2002 LIGHTNING PROTECTION for AIR FORCE FACILITIES TSgt

2002 LIGHTNING PROTECTION for AIR FORCE FACILITIES TSgt Gilbert Martinez Det 1 PACAF-CES

Summary Slide • INTRODUCTION • REGULATORY GUIDANCE • MATERIAL REQUIREMENTS • STRIKE TERMINATION DEVICES • CONDUCTORS • TYPES OF SYSTEMS • ZONE OF PROTECTION • BONDING • SIDEFLASH REQUIREMENTS • SURGE PROTECTION • GROUND SYSTEMS • INSPECTION AND TESTING • TEST PLANS AND RECORD KEEPING

INTRODUCTION The intent of this course is to familiarize and improve the skills of personnel involved in the installation and maintenance of lightning protection systems. We will discuss the design, installation, and maintenance of lightning protection systems for structures housing explosives in accordance with applicable standards.

REGULATORY GUIDANCE AFMAN 91 -201 – Implements AF policy and DOD 6055. 9 STD It applies to everyone involved in any explosive operation in the Air Force, and compliance is mandatory. Chapter 2, Section D deals with; Electrical Hazards; Hazardous locations (2. 46), Electrical Service (2. 48), Static (2. 51 & 2. 52), Grounds (2. 53), Lightning Protection (2. 54) DOD 6055. 9 STD – Defines minimum explosive safety criteria for the design, maintenance, testing and inspection of lightning protection systems.

REGULATORY GUIDANCE AFI 32 -1065 – Implements maintenance requirements of DOD 6055. 9 STD, chapter 7 “Lightning Protection” and assigns maintenance responsibilities and requirements for grounding, static, and lightning protection systems on Air Force installations. NFPA 780 – (1997 edition) Provides practical safeguarding for persons and property from hazards arising from exposure to lightning. Does not cover: explosive manufacturing buildings and magazines.

MATERIAL REQUIREMENTS § AFI 32 -1065 Requirements § NFPA 780 Requirements § Main Conductor Example

MATERIAL REQUIREMENTS AFI 32 -1065 Requirements 14. 1. General. Systems must comply with NFPA 780 and AFM 88 -9, Chapter 3, Electrical Design Lightning and Static Electricity Protection (except as modified herein). Early streamer emission systems or charge dissipation systems are not permitted. Parts and materials must carry the Underwriters Laboratories (UL) label or equivalent. Otherwise, such components must be approved by the MAJ-COM electrical engineer in charge of lightning protection. Facilities in foreign countries may use host nation codes and standards if they offer equivalent protection, as determined by the MAJCOM electrical engineer with concurrence from HQ AFCESA/CESE and approval of the Do. D Explosive Safety Board (DDESB). Otherwise, the Status of Forces Agreement (SOFA) must permit their use. Where the SOFA requires compliance with host nation codes, translate those required codes into English, make them available to all appropriate personnel, and perform necessary training. Maintain all installed systems according to this instruction. If not required, remove the system with coordination through the using agency.

MATERIAL REQUIREMENTS NFPA 780 Requirements Material Requirements, Class I Table 3. 1. 1 (a) NFPA 780 Buildings and Structures less than 75 feet in Height Material Requirements, Class II Table 3. 1. 1 (b) NFPA 780 Buildings and Structures greater than 75 feet in Height

MATERIAL REQUIREMENTS Main Conductor Example NO. 29 R Copper cable consisting of 29 strands of No. 16 AWG wire. This cable has a cross-sectional area of 72, 500 cm and a weight of 215 pounds per 1000 feet. The outside diameter is approximately 3/8".

STRIKE TERMINATION DEVICES § NFPA 780 Requirements § Air Terminal Height § Air Terminal Support § Chimneys and Vents

STRIKE TERMINATION DEVICES NFPA 780 Requirements 3. 6 Termination Devices shall meet material and size requirements in accordance with NFPA 780 Table 3. 1. 1 (a) & (b) Table 3. 1. 1(a) Minimum Class I Material Requirements Copper Aluminum Type of Conductor Standard Metric Standard Metric Air Terminal, Solid Diameter 3/8 in. 9. 5 mm 1/2 in. 12. 7 mm Air Terminal, Tubular Diameter 5/8 in. 15. 9 mm 5/8 in. 15. 9 mm Table 3. 1. 1(b) Minimum Class II Material Requirements Copper Aluminum Type of Conductor Standard Metric Standard Metric Air Terminal, Solid Diameter 1/2 in. 12. 7 mm 5/8 in. 15. 9 mm

STRIKE TERMINATION DEVICES 3. 6. 1 Air Terminal Height § The tip of an air terminal shall be not less than 10 in. above the object or area it is to protect • Air terminal exceeding 24 in. in height shall be supported at a point not less than one-half its height. § EXCEPTIONS Strike termination devices shall not be required for • Metal parts of a structure that are exposed to direct lightning flashes and that have a metal thickness of 3 /16 in. or greater shall only require connection to the lightning protection system. (minimum of two paths to ground) • Those parts of a structure located within a zone of protection.

STRIKE TERMINATION DEVICES 3. 6. 2 Air Terminal Support § Air terminals shall be secured against overturning by attachment to the object to be protected or by means of braces that shall be permanently and rigidly attached to the building.

