Lightning Calculations

LIGHTNING CALCULATION CLIENT

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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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1.0

PURPOSE The calculations are done for the following purposes :

a) Lightning protection requirement for Old wadi Cement plant,Power plant and Colony 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) NFPA78.

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

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 Structure Common 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 risk

index 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 large number of people congregate, essential public services are concerned, tall/isolated structures, structures of historic and cultural importance should be provided with lightning protection system 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 given 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

3.3.1 3.3.2

Size and Material of Conductors The materials of air termination network, down conductors and earth terminals shall be GI as per Table 3 of IS 2309:1989. Lightning currents have very short duration. Therefore, thermal factors are of little consequence in deciding the cross-section of the conductor. The minimum size of the various components of the system are given below: Sl.No 1.

2.

Item Vertical Air Terminations

Material Copper

20 mm dia,1000 mm Long

G.S

20 mm dia,1000 mm Long

Horizantal air Terminations copper G.S

3.

Down Conductors

4.

Earth Terminations a) Horizontal conductors b) Rod Electrodes c)Pipe Electrode

Size

20 X 3 mm Flat 25X 6mm Flat.

Same as Horizontal Air Terminations.

Cu. Strip G.S Strip Cu Steel Steel

32 X 6 mm 50 X 6 mm 20mmDia, 3000 mm Long. 20mmDia, 3000 mm Long. 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 over or 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 probability Direct 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 is called protective angle.

3.4.4

Horizontal air terminations: Arranged along the contours such as parapets, ridges and edges of the roof and wherever necessary, over the flat surfaces, horizontal air termination network form 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 higher protection is needed.

3.4.6 Protective angle for two horizontal air terminations, spaced at a distance not greater than twice 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 Terminations a) A horizontal air termination shall run along the periphery of the roof. b) Additional parallel horizontal conductors shall be provided if spacing between the conductors 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 higher 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 the lower 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 Conductors The 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 than 1.5 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 smaller the 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 thereof ii) 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 shall 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 down conductor per 10 mtr or part thereof. 3.5.3 Route of Down Conductors a) Unless aesthetic and architectural considerations prohibit, down conductors shall be uniformly distributed around the outside walls of the structure. b) The path between the air terminations and earth terminations shall be as direct as possible and 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 times the 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 the contour 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 mm or 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 given under 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 interconnected.’

3.6.3 Earthing resistance of earth terminations shall be such that the combined resistance is not more than 3 ohms. In case, the earthing resistance is not within limits, the earth electrodes shall be located in treated earth pit. 3.6.4 Disconnecting facility shall be provided in some of the earth electrodes so that it is possible to measure 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 site conditions, soil resistivity and economic considerations. In general, the use of pipe electrodes is recommended. b) The material of earth electrodes shall be either galvanised steel or copper. The choice will depend 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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Horizontally buried interconnecting conductors shall be laid at minimum 600 mm depth. Earthing system shall be in accordance with IS: 3043.Minimum spacing between rod/pipe electrodes and plate electrodes shall be 6 and 8 metres respectively.

4.0

Lightning protection for structure- Evaluation of lightning flash density,collection area of structure and overall risk factor.

4.1

Evaluation of lightning ground flash density: The lightning ground flash density can be estimated using the following formula indicated in IEC 61024-1-1. Lightning groung flash density Ng=0.04x(Td)

1.25

per Km2 per year

Where Td is the number of thunderstorm days per year In Gulbarga the Annual thunderstorm days is 34 days( As per IS 2309:1989 Page number 5).Therefore the lightning ground flash density per Km2 per year is calculated using the above formula as follows Ng=0.04x(34)

1.25

=3.284 per Km2 per year which is commen throughout the plant area 4.2

Evaluation of probable No of strikes for the structure per year P: Probable No of strikes for the structure per year P can be calculated using the formula P= Ng x Ac x 10

–6

per year

Where Ac is the equivalent collection area of structures on a plain surface. Ac=(L XB)+2(L X H)+2(B X H)+

π H2

For complex structure it can be calculated based on the guidelines given in item 4.2 of IEC 61024-1-1 standard. The risk factor P is multiplied by the product of the weighting factors( Table 1A-1E of IS 2309:1989). If the overall risk factor is greater than 10-5 protection is required for the structure. Calculation for the overall risk factor is done below for each building in the Old Wadi Cement plant, Colony and Power plant.

