Lightning Calculations

7/29/2019 Lightning Calculations

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LIGHTNING CALCULATION

CLIENT : ACC WADI LIMITED REV/DATE : 0/18.07.05

PROJECT : LIGHTNING ARRESTOR REQUIREMENT CALCULATION PRE/CHKD : LB/ MK

TITLE :LIGHTNING CALCULATION SHEET : Page 1 of 48

CONTENTS

SL.NO. DESCRIPTION SHEET NO.

1.0 PURPOSE 2

2.0 REFERENCES DOCUMENTS 2

3.0 ASSUMPTIONS 2

4.0 RISK FACTOR CALCULATION 7

5.0 STRIP SIZE CALCULATION 32

6.0 RESULT 46


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CLIENT : ACC LIMITED REV/DATE : 0 /24.06.05


TITLE : LIGHTINING CALCULATION SHEET : Page 2 of 48

1.0 PURPOSE

The calculations are done for the following purposes :

a) Lightning protection requirement for Old wadi Cement plant,Power plant andColony Area.

b) To estimate the number of Lightning electrodes required at the above area.c) To prove that the maximum value of resistance of the earthing system shall not be

more than 3 ohms as per 12.3.1 of IS 2309:1989 .

2.0 REFERENCE DOCUMENTS, CODES AND STANDARDS

a) IS: 2309-1989-Indian Standard Code of Practice for Protection against Lightning.&NFPA78.

ASSUMPTIONS & RECOMMENDED DESIGN PROCEDURE.

a) Soil resistively is equal to 312 ohm-m , which is assumed to be uniform throughout

the plant.b) Pipe electrode in contact with earth is 300 cm and the diameter of the pipe

electrode is 3.8 cm .c) The effect of interconnection and links between other earthing grids is ignored for

the purpose of this calculation.

3.1 Protected StructureCommon structures are structures used for ordinary whether commercial, Industrial,

institutional or research.

3.2 Need for Protection

3.2.1Desirability of providing lightning protection shall be assessed either by calculating the riskindex or by judgement. Structures with inherent explosive risks like factories, fuel tanks etc.

need the highest possible class of lightning protection system. Other structures where largenumber of people congregate, essential public services are concerned, tall/isolated structures,

structures of historic and cultural importance should be provided with lightning protectionsystem irrespective of risk index.

3.2.2 Risk Index Weighting Factors

Indian standard recommends the following factors which form the basis of calculating the risk

index.

a) Weighting factor A Use of structure (Table 1 A).b) Weighting factor B Type of Construction (Table 1 B)

c) Weighting factor C Contents or consequential effects (Table 1C)d) Weighting factor D Degree of Isolation (Table 1D)

e) Weighting factor E Type of Country (Table 1E)

Depending upon the characteristic features of above factors, various weighting factors are give

in Table 1A to 1E of IS:2309. The probability of the structure being struck by lightning in one


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year is the product of lightning flash density and the effective collection area of the

structure to be protected.

The probable number of strikes/year (Risk) is:

P = Ac * Ng * 10 6

Ng = Number of lightning flashes to ground per Km 2 per year.

Ac = Effective area of collection of the structure.Risk, P, multiplied by weighting factors A to E gives the risk index.

3.2.3 If the value of risk index is less than 10 -5, then in the absence of other Overriding

consideration, protection shall not be necessary.3.2.4 If the risk index is more than 10 -5 then sound reasons shall be necessary to

Support the decision of not providing the lightning protection.

3.3 Size and Material of Conductors

3.3.1 The materials of air termination network, down conductors and earth terminals shall be GI as

per Table 3 of IS 2309:1989.

3.3.2 Lightning currents have very short duration. Therefore, thermal factors are of little consequen

in deciding the cross-section of the conductor. The minimum size of the various components o

the system are given below:

Sl.No Item Material Size

1. Vertical Air Terminations Copper 20 mm dia,1000 mm Long

G.S 20 mm dia,1000 mm Long

2. Horizantal air Terminations copper 20 X 3 mm Flat

G.S 25X 6mm Flat.

3. Down Conductors Same as Horizontal Air Terminations.

4. Earth Terminations

a) Horizontal conductors Cu. Strip 32 X 6 mm

G.S Strip 50 X 6 mmb) Rod Electrodes Cu 20mmDia, 3000 mm Long.

