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Advancement of Lightning Protectionand Prevention in the 20th Century

Donald Zipse, Guest Author

Part 1 of this two-partseries covered the prim-itive observations inancient history, theexperiments by Benja-

min Franklin, and the early technicalwork by Nikola Tesla. This part willcontinue to explore the history oflightning protection further into the20th century and touch on some ofthe controversies that have eruptedin the recent years.

Carpenter’s DissipationArray SystemIn 1930, J.M. Cage patented a multi-point discharge system to preventlightning. The concept was to use asharp-pointed conductive metal sim-ilar to a barbed wire wrapped arounda beach umbrella, connected to earthand positioned above the structuresto be protected [1], [2].

In 1971, Roy B. Carpenter, Jr.,began marketing an application ofthis concept (1922–2007, IEEE LifeSenior Member). It is believed thathe came across the Cage patent dur-ing his work as a system reliabilityanalyst on the Apollo Space Program,although he never confirmed ordenied when asked about this. Hismultipoint discharge system is alsoknown as the dissipation array sys-tem (DAS).

NASA’s Space Center in Floridais located in a region known forhigh-lightning activity. Hence, theagency had a great deal of interest infinding ways to protect both itsfixed facilities as well as movable

launching structures and rocketsagainst direct lightning strokes.Carpenter proposed applying hisDAS to not only protect NASA’sSpace Center facilities but also pre-vent lightning strikes to the facil-ities. There is a big differencebetween protection from lightingand prevention oflightning, and so hisproposal stimulatedheated argumentsacross industry.

Two extensive in-vestigations havebeen conducted onthe performance ofthe DAS, whichculminated in a re-port containing morethan 250 pages ofdiscussion. Advo-cates concluded thatthe multipoint dis-charge systems func-tion like a Franklinrod system, and amajor factor in theeffectiveness of thesystem in dissipat-ing lightning is aconsequence of theextremely low-re-sistance connection to earth. Conversely,detractors argue that it has never beendemonstrated that the presence of aDAS actually eliminates lightning.

Hughes organized a symposium,‘‘Review of Lightning ProtectionTechnology for Tall Structures,’’ atthe Lyndon B. Johnson Space FlightCenter in Clear Lake City, Houston,Texas, on 6 November 1976. The

agenda had Carpenter presenting ‘‘170System Years of Lightning Prevention.’’Twelve distinguished experts presenteddifferent views of the efficiency of themultipoint discharge system.

In essence, the debate came downto the fact that the advocates of theDAS could not explain why it worked,

and they could notprovide anythingmore than anecdot-al stories that sug-gested that facilitieswith DAS installa-tions were not expe-riencing lightningstrokes. At that time,conventional wis-dom suggested thatthe physics behindlightning dischargewas beyond the scopeof human interven-tion. However, theabove has beenresolved, and pre-vention has beenaccepted in Japanand Southeast Asia.

The Franklin RodControversyThe first part of this

series mentioned that Franklin had ini-tially advocated the use of pointed rodsfor lightning protection. Subsequently,Tesla observed that rods with roundedends appeared to be more effective.Dichotomy also became the basis forcontroversy in the 20th century.

In the 1980s, Heary Brothers devel-oped a modification of the Franklinrod. A metal globe was installed at theDigital Object Identifier 10.1109/MIAS.2008.918499

CONVENTIONALWISDOM

SUGGESTEDTHAT THE

PHYSICS BEHINDLIGHTNINGDISCHARGE

WAS BEYONDTHE SCOPE OF

HUMANINTERVENTION.

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Digital Object Identifier 10.1109/MIAS.2008.92155113

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base of the Franklin rod, which held anionizing material. The purpose was toincrease the height of the ionizedstreamer rising from the rod, thusincreasing the effective height of theFranklin rod. Initially, the fear of ioniz-ing material dampened the sale of thedevice. It was subsequently redesignedto eliminate the ionizing element.

Heary Brothers approached theNational Fire Protection Association(NFPA) requesting a new standardon the ionizing air terminal, alsoknown as early streamer emission(ESE). At that time, the NFPAstandard on lightning protectionwas Standard 78. This was renamedto Standard 780 to allow for the gen-eration of an expected series ofrelated standards dealing withlightning protection, and a workinggroup developed Standard 781 onionizing air terminals.

A draft of the proposed Standard781 on ESE was completed but wassubsequently rejected as a whole byNPFA in 1995. Heary Brothers theninitiated legal action against NFPA.

The suit was settled out of court,and, as part of the settlement, NFPAagreed to reopen consideration of astandard for ESE protection. Thisreconsideration led to a reaffirmationof the decision not to proceed withStandard 781. In addition, it alsoraised questions about the under-standing of Franklin rods and sug-gested that Standard 780 should alsobe revisited.