OLD WADI CEMENT PLANT


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BULK LOADING SILO: Diameter(D)

: 11 M

Height (H)

: 49.5 M

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

: 3.284 (AS CALCULATED ABOVE)

Weighing Factors A

: 1.0

B

: 0.8

C

: 0.8

D

: 1.0

E

: 0.3

Overall weighing Factors

:AxBxCxDxE : 1.0 x 0.8 x 0.8 x 1.0 x 0.3 : 0.192

Collection Area AC

:

π H2

:

π (49.5) 2 2

: 7693.785 m

6

Probable no.of strikes for the

: Ac x Ng x 10-

structure per year P

: 7693.785 x 3.284 x 10-

6

: Therefore, the overall risk Factor

2.526 x 10-2

: P x Overall Weighing Factor : 2.526 x 10-2 x 0.192 3

: 4.84 x 10- which is greater than 10Therefore 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) - Rating factor for Wadi

: 3.284

Weighing Factors

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A

: 1.0

B

: 0.8

C

: 0.8

D

: 1.0

E

: 0.3


:AxBxCxDxE : 1.0 x 0.8 x 0.8 x 1.0 x 0.3 : 0.192

Collection Area AC

:

π H2

:

π (29.8) 2 2

: 2788.45 m

6


: Ac x Ng x 10-


: 2788.45 x 3.284 x 10:

Therefore, the overall risk Factor

6

9.157 x 10-3


: 1.75 x 10- which is greater than 10-

Therefore for Cement storage Silo Lightning Protection is essential. KILN NO.3 PREHEATER: Length (L)

: 19.2 M

Width ( W)

: 16 M

Height (H)

: 106 M


: 3.284

Weighing Factors A

: 1.0

B

: 0.8

C

: 0.8

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D

: 1.0

E

: 0.3


:AxBxCxDxE : 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) +

πΗ

2

: (19.2x16)+2(19.2x106)+2(16x106)+π :

2

1290105.505 m 6


: AC x Ng x 10-


: 1290105.505 x 3.284 x 10-

6

: 4.236 Therefore, the overall risk Factor

: P x Overall Weighing Factor : 4.236 x 0.192 : 0.8133

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


: 3.284

Weighing Factors A

: 1.0

5

which is greater than 10-

(107.5)

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B

: 1.0

C

: 0.8

D

: 1.0

E

: 0.3


:AxBxCxDxE : 1.0 x 1.0 x 0.8 x 1.0 x 0.3 : 0.24

Collection Area AC

: (L x W) + 2(L x H) + 2(W x H) +

πΗ

2

: (12x36)+2(12x11.5)+(36x11.5)+ (22x36)+2x(22x16.5)+(36x16.5)+π :

4088.86 m

(16.5)

2

6


: AC x Ng x 10-


: 4088.86 x 3.284 x 10-

6

: 1.44 x 10-2 Therefore, the overall risk Factor

: P x Overall Weighing Factor :

1.34 x 10-2 x 0.24

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

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


: 3.284

Weighing Factors A

: 1.0

5

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B

: 1.0

C

: 0.8

D

: 1.0

E

: 0.3


:AxBxCxDxE : 1.0 x 1.0 x 0.8 x 1.0 x 0.3 : 0.24

Collection Area AC

: (L x W) + 2(L x H) + 2(W x H) +

πΗ

: (34x36)+2(34x16.5)+2(36x16.5)+π :

4388.86 m

2

(16.5)

2

6


: AC x Ng x 10-


: 4388.86 x 3.284 x 10-

6



1.44 x 10-2 x 0.24


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

5

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CEMENT MILL CONTROL ROOM: Length (L)

: 16 M

Width ( W)

: 7.5 M

Height (H)

: 11.5 M


: 3.284

Weighing Factors A

: 1.0

B

: 1.0

C

: 0.8

D

: 1.0

E

: 0.3


:AxBxCxDxE : 1.0 x 1.0 x 0.8 x 1.0 x 0.3 : 0.24

Collection Area AC

: (L x W) + 2(L x H) + 2(W x H) +

πΗ

2

: (4x16)+(3.5X6)+(5.25x7.5)+(5.25x13)+ (6X5.25) +(7X5.25)+2X(11.5X3.5)+(11.5X4)+5/4π :

2

552.32 m

6


: AC x Ng x 10-


: 552.32 x 3.284 x 10-

6



1.81 x 10-3 x 0.24 5


Therefore Lightning Protection is essential for Cement Mill Control room .

