A - Excellent
A1 - Excellent, Satisfactory to 72°F (22°C)
A2 - Excellent, Satisfactory to 120°F (48°C)
B - Good: Minor Effect, slight corrosion, or discoloration
B1 - Good: Minor Effect, slight corrosion, or discoloration, Satisfactory to 72°F (22°C)
B2 - Good: Minor Effect, slight corrosion, or discoloration, Satisfactory to 120°F (48°C)
C - Fair: Moderate Effect, not recommended for continuous use. Softening or loss of strength, and swelling may occur.
C1 - Fair: Moderate Effect, not recommended for continuous use. Softening or loss of strength, and swelling may occur, Satisfactory to 72°F (22°C)
C2 - Fair: Moderate Effect, not recommended for continuous use. Softening or loss of strength, and swelling may occur, Satisfactory to 120°F (48°C)
D - Severe Effect: Not recommended for any use
D1 - Severe Effect: Not recommended for any use, Satisfactory to 72°F (22°C)
D2 - Severe Effect: Not recommended for any use, Satisfactory to 120°F (48°C)