The insulation classes are designated as follows:
Code Description Abbreviation
0. No Insulation NI
1. Heat Conservation HC
2. Cold Medium Conservation CC
3. Personnel Protection PP
4. Frost Proofing FP 5. Fire Proofing (Insulation) FI
6. Acoustic 10 dB AI
7. Acoustic 20 dB AI
8. Acoustic 30 dB AI
9. External Condensation and Icing Protection EP