(11.5)

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of 48 PACKING PLANT: Length (L)

: 36.9 M

Width ( W)

: 27 M

Height (H)

: 24.75 M


: 3.284

Weighing Factors A

: 1.0

B

: 1.0

C

: 0.8

D

: 1.0

E

: 0.3


:AxBxCxDxE : 1.0 x 1.0 x 0.8 x 1.0 x 0.3 : 0.24

Collection Area AC

: (L x W) + 2(L x H) + 2(W x H) +

πΗ

2

: (23.4x27)+(13.5X15.5)+(24.75x27)+(24.75x11.5)+ (8.5X13.5)+(8.5X15.5)+(36.9X8.5)+ (15.5X8.5)+5/4π :

4890.132 m

(24.75)

2

2

6


: AC x Ng x 10-


: 4890.132 x 3.284 x 10-

6



1.6 x 10-2 x 0.24 5


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


: 3.284

Weighing Factors A

: 1.0

B

: 0.8

C

: 0.8

D

: 1.0

E

: 0.3


:AxBxCxDxE : 1.0 x 0.8 x 0.8 x 1.0 x 0.3 : 0.192

Collection Area AC

:

π H2

:

π (37) 2 2

: 4298.66 m

6


: Ac x Ng x 10-


: 4298.66 x 3.284 x 10:


6

1.41 x 10-2


: 2.71 x 10- which is greater than 10-

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


: 3.284

Weighing Factors A

: 1.0

B

: 1.0

C

: 0.8

D

: 1.0

E

: 0.3


:AxBxCxDxE : 1.0 x 1.0 x 0.8 x 1.0 x 0.3 : 0.24

Collection Area AC

: (L x W) + 2(L x H) + 2(W x H) + : (14x16)+2(14X30)+2(16x30)+

:

πΗ

2

π (30)

2

2024 m

6


: AC x Ng x 10-


: 2024 x 3.284 x 10-

6



6.646x 10-3 x 0.24


Therefore Lightning Protection is essential for Cement Packing plant.

5

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KILN NO. 1 & 2 PREHEATER: Length (L)

: 11 M

Width ( W)

: 24 M

Height (H)

: 69.36 M


: 3.284

Weighing Factors A

: 1.0

B

: 0.8

C

: 0.8

D

: 1.0

E

: 0.3


:AxBxCxDxE : 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) +

πΗ

2

: (11x24)+2(11x69.36)+2(24x69.36)+π :

20225.142 m

2

6


: AC x Ng x 10-


: 20225.142 x 3.284 x 10-

6




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

(69.36)

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RAW MILL 4& 5: Length (L)

: 60.1 M

Width ( W)

: 36 M

Height (H)

: 31.35 M


: 3.284

Weighing Factors A

: 1.0

B

: 1.0

C

: 0.8

D

: 1.0

E

: 0.3


:AxBxCxDxE : 1.0 x 1.0 x 0.8 x 1.0 x 0.3 : 0.24

Collection Area AC

: (L x W) + 2(L x H) + 2(W x H) +

πΗ

2

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

11275.132 m

2

6


: AC x Ng x 10-


: 11275.132 x 3.284 x 10-

6


: P x Overall Weighing Factor : 3.7 x 10-2 x 0.192 : 7.1 x 10-3 which is greater than 10-

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

5

(31.35)

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COAL MILL : Length (L)

: 46 M

Width ( W)

: 33 M

Height (H)

: 44 M


: 3.284

Weighing Factors A

: 1.0

B

: 0.8

C

: 0.8

D

: 1.0

E

: 0.3


:AxBxCxDxE : 1.0 x 0.8 x 0.8 x 1.0 x 0.3 : 0.192

Collection Area AC

2

: (L x W) + 2(L x H) + 2(W x H) +

πΗ

: (46x33)+2(46x44)+2(33x44)+π

(44)

:

2

14549.04 m

6


: AC x Ng x 10-


: 14549.04 x 3.284 x 10-

6




Therefore Lightning Protection is essential for Coal mill .

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POWER PLANT AREA : DG SET BUILDING: Length (L)

: 52 M

Width ( W)

: 20 M

Height (H)

: 15 M


: 3.284

Weighing Factors A

: 1.0

B

: 0.4

C

: 1.0

D

: 1.0

E

: 0.3


:AxBxCxDxE : 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) + : (52x20)+2(20x15)+π :

(15)

πΗ

2

2

2

2346.5 m

6


: AC x Ng x 10-


: 2346.5 x 3.284 x 10-

6



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

Height (H)

: 23.56 M


: 3.284

Weighing Factors A

: 1.0

B

: 0.4

C

: 1.0

D

: 1.0

E

: 0.3


:AxBxCxDxE : 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) +

πΗ

2

: (8x52.5)+(18.7x37.5)+(14.5x12.2)+2(8x14.86) +(52.5x14.86)+2(18.7x23.56)+2(14.5x15.26) +π : There are 3 Nos of 1x25 MW Generator Areas. Therefore Total collection area is

(23.56)

2

5382.67 m

2

: 3x5382.67 m

2

2

: 16146 m

6


: AC x Ng x 10-


: 16146 x 3.284 x 10-

6



: 6.36 x 10-3 which is greater than 10Therefore Lightning Protection is essential for TG Building .