STRIKE TERMINATION DEVICES 3. 8. 7 Chimneys and Vents § Strike termination devices shall be required on all chimneys and vents that are not located within a zone of protection § Chimneys or vents with a metal thickness of 3 /16 in. or more shall require only a connection to the lightning protection system, and shall be made using a main size lightning conductor and a bonding device having a surface contact area of not less than 3 in. square, and shall provide two or more paths to ground. § Where only one strike termination device is required on a chimney or vent, at least one main sized conductor shall connect the strike termination device to a main conductor at the location where the chimney or vent meets the roof surface and provides two or more paths to ground from that location

CONDUCTORS § § § One Way Path Dead Ends Substitution of Metals “U” or “V” Pockets Conductor Bends § Protection and Securing § § Location and Spacing § Connector Fittings Structural Steel as Down Conductors

CONDUCTORS 3. 9. 1 One Way Path § Strike termination devices on a lower roof level that are interconnected by a conductor run from a higher roof level shall only require one horizontal or down-ward path to ground provided the lower level roof conductor run does not exceed 40 ft.

CONDUCTORS 3. 9. 2 Dead Ends § Strike termination devices shall be Dead permitted to be “dead ended” with only one path to a main conductor on Ends roofs below the main protected level provided the conductor run from the strike termination device to a main A conductor is not more than 16 ft in total length and maintains a horizontal or downward coursing. A – Permissible total conductor length not over 16 ft

CONDUCTORS 3. 9. 3 Substitution of Metals § Metal parts of a structure, such as eave troughs, down spouts, ladders, chutes, or other metal parts, shall not be substituted for the main lightning conductor. Like-wise, metal roofing or siding having a thickness of less than 3 /16 in. (4. 8 mm) shall not be substituted for main lightning conductors. A – Permissible total conductor length not over 16 ft

CONDUCTORS 3. 9. 4 “ U” or “ V” Pockets § Conductors shall maintain a horizontal or downward coursing free from “U” or “V” (down and up) pockets. Such pockets, often formed at low-positioned chimneys, dormers, or other projections. § A down conductor shall be provided from the base of the pocket to ground or to an adjacent down-lead run conductors, and so on. “U” or “V” Pockets Incorrect Correct

CONDUCTORS 3. 9. 5 Conductor Bends § Down conductors must not have sharp bends or loops. Radius of Bend R Not less than 8 in. § All bends must have a radius of 8 inches or greater and measure not less than 90 degrees from the inside of the bend. 90 Degrees min.

CONDUCTORS 3. 9. 6 Conductor Supports 3. 9. 11 Protecting Down Conductors Conductor Supports § Support or secure at intervals not to exceed 3 ft. Protecting Down Conductors § Any down conductors subject to mechanical damage must be protected with a protective molding or covering for a minimum of 6 ft above grade. • If protective covering is metallic tube/pipe the conductor must be bonded to both ends of the tube/pipe.

CONDUCTORS 3. 9. 7 Roof Conductors § All main conductors will maintain a downward and horizontal direction, never rising more than ¼ pitch. 3. 9. 8 Cross Run Conductors § Required on flat and gently sloping roofs that exceed 50 ft in width. § Shall be connected to main perimeter cable at intervals not exceeding 150 ft.

CONDUCTORS 3. 9. 10 Number of Down Conductors § Pitched Roof Structures Less than 250 feet in Perimeter • Minimum of two down conductors on opposite corners, preferably all four corners § Pitched Roof Structures More than 250 feet in Perimeter • One down conductor for every 100 feet, or fraction of . § Irregular- Shaped structures • May require additional down conductors to provide two paths to ground for each air terminal § Flat or Gently Sloping Roofs • Average distance between down conductors will be no greater than 100 ft

CONDUCTORS 3. 9. 13 Down Conductors and Structural Columns Structural steel shall be permitted to be utilized as the main conductor of a LPS, IF it is electrically continuous, or it is made so § Air terminals Shall be connected to the structural steel by direct connection, by use of individual connectors through the roof or walls to the frame work or by use of an exterior conductor that interconnects all air terminals, “AND” • Is connected to the steel frame work at intervals not greater than 100 feet § Ground terminals shall be connected approximately every other steel column at intervals not to exceed 60 feet

CONDUCTORS 3. 12 Connector Fittings Connector fittings shall be used at all “ end-to-end, ” “ tee, ” or “ Y” splices of lightning conductors. § They shall be attached so as to withstand a pull test of 200 lb §Conductor connections shall be of the bolted, welded, high compression, or crimp -type. Crimp-type connections shall not be used with Class II conductors.

CONDUCTORS 3. 12 Connector Fittings § Fittings used for required connections to metal bodies in or on a structure shall be secured to the metal body by bolting, brazing, welding, or using highcompression connectors listed for the purpose. §Do not paint Down Conductor connectors unless they are the high compression or exothermic (or welded) type.

TYPES OF SYSTEMS • MAST SYSTEM • CATENARY SYSTEM • INTEGRAL SYSTEM

TYPES OF SYSTEMS K. 3. 1 Mast-Type Systems Mast-type systems should be designed as specified in 6. 3. 3. 2 § Each non-metallic pole must have two down conductors and an air terminal extending at least 2 ft above the top of the pole, securely attached to the pole, and connected to the grounding system § Metal masts do not require air terminals and down conductors, but must have two connections to the grounding system. § Separate each mast from any part of the facility by at least the bonding distance or side flash distance specified in Chapter 3 & 6 of NFPA 780, but not less than 6 feet.