Steel 20mmDia, 3000 mm Long.c)Pipe Electrode Steel 40mmDia, 3000 mm Long.


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3.4 Air termination Systems

Air Terminations: The vertical and horizontal conductors or combination of both, installed oveor near the structure to attract the lightning stroke to themselves are called air terminations

3.4.2 Protective Zone : The space around the air terminations in which there is almost no

probabilityDirect lightning discharge is called the protective zone of air termination. Protective zones of

various arrangements shall be as given in IS: 2309 - 1989 etc. for correctness.

3.4.3 The angle between vertical line passing through the conductor and side of protective zone iscalled protective angle.

3.4.4 Horizontal air terminations: Arranged along the contours such as parapets, ridges and edges

the roof and wherever necessary, over the flat surfaces, horizontal air termination networkform basic protection arrangement, if roof of the building has large horizontal dimensions.

3.4.5 Protective angle of horizontal air termination is 45 for normal protection and upto 30 if high

protection is needed.

3.4.6 Protective angle for two horizontal air terminations, spaced at a distance not greater than twic

the height, shall be used within the space between conductors and 45 and 30 respectively if

higher protection is needed.

3.4.7 The spacing, between adjacent horizontal air terminations shall not be more than 10 metres

and no part of the roof shall be more than 5 metres away from the nearest horizontal

conductor.

3.4.8 Layout of Horizontal Air Terminationsa) A horizontal air termination shall run along the periphery of the roof.

b) Additional parallel horizontal conductors shall be provided if spacing between theconductors is more than 10 metres or any part of the roof is more than 5 metres

away from the nearest horizontal conductor.C) Conductors shall be interconnected to form a closed loop.

3.4.9 Vertical Air Terminations

a) Vertical air terminations shall be used for very high structures with small base area.b) Protective angles of vertical air terminations shall be same as given for horizontal air

terminations under clause 3.4.5/.6.

c) Vertical air terminations shall project at least 300 mm above the protected structure.d) All the vertical air terminations provided on the same structure shall be interconnected.e) All the air termination network shall be effectively secured to the roof against

overturning. The fasteners shall be of the same material as the conductor to avoid

bimetallic corrosion.

3.4.10 Where a structure has two elevations, out of which lower is projecting outside the high

elevation such that the network in higher elevation does not protect the lower elevation, both

networks shall be interconnected by connecting the higher elevation down conductors to thelower network.


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3.4.11 If a particular small portion in the structure is projecting above the level of horizontal

conductors by more than 1000 mm, a separate network shall be formed for the same.

3.4.12 All the metal piping, railing, etc. on the roof shall be bonded to the protective network

with a bolted connection.

3.5 Down ConductorsThe conductors which connect air terminations to earth terminations are called down

Conductors.

3.5.1 Size and material of the down conductors shall be given under clause 3.3.

3.5.2 Number

a) As per IS.2039, a structure having a base area less than 100 sq. mtr shall be provided with

only one down conductor. Chimneys, whose over all width at the top or diameter is less than1.5 metres shall be provided with only one down conductor.

b) For buildings having base area more than 100 m 2 , the number of down conductors shall be

smallerthe number obtained by the following two criteria

i) one down conductor for first 100 m 2 area plus one for every additional 300 m 2 area or part

thereofii) one down conductor for every 30 metres of periphery

Non-conducting chimneys whose overall width at the top or diameter is more than 1.5 metres sha

be provided two down conductors. Structures on rocky terrain where testing and inspection is

difficult shall be provided with minimum two down conductors.

As per BS: 6651 1999 at least one down conductor should be provided for each 20 mtr or part

thereof of the perimeter at roof level. Structures greater than 20-mtr height, shall have a downconductor per 10 mtr or part thereof.

3.5.3 Route of Down Conductors

a) Unless aesthetic and architectural considerations prohibit, down conductors shall be uniformlydistributed around the outside walls of the structure.

b) The path between the air terminations and earth terminations shall be as direct as possible an

shall avoid sharp bends upturns and kinks.

c) No deep re-entrant loop, in which length of the conductor forming the loop is more than 8 timthe width of open side of the loop, shall be recommended. This is shown in Figure-1 and is

avoided to prevent large inductive voltage drop across the open side of the loop.

d) In a building cantilevered from first storey onwards, the down conductors shall not follow thecontour of the building as shown in Figure-2.

e) Down conductors shall not be attached to lift shafts.


