Table 1.
Decay rating scheme in AWPA standard E25-08

Decay Rating	Condition of the board
10	Sound: No evidence of decay.
9.5	Trace or suspicion of attack.
9	Minor softening on end-grain or on sides of checks, or up to 3% of any-given cross-section decayed.
8	Small pockets of decay on end-train or on sides of checks, or up to 10% of any given cross section decayed.
7	Moderate decay or sample has between 10-30% of any given cross section decayed. Presence of a fruit body is an automatic rating of no higher than 7.
6	Severe decay. Sample has between 30-50% of any given cross section decayed.
4	Very severe decay with greater than 50% of a cross-section affected, likely to seriously affect load-bearing capacity but not broken when stressed as described below.
0	Failure when stepped on sharply by a person of moderate weight (60 - 80 kg). This could be breakage of the board or severe surface collapse, or an inspection tool can pass totally through the board.