TYPES OF SYSTEMS K. 3. 2 Overhead Wire (Catenary) Systems § Each non-metallic pole must have two down conductors § Each wire must be a continuous run of at least AWG No. 6 copper, or equivalent. § Separate each mast from any part of the facility by at least the bonding distance or side flash distance specified in Chapter 3 & 6 of NFPA 780, but not less than 6 ft Catenary systems should be designed as specified in 6. 3. 3. 2

TYPES OF SYSTEMS K. 3. 2 Overhead Wire (Catenary) Systems § Shall have an air terminal extending at least 2 ft above the top of the pole, securely attached to the pole, and connected to the grounding system. § Alternate grounding method The pole guy wire shall be permitted to be used as the down conductor.

TYPES OF SYSTEMS K. 3. 3 Integral Systems An integral lightning protection system is a system that utilizes air terminals mounted directly on the structure to be protected. These types of air termination systems are as described in Chapter 3. Air terminal spacing should be modified as necessary to provide a zone of protection defined by a 100 -ft (33 -m) striking distance. Where an integral lightning protection system is used to protect the structures covered by this appendix, it is critical that the bonding requirements of Chapter 3 be met. It is also critical that a rigorous maintenance schedule be maintained for this type of system

TYPES OF SYSTEMS K. 3. 3 Integral Systems § Pitched roofs shall be defined as roofs having a span of 40 ft or less and a pitch 1 /8 or greater; and roofs having a span of more than 40 ft and a pitch 1 /4 or greater. All other roofs shall be considered flat or gently sloping. § A pitched roof with eaves height of 50 ft or less above grade shall require protection for the ridge only when there is no horizontal portion of the building that extends beyond the eaves, other than a gutter.

TYPES OF SYSTEMS K. 3. 3 Integral Systems § Each air terminal must have at least two paths to ground. § Air terminals shall be located within 24 inches of roof edge § Each building must A - 50 ft maximum spacing between air have a minimum of two terminals down conductors, one B – 150 ft maximum length of cross run each at opposite conductor permitted without a connection to corners (one each on the main perimeter or down conductor all corners is preferred). C – 20 -25 ft maximum spacing between air terminals along edge

ZONE OF PROTECTION NFPA 780 2. 1. 39 The space adjacent to a lightning protection system that is substantially immune to direct lightning flashes. AFI-32 -1065 also states that is necessary to provide a zone of protection defined by a 100 -ft (33 -m) striking distance.

ZONE OF PROTECTION § § § 100 Foot Rolling Ball Theory Proper Air Terminal Placement Proper Air Terminal Spacing § Structures that do not exceed 25 ft above earth § Structures that do not exceed 50 ft above earth § Mast Systems Formula § § § Student Exercises Catenary Systems Formula § § Example Question Student Exercises Integral Systems Formula § Student Exercises

ZONE OF PROTECTION 3. 7. 3 100 Foot Rolling Ball Theory 100 ft Radius The zone of protection shall include the space not intruded by a rolling sphere having a radius of 100 ft. When the sphere is tangent to earth and resting against a strike termination device, all space in the vertical plane between the two points of contact and under the sphere are in the zone of protection.

ZONE OF PROTECTION 3. 8 Proper Air Terminal Placement INCORRECT Improper spacing from edge of roof Proper spacing from edge of roof Air terminal 4’ from edge Air terminal no more than 2’ from edge The zone of protection shall include the space not intruded by a rolling sphere having a radius of 100 ft. When the sphere is tangent to earth and resting against a strike termination device, all space in the vertical plane between the two points of contact and under the sphere are in the zone of protection.

ZONE OF PROTECTION 3. 8 Proper Air Terminal Spacing Proper spacing between air terminals Improper spacing between air terminals Air terminals 2’ long and Spaced 20 -25’ along edge and 50’ maximum spacing A zone of protection is also formed when such a sphere is resting on two or more strike termination devices and shall include the space in the vertical plane under the sphere and between those devices.

ZONE OF PROTECTION 3. 7. 2. 1 Structures that do not exceed 25 ft above earth § Considered to protect lower portions of a structure located in a one-to-two zone of protection as shown below. §The zone of protection shall form a cone having an apex at the highest point of the strike termination device, with walls forming approximately a 22. 5 degree angle from the vertical. 2 1 25 ft

ZONE OF PROTECTION 3. 7. 2. 2 Structures that do not exceed 50 ft above earth §Considered to protect lower portions of a structure located in a one-to-one zone of protection as shown below § The zone of protection shall form a cone having an apex at the highest point of the strike termination device, with walls forming approximately a 45 -degree angle from the vertical. 1 1 50 ft

ZONE OF PROTECTION 6. 3 Mast Systems Formula Based on mast height and 100 ft Ball Theory Center for_____ height 25 50 75 100 100 D= h 1 (200 -h 1) - h 2 (200 -h 2) D = horizontal distance (ft) H 1 = height of the pole mast (ft) H 2 = height of structure (ft) Height protected (ft) 75 100 50 75 25 50 25 50 75 100 Horizontal distance (ft)

ZONE OF PROTECTION Mast Systems Example Question Mast Height VS Building Size D= h 1 (200 -h 1) - h 2 (200 -h 2) D = horizontal distance (ft) H 1 = height of the pole mast (ft) 100 ft Radius H 2 = height of structure (ft) 80 Foot Mast 60 ft long and 26 ft high building

ZONE OF PROTECTION Mast Systems Example Question Answer D = horizontal distance (ft) D = h 1 (200 -h 1) - h 2 (200 -h 2) H 1 = height of the pole mast (ft) 80 x (200 -80) - 26 x (200 -26) H 2 = height of structure (ft) 80 x 120 - 26 x 174 9, 600 - 4, 524 97. 97 - 67. 26 = 30. 71 60 / 2 = 30 Mast Height 80 Feet Building Size 60 Ft Long 26 Ft High Building is in the Zone of Protection?

