Table 1.
ASTM D1758-05 termite grade rating of field test specimens

Visual Rating	Description of condition
10	Sound timber, no termite attack
9	Trace of termite attack less than 3% of cross section
8	Termite attack 3% to 10% of cross section
7	Termite attack 10% to 30% of cross section
6	Termite attack 30% to 50% of cross section
4	Termite attack 50% to 75% of cross section
0	Failure due to termite attack