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f) When suitable external route for down conductors is not possible or advisable, the conductors

may run in air space provided by non-metallic, non-combustible ducts not smaller than 75 x 15 mor in any vertical, service duct running through the height of the building, provided it does not

contain any unarmoured, non-metal sheath cable.

g) Down conductors may be embedded in the wall of the structure. In such case, reinforcing bars

shall be bonded to the down conductor.

h) In case metallic object such as pipes, structures etc. exists in the vicinity of down conductors,there is a risk of side flash over between the down conductor and these objects. In such

cases, the object shall be bonded to or installed on the basis of the recommendations givenunder

Clause3.7.1.

Each down conductor shall be provided with testing point as discussed in Clause 3.7.2 (f)

j)Holes in cornice and parapet walls shall be used for the passage of down conductors,wherever possible.

3.6Earth Terminations

3.6.1 Earthing conductors embedded in the soil and designed for the safe discharge of lightning

currents into the soil are called earth terminals.3.6.2 Down conductor shall be provided an earth electrode and all earth electrodes shall be intercon

nected.

3.6.3 Earthing resistance of earth terminations shall be such that the combined resistance is not mothan 3 ohms. In case, the earthing resistance is not within limits, the earth electrodes shall belocated in treated earth pit.

3.6.4 Disconnecting facility shall be provided in some of the earth electrodes so that it is possible tomeasure the earthing resistance.

3.6.5 Lightning protective earthing system may be interconnected with operational and safety

earthing system.

3.6.6 Earthing conductors shall not be more than 1.5 to 2.0 metres away from the structure except

when high temperatures are likely to be encountered in subsoil or when sufficient space near

the structure is not available.3.6.7 Metal pipes and other structures buried in earth shall be bonded to or isolated from the

earthing conductors on the basis of the recommendation given under clause 3.7.1.

3.6.7 Earth Electrodes

a) The use of rod/pipe/plate electrodes is permissible. their choice will depend upon the siteconditions, soil resistivity and economic considerations. In general, the use of pipe electrodes

recommended.

b) The material of earth electrodes shall be either galvanised steel or copper. The choice willdepend upon the material of the air termination, down conductors and soil resistivity. It is

preferable to use the same material throughout the system.


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BULK LOADING SILO:

Diameter(D) : 11 M

Height (H) : 49.5 M

Lightning Flashes/Sq.Km / year(Ng) : 3.284 (AS CALCULATED ABOVE)-Rating factor for Wadi

Weighing Factors

A : 1.0

B : 0.8

C : 0.8

D : 1.0

E : 0.3

Overall weighing Factors : A x B x C x D x E

: 1.0 x 0.8 x 0.8 x 1.0 x 0.3

: 0.192

Collection Area AC : H2

: (49.5)2

: 7693.785 m2

Probable no.of strikes for the : Ac x Ng x 10-6

structure per year P : 7693.785 x 3.284 x 10-6

: 2.526 x 10-2

Therefore, the overall risk Factor : P x Overall Weighing Factor

: 2.526 x 10-2 x 0.192

: 4.84 x 10-3

which is greater than 10-5

Therefore for Bulk loading Silo Lightning Protection is essential.

CEMENT STORAGE SILO:

Diameter(D) : 10 M

Height (H) : 29.8 M

Lightning Flashes/Sq.Km / year(Ng) : 3.284

- Rating factor for Wadi

Weighing Factors


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A : 1.0

B : 0.8

C : 0.8

D : 1.0

E : 0.3


: 1.0 x 0.8 x 0.8 x 1.0 x 0.3

: 0.192


: (29.8)2

: 2788.45 m2



: 9.157 x 10-3


: 9.157 x 10-3 x 0.192

: 1.75 x 10-3


Therefore for Cement storage Silo Lightning Protection is essential.

