An Overview of Lightning Safety

Richard Kithil
President and CEO
National Lightning and Safety Institute
Louisville, CO 80027
rkithil@ix.netcom.com

Summary

Lightning is an underrated hazard. As a result, applied safety initiatives from its effects have been studied little and applied even less. On a continuing global scale, there are some 2000 thunderstorms producing 100 lightning strikes per second. Long term statistical averaging shows that lightning causes more deaths than floods, hurricanes, or tornadoes (Number of Deaths by Natural Hazards, 1940-1981). Yearly lightning costs can be shown to exceed $2 billion (Annual USA Lightning Losses).

Many USA lightning codes are incomplete and superficial, providing more benefit to commercial vendors than to those seeking relief from the strike event. Many devices are promoted that offer "no strike - absolute protection." Such unsubstantiated claims only serve to confuse specifying architects, engineers, and facilities managers.

Lightning cannot be "stopped" or "prevented" and in this sense absolute lightning protection is impossible. Preparedness can mitigate lightning consequences. A comprehensive risk management guideline can provide a rational and systematic approach towards lightning safety (Lightning Safety Tips).

Risk Management of the Lightning Hazard.

Preparedness for the lightning event is addressable by a mix of hardware and software. Hardware (equipment) is a combination, where appropriate, of devices such as lightning detectors and related warning equipment, air terminals (lightning rods), surge protectors, and grounding, bonding and shielding techniques. Hardware generally provides improved safety for facilities. Software (education, information and training - EIT) mainly benefits employee safety thresholds.

As a general minimum requirement, all personnel should have a general understanding of basic lightning safety terms such as:

FLASH-TO-BANG --- STEP VOLTAGE --- TOUCH VOLTAGE SIDEFLASH --- FARADAY SHIELD --- SAFE/NOT SAFE ZONES --- AVOID ALL WATER --- AVOID ALL METALLICS, INCLUDING TELEPHONES & HEADSETS --- LIGHTNING SAFE POSITION.

(Note: The USA lightning standard NFPA-780-1995, C-2.5.d descriptor for a lightning safe position is incorrect and should NOT be followed.) (NLSI Lightning Safety Tips)

For most employee situations a phased EIT program is suggested, consisting of the following elements:

Category I: EIT Training-In-A-Box. This is intended for presentation of lightning safety information by designated trainers. The package consists of a video, an instructor tutorial, handouts, booklets, and posters which focus on the lightning safety theme. All employees should be exposed to this information, with annual repetition.

Category II: EIT Workshop. All supervisory personnel should attend a focused 3 hour Lightning Safety Seminar annually.

Category III: A designated Safety Officer within the organization should have a comprehensive understanding of lightning safety issues. Professional accredited training in this field is available.

Conclusion

The arbitrary nature of lightning makes absolute safety from its effects unlikely. Hazard levels, however, can be mitigated. Safety margins can be improved. Deployment of site-specific equipment is useful. Education, information, and training of employees is an effective investment towards confronting the lightning hazard.

Societal Aspects of Weather

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