Installations in buildings
- 91/91.140/91.140.01 Installations in buildings in general
- 91/91.140/91.140.10 Central heating systems
- 91/91.140/91.140.30 Ventilation and air-conditioning systems
- 91/91.140/91.140.40 Gas supply systems
- 91/91.140/91.140.50 Electricity supply systems
- 91/91.140/91.140.60 Water supply systems
- 91/91.140/91.140.65 Water heating equipment
- 91/91.140/91.140.70 Sanitary installations
- 91/91.140/91.140.80 Drainage systems
- 91/91.140/91.140.90 Lifts. Escalators
- 91/91.140/91.140.99 Other installations in buildings