KILN NO.3 PREHEATER:

Length (L) : 19.2 M

Width ( W) : 16 MHeight (H) : 106 M



Weighing Factors

A : 1.0

B : 0.8

C : 0.8


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D : 1.0

E : 0.3


: 1.0 x 0.8 x 0.8 x 1.0 x 0.3

: 0.192

Collection Area AC : (L x W) + 2(L x H) + 2(W x H) + 2

: (19.2x16)+2(19.2x106)+2(16x106)+ (107.5)2

: 1290105.505 m2

Probable no.of strikes for the : AC x Ng x 10-6


: 4.236


: 4.236 x 0.192

: 0.8133 which is greater than 10-5

Therefore Lightning Protection is essential for Kiln No.3 Preheater.

CEMENT MILL BUILDING :

Length (L) : 34 M

Width ( W) : 36 M

Height (H) : 11.5 M

Length (L) : 22 M

Width ( W) : 36 M

Height (H) : 16.5 M



Weighing Factors

A : 1.0


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B : 1.0

C : 0.8

D : 1.0

E : 0.3


: 1.0 x 1.0 x 0.8 x 1.0 x 0.3

: 0.24


: (12x36)+2(12x11.5)+(36x11.5)+

(22x36)+2x(22x16.5)+(36x16.5)+ (16.5)2

: 4088.86 m2



: 1.44 x 10-2


: 1.34 x 10-2 x 0.24

: 3.22 x 10-3 which is greater than 10-5

Therefore Lightning Protection is essential for Cement Mill Building.

CEMENT MILL 4 & 5 BUILDINGS:

Length (L) : 34 M

Width ( W) : 36 M

Height (H) : 16.5 M



Weighing Factors

A : 1.0


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B : 1.0

C : 0.8

D : 1.0

E : 0.3


: 1.0 x 1.0 x 0.8 x 1.0 x 0.3

: 0.24


: (34x36)+2(34x16.5)+2(36x16.5)+ (16.5)2

: 4388.86 m

2



: 1.44 x 10-2


: 1.44 x 10-2 x 0.24


Therefore Lightning Protection is essential for Cement Mill 4 & 5 Buildings .


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PROJECT : LIGHTNING ARRESTOR REQUIREMENT CALCULATION PRE/CHKD : LB/MK


CEMENT MILL CONTROL ROOM:

Length (L) : 16 M

Width ( W) : 7.5 M

Height (H) : 11.5 M

Lightning Flashes/Sq.Km / year(Ng) : 3.284- Rating factor for Wadi

Weighing Factors

A : 1.0

B : 1.0

C : 0.8

D : 1.0

E : 0.3


: 1.0 x 1.0 x 0.8 x 1.0 x 0.3

: 0.24


: (4x16)+(3.5X6)+(5.25x7.5)+(5.25x13)+ (6X5.25)

+(7X5.25)+2X(11.5X3.5)+(11.5X4)+5/4 (11.5)2

: 552.32 m2



: 1.81 x 10-3


: 1.81 x 10-3 x 0.24


Therefore Lightning Protection is essential for Cement Mill Control room .


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CLIENT : ACC LIMITED REV/DATE :

0/24.06.05

PROJECT : LIGHTNING ARRESTOR REQUIREMENT CALCULATION PRE/CHKD: LB/MK

TITLE : LIGHTINING CALCULATION SHEET : Page 14

of 48

PACKING PLANT:

Length (L) : 36.9 M

Width ( W) : 27 M

Height (H) : 24.75 M


Weighing Factors

A : 1.0

B : 1.0

C : 0.8

D : 1.0

E : 0.3


: 1.0 x 1.0 x 0.8 x 1.0 x 0.3

: 0.24


:

(23.4x27)+(13.5X15.5)+(24.75x27)+(24.75x11.5)+

(8.5X13.5)+(8.5X15.5)+(36.9X8.5)+

(15.5X8.5)+5/4 (24.75)2

: 4890.132 m2



: 1.6 x 10-2


: 1.6 x 10-2 x 0.24


Therefore Lightning Protection is essential for Cement Packing plant.


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CEMENT SILO EXPANSION AND PACKING PLANT:

CEMENT SILO:

Diameter(D) : 12 M

Height (H) : 34.5+2.5=37 M


Weighing Factors

A : 1.0

B : 0.8

C : 0.8

D : 1.0

E : 0.3


: 1.0 x 0.8 x 0.8 x 1.0 x 0.3

: 0.192


: (37)2

: 4298.66 m2



: 1.41 x 10-2


: 1.41 x 10-2

x 0.192

: 2.71 x 10-3


Therefore for Cement Silo Lightning Protection is essential.


