According to GB 18564.1 and JT/T 1178.2, what is the mandatory technical requirement for the Emergency Cut-off Device (紧急切断装置 / 紧急切断阀) installed on liquid chemical and fuel road tanker vehicles?

1. It must be capable of closing within 5 seconds when operated manually or automatically upon thermal trigger (fusible link at 75°C ± 5°C)
2. It must require at least 30 minutes of continuous mechanical cranking to close fully
3. It must only close when the vehicle's speed reaches 100 km/h on an expressway
4. It must remain permanently wired in the open position with steel lockwire