such as ash, walnut, maple, hickory, pecan, beech and birch.
Board/plank flooring grades tend to relate to the NHLA lumber grade the flooring profile is manufactured from, for example ex No 1 Common, or ex FAS.