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CHIMNEY -1 Diameter(D)

:4 M

Height (H)

: 113 M


: 3.284

Weighing Factors A

: 1.0

B

: 0.4

C

: 1.0

D

: 2.0

E

: 0.3


:AxBxCxDxE : 1.0 x 0.4x 1.0 x 2.0 x 0.3 : 0.24

Collection Area AC

:

π H2

:

π (113) 2 2

: 40094.66 m

6


: Ac x Ng x 10-


: 40094.66 x 3.284 x 10:


6

13.16x 10-2



Therefore for Chimney Lightning Protection is essential.


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CHIMNEY -2 Diameter(D)

:4 M

Height (H)

: 106.8 M


: 3.284

Weighing Factors A

: 1.0

B

: 0.4

C

: 1.0

D

: 2.0

E

: 0.3


:AxBxCxDxE : 1.0 x 0.4x 1.0 x 2.0 x 0.3 : 0.24

Collection Area AC

:

π H2

:

π (106.8) 2 2

: 35815.59 m

6


: Ac x Ng x 10-


: 35815.59 x 3.284 x 10:


6

11.76x 10-2



Therefore for Chimney Lightning Protection is essential.


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COLONY AREA WATER TANK (454000 LITRES): Diameter(D)

:13.90 M

Height (H)

: 23.40 M


: 3.284

Weighing Factors A

: 0.7

B

: 0.4

C

: 0.8

D

: 1.0

E

: 0.3


:AxBxCxDxE : 0.7 x 0.4x 0.3x 1.0 x 0.3 : 0.0252

Collection Area AC

:

π H2

:

π (23.4) 2 2

: 1719.338 m structure per year P

: 1719.338 x 3.284 x 10-


: Ac x Ng x 10-

6

: Therefore, the overall risk Factor

6

5.67x 10-3


Therefore for Water tank Lightning Protection is essential.

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WATER TANK (227000 LITRES) 2 Nos: Diameter(D)

:9.4 M

Height (H)

: 24.55 M


: 3.284

Weighing Factors A

: 0.7

B

: 0.4

C

: 0.8

D

: 1.0

E

: 0.3


:AxBxCxDxE : 0.7 x 0.4x 0.3x 1.0 x 0.3 : 0.0252

Collection Area AC

:

π H2

:

π (24.55) 2 2

: 1892.485 m

6


: Ac x Ng x 10-


: 1892.485 x 3.284 x 10:


6

6.21x 10-3



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KAGINA GUEST HOUSE: Length (L)

: 40 M

Width ( W)

: 15 M

Height (H)

: 10 M


: 3.284

Weighing Factors A

: 1.2

B

: 0.4

C

: 1.7

D

: 0.4

E

: 0.3


:AxBxCxDxE : 1.2 x 0.4 x 1.7 x 0.4 x 0.3 : 0.0979

Collection Area AC

2

: (L x W) + 2(L x H) + 2(W x H) +

πΗ

: (40x15)+2(40x10)+2(15x10) +π

(10)

:

2

2014 m

6


: AC x Ng x 10-


: 2014 x 3.284 x 10-

6



: 6.47 x 10-4 which is greater than 10Therefore Lightning Protection is essential for Kagina Guest House .

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MANAGEMENT TRAINEE HOSTEL: Length (L)

: 17 M

Width ( W)

:

Height (H)

: 10 M


: 3.284

M

Weighing Factors A

: 1.2

B

: 0.4

C

: 1.7

D

: 0.4

E

: 0.3


:AxBxCxDxE : 1.2 x 0.4 x 1.7 x 0.4 x 0.3 : 0.0979

Collection Area AC

2

: (L x W) + 2(L x H) + 2(W x H) +

πΗ

: (40x15)+2(40x10)+2(15x10) +π

(10)

:

2

2014 m

6


: AC x Ng x 10-


: 2014 x 3.284 x 10-

6



: 6.47 x 10-4 which is greater than 10Therefore Lightning Protection is essential for Management Trainee hostel .