ZONE OF PROTECTION Mast Systems Student Exercise 1 D= h 1 (200 -h 1) - h 2 (200 -h 2) D = horizontal distance (ft) H 1 = height of the pole mast (ft) H 2 = height of structure (ft) Mast Height Building Size 85 feet 60 Ft Long 28 Ft High Is the building in the Zone of Protection?

ZONE OF PROTECTION Mast Systems Student Exercise Answer 1 D = horizontal distance (ft) D = h 1 (200 -h 1) - h 2 (200 -h 2) H 1 = height of the pole mast (ft) 85 x (200 -85) - 28 x (200 -28) H 2 = height of structure (ft) 85 x 115 - 28 x 172 9, 775 - 4, 816 98. 86 - 69. 39 = 29. 47 ft 60 / 2 = 30 ft Mast Height 85 Feet Building Size 60 Ft Long 28 Ft High Building is not in the Zone of Protection?

ZONE OF PROTECTION Mast Systems Student Exercise 2 D= h 1 (200 -h 1) - h 2 (200 -h 2) D = horizontal distance (ft) H 1 = height of the pole mast (ft) H 2 = height of structure (ft) Mast Height Building Size 90 feet 40 Ft Long 38 Ft High Is the building in the Zone of Protection?

ZONE OF PROTECTION Mast Systems Student Exercise Answer 2 D = horizontal distance (ft) D = h 1 (200 -h 1) - h 2 (200 -h 2) H 1 = height of the pole mast (ft) 90 x (200 -90) - 38 x (200 -38) H 2 = height of structure (ft) 90 x 110 - 38 x 162 9, 900 - 6, 156 99. 49 - 78. 46 = 21. 03 ft 40 / 2 = 20 ft Mast Height 90 Feet Building Size 40 Ft Long 38 Ft High Building is in the Zone of Protection?

ZONE OF PROTECTION 6. 3 Catenary Systems Formula D= h 1 (200 -h 1) h 2 (200 -h 2) D = horizontal distance (ft) H 1 = height of the mast H 2 = height of the lower mast (object concerned) (ft)

ZONE OF PROTECTION Catenary Systems Student Exercise 3 D= h 1 (200 -h 1) - h 2 (200 -h 2) D = horizontal distance (ft) H 1 = height of the higher mast H 2 = height of the lower mast (object concerned) (ft) H 1 = 100 ft 15 ft 50 ft H 2 = 50 ft Is the object in the Zone of Protection?

ZONE OF PROTECTION Catenary Systems Student Exercise Answer 3 D = h 1 (200 -h 1) - h 2 (200 -h 2) D = horizontal distance (ft) 100 x (200 -100) - 50 x (200 -50) H 1 = height of the higher mast 100 x 100 - 50 x 150 H 2 = height of the lower mast (object concerned) (ft) 10, 000 - 7, 500 100 - 86. 60 = 13. 4 ft H 1 = 100 ft H 2 = 50 ft Object is not in the Zone of protection? 15 ft 50 ft

ZONE OF PROTECTION Catenary Systems Student Exercise 4 D= h 1 (200 -h 1) - h 2 (200 -h 2) D = horizontal distance (ft) H 1 = height of the higher mast H 2 = height of the lower mast (object concerned) (ft) H 1 = 90 ft 12 ft 30 ft H 2 = 30 ft Is the object in the Zone of Protection?

ZONE OF PROTECTION Catenary Systems Student Exercise Answer 4 D = h 1 (200 -h 1) - h 2 (200 -h 2) D = horizontal distance (ft) 90 x (200 -90) - 30 x (200 -30) H 1 = height of the higher mast 90 x 110 - 30 x 170 H 2 = height of the lower mast (object concerned) (ft) 9, 900 - 5, 100 99. 49 - 71. 41 = 28. 08 ft H 1 = 90 ft H 2 = 30 ft Object is in the Zone of protection? 12 ft 30 ft

ZONE OF PROTECTION Integral Systems Formula D= h 1 (200 -h 1) - h 2 (200 -h 2) D = Horizontal distance H 1 = height of the higher roof (ft) H 2 = height of the lower roof (ft) 100 ft Radius

ZONE OF PROTECTION Integral Systems Student Exercise 5 D= h 1 (200 -h 1) - h 2 (200 -h 2) D = Horizontal distance H 1 = height of the higher roof H 2 = height of the lower roof (ft) 30 ft 85 ft 30 ft Is the lower roof of the building in the Zone of Protection?

ZONE OF PROTECTION Integral Systems Student Exercise Answer 5 h 2 (200 -h 2) D = Horizontal distance - 30 (200 -30) 85 x (115) - 30 x 170 H 1 = height of the higher roof 9, 775 - 5, 100 - 71. 41 = 27. 45 D= h 1 (200 -h 1) D = 85 (200 -85) 98. 86 - 30 ft H 2 = height of the lower roof (ft) 85 ft 30 ft Building is not in the Zone of Protection?

ZONE OF PROTECTION Integral Systems Student Exercise 6 D= h 1 (200 -h 1) - h 2 (200 -h 2) D = Horizontal distance H 1 = height of the higher roof H 2 = height of the lower roof (ft) 20 ft 60 ft 25 ft Is the lower roof of the building in the Zone of Protection?

