Recording Strikes

1
Recording Strikes the Radius of Effectiveness
of Tree Protection

• A. William Graham, Jr.
• Formerly of Morris Arboretum of the U. of PA

2
Morris Arboretum in Philadelphia, PA
3
Top of a Westerly Facing Slope
4
Leading Edge of the Slope
5
This area has a history of Many Lightning strikes
6
Because of the number of lightning strikes in
this area the Morris Arboretum began protecting
the trees with LPS in the early 80s
7
(No Transcript)
8
(No Transcript)
9
(No Transcript)
10
(No Transcript)
11
(No Transcript)
12
(No Transcript)
13
Parking
Entry Drive
Ginkgo biloba
Quercus rubra
Abies nordmanniana
Quercus Imbricaria
Quercus x benderi
Quercus phellos
Morris Arboretum of the U of PA
An unplanned matrix of LPS protected trees with
interspersed unprotected trees
Plan View
14
Willow Oak
Black Oak
Former location of Shingle Oak (Quercus
imbricaria)
Trunk diameter 44 Inches DBH Crown Spread
60 feet Height 70 feet
15
Tree Died from Bacterial Leaf Scorch and other
problems
Trunk diameter 44 Inches DBH Crown Spread
60 feet Height 70 feet
16
Willow Oak
Black Oak
Location of Shingle Oak
All three trees protected with lightning
protection systems with a common ground
Trunk diameter 44 Inches DBH Crown Spread
60 feet Height 70 feet
17
Replacement tree in same location as Shingle Oak
Formerly with a Lightning Protection System (LPS)
18
69 feet
19
Bender Oak with Lightning Protection System
69 feet
20
Former Location of an unprotected lightning
killed Nordmann Fir
Willow Oak
Black Oak
Former location of Shingle Oak
21
Former Location of an unprotected lightning
killed Nordmann Fir
Dead - Removed 1988
Struck by Lightning 12 July 1987
22
Former Location of an unprotected lightning
killed Nordmann Fir
Trunk diameter 54 inches Crown Spread 25
feet Height about 70 feet
23
Former Location of an unprotected lightning
killed Nordmann Fir
Protected with LPS
24
Trunk diameter 79 Inches _at_ 3 feet Crown
Spread 100 feet Height 70 feet
25
Communication cable passing by the ground
terminal was burned out several times before it
was replaced by fiber optics
26
Lightning Protection System
27
Former Location of an unprotected lightning
killed Nordmann Fir
109 feet
28
90 feet
Branch Conductor to lightning killed Nordmann Fir
29
Two Lines Kinetic Metal Sculpture
Bender Oak
Ginkgo
30
Two Lines Kinetic Metal Sculpture
Bender Oak
Ginkgo
Protected
Unprotected struck
Protected
31
Trunk diameter 37 Inches DBH Crown Spread
35 feet Height 60 feet
32
Lightning Struck Unprotected
Stuck by Lightning 12 July 1993
33
Two Lines Kinetic Metal Sculpture
Bender Oak
Ginkgo
105 feet trunk to trunk
34
Two Lines Kinetic Metal Sculpture
Bender Oak
Ginkgo
69 feet Branch conductor to trunk
35
(No Transcript)
36
30 ft.
20 ft.
Grounded
37
65 feet
38
65 feet
39
Ginkgo
Protected
Two Lines Kinetic Metal Sculpture
Protected
Red Oak
40
Trunk diameter 56 Inches DBH Crown Spread
85 feet Height 70 feet
41
Lightning Conductor
42
Ginkgo
Protected
Unprotected struck
Two Lines Kinetic Metal Sculpture
Protected
Red Oak
109 feet trunk to trunk
43
Radius of Effectiveness of Tree Protection
44
Radius of Effectiveness of Tree Protection
45
Radius of Effectiveness of Tree Protection
46
Radius of Effectiveness of Tree Protection
47
Radius of Effectiveness of Tree Protection

• Conclusion is that the radius of protection is
  less than 65 feet

48
Radius of Effectiveness of Tree Protection

• Conclusion is that the radius of protection is
  less than 65 feet
• This chart does not take into consideration the
  height of the air terminal

49
Radius of Effectiveness of Tree Protection

• In my opinion, it is unusual to have the
  opportunity to witness lightning struck trees
  interspersed with unprotected ones as occurred at
  the Arboretum
• Unique opportunity to make these measurements

50
Franklin Institute in Philadelphia
51
Induction Loop Fuse Lightning Indicator

• Franklin Institute in Philadelphia
• Static Electric Generator
• Use for testing how to make a simple device that
  indicates that lightning used a Tree Lightning
  Protection System
• Such a device empowers lightning research.
• Once confirmed, detailed inspection of trees with
  different treatments can measure effectiveness

52
Principle of a Transformer
53
Induction Loop Lightning Indicator
54
Induction Loop Lightning Indicator

• Use of inexpensive and easily purchased
  materials
• Household electrical wire
• Car bus fuse holder
• Low amperage fuses