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PACKING PLANT:

Length (L) : 14 M

Width ( W) : 16 M

Height (H) : 30 M


Weighing Factors

A : 1.0

B : 1.0

C : 0.8

D : 1.0

E : 0.3


: 1.0 x 1.0 x 0.8 x 1.0 x 0.3

: 0.24


: (14x16)+2(14X30)+2(16x30)+ (30)2

: 2024 m2


structure per year P : 2024 x 3.284 x 10-6

: 6.646 x 10-3


: 6.646x 10-3 x 0.24


Therefore Lightning Protection is essential for Cement Packing plant.


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CLIENT : ACC -WADI REV/DATE : 0 /24.06.05


TITLE : LIGHTNING CALCULATION SHEET : Page 17 of 48

KILN NO. 1 & 2 PREHEATER:

Length (L) : 11 M

Width ( W) : 24 M



Weighing Factors

A : 1.0

B : 0.8

C : 0.8

D : 1.0

E : 0.3


: 1.0 x 0.8 x 0.8 x 1.0 x 0.3

: 0.192


: (11x24)+2(11x69.36)+2(24x69.36)+ (69.36)2

: 20225.142 m2



: 6.64 x 10-2


: 6.64 x 10-2 x 0.192


Therefore Lightning Protection is essential for Kiln No.1 & 2 Preheater.


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RAW MILL 4& 5:

Length (L) : 60.1 M

Width ( W) : 36 M



Weighing Factors

A : 1.0

B : 1.0

C : 0.8

D : 1.0

E : 0.3


: 1.0 x 1.0 x 0.8 x 1.0 x 0.3

: 0.24


: (60.1x36)+2(60.1x31.35)+2(36x31.35)+ (31.35)2

: 11275.132 m2



: 3.7 x 10-2


: 3.7 x 10-2 x 0.192


Therefore Lightning Protection is essential for Raw mill 4 & 5.


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POWER PLANT AREA :

DG SET BUILDING:

Length (L) : 52 M

Width ( W) : 20 M

Height (H) : 15 M



Weighing Factors

A : 1.0

B : 0.4

C : 1.0

D : 1.0

E : 0.3


: 1.0 x 0.4 x 1.0 x 1.0 x 0.3

: 0.12

Collection Area AC : (L x W) + 2(L x H) + 2(W x H) +

2

: (52x20)+2(20x15)+ (15)2

: 2346.5 m2



: 7.705 x 10-3


: 7.705 x 10

-3

x 0.12: 9.247 x 10-4 which is greater than 10-

5

Therefore Lightning Protection is essential for DG Set Building .


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3 NOS. OF 1 X 25 MW TG BUILDING :

Length (L) : 52.5 M

Width ( W) : 26.7 M




Weighing Factors

A : 1.0

B : 0.4

C : 1.0

D : 1.0

E : 0.3


: 1.0 x 0.4 x 1.0 x 1.0 x 0.3

: 0.12


: (8x52.5)+(18.7x37.5)+(14.5x12.2)+2(8x14.86)

+(52.5x14.86)+2(18.7x23.56)+2(14.5x15.26)+ (23.56)

2

: 5382.67 m2

There are 3 Nos of 1x25 MW Generator

Areas. Therefore Total collection area is : 3x5382.67 m2

: 16146 m2



: 5.3 x 10-2


: 5.3 x 10-2 x 0.12


Therefore Lightning Protection is essential for TG Building .


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CHIMNEY -1

Diameter(D) :4 M

Height (H) : 113 M

Lightning Flashes/Sq.Km / year(Ng) : 3.284-Rating factor for Wadi

Weighing Factors

A : 1.0

B : 0.4

C : 1.0

D : 2.0

E : 0.3


: 1.0 x 0.4x 1.0 x 2.0 x 0.3

: 0.24


: (113)2

: 40094.66 m2



: 13.16x 10-2


: 13.16 x 10-2 x 0.24


Therefore for Chimney Lightning Protection is essential.


