UL 北美防爆認證將「危險環境 (hazardous location)」或 「危險分類 (hazardous classified)」依爆炸物的存在狀況分為以下兩級 (Division):
● 1 級區 (Division 1):
在正常工作條件下「持續或可能存在」(exist all of the time or some of the time)。
● 2 級區 (Division 2):
在正常工作條件下「不太可能存在」(not likely to exist)。

[註]
UL 北美防爆認證基本常用規範:

• UL 913, Intrinsically Safe Apparatus and Associated Apparatus for Use in Class I, II, and III, Division 1, Hazardous (Classified) Locations
• UL 1203, Explosion-Proof and Dust-Ignition-Proof Electrical Equipment for Use in Hazardous (Classified) Locations
• UL 121201, Nonincendive Electrical Equipment for Use in Class I and II, Division 2 and Class III, Divisions 1 and 2 Hazardous (Classified) Locations

[睿豐 GCS 安規團隊]