This section covers the specific requirements and information for installing electrical equipment and wiring in explosive and hazardous locations and underground facilities. Classifications of areas or locations with respect to hazardous conditions are discussed. Information is provided on the correct methods and techniques needed for system grounding, lightning protection, and controlling of static electricity.

5.1 EXPLOSIVES

This section references DOE M440.1-1, "DOE Explosives Safety Manual," NFPA 70 (NEC), NFPA 77, NFPA 780, and DOD 6055.9-STD, "DOD Ammunition and Explosives Safety Standards." These standards and manuals should be referenced to ensure safe and reliable installations of electrical equipment and wiring methods in explosive and hazardous locations.

5.1.1 EVACUATION

Whenever an electrical storm approaches, personnel shall exit any location where a hazard exists from explosives being detonated by lightning. Evacuation may be necessary from locations listed below:

1. All outdoor locations, locations in buildings that do not have lightning protection, and locations within inhabited building distance of the hazard. (When an electrical storm is imminent, work with explosives operations shall not be undertaken.)

2. Locations (with or without lightning protection) where operations use electrostatic-sensitive bulk explosives or electroexplosive devices (EEDs).

5.1.2 SHUTDOWN OF OPERATIONS

The following guidelines shall be used for shutdown of an operation during an electrical storm:

1. Process equipment containing explosives shall be shut down as soon as safety permits.

2. When buildings or bays containing explosives are evacuated, functions that cannot be shut down immediately shall be operated by the minimum number of personnel required for safe shutdown. When the operation has been brought to a safe condition, those remaining shall evacuate.

3. Automatic emergency power equipment shall be provided if electrical power is critical to an explosives operation during a power shutdown or interruption.

5.1.3 LIGHTNING PROTECTION

It is DOE policy (See DOE M440.1-1, "DOE Explosives Safety Manual") to install lightning protection on all facilities used for storage, processing, and handling of explosive materials where operations cannot be shut down and personnel evacuated during electrical storms. Specific operations shall be assessed for the risk of detonation of explosives by lightning. Such assessment shall consider the need for the protection factors outlined in Appendix I, NFPA 780. When risk is high, as in operations with highly sensitive electrostatic materials or components, operations shall be conducted only in lightning-protected facilities. Approved lightning protection systems shall conform with the requirements of Appendix I, NFPA 780. Examples of acceptable lightning protection systems can be found in DOD 6055.9-STD, Chapter 7.

Lightning-protection systems should be visually inspected every 7 months and a report on their conditions filed at least annually. Any evidence of corrosion, broken wires or connections, or any other problem that negates the system's usefulness shall be noted and the problem repaired.

Lightning protection systems should be tested electrically every 14 months to ensure testing during all seasons, or immediately following any repair or modification. The testing shall be conducted only with instruments designed specifically for earth-ground system testing. The instruments shall be able to measure 10 ohms 1010 for ground resistance testing and 1 ohm 1010 for bonding testing. Electrical resistance readings shall be recorded.

Inspection records shall contain the most recent electrical test report and any subsequent visual inspection reports for each building with a lightning-protection system.