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WATER TANK (227000 LITRES) 2 Nos:

Diameter(D) :9.4 M


Lightning Flashes/Sq.Km / year(Ng) : 3.284-Rating factor for Wadi

Weighing Factors

A : 0.7

B : 0.4

C : 0.8

D : 1.0

E : 0.3


: 0.7 x 0.4x 0.3x 1.0 x 0.3

: 0.0252


: (24.55)2

: 1892.485 m2



: 6.21x 10-3


: 6.21 x 10-3 x 0.0252


Therefore for Water tank Lightning Protection is essential.


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KAGINA GUEST HOUSE:

Length (L) : 40 M

Width ( W) : 15 M

Height (H) : 10 M


Weighing Factors

A : 1.2

B : 0.4

C : 1.7

D : 0.4

E : 0.3


: 1.2 x 0.4 x 1.7 x 0.4 x 0.3

: 0.0979


: (40x15)+2(40x10)+2(15x10) + (10)2

: 2014 m2



: 6.613 x 10-3


: 6.613 x 10-3 x 0.0979


Therefore Lightning Protection is essential for Kagina Guest House .


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MANAGEMENT TRAINEE HOSTEL:

Length (L) : 17 M

Width ( W) : M

Height (H) : 10 M


Weighing Factors

A : 1.2

B : 0.4

C : 1.7

D : 0.4

E : 0.3


: 1.2 x 0.4 x 1.7 x 0.4 x 0.3

: 0.0979


: (40x15)+2(40x10)+2(15x10) + (10)2

: 2014 m2



: 6.613 x 10-3


: 6.613 x 10-3 x 0.0979


Therefore Lightning Protection is essential for Management Trainee hostel .


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V. P BUNGALOW:

Length (L) : 22.76 M

Width ( W) : 15.25M

Height (H) : 6.80 M


Weighing Factors

A : 1.2

B : 0.4

C : 1.7

D : 0.4

E : 0.3


: 1.2 x 0.4 x 1.7 x 0.4 x 0.3

: 0.0979


: (10x22.76)+(5.58x14.11)+(10x4.1)+2(8.65X4.1)

+(5.58X6.8)+2(14.11X6.8)+(15.25X6.8)+ (6.8)2

: 861.53 m2



: 2.829 x 10-3


: 2.829 x 10-3 x 0.0979

: 2.76 x 10-4


Therefore Lightning Protection is essential for Vice president Bungalow .


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QUARY CRUSHER:

Length (L) : 24 M

Width ( W) : 12M

Height (H) : 15 M


Weighing Factors

A : 1.0

B : 0.8

C : 0.8

D : 1.0

E : 0.3


: 1.0 x 0.8 x 0.8 x 1.0 x 0.3

: 0.192


: (24x12)+2(24x15)+2(12x15)+ (15)2

: 2074.9 m2



: 0.6812 x 10-2


: 0.6812 x 10-2 x 0.192


Therefore Lightning Protection is essential for Quary crusher .


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5.0Resistance of Pipe Electrode (Ref. 9.2.2 of IS: 3043-1987)

Re = 100 x loge 4 x l

2 x x l d

Where l = length of the rod or pipe = 300 cm.

d = diameter of the rod or pipe = 3.8 cm.

= resistivity of soil = 312 -m assumed uniform.

Re = 100 x 312 loge 4 x 300

2 x x 300 3.8

= 16.55 loge 315.789

= 41.36 .

Resistance of the Earth Strip 50 x 6 G.I Flat

Old Wadi plant

5.1.1 Bulk loading silo

Rs = 100 Log e 2L2

2 L wt

L=Estimated Length Strip : 12500 cm

Width of the Strip (t) : 50 x 6 mm

Depth of the Buried Strip (W) : 60 cm

Rs = 100 x 312 Loge 2 x 125002 = 2.38

2x3.14x12500 60x5

There are 3 Nos of earth pits are used, therefore

Re = Re/3 = 41.36 / 3 = 13.78

Rt = Re xRs = 13.78 X 2.38 = 2.03

Re +Rs 13.78+2.38

Thus the Total resistance is less than 3 ohms .

50x6 G.I Flat strip is selected for vertical down conductor and horizondal earthconductor.