Because the NFPA had declinedto address the DAS technology, aneffort to initiate astandards project onDAS was startedwithin the IEEE.To avoid conflictwith commercialtrademarks, the pro-posed standard wastitled, ‘‘Standard forLightning Protec-tion System Usingthe Charge TransferSystem for Indus-trial and Commer-cial Installations.’’

The efforts of thisworking group hadsignificant supportfrom Carpenter, whohad employed atmo-spheric scientists inRussia to simulatethe performance ofhis lightning protec-tion system. In addi-tion, several firms inJapan were interestedin the technologyand did extensivetesting. Although some draft conclu-sions were presented, the workinggroup was unable to arrive at a finalconsensus standard within the timeperiod allowed in the IEEE standards-making process.

Ralph Lee andthe Rolling BallThe traditional view of lightning pro-tection was that a grounded rod wouldprevent a direct stroke to a structurethat was completely contained withina cone surrounding that rod. It wasgenerally believed that the angle ofprotection of the rod was 45�.

Ralph H. Lee (1911–1987), LifeFellow, an electrical engineer associ-ated with DuPont in the UnitedStates, proposed a modification to

the traditional angle of protectionconcept. He suggested that the re-gion of protection could better be de-fined as the surface traced by a sphereas it rolls across the region contain-ing the rod; structural elements with-in the shadow of this surface arepresumed to be protected whereaselements that project through thesurface are exposed to potential strikes.Subsequent research in Europe has ledto the refinement contained in the lat-est revision of NFPA 780 that the

radius of the sphereconsidered for thispurpose should be150 ft.

LightningResearchin FloridaAnother contribu-tor to our modernunderstanding oflightning is MartinA. Uman, distin-guished professorand director of theLightning ResearchLaboratory at theUniversity of Flor-ida. He was instru-mental in developingthe lightning locat-ing system based onelectromagnetic fieldtheory. The resultsof this work can bereadily seen duringa thunderstorm byvisiting the Weath-er Channel Web site

and clicking on the screen that displayslightning strokes on a weather map.

In his field laboratory near Gain-esville, Uman is experimenting withtechniques to control the dischargeof lightning containing clouds anddirect that discharge to items understudy. His particular focus is on pro-tecting lightning strikes to airportrunway lighting facilities. He is alsoworking on directing lightning strikesinto explosive compounds to correlatethe resistance of the explosive withignition. The latter effort has alreadyproduced important improvements insafety with regard to handling ofexplosives. Obviously, his workpromises to offer a better under-standing of the physics of lightningthat may eventually lead to definitive

WE’VE COME ALONG WAY

FROM THE DAYSWHEN

LIGHTNING WASPERCEIVED TOBE THE RESULT

OF ZEUSHURLING

THUNDERBOLTSAT SOMERANDOMTARGET.

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answers to some of the ongoing debatesabout ESE.

There Is More to LearnWe’ve come a long way from thedays when lightning was perceivedto be the result of Zeus hurling thun-derbolts at some random target. Ouradvancing knowledge has contrib-uted to an evolution in the science ofprotecting structures from lightning.At the same time, conflicting theo-ries continue to be there about how

(or even whether) lightning can becontrolled and prevented, and thesetheories are the subject of fascinatingand energetic discussions. (The authorbelieves lightning can be prevented.)Eventually, as our understandingmatures, we will have answers. Fornow, having an open mind helps usenjoy the process of debate.

References[1] D. W. Zipse, ‘‘Lightning protection systems:

Advantages and disadvantages,’’ in Conf. Rec.

IEEE Petroleum and Chemical Industry Tech.Conf., Sept. 13, 1993, pp. 51–64.

[2] D. W. Zipse, ‘‘Lightning protection sys-

tems: Advantages and disadvantages,’’ IEEETrans. Ind. Applicat., vol. 30, pp. 1351–1361,

Sept.–Oct. 1994.

[3] K. P. Heary, A. Z. Chaberski, F. Richens, and

J. H. Moran, ‘‘An experimental study of ioniz-

ing air terminal performance,’’ presented at

the 1988 IEEE Power Engineering Soc.

Summer Power Meeting, Paper 88 SM 572-0.

[4] K. P. Heary, A. Z. Chaberski, F. Richens, and

J. H. Moran, ‘‘Early streamer emission enhanced

air terminal performance and zone of protection,’’

in Conf. Rec. IEEE Industrial & Commercial PowerSystems Tech. Conf., May 1993, pp. 26–31. IAS

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