LIGHTNING & LIGHTNING PROTECTION ITS HEARTLAND CONFERENCE MARCH 27, 2013 BUD VANSICKLE LIGHTNING PROTECTION INSTITUTE
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LIGHTNING & LIGHTNING PROTECTION
I T S H E A R T L A N D C O N F E R E N C EM A R C H 2 7 , 2 0 1 3
B U D VA N S I C K L EL I G H T N I N G P R O T E C T I O N I N S T I T U T E
Lightning strikes the United States 20 million times each year.
A bolt of lightning can generate heat in excess of 50,0000 F.
Lightning travels 90,000 miles per SECOND.
Ligh
tnin
g Fa
cts
& F
igur
es
Dev
asta
tion
Dev
asta
tion
Empi
re S
tate
Bui
ldin
g
Wha
t is
Ligh
tnin
g?
Ana
tom
y of
Lig
htni
ng
Neg
ativ
e Li
ghtn
ing
Pos
itive
Lig
htni
ng
Clo
ud-to
-Gro
und
Ligh
tnin
g
NASA Global Lightning 1995 -2002
Flas
h D
ensi
ty M
aps
1996 -2004
Flas
h D
ensi
ty M
aps
2009
lightning related – Insurance Information Institute
(I.I.I.)
Annual property losses due to lightning in the
United States exceeded $1.03 billion in 2010 (2011
$.952 billion) – I.I.I.
213,000 insurance claims for lightning damage were
paid in 2010, (186,000 in 2011) avg. claim up 5% -
I.I.I.
The FAA estimates that lightning costs the airlines
$2 billion annually in operating costs and passenger
delays.
Lightning is the leading cause of all church fires.
Lightning is one of the leading causes of weather
Saf
ety
& E
cono
mic
C
onse
quen
ces
Ligh
tnin
g Pr
otec
tion
NFPA 780: Standard for the Installation of Lightning Protection Systems
UL96A: Installation Requirements for Lightning Protection Systems
LPI 175: Lightning Protection Institute –Standard of Practice
Inst
alla
tion
Stan
dard
s
Strike Termination Devices
Conductors
Ground Terminations
Bonding Connections
Surge Protection Devices (SPD)
Five
Ele
men
ts
NFPA ROLLING SPHERESt
rikin
g D
ista
nce
Stepped Leader
Corners, edges, ridges of structures naturally accumulate ions in the electrical field, so they are likely candidates for lightning attachments. Tall slender items disrupt the field in the same manner, releasing ions easily or providing leaders for the lightning stroke
National Geographic Photo
NFPA ROLLING SPHERESt
rikin
g D
ista
nce
EFFECTS OF CURRENT FLOW THROUGH A CONDUCTOR
Current flow through an impedance leads to a voltage.An electric field (E) will develop.A magnetic field (B) will develop.Coupling (capacitive & inductive) can occur through these fields.
Vo
V
I B
SIDEFLASH
An electric field can develop between the conductor and nearby objects, at different electrical potential.Once the field value exceeds a breakdown value, Ebr, sideflash, or arcing, can occur.Air breakdown:Ebr ~ 1 MV/m
Vo
V
I VoE
r
BONDING
Ideal electrical connection results in equipotential. Since no electrical potential (voltage) difference exists, no field is developed, preventing flashover.In reality, connection is imperfect (since bonding conductor has impedance) so field will be minimized.
Vo
V
I V
HOW SURGE OCCURS – MAGNETIC FIELD COUPLING
Service conductors in a magnetic field can have a current (and consequently a voltage) induced upon it, particularly if it’s parallel to the current path.
Vo
V
I
B
Ii
OPERATION OF THE GROUNDING SYSTEM
GROUNDING ELECTRODE (GROUND ROD)
CONDUCTOR
GRADE
Consider current injection into the grounding electrode.
I
OPERATION OF THE GROUNDING SYSTEM
GRADE
I
CURRENT FLOWS THROUGH ‘SHELLS’ OF EARTH, EACH WITH A RESISTANCE.I I
RR R R R R R R
v v v vvv v v
A VOLTAGE DEVELOPS ACROSS EACH SHELL
OPERATION OF THE GROUNDING SYSTEM
GRADE
I
I I
RR R R R R R R
v v v vvv v v
STEP POTENTIAL V1 – V2
GRADE
V
HOW SURGE OCCURS – GPR EFFECTS
V1 V2
Unbonded grounding systems can develop severe voltage differences. If connected within a structure, very high currents can develop leading to magnetic coupling or arcing within equipment.
Pers
onal
Saf
ety
Step Voltage
AVERAGE NUMBER OF U.S. LIGHTNING DEATHS*SINCE THE CAMPAIGN BEGAN (2000)
50
55
60
65
70
75
00 01 02 03 04 05 06 07 08 09 10 11 12
Deaths
Year
*30-year average
2012 Lightning Deaths: A Closer Look
• 89% were male• 6 were children• 7 were on fishing trips• 7 left safe shelter or were steps
away• 6 were in or near water• 12 were under or near trees• Many were resuscitated but died
later
Lightning Deaths in 17 States
Leon
the
Lig
htni
ng L
ion
The
End
Phone: 800-488-6864 E-mail: [email protected] Website: www.lightning.org
Bud VanSickle Lightning Protection Institute
Quality Program General• Exam program for certification• LPI‐IP field inspection program• 4 National tradeshows• A&E information CD• NFPA, UL STP, IEC Committees• Annual Conference• Research funding• LPI 175 Installation & 177
Inspection Standards
Communication• Newsletters & E‐blasts• Brochures & materials• Feature articles• DVDs “infomercials”• Releases on national wire services• Lightning Safety Awareness Week• “Leon” the lightning lion• I.I.I., IBHS, & FLASH – insurance
industry
Website• Find an Installer• FAQ• Links• Specifications
• Research papers• Non‐compliant systems• Educational tools – Children’s section• Store• Blog
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