If you have an open face paint booth, understanding how far the electrical area classification extends beyond the open face of the booth is crucial for achieving code compliance.
For open face spray booths, the Class I, Division 2 area extends 3 feet from the opening of the booth. That requirement does not change, regardless of whether the booth’s ventilation system is interlocked with the spray application equipment.
Chapter 6 of NFPA 33 (Standard for Spray Application Using Flammable or Combustible Materials) has been extensively revised in recent years. Changes included revisions of the figures illustrating the area classifications in and around spray areas, paint booths, paint rooms and equipment.
Code 6.5.2 of NFPA 33 reads: “If spray application operations are conducted within a closed-top, open face or open front booth or room, any electrical wiring or utilization equipment located outside the booth or room but within the boundaries designated as Division 2 or Zone 2 in Figure 6.5.2(a) and Figure 6.5.2(b) shall be suitable for Class I, Division 2; Class I, Zone 2; or Class II, Division 2 locations, whichever is applicable.”
Previous editions of NFPA 70, also known as the National Electrical Code (NEC), specified that the Class I, Division 2 area extended 5 feet from the opening of the booth if the exhaust ventilation system was interlocked with the spray application equipment and 10 feet if it was not interlocked. The NEC has since been modified so that it is in agreement with NFPA 33.