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5.1.2 Cement storage silo

Rs = 100 Loge

2L2

2 L wt


Width of the Buried Strip (t) : 50 x 6 mm


Rs = 100 x 312 Loge 2 x 146402 = 2.0

2x3.14x14640 60x5


Re = Re/2 = 41.36 / 2 = 20.68

Rt = Re xRs = 20.68 X 2 = 1.8

Re +Rs 20.68+2.


50x6 G.I Flat strip is selected for vertical down conductor and horizondal earth

conductor.

5.1.3 Kiln No:3 Preheater

Rs = 100 Log e 2L2

2 L wt




Rs = 100 x 312 Loge 2 x 301602 = 1.1172

2x3.14x30160 60x5


Re = Re/2 = 41.36 / 2 = 20.68


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Rt = Re xRs = 20.68 X 1.1172 = 1.054

Re +Rs 20.68+1.1172.



conductor.

5.1.4 Cement Mill Building

Rs = 100 Log e 2L2

2 L wt

L=Estimated Length Strip : 20405.6 cm



Rs = 100 x 312 Loge 2 x 20405.62 = 1.568

2x3.14x20405.6 60x5


Re = Re/2 = 41.36 / 2 = 20.68

Rt = Re xRs = 20.68 X 1.568 = 1.4469

Re +Rs 20.68+1.568.




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5.1.5 Cement Mill Building 4 & 5

Rs = 100 Log e 2L2

2 L wt




Rs = 100 x 312 Loge 2 x 20405.62 = 1.568

2x3.14x20405.6 60x5


Re = Re/2 = 41.36 / 2 = 20.68

Rt = Re xRs = 20.68X 1.568 = 1.4469

Re +Rs 20.68+1.568.



conductor.

5.1.6 Cement Mill Control Room

Rs = 100 Log e 2L2

2 L wt




Rs = 100 x 312 Loge 2 x 10394.82 = 2.799

2x3.14x10394.8 60x5

Only one earth pit is used, therefore

Re = Re/1 = 41.36 / 1 = 41.36


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Rt = Re xRs = 41.36 X 2.799 = 2.6

Re +Rs 41.36+2.799.



conductor.

5.1.7 Packing Plant

Rs = 100 Log e 2L2

2 L wt




Rs = 100 x 312 Loge 2 x 177302 = 1.77

2x3.14x17730 60x5


Re = Re/2 = 41.36 / 2 = 20.68

Rt = Re xRs = 20.68 X 1.77 = 1.68

Re +Rs 20.68+1.77.



5.1.8 Cement silo Expansion

Rs = 100 Log e 2L2

2 L wt





37/48





Rs = 100 x 312 Loge 2 x 320332 = 1.07

2x3.14x32033 60x5


Re = Re/2 = 41.36 / 2 = 20.68

Rt = Re xRs = 20.68 X 1.07 = 1.0

Re +Rs 20.68+1.07.



5.1.9 Kiln No:1& 2 Preheater

Rs = 100 Log e 2L2

2 L wt




Rs = 100 x 312 Loge 2 x 256722 = 1.285

2x3.14x25672 60x5

Only one earth pit is used, therefore

Re = Re/1 = 41.36 / 1 = 41.36

Rt = Re xRs = 41.36X1.285 = 1.240

Re +Rs 41.36+1.285.




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5.1.10 Raw Mill 4 & 5

Rs = 100 Log e 2L2

2 L wt

L=Estimated Length Strip : 56730cm



Rs = 100 x 312 Loge 2 x 567302 = 0.64

2x3.14x56730 60x5


Re = Re/2 = 41.36 / 2= 20.68

Rt = Re xRs = 20.68X0.64 = 0.62

Re +Rs 20.68+0.64.



conductor.

5.1.11 Coal Mill

Rs = 100 Log e 2L2

2 L wt




Rs = 100 x 312 Loge 2 x 520002 = 0.64

2x3.14x52000 60x5


Re = Re/2 = 41.36 / 2= 20.68


39/48





Rt = Re xRs = 20.68X0.64 = 0.62

Re +Rs 20.68+0.64.



conductor.