ZONE OF PROTECTION Integral Systems Student Exercise Answer 6 h 2 (200 -h 2) D = Horizontal distance - 25 (200 -25) 60 x (140) - 25 x 175 H 1 = height of the higher roof 8, 400 - 4, 375 - 66. 14 = 25. 51 D= h 1 (200 -h 1) D = 60 (200 -60) 91. 65 - 20 ft H 2 = height of the lower roof (ft) 60 ft 25 ft Building is in the Zone of Protection?

BONDING • • • Bonding Defined Material Requirements Bonding Requirements Determining the Necessity of Bonding Conditions Condition 1 A Condition 1 B Condition 1 C Condition 2 • • The Basic Bonding Formula (BBF) Condition 2 A and 2 B (1) Condition 2 A Condition 2 B (2) Condition 3 Example Bonding of movable objects Fences and Railroad Tracks

BONDING Bonding Defined § Bonding is the electrical connection between an electrically conductive object and a component of a lightning protection system that is intended to significantly reduce the potential differences created by lightning currents. § The rational behind this is to prevent side flash (arcing) between metal objects that could create a fire hazard. § Basic requirements for bonding are found in AFI 32 -1065 Attachment 3 & NFPA 780, 3. 21

BONDING Material Requirements § Bonding Conductors shall meet material and size requirements in accordance with NFPA 780 Table 3. 1. 1 a & b Table 3 -1. 1(a) Minimum Class I Material Requirements Copper Type of Conductor Standard Bonding Conductor Cable, solid or stranded Min size ea strand 17 AWG Cross sect. Area 26, 240 CM Bonding Conductor, solid strip Min. size/Thickness width . 051 in / ½ in Table 3 -1. 1(b) Minimum Class II Material Requirements Copper Type of Conductor Standard Bonding Conductor Cable, solid or stranded Min size ea strand 17 AWG Cross sect. Area 26, 240 CM Bonding Conductor, solid strip Min. size/Thickness width . 051 in / ½ in

BONDING Bonding Requirements § All conductors (piping, phone lines, power cables and etc) buried underground for a minimum distance of 50 feet prior to entering the building. § Earth covered igloos- all metal objects, within side flash distance bonded to the LPS. § Grounded metal objects within side flash distance of a down conductor Bonded to the down conductor. § Isolated (Ungrounded) metal bodies located close to a lightning conductor and to a grounded metal body bonded is bonded when within side flash distance.

BONDING Bonding Requirements § Static ground systems located on interior walls opposite a down conductor. (Recommend moving static system) § Metal objects located outside the facility, within side flash distance of a conductor, bonded to the conductor. § All conductors NOT entering the facility, within side flash distance shall be bonded to the LPS (fences, railroad tracks, above ground piping) § All connections must be strong enough to withstand a pull test of 200 pounds. § Steam, water and air conditioning lines may be run on the ground if bonded to the facilities LPS before entering the structure.

BONDING Determining the Necessity of Bonding requirements depend on: § The number of down conductors and their location § The interconnection of other grounded systems § Proximity of Grounded metal bodies to the down conductors § The flashover medium: (either AIR or SOLID MATERIALS)

BONDING Bonding Conditions Three different conditions or situations dictate the requirements for bonding within a structure CONDITION 1 – Long Vertical Metal Bodies CONDITION 2 – Grounded Metal Bodies CONDITION 3 – Isolated Metal Bodies

BONDING Condition 1 A 3. 21. 1 Long Vertical Metal Bodies GREATER than 60 feet in height A. Steel Framed Structures § Grounded and ungrounded metal bodies shall be bonded to structural steel members as near to their extremities as possible unless inherently bonded through construction “at these locations” § To conductors “when” within side flash distance

BONDING Condition 1 B 3. 21. 1 Long Vertical Metal Bodies GREATER than 60 feet in height B. Reinforced Concrete Structures: where the rebar is interconnected, and grounded IAW NFPA 780, Section 3. 15. 3 § Grounded and ungrounded metal bodies shall be bonded to the LPS as near as practical to their extremities, unless inherently bonded through construction at these locations

BONDING Condition 1 C 3. 21. 1 Long Vertical Metal Bodies GREATER than 60 feet in height C. Other Structures: (Composite) § Bonding of grounded and ungrounded long vertical metal bodies shall be determined by NFPA 780, Sections 3. 21. 2 and 3. 21. 3

BONDING Condition 2 3. 21. 2 Grounded Metal Bodies Grounded metal bodies shall be bonded to the LPS when the body is located within the distance “D” as determined by the Basic Bonding Formula (BBF) The “BBF” for grounded metal bodies will be used when: § Grounded metal bodies are connected to the LPS at “only one” extremity and: § Branches of grounded metal bodies connected to the LPS at their extremities if they change vertical direction more than 12 feet

BONDING The Basic Bonding Formula (BBF) D = h/6 n x Km D = Minimum side flash distance between a grounded body and a conductor at which a bond becomes necessary h = Height of the building, or the vertical distance from the bond being considered, to the nearest LPS bond n = number of down conductors Km = 1 if the flashover is through air, or 0. 50 if through dense material (concrete, brick, wood)

BONDING The Basic Bonding Formula (BBF) D = h/6 n x Km Grounded object (water pipe, panel, etc…)

