UL 1203
Explosion-Proof and Dust-Ignition Electrical Equipment for Use in Hazardous (Classified) Locations
standard by Underwriters Laboratories, 01/01/2000
UL Subject 1450
Standard for Motor-Operated Air Compressors, Vacuum Pumps, and Painting Equipment (Bulletin, 12/24/1999)
standard by Underwriters Laboratories, 12/24/1999
UL Subject 181B
Standard for Closure Systems for Use With Flexible Air Ducts and Air Connectors (Bulletin, 12/23/1999)
standard by Underwriters Laboratories, 12/23/1999