| Class | Material | Service | Working Pressure | Working Temperature |
| 90 | asbestos free | Non-aromatic solvents, oil products, medium acid and alkalis, service fluids (except for steam and dowtherm). | = 20 bar. | -50° C + 200° C |
| 93 | asbestos free + carbon | Gaseous hydrocarbons, saturated steam. | = 20 bar. | -30° C + 200° C |
| 94 | asbestos free + graphite | For saturated and super heated steam (dowtherm excluded). | = 20 bar. | 280° C |