BONDING Condition 2 A and 2 B (1) Condition 2 A – Structures 40 feet and less in height Condition 2 B (1) – Structures over 40 feet – bonding required within 60 ft of the top of the structure D = h/6 n x Km h = Height of the building, or the greatest vertical distance between the bond being considered and the nearest other lightning Protection system bond, (or to ground if no other bond is present) n = number of down conductors spaced more than 25 feet apart and located within 100 feet of the bond in question: n = 1 (if only 1 down conductor); n = 1. 5 (if only 2 down conductors); n = 2. 25 (if 3 or more down conductors) Km = 1 if the flashover is through air, or 0. 50 if through dense material (concrete, brick, wood)

BONDING Condition 2 A Structures 40 feet and less in height h = Height of the building, or the D = h/6 n x Km greatest vertical distance between 40/6 x 1. 5(N) x 1(Km) the bond being considered and the = 9. 99 ft nearest other lightning Protection system bond, (or to ground if no Down conductors 30 ‘ other bond is present) currently 3’ away n = number of down conductors from grounded spaced more than 25 feet apart and metal body located within 100 feet of the bond in question: n = 1 (if only 1 down conductor); n 40 ‘ = 1. 5 (if only 2 down conductors); n = 2. 25 (if 3 or more down conductors) Km = 1 if the flashover is through air, or 0. 50 if through dense material (concrete, brick, wood) Must down conductors be bonded?

BONDING Condition 2 B (2) Structures over 40 feet – bonding required below 60 ft from the top of the structure D = h/6 n x Km h = The vertical distance between the bond being considered and the nearest LPS bond, (or ground if no other bond is present) n = The TOTAL number of down conductors in the LPS Km = 1 if the flashover is through air, or 0. 50 if through dense material (concrete, brick, wood)

BONDING Condition 2 B (1) and 2 B (2) Example Condition 2 B (1) – Structures over 40 feet – bonding required within 60 ft of the top of the structure Condition 2 B (2) – Structures over 40 feet – bonding required below 60 ft from the top of the structure D = h/6 n x Km Condition 2 B (1) D = 100/6 (1. 5) x 1 60 ft = 25 ft 100 ft 40 ft 30 ft Condition 2 B (2) D = 30/6 (3) x 1 = 15 ft

BONDING Condition 3 Example 3. 21. 3 Isolated (non-grounded) Metallic Bodies Down Conductor If a + b < Calculated bonding distance, then bond A to B directly A D = h/6 n x Km 40/6 x 1. 5(N) x 1 = 9. 99 ft If a + b > Calculated bonding distance, bonds not required a 2 ft Window Frame b 4 ft Grounded object B

BONDING Bonding of movable objects § Bond Connections MUST BE of the flexible conductor or strap type § When conductors are mechanically protected or concealed conductors may be No. 10 AWG copper Otherwise NO. 6 AWG copper wire or larger § At least two separate flexible bonding straps will be provided § Bonding Resistance – Maximum – 1 Ohm § Replace Braided bonding wires excessively frayed – 1/2

BONDING Fences and Railroad Tracks Fences: § Bond across gates and other discontinuities § Shall be bonded to the Lightning Protection System (LPS) ground loop conductor if they cross or come within 6 feet of the structure’s LPS Railroad Tracks: § All tracks within 6 feet of the LPS or sideflash distance § Tracks that enter a facility shall be bonded to the frame of the structure or equivalent

SIDEFLASH REQUIREMENTS § Mast Systems Student Exercise § Catenary Wire to Structure Student Exercise

SIDEFLASH REQUIREMENTS 6. 3. 3. 3 Mast Systems Sideflash distances – Mast to Structure D = h/6 h = height of structure or the object under consideration

SIDEFLASH REQUIREMENTS 6. 3. 3. 3 Mast Systems Student Exercise 7 Sideflash distances – Mast to Structure D = h/6 h = height of structure or the object under consideration 30 ft

SIDEFLASH REQUIREMENTS 6. 3. 3. 3 Catenary Wire to Structure D = L/6 n L = length of lightning protection conductor between its grounded point and the point under consideration (closest to roof) n = 1 where there is a single overhead conductor that exceeds 200 ft in horizontal length n = 1. 5 where there is a single overhead wire or more than one wire interconnected above the structure to be protected, such that only two down conductors are located greater than 20 ft and less then 100 ft apart n = 2. 25 where there are more than two down conductors spaced more than 25 ft apart within a 100 -ft wide area that are interconnected above the structure being protected

SIDEFLASH REQUIREMENTS 6. 3. 3. 3 Catenary wire to Structure Student Exercise 8 D = L/6 n 95 ft L = length of lightning protection conductor between its grounded point and the point under consideration (closest to roof) n = 1 where there is a single overhead conductor that exceeds 200 ft in horizontal length 185 ft 6 ft n = 1. 5 where there is a single overhead wire or more than one wire interconnected above the structure to be protected, such that only two down conductors are located greater than 20 ft and less then 100 ft apart n = 2. 25 where there are more than two down conductors spaced more than 25 ft apart within a 100 -ft wide area that are interconnected above the structure being protected Does building meet sideflash requirements?

