深海防爆
如果某個區域需要安裝防塵防爆電氣設備, 區域設備防爆標準 20 必須超過Zones所需嘅值 21 和 22.
| 區 20 | 區 21 | 區 22 |
|---|---|---|
| An explosive environment in the air that continuously appears in the form of combustible dust clouds, exists for a long time or frequently. | Places where explosive environments in the air may appear or occasionally appear in the form of combustible dust clouds during normal operation. | In the normal operation process, an explosive environment in the air in the form of combustible dust clouds is impossible to occur in places where the instrument exists for a short period of time. |
具體說來, IN區 20, 只允許使用本質安全或封裝嘅設備, 唔允許使用隔爆設備.