5.1 Power plant

5.2.1 DG Set

Rs = 100 Log e 2L2

2 L wt




Rs = 100 x 312 Loge 2 x 638002 = 0.578

2x3.14x63800 60x5


Re = Re/3 = 41.36 / 3= 13.78

Rt = Re xRs = 13.78X0.578 = 0.55

Re +Rs 13.78+0.578



conductor.

5.2.2 T.GCPP Building

Rs = 100 Log e 2L2

2 L wt


40/48





L=Estimated Length Strip : 81802.2cm



Rs = 100 x 312 Loge 2 x 81802.22 = 0.588

2x3.14x81802.2 60x5


Re = Re/4 = 41.36 / 4= 10.34

Rt = Re xRs = 10.34X0.588 = 0.5532

Re +Rs 10.34+0.588



conductor.

5.2.3 Chimney-1

Rs = 100 Log e 2L2

2 L wt




Rs = 100 x 312 Loge 2 x 236592 = 1.379

2x3.14x23659 60x5


Re = Re/2 = 41.36 / 2= 20.68


41/48


42/48


43/48





Rs = 100 x 312 Loge 2 x 13329.22 = 2.26

2x3.14x13329.2 60x5


Re = Re/2 = 41.36 / 2= 20.68

Rt = Re xRs = 20.36X2.26 = 2.0

Re +Rs 20.36+2.26.



conductor.

Kagina Guest house

Rs = 100 Log e 2L2

2 L wt




Rs = 100 x 312 Loge 2 x 221002 = 1.46

2x3.14x22100 60x5


Re = Re/2 = 41.36 / 2= 20.68

Rt = Re xRs = 20.36X1.46 = 1.35

Re +Rs 20.36+1.46.


44/48







V.P Bungalow

Rs = 100 Log e 2L2

2 L wt

L=Estimated Length Strip : 14194m



Rs = 100 x 312 Loge 2 x 141942 = 2.14

2x3.14x14194 60x5


Re = Re/2 = 41.36 / 2= 20.68

Rt = Re xRs = 20.36X2.14 = 1.925

Re +Rs 20.36+2.14.




45/48


46/48





6.0 RESULTS

a) 38 mm ID,3 M long pipe suggested for earth pit refer drg. No. E-ECB-A565-LTNG-001(Sheet 2 of 4).

b) 50 x 6 G.I flat strip suggested for down conductors and burried conductor.

c) The No.of Lightning conductors and earth pits required are as shown in thedrawing.

d) The Lightning conductor shall be placed at the topmost height of everyBuilding.

e) The Location of Earthpits shall be fixed as per the site conditions.f) The Earthing Resistance shall be maintained below 3 ohms.

g) The down conductors shall be insulated from the metal structures inorderto reduce the leakage current.

h) All the down conductors shall have a test Link arrangement between thearrestor and Earthpit.

Old Wadi plant Area:

Location of theLightning

Conductor

No.ofLightnin

gConduct

or.

No.ofEarth Pits

Remarks

KilnNo-1&2

Preheater

2 2

Bulk loading cement

silo

2 3 One Arrestor at

each silo.

Packing plant 1 2 Shall be placedat the topmost

structure.

Cement storage silo 2 2 Arrestor Shall beplaced at the

topmoststructure.

Cement mill building

4&5

2 2 Arrestor Shall be

placed at

topmoststructure.

Raw mill 4&5 2 2 Arrestor Shall beplaced at the

topmoststructure.

Coal mill 2 2 Arrestor Shall be

placed at thetopmost


47/48


48/48





Power plant Area

Note: The Horizotal Air terminations to be Placed as marked in the drawing forD.G set building & T.G building.

As the Chimneys are provided with the 2 nos of 25x3 GI Flat as downconductor, the same shall be retained as it is and the required earth value

of less than 3 ohms should be confirmed.

Description No.of

Arrestor

No.of Earth

Pit

Remarks

D.G Set 2 3 Two Arrestor is

existing. No needto provide.

T.G CPP building 10 4 7 Arrestor is

already existingremaining 3

should be placedas per drawing.

Chimney 2Nos 2 4 One Arrestor is

existing in each

chimney. No needto provde.

River pump Area

a) There are three Tank in this area ,in each Tank one Arrester shall be

placed.

c) In quary crusher area one Arrestor and Two nos. of earth pits shall be placed as

marked in the drawing.

Date post:	04-Apr-2018
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