SIDEFLASH REQUIREMENTS 6. 3. 3. 3 Catenary wire to Structure Student Exercise Answer 8 D = L/6 n 185/ 6 x 1. 5 185/ 90 = 2. 05 ft L = length of lightning protection conductor between its grounded point and the point under consideration (closest to roof) 95 ft n = 1 where there is a single overhead conductor that exceeds 200 ft in horizontal length 185 ft 6 ft n = 1. 5 where there is a single overhead wire or more than one wire interconnected above the structure to be protected, such that only two down conductors are located greater than 20 ft and less then 100 ft apart n = 2. 25 where there are more than two down conductors spaced more than 25 ft apart within a 100 -ft wide area that are interconnected above the structure being protected Building meets sideflash requirements?

SURGE PROTECTION Lightning protection systems that protects structures that HOUSE EXPLOSIVES shall include surge protection for all incoming and exiting lines to include: § Overhead or underground power lines § Communication systems (instrumentation & intrusion detection) § Television or radio antennas not necessarily restricted to associated wiring systems and appliances Therefore, such systems should be equipped with appropriate protective devices, bonded to ensure a common potential, and must enter the facility in shielded cables, or metallic conduits buried underground for a minimum of 50 feet prior to entering the structure.

GROUND SYSTEMS • Ground Terminals • Ground Rod Terminations • Ground Rod Depth • Concrete Encased Electrodes • Concrete Encased Electrode Terminations • Ground Ring Electrode Terminations • Shallow Topsoil • Sandy Soil Conditions • Combinations • Common Grounding

GROUND SYSTEMS 3. 13 Ground Terminals Each down conductor shall terminate at a ground terminal dedicated to the lightning protection system. The design, size, depth, and number of ground terminals used shall comply with 3. 1 through 3. 13. 4 and AFI 32 -1065. § Electrical system and telecommunication grounding electrodes shall not be used in lieu of lightning ground electrodes. § The down conductor(s) shall be attached permanently to the grounding electrode system by bolting, brazing, welding, or high-compression connectors listed for the purpose, and clamps shall be suitable for direct burial.

GROUND SYSTEMS 3. 13 Ground Terminals § Ground terminals shall be copper-clad steel, solid copper, hot-dipped galvanized steel, or stainless steel. Stainless steel ground rods are prohibited by AFI 32 -1065 A 2. 2. 1 § Ground electrodes shall be installed below the frost line where possible (excluding shallow topsoil conditions). § Ground rods must be at least 10 feet long, made of not less than 0. 75 inch diameter pipe or equivalent solid rod made of copper or copper clad steel.

GROUND SYSTEMS Ground Rod Terminations Attached to the ground rod by: § Bolting (Clamps shall be suitable for direct soil burial) § Exothermic Welding § High-compression connectors listed for the purpose

GROUND SYSTEMS 3. 1 Ground Rods Ground rods shall be not less than 1 /2 in. (12. 7 mm) in diameter and 8 ft (2. 4 m) long. Rods shall be free of paint or other nonconductive coatings. AFI 32 -1065 Ground rods must be at least 10 feet long, made of not less than 0. 75 inch diameter pipe or equivalent solid rod made of copper or copper clad steel.

GROUND SYSTEMS 3. 1. 1 Ground Rod Depth § 1 foot below grade 1 ft § Not less than 10 feet deep 3 ft § 3 ft from building walls § Spaced no closer than 10 feet § Maximum of 25 ohms of earth resistance 10 ft

GROUND SYSTEMS 3. 13. 2 Concrete-Encased Electrodes § § Shall only be used in new construction. The electrode shall be located near the bottom of a concrete foundation or footing that is in direct contact with the earth and shall be encased by not less than 2 in. of concrete. Encased electrode shall consist of; A. Not less than 20 ft of bare copper main size conductor OR B. An electrode consisting of at least 20 ft of one or more steel reinforcing bars or rods not less than 1 /2 in. diameter that have been effectively bonded together by either welding or overlapping 20 diameters and securely wire-tying.

GROUND SYSTEMS Concrete Encased Electrode Terminations Shall be permanently attached to the encased system by; § Bolting connectors listed for the purpose § Exothermic Welding § High-compression connectors listed for the purpose

GROUND SYSTEMS 3. 13. 3 Ground Ring Electrode A ground ring electrode encircling a structure shall be NFPA 780 and as shown in Figure 3. 13. 3, in direct contact with earth AFI 32 -1065 at a depth of not less than 18 in. (457 mm) or Attachment 2. 2. 1. 4 and 4 encased in a concrete footing in accordance with 3. 13. 2. The encased electrode shall consist of not less than 20 continuous ft (6. 1 m) of bare copper main-size conductor. The ground ring electrode shall be not smaller than the equivalent of a main-size lightning conductor. AFI 32 -1065 specifies AWG 1/0 copper

GROUND SYSTEMS Ground Ring Electrode Terminations Down conductors shall be permanently attached to the ground ring by; § Exothermic Welding § High-Compression fittings § Bolting § Brazing Connections shall be Suitable for direct burial

GROUND SYSTEMS 3. 13. 7. 1 Shallow Topsoil Where bedrock is near the surface, the conductor shall be laid in trenches extending away from the building at each down conductor not less than 12 ft in length. § Clay Soil – Buried 1 - 2 ft in depth § Sandy or Gravelly Soil – Buried 2 ft in depth. If these methods prove impractical or impossible, bury directly on bedrock a minimum distance of 2 ft from the foundation or exterior footing. The cable shall terminate by attachment to a buried copper ground plate at least 0. 032 in. thick and having a minimum surface area of 2 ft square

GROUND SYSTEMS 3. 13. 7. 2 Sandy Soil Conditions § Two or more ground rods, at not less than 10 -ft spacings § 1 foot below grade § Not less than 10 feet deep 3 ft 12 inches 10 ft § 3 ft from building walls § Maximum of 25 ohms of earth resistance 10 ft