2


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V. P BUNGALOW: Length (L)

: 22.76 M

Width ( W)

: 15.25M

Height (H)

: 6.80 M


: 3.284

Weighing Factors A

: 1.2

B

: 0.4

C

: 1.7

D

: 0.4

E

: 0.3


:AxBxCxDxE : 1.2 x 0.4 x 1.7 x 0.4 x 0.3 : 0.0979

Collection Area AC

: (L x W) + 2(L x H) + 2(W x H) +

πΗ

2

: (10x22.76)+(5.58x14.11)+(10x4.1)+2(8.65X4.1) +(5.58X6.8)+2(14.11X6.8)+(15.25X6.8)+π :

2

861.53 m

6


: AC x Ng x 10-


: 861.53 x 3.284 x 10-

6



: 2.76 x 10-4 which is greater than 10Therefore Lightning Protection is essential for Vice president Bungalow .

(6.8)

2


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SPORTS CLUB: Length (L)

: 55 M

Width ( W)

: 20M

Height (H)

: 18 M


: 3.284

Weighing Factors A

: 1.3

B

: 0.4

C

: 1.7

D

: 1.0

E

: 0.3


:AxBxCxDxE : 1.3 x 0.4 x 1.7 x 1.0 x 0.3 : 0.2652

Collection Area AC

: (L x W) + 2(L x H) + 2(W x H) + : (55x20)+2(55x18)+2(20x18)+ :

πΗ

2

π (18)

2

4817.36 6


: AC x Ng x 10-


: 4817.36 x 3.284 x 10-

6



Therefore Lightning Protection is essential for Sports club building .

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QUARY CRUSHER: Length (L)

: 24 M

Width ( W)

: 12M

Height (H)

: 15 M


: 3.284

Weighing Factors A

: 1.0

B

: 0.8

C

: 0.8

D

: 1.0

E

: 0.3


:AxBxCxDxE : 1.0 x 0.8 x 0.8 x 1.0 x 0.3 : 0.192

Collection Area AC

πΗ

: (24x12)+2(24x15)+2(12x15)+π

(15)

:

2

2074.9 m

6


: AC x Ng x 10-


: 2074.9 x 3.284 x 10-

6


2

: (L x W) + 2(L x H) + 2(W x H) +


Therefore Lightning Protection is essential for Quary crusher .

5

2


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WATER TANK IN RIVER PUMP AREA 3 Nos: Diameter(D)

:4 M

Height (H)

: 12 M


: 3.284

Weighing Factors A

: 0.7

B

: 0.4

C

: 0.8

D

: 1.0

E

: 0.3


:AxBxCxDxE : 0.7 x 0.4x 0.3x 1.0 x 0.3 : 0.0252

Collection Area AC

:

π H2

:

π (12) 2

: 452.16 m

2

6


: Ac x Ng x 10-


: 452.16 x 3.284 x 10:


6

1.48x 10-3



5


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5.0 Resistance of Pipe Electrode (Ref. 9.2.2 of IS: 3043-1987) Re = 100 x ρ 2xπxl Where

loge 4 x l d

l = length of the rod or pipe = 300 cm. d = diameter of the rod or pipe = 3.8 cm. ρ = resistivity of soil = 312 Ω -m assumed uniform. Re = 100 x 312 2 x π x 300

loge 4 x 300 3.8

= 16.55 loge 315.789 = 41.36 Ω. Resistance of the Earth Strip 50 x 6 G.I Flat Old Wadi plant 5.1.1 Bulk loading silo Rs

= 100

ρ Log e

2π L

2L

2

wt

L=Estimated Length Strip

: 12500 cm

Width of the Strip (t)

: 50 x 6 mm

Depth of the Buried Strip (W)

:

Rs

= 100 x 312

Log

e

2 x 12500

2x3.14x12500

60 cm 2

=

2.38 Ω

60x5

There are 3 Nos of earth pits are used, therefore Re

Rt

=

=

Re /3

Re

x Rs

Re + Rs

=

=

41.36 / 3

13.78 X 2.38

= 13.78 Ω

=

2.03 Ω

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 conductor.

earth


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5.1.2

Cement storage silo Rs

= 100

ρ Log e

2π L

2L

2

wt


: 14640 cm

Width of the Buried Strip (t)

: 50 x 6 mm


:

Rs

= 100 x 312

Log

e

2 x 14640

2x3.14x14640

60 cm 2

=

2.0 Ω

60x5


=

Rt

=

Re /2 Re

=

x Rs

=

Re + Rs

41.36 / 2 20.68 X 2

= 20.68 Ω =

1.8 Ω

20.68+2.


