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Air Force Reserve CommandI n t e g r i t y - S e r v i c e - E x c e l l e n c e

Air Force Reserve Command

Lightning Protection Systems (LPS)Lightning Protection Systems (LPS) and You

MSgt Mike Sherman301 FW/SEW

1

Lightning Protection

The U.S. Has 20 Million Cloud-To-Ground Lightning Flashes Each Year

Th U S H Ab t 100 000 Th d t P Y ! The U.S. Has About 100,000 Thunderstorms Per Year!

The Odds Of An Individual Being Struck By Lightning The Odds Of An Individual Being Struck By Lightning Each Year In The U.S. Is About 300,000 To 1

Florida 100,000 To 1 (#1 Lightning Area USA)

I n t e g r i t y - S e r v i c e - E x c e l l e n c e 2


NUMBER OF DEATHS BY NATURAL HAZARDS 1940-1981HAZARDS, 1940-1981

LIGHTNING 7,741 TORNADO 5 268 TORNADO 5,268 FLOOD 4,481

HURRICANE 1 923 HURRICANE 1,923



Strike Locations 40% Unreported 27% Open fields 14% Under trees (not golf) 8% Water-related (boating, fishing, swimming…) 5% Golf/golf under trees 3% Heavy equipment and machinery-related

2 4% T l h l t d 2.4% Telephone-related 0.7% Radio, transmitter & antenna-related.



Lightning Casualties In U.S. (1959-1994)

Radio and Radio Equipment(1.2%)

Telephone

Open Fields(45.0%)

Trees(1.7%)

Farm and

Telephone(4.0%)

Under Treesa a dHeavy Equipment

(5.0%)

Under Trees(23.0%)

Water(13 6%)


Golf(6.5%)

(13.6%)


"Fast" imagery of plane being affected by the


Fast imagery of plane being affected by the flash.


What to do when Lightning shows up?

Evacuate personnel from these locations when lightning is with-in 5 Nautical Miles (5.75 Miles):

Any explosive location without lightning protection (Licensed Any explosive location without lightning protection (Licensed facilities are exempt).

Facilities containing exposed explosives, vapors or dust, even if protected by lightning rods.p y g g

Parked vehicles & rail cars. All locations and personnel within PTR distance of the above. Stop aircraft munitions loading / unloading.p g g Stop aircraft refueling / de-fueling.

These types of locations (facilities or areas) are considered unprotected if they have no lightning


considered unprotected if they have no lightning protection installed.


Lightning Protection -

Properly maintained lightning protection is required (with exceptions) for ammunition and explosives facilities (e g open pads revetments and modulesfacilities (e.g., open pads, revetments, and modules used for manufacturing, processing, handling or storing explosives and ammunition).



DoD 6055.9 STD - Explosive Safety Standards Chapter 7:

Defines minimum explosives safety criteria for the design Defines minimum explosives safety criteria for the design, maintenance, testing and inspection of lightning protection systems.

Also addresses exceptions to required lightning protection systems.



AFMAN 91-201 - Explosive Safety Standards Implements AF safety policy and DoD 6055.9 Std

It applies to everyone involved in any explosives 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)Static (2.51& 2.52) Grounds and Bonding (2.53) Lightning Protection (2.54)



AFI 32-1065 - Grounding Systems

Implements maintenance requirements of DoD 6055.9 Std Chapter 7 “Lightning Protection” and AssignsStd, Chapter 7 Lightning Protection and, Assigns maintenance responsibilities and requirements for grounding, static, & lightning protection systems on AF i t ll tiinstallations.



NFPA 780 (National Fire Protection Association)-

Standard for the Installation of Lightning Protection Systems - 2004y

LPSs must comply with, Standards for the Installation of Lightning Protections Systems, the National ElectricLightning Protections Systems, the National Electric Code, NFPA 70, reference (l), and MIL-HDBK-419.

All locations where explosives are involved (with All locations where explosives are involved (with exceptions) should be equipped with an LPS, and the systems maintained regularly.



Provides practical safeguarding for persons and property from hazards arising from exposure to lightning.

These traditional LPS installation requirements are intended for; Ordinary Structures Miscellaneousintended for; Ordinary Structures, Miscellaneous structures, Structures containing flammable vapors and gases, but NOT explosives manufacturing buildings and magazinesbuildings and magazines.



AFI 32-1065- Responsibilities - The Base Civil Engineers (BCE):

Maintain lightning and grounding systems specifically Maintain lightning and grounding systems specifically identified in Table 1. according to the procedures in AFI 32-1065

M k th t i ti id tifi d i T bl 1 Make sure that user organizations identified in Table 1. are aware of their maintenance responsibilities.