GROUND SYSTEMS 3. 13. 7. 2 Sandy Soil Conditions Alternate Configurations 3 ft 10 ft

GROUND SYSTEMS 3. 13. 6 Combinations of the grounding terminals in Section 3. 13 shall be permitted. Common Grounding All grounding media in, or on, a structure shall be interconnected to provide a common ground potential and bonding as per NFPA 780 and AFI 32 -1065

INSPECTION AND TESTING § SCHEDULED MAINTENANCE § VISUAL INSPECTIONS § TESTING REQUIREMENTS § TESTS PERFORMED § GROUND RESISTANCE TEST § CONTINUITY TEST

INSPECTION AND TESTING Scheduled Maintenance for Grounding Systems must be done in accordance with AFI 32 -1065 Table 1 Reference AFMAN 91 -201 Lightning Protection (Base Civil Engineer Responsibilities) Visual Inspections 12 months Ground Resistance Check 24 months Continuity Checks 24 months

INSPECTION AND TESTING Visual Inspections Must be accomplished in accordance with AFI 32 -1065 Visual/physical inspection must determine if: § The system is in good repair. No loose connections that might cause high resistance joints. § Corrosion or vibration has weakened any part of the system. § Braided bonding wires are excessively frayed (cross sectional area reduced by half). § Ground wires on lightning protection masts are damaged by lawn mowers or other equipment. § Conductors and system components are securely fastened. Down conductors, roof conductors, and ground terminals are intact. § Additions or alterations to the protected structure require additional protection.

INSPECTION AND TESTING Testing Requirements AFI-32 -1065 Attachment 6 for resistance and continuity test requirements for typical systems. § Instruments must be able to measure 10 ohms +/- 10 percent for ground resistance tests, and 1 ohm +/- 10 percent for continuity testing. § Only instruments designed specifically for earth-ground systems are acceptable for ground resistance testing. § MAJCOM electrical engineer may modify the test procedures due to local conditions, as long as the intent of the test is still achieved.

INSPECTION AND TESTING Tests Performed Grounding System Resistance Test (Earth Ohms Test) § Use the procedure described in AFI 32 -1065 or the procedure recommended by the test instrument manufacturer except as modified by AFI 32 -1065. § Periodic tests should be made at approximately the same time each year to minimize confusion resulting from seasonal changes. Continuity Tests § If the resistance measured during continuity tests is greater than 1 ohm, check for deficiencies and repair, then retest. § When per-forming a continuity test over very long lengths of conductors (more than 20 m with no parallel paths), readings above one ohm but less than 3 ohms may occur. This is acceptable.

INSPECTION AND TESTING Ground Resistance Test Fall of Potential Method Potential Distances X and Y Must Be Greater Than D/2 But Not Less Than 25 ft Y Probe Current X Probe Ground Rod Service Entrance D Ground Loop Conductor

INSPECTION AND TESTING Ground Resistance Test Fall of Potential Method Distances X and Y Must Be Greater Than D/2 But Not Less Than 25 ft Ground Rod Potential Current Probe Y X Service Entrance D X 1 2 Ground Loop Conductor

INSPECTION AND TESTING Ground Resistance Test Fall of Potential Method Distances X and Y Must Be Greater Than D/2 But Not Less Than 25 ft Ground Rod Potential Current Probe Y X Service Entrance D C 1 P 2 C 2 Ground Loop Conductor

INSPECTION AND TESTING Continuity Test Ground Rod OHM Meter 1 4 Service Entrance 2 Top of building 3 Ground Loop Conductor

INSPECTION AND TESTING Continuity Test Ground Rod 1 OHM Meter 4 Service Entrance 2 Top of building 3 Ground Loop Conductor

INSPECTION AND TESTING Continuity Test Static Buss Bars Ground Rod X Service X X Inside Building X Connect one lead to the Ground rod and the Other lead to the Static Buss bars at all free ends OHM Meter Entrance Ground Loop Conductor

TEST PLANS AND RECORD KEEPING • Test Plan Requirements • Test Plan Sample Sketch • Record Keeping Requirements • Common Deficiencies

TEST PLANS Requirements § Developed by Organization performing inspections & tests § Must include sketch of grounding and LPS test points § Date action performed § Name of person(s) performing tests § General condition of components

TEST PLANS Requirements Continued § Condition of corrosion protection measures § Resistance measurements at various Parts of ground terminal system § Discrepancies noted and corrective Actions taken with dates of repairs § Review Process

TEST PLANS Sample Sketch Include a facility drawing containing § Building & area configuration § Location of LPS components § Test Point identification

TEST PLANS Sample Sketch BLDG. 10655 A Current as of: 27 Mar 01 N 4 3 5 7 6 8 16 9 15 17 2 10 18 19 Service 1 B 14 13 12 11 OUTSIDE INSPECTION POINTS Entrance

RECORD KEEPING Requirements § Use of locally generated form recommended § Keep record for 6 inspection cycles for explosive facilities § Records kept by organization performing tests and inspections § Copy of test results given to user

RECORD KEEPING Common Deficiencies § Several paths to ground exceed allowed rate of rise § Air terminals with loose connections § Air terminals over 24 inches from edge of roof § Air terminals taller than 24 inches without required supports § Down conductor not attached to cross run conductors § Dissimilar metals to join system components § Improper conductor radius of bend § User did not have copies of test results