Class I identifies a flammable gas or vapor hazard. Division 1 and Division 2 distinguish conditions used to classify the location. The site classification comes first; it should not be changed to fit a preferred or less expensive light.
Division 1 covers more than continuous exposure
Division 1 can include ignitable concentrations during normal operation and other conditions described by the governing classification rules. It is not simply a synonym for Zone 0. The responsible design team should establish the classified boundaries and substances involved.
Division 2 remains a classified location
Division 2 commonly involves gases or vapors normally confined within systems, with release under specified abnormal conditions or related classification circumstances. It is not an ordinary location merely because a release is unlikely.
Match the full approval
Review the class, division, group, temperature marking and ambient limits for the exact fixture. OSHA permits Division 1 equipment in a Division 2 location of the same class and group, but the remaining equipment and installation conditions must still be met. Do not infer a gas group or temperature suitability from the division number alone.
Protection and installation depend on the assembly
Explosionproof, intrinsic-safety and other permitted techniques have different requirements. Confirm entries, wiring, seals, mounting, bonding and maintenance against the equipment instructions and applicable rules. A short comparison cannot replace a location-specific installation design.
For portable work, check the complete lamp, cord and connection configuration. Hand lamps و string lights solve different positioning problems once the required approval is established.
References: OSHA 1910.307 — Hazardous (classified) locations · UL Solutions — North American hazardous-area certification