GB 51309-2018 第3.2.1条
| **** | Wiring for the system shall use cables with a combustion performance rating of not less than B1; in densely occupied areas such as evacuation corridors and stairwells, exposed wiring shall be protected by metal conduits or closed metal trunking, and concealed wiring shall be run in conduits embedded in non-combustible structures with a protective layer thickness of not less than 30 mm. |