Static Electricity - hdbk10920078

DOE-HDBK-1092-98

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 10% for ground resistance testing and 1 ohm 10% 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.

5.1.4 STATIC ELECTRICITY

Static electricity shall be controlled or eliminated in areas where materials are processed or handled

that are ignitable by static spark discharge. This category includes spark-sensitive explosives,

propellants, and pyrotechnics, as well as solvent vapors and flammable gases. Approved systems to

dissipate static electricity shall conform to the requirements of NFPA 77 and IEEE 142.

5.1.4.1 BONDING AND GROUNDING EQUIPMENT

Bonding straps shall be used to bridge locations where electrical continuity may be broken by the

presence of oil on bearings, or by paint or rust at any contact point. Permanent equipment in contact

with conductive floors or tabletops is not considered adequately grounded. Static grounds shall not

be made to gas, steam, or air lines; dry-pipe sprinkler systems; or air terminals of lightning protection

systems. Any ground that is adequate for power circuits or lightning protection is more than adequate

for protection against static electricity.

5.1.4.2 TESTING EQUIPMENT GROUNDING SYSTEMS

Grounding systems shall be tested for electrical resistance and continuity when installation is

complete and, in the case of active equipment, at intervals to be locally determined. The grounding

system shall be visually inspected for continuity (before reactivation of the system) if the equipment

has been inactive for more than 1 month. All exposed explosives or hazardous materials shall be

removed before testing. During a test for resistance to ground, all equipment, except belt-driven

machines, shall be considered as a unit. In measuring the total resistance to ground for belt-driven

machinery (to ensure compliance with Section 5.1.4.3), resistance of the belt is to be excluded. All

conductive parts of equipment shall be grounded so that resistance does not exceed 25 ohms, unless

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