Train users to perform their responsibilities to inspect and maintain lightning and grounding systems as identified in Table 1. when requested



AFI 32-1065, Table 1

FACILITY ACTION REQUIRED FREQUENCY RESPONSIBILITY REFERECE

6. Aircraft Parking Apron Grounds and

Resistance check on static grounds (10,000 ohms max)

When installed or physically damaged

Base Civil Engineer AFM 88-9, Chapter 3


Hanger Floor Static Grounds


FACILITY ACTION REQUIRED FREQUENCY RESPONSIBILITY REFERECE

12. Non-Hazardous Explosive Area

a, Visual inspection of static wire bonds

Quarterly User AFMAN 91-201; this AFIExplosive Area (Weapons)

wire bonds

b. Continuity check on static bond from equipment to static ground

24 months User AFMAN 91-201

c. Visual inspection of lightning protection

12 months Base Civil Engineer AFMAN 91-201; this AFI

d. Resistance check on 24 months Base Civil Engineer AFMAN 91-201; this AFId. Resistance check on lightning protection earth ground system (25 ohms max except Ground Loop System)

24 months Base Civil Engineer AFMAN 91 201; this AFI

Continuity check on air terminals, bonds, and conductors (1 ohm)



Static bus bar continuity to ground (1 ohm)


Lightning Protection All Inspection Records are kept for:

6 Inspection Cycles (BCE and Munitions)



Who is an Authorized Inspector?

Personnel Maintaining, Repairing, Modifying, and Testing grounding systems must be thoroughlyTesting grounding systems must be thoroughly familiar with test equipment operation, lightning protection grounding and bonding theory and practices; referenced codes and standards and thepractices; referenced codes and standards, and the specific requirements and procedures set forth in the regulations.

Base Civil Engineering


DoD 6055.9-STD, C7.3.4AFI 32-1065, para 6


Different kinds of protection-

Mast

Catenary Catenary

Integral System100 FT

RADIUS 100FT

MAST HEIGHT = H

OVERHEAD GROUND

WIRESRADIUS 100FT (30M)

MAST

100 FT ( )

RADIUS 100FT (STRIKING DISTANCE)

H

100FT

Single mast zone of protection defined by dashed lines


GROUND SURFACE Overhead ground wires zone of protection defined by ground wire(s) and dashed lines


Mast System- The required zone of protection determines the height

of the Mast Provides a primary attachment point for lightning Provides a primary attachment point for lightning

“remote” from the structure to be protected


AFI 32-1065, para. 14.5


Catenary System- The primary benefit of a Catenary System over a Mast

System, is it provides “GREATER” protection coveragecoverage


AFI 32-1065, para. 14.5


Integral System-

Air terminals - Strike Termination Devices

Conductors - Roof Perimeter, Cross Run and Down Conductors

Earth Electrode System - Ground Rods or Plates and a Ground Loop System



Air Terminals –

An air terminal is a component of a lightning protection system that is intended to safely intercept li ht i t iklightning strikes.



Conductors- Provide low impedance paths from the air terminals to the earth electrode (ground) system.

Roof Perimeter Cross Run and Down Conductors Roof Perimeter, Cross Run and Down Conductors



Earth Electrode System - Earth electrode systems dissipate the current from a lightning strike to ground.

Ground Rods or Plates and a Ground Loop System



Earth Electrode System -



An LPS also consists of:

Interconnecting Conductors

Surge Suppression Devices

Other connections or fittings required to complete the system



Lightning Protection Exceptions -

Explosive operations served by a local lightning warning system to permit operations to be terminated before the incidence of an electricalterminated before the incidence of an electrical storm if all personnel can and will be provided protection equivalent to public traffic route distance An approved operating instruction (OI)distance. An approved operating instruction (OI) governing withdrawal of personnel from the area is required.Structures and facilities limited to the storage or Structures and facilities limited to the storage or handling of small arms ammunition where the value of the ammunition is $10,000 or less.




Lightning protection systems may be omitted on flightline Potential Explosion Sites (PES) if the system interferes with flightline criteriasystem interferes with flightline criteria.

Facilities used for temporary (non-recurring) t f itistorage of munitions.

Structures, facilities, or mobile equipment housing l i l i ti t l lexplosives or explosives operations not regularly

situated at a fixed location.




Licensed explosives locations outside the explosives storage area but situated in buildings primarily used for other purposes and that have relatively small quantities of explosives.