55
(No Transcript)
56
Lightning Conductor
57
Pulse of Electrical Current
58
Pulse of Electrical Current
59
Pulse of Electrical Current
60
Pulse of Electrical Current
61
Pulse of Electrical Current
62
Pulse of Electrical Current
63
Induction Loop with car bus cartridge and low
amperage fuse
64
Induction Loop with car bus cartridge and low
amperage fuse
65
Induction Loop with car bus cartridge and low
amperage fuse
66
Induction Loop with car bus cartridge and low
amperage fuse
67
Induction Loop with car bus cartridge and low
amperage fuse
68
Induction Loop with car bus cartridge and low
amperage fuse
Fuse burns out
69
Induction Loop with car bus cartridge and low
amperage fuse
Fuse burns out
70
(No Transcript)
71
Willow Oak
Black Oak
Morris Arboretum of the U of PA
72
Willow Oak
Black Oak
Fuses were recently checked the fuse on this
tree was burned out on the Willow Oak another
tree.
73
Significance of Fuse Systems

• Enables future LPS research
• Can be a convincing sales tool providing feedback
  to customers who have invested in LP System
• An incentive for customers with LPS protected
  trees to install more systems
• Encouragement for new and old clients to
  seriously consider installing LP Systems

74
Thank You!
75
Investigation of aLightning Struck Tree

• Witnessed by observers at Chanticleer display
  garden outside of Philadelphia
• Red Oak tree with a large diameter stem that
  required two separate lightning systems in
  accordance with the old standard in effect at the
  time.

76
Investigation of aLightning Struck Tree

• Critical observations
• Entry of lightning electrical current marked by
  a brightening of copper downlead and formation of
  a droplet of copper,
• English Ivy growing on the side of the tree
  turned brown adjacent to the downlead cable at
  the bottom of the trees trunk.
• The soil over the top of the copper ground rod
  was blown off exposing the rod.

77
Investigation of aLightning Struck Tree

• Critical observations
• This point of entry was well below the top of
  the tree and about 23 feet below the air terminal
  of the system.
• Note that the air terminal was formed by fraying
  the end of the conductor cable.

78
Investigation of aLightning Struck Tree

• Critical observations
• Standoffs used at base of trees and wire fence
  staples used in the upper crown
• Some staples were overgrown by bark
• Support cable was wrapped with lightning cable
  and joined to the two LPS down leads

79
Investigation of aLightning Struck Tree

• Critical observations
• Although there were two LP systems installed,
  once underground, the two systems were joined
  together leading a single ground rod

80
Investigation of aLightning Struck Tree

• Conclusion
• This lightning protection system did not meet
  the NAA standards in effect at that time on at
  least 6 different points, yet it performed
  perfectly.
• Until the new ANSI A300 standards became
  effective, LPS were over designed for their
  intended purpose.

81
Thank You!
82
Tree Lightning Protection DesignAbove Ground
83
Tree Lightning Protection Design
Main Conductor
84
Tree Lightning Protection Design
Main Conductor
Made from Copper, stainless steel, bronze, or
clad with one of these.
85
Branch Conductors
Acceptable rope lay, smooth-twist, or
loose-weave construction at least 14 strands of
17 AWG copper wire
86
Y- Cable Splicer
87
Tree Lightning Protection Design
Mini Conductor
Main Conductor
88
Tree Lightning Protection Design
Splicing Hardware
89
Tree Lightning Protection Design
90
Tree Lightning Protection Design
Air Terminals
91
Air Terminals
92
How Lightning Works
Stepped Leader
Ground Leader or Discharge
93
Tree Lightning Protection Design

• Branch conductors should be installed so that no
  aerial portion of the tree is farther than 35
  feet from a conductor
• Air Terminals shall be located on leaders, limbs
  and/or branches as far out as practical in the
  crown

94
Tree Lightning Protection Design
95
Bonding Lightning Protection Down-Lead to Support
Cable
A bimetallic or bronze clamp-type connector shall
be used
96
Tree Lightning Protection DesignBelow Ground
97
Tree Lightning Protection Design
Ground Terminal
98
Tree Lightning Protection Design

• Ground Rod
• Minimum of ½ inch 8 feet long
• Driven minimum depth of 9 feet

99
Tree Lightning Protection Design
100
Tree Lightning Protection Design
101
Tree Lightning Protection Design
102
Tree Lightning Protection Design
Multiple Ground System recommended for sandy or
gravely soils
103
Lightning Protection Vendors
Independent Protection Co., Inc PO Box
537 Goshen, IN 46527-0537 1-800-860-8388 www.ipclp
.com 
Thompson Lightning Protection 901 Sibley
Highway St. Paul, MN 55118-1792 651-455-7661 www.t
lpinc.com
104
Induction Loop with car bus cartridge and low
amperage fuse
105
Pulse of Electrical Current
106
(No Transcript)
107
(No Transcript)
108
(No Transcript)
109
(No Transcript)