Lighting types can be divided into: normal lighting, emergency lighting, duty lighting, guard lighting and obstacle lighting. Among them, emergency lighting includes backup lighting, safety lighting and evacuation lighting, and its applicable principles should meet the following requirements: as shown in Figure 1.

1. When the normal lighting is extinguished due to a fault, lighting for equipment should be installed in places that need to ensure normal work or continuation of activities;

2. When the normal lighting is extinguished due to a fault, safety lighting should be installed in places that need to ensure the safety of persons in danger;

3. When the normal lighting is extinguished due to failure, evacuation lighting should be installed for exits and passages that need to ensure the safe evacuation of personnel;

4. The duty lighting should use part or all of the normal lighting that can be controlled independently or use part or all of the emergency lighting;

5. Guard lighting should be installed within the guard range as needed;

6. The installation of obstacle lighting should strictly implement the relevant regulations of the local aviation or transportation department.