NEC definitions of and requirements for hazardous locations Class I and Class II are modified as follows for application to DOE explosives facilities:

1. Areas containing explosive dusts or explosives which may, through handling or processing, produce dust capable of being dispersed in the atmosphere shall be regarded as Class II Division 1 hazardous locations.

2. Areas that contain exposed explosives but where no dust hazard exists shall be regarded as Class 11 Division 2 hazardous locations.

3. Suitable NEMA rated enclosures shall be provided in those locations where water/ explosives mixtures may contact electrical equipment and wiring.

4. Areas where explosives are processed and sublimation may occur or where flammable gases or vapor may be present in quantities sufficient to produce explosive or ignitable mixtures shall be regarded as Class I Division 1 and Class II Division 1 hazardous locations.

5. To ensure a location is assigned to the proper hazardous location class and division, it is necessary to know the properties of the explosives involved there, including, at a minimum, sensitivity to heat and spark and thermal stability. If the properties of an explosive area are such that Class II Group G equipment provides inadequate surface temperature limits, special protection shall be provided or the equipment excluded from the hazardous location. This equipment shall not have a surface temperature exceeding the lowest onset of the exotherm of the explosive as determined by the differential thermal analysis test or the differential scanning calorimetry test. When NEC Class I or II equipment is not available, the substitute equipment shall be purged (in accordance with NFPA 496) or sealed to prevent explosives contamination, shall be determined intrinsically safe by facility management, or shall be administratively controlled. If the equipment is purged, it shall be monitored for flow.

6. Areas that contain explosives that are not defined as hazardous locations (areas containing no dust, vapor, gas hazards, or exposed explosives; for example, storage magazines), shall be evaluated and documented by facility management to ensure that electrical ignition sources are minimized or shall be regarded as NEC Class II.

7. Procedures shall be established by each DOE facility to control the use and modification of electrical equipment in explosives areas and ensure that uniform standards are adhered to throughout the facility.