1 General Provisions 1 2 Terms and Symbols 3 2. 1 Terms 3 2. 2 Symbols 4 3 Maintenance Class and Technical Condition Assessment 5 3. 1 Maintenance class 5 3. 2 Technical condition assessment 5 4 Tunnel Structure 8 4. 1 General provisions 8 4. 2 Daily patrol 8 4. 3 Cleaning 9 4. 4 Structural inspection 11 4. 5 Technical condition assessment of tunnel structure 19 4. 6 Maintenance and repair 21 4. 7 Structural degradation treatment 24 5 M&E Equipment 26 5. 1 General provisions 26 5. 2 Daily patrols 28 5. 3 Cleaning and maintenance 29 5. 4 Inspection and repair for power supply and distribution facilities 30 5. 5 Inspection and repair for lighting facilities 42 5. 6 Inspection and repair for ventilation facilities 44 5. 7 Inspection and repair for fire-fighting facilities 47 5. 8 Inspection and repair for monitoring and communication facilities 50 5. 9 Technical condition assessment of M&E equipment 57 6 Other Facilities 61 6. 1 General provisions 61