Note: This exemption from additional or special lightning protection is made because of the explosives. Other contents of the building may require protection.



Installed Systems and Equipment Ground: (2.53) All grounding mediums should be bonded together. Test grounds when installed. Test grounds per AFI 32-1065.Test grounds per AFI 32 1065.

Non - Hazardous Locations (2.53.2) Static bonding straps will be inspect Quarterly for

breaks and corroded connections. Test for electrical continuity and resistance. y Test grounds IAW AFI 32-1065. (24 months)



Static Grounding: (2.52)

The method generally used to eliminate or reduce the hazard from static electricity is to provide an l t i ll ti th t delectrically continuous path to ground.

Electrical continuity may be broken by oil, on y y y ,bearings, paint, or rust at any contact point.

Grounding straps should be used to bridge such locations.



Static Grounding: Static grounds will NOT be made to:

Telephone grounds. Telephone grounds.

Electrical conduit systems.

Gas, steam, hot water, or airlines.

Sprinkler systems; or Air terminals of lightning Sprinkler systems; or Air terminals of lightning protection system.

(connection to the “down wire” of the system at the ground level is authorized)


the ground level is authorized).


Equipment Grounds:



Ground Test Locations37 38 35 34

6 5 1234A

37 38 35 34

7

24 23 20 19 16 1543

38 33

725 26 21 22 17 18

14

B

273 41 42

328 9 10 11 12 13

B 9 40

28 29

32

30 31



Equipment Grounds Tracking:



Ground Terminals

The portion of a lightning protection system such as a ground rod, ground plate, or ground conductor that is i t ll d f th f idi l t i linstalled for the purpose of providing electrical contact with the earth

Placed "symmetrically" about the circumference of the facility

I n t e g r i t y - S e r v i c e - E x c e l l e n c e 37Ammo 47 - 11 - 1


Ground Rods

Explosive Operating Buildings

3/4 inch in diameter3/4 inch in diameter

10 feet long

Spaced no closer than 10 feet

3 feet away from walls or footings

Max. 25 ohms earth resistance

Top of rod 1 foot below grade



BondingBonding is the electrical connection between anBonding is the electrical connection between anelectrically conductive object and a component of alightning protection system that is intended tosignificantly reduce the potential differences createdsignificantly reduce the potential differences createdby lightning currents.

The rational behind this is to prevent side flashThe rational behind this is to prevent side flash(arching) between metal objects that could create afire hazard.

All components of a bonding system shall be sizedIAW the bonding requirements of NFPA 780, Tables4 1 1 1(A) d (B) d AFI 32 1065 Att h t 3

I n t e g r i t y - S e r v i c e - E x c e l l e n c e 39Ammo - 47 - 10 - 1

4.1.1.1(A) and (B) and AFI 32-1065 Attachment 3.


BondingAll conductors (piping, phone lines, power cables etc)All conductors (piping, phone lines, power cables etc) buried underground for a minimum distance of 50 feetprior to entering the facility.

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

I n t e g r i t y - S e r v i c e - E x c e l l e n c e 40Ammo - 47 - 10 - 5

bonded is bonded when within side flash distance


Bonding



Why Inspect and Test

Lightning Protection Systems Contact with Earth

Electrically Intact

P l D i dProperly Designed



Where do you go for training:

From the Defense Ammunition Center (DAC): Course Title: AMMO-47 Lightning Protection for Air Force

Facilities

Classes are presented at different US Bases.

The WEB Address for the classes and additional information https://www3.dac.army.mil/AS/cou06o.html

There is also a link on the AFRC Weapons Safety page p y p gthat will take you there.



Locations for Upcoming LPS Training



Who Should Attend:

Base Civil Engineer Personnel - Engineers & Technicians Engineers & Technicians

Explosive Safety - Managers NCO’s

Munitions Personnel & Civilian Contractors



Rolling Ball Theory

R

100’ R



Zone of Protection

100 Ft100 Ft.

Zone of Protection



Mast and Catenary Systems

RADIUS

MAST HEIGHT = H

OVERHEAD

MAST

100 FT

100FT GROUND WIRES

RADIUS 100FT (30M)

H

RADIUS 100FT (STRIKING DISTANCE)

H

100FT

Single mast zone of protection defined by dashed lines


GROUND SURFACE Overhead ground wires zone of protection defined by ground wire(s) and dashed lines


Air terminal design showing both Franklin rods and tall steel masts.



Defective bonding strap shows poor maintenance.



Ufer groundg


Questions


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