5.1.3

Kiln No:3 Preheater Rs

= 100

ρ Log e

2π L

2L

2

wt


: 30160 cm


: 50 x 6 mm


:

Rs

= 100 x 312

Log

e

2 x 30160

2x3.14x30160

60 cm 2

=

60x5


=

Re /2

=

41.36 / 2

= 20.68 Ω

1.1172 Ω

earth


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Rt

=

Re

x Rs

=

Re + Rs

20.68 X 1.1172

=

1.054 Ω

20.68+1.1172.

Thus the Total resistance is less than 3 ohms . 50x6 G.I Flat strip is selected for vertical down conductor and horizondal conductor. 5.1.4

earth

Cement Mill Building Rs

= 100

ρ Log e

2L

2π L

2

wt


: 20405.6 cm


: 50 x 6 mm


:

Rs

= 100 x 312

Log

e

60 cm

2 x 20405.6

2x3.14x20405.6

2

=

1.568 Ω

60x5

There are 2 Nos of earth pits are used, therefore Re Rt

= =

Re /2 Re

x Rs

Re + Rs

= =

41.36 / 2 20.68 X 1.568

= 20.68 Ω =

1.4469 Ω

20.68+1.568.


earth


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5.1.5

Cement Mill Building 4 & 5 Rs

= 100

ρ Log e

2L

2π L

2

wt


: 20405.6 cm


: 50 x 6 mm


:

Rs

= 100 x 312

Log

e

60 cm

2 x 20405.6

2x3.14x20405.6

2

=

1.568 Ω

60x5


= =

Re /2 Re

x Rs

= 20.68 Ω

=

41.36 / 2

=

20.68X 1.568

Re + Rs

=

1.4469 Ω

20.68+1.568.


Cement Mill Control Room Rs

= 100

ρ Log e

2L

2π L

2

wt


: 10394.8 cm


: 50 x 6 mm


:

Rs

= 100 x 312

Log

2x3.14x10394.8

e

60 cm

2 x 10394.8 60x5

Only one earth pit is used, therefore Re

=

Re /1 =

41.36 / 1

= 41.36 Ω

2

=

2.799 Ω

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Rt

=

Re

x Rs

=

Re + Rs

41.36 X 2.799

=

2.6 Ω

41.36+2.799.


earth

Packing Plant Rs

= 100

ρ Log e

2π L

2L

2

wt


: 17730 cm


: 50 x 6 mm


:

Rs

= 100 x 312

Log

e

2 x 17730

2x3.14x17730

60 cm 2

=

1.77 Ω

60x5


Rt

=

=

Re /2 =

Re

x Rs

41.36 / 2

=

Re + Rs

= 20.68 Ω

20.68 X 1.77

=

1.68 Ω

20.68+1.77.


Cement silo Expansion Rs

= 100

ρ Log e

2π L

2L

2

wt


: 32033 cm


: 50 x 6 mm


:

60 cm

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Rs

= 100 x 312

Log

e

2 x 32033

2x3.14x32033

2

=

1.07 Ω

60x5


Rt

=

=

Re /2 =

Re

= 20.68 Ω

41.36 / 2

x Rs

=

Re + Rs

20.68 X 1.07

=

1.0 Ω

20.68+1.07.


earth

Kiln No:1& 2 Preheater Rs

= 100

ρ Log e

2π L

2L

2

wt


: 25672 cm


: 50 x 6 mm


:

Rs

= 100 x 312

Log

e

2 x 25672

2x3.14x25672

60 cm 2

=

1.285 Ω

60x5

Only one earth pit is used, therefore Re

Rt

=

=

Re /1 =

Re

x Rs

Re + Rs

41.36 / 1

=

= 41.36 Ω

41.36X1.285

=

1.240 Ω

41.36+1.285.


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5.1.10

Raw Mill 4 & 5 Rs

= 100

ρ Log e

2π L

2L

2

wt


: 56730cm


: 50 x 6 mm


:

Rs

= 100 x 312

Log

e

60 cm

2 x 56730

2x3.14x56730

2

=

0.64 Ω

60x5


Rt

=

=

Re /2 =

Re

41.36 / 2= 20.68 Ω

x Rs

=

Re + Rs

20.68X0.64

=

0.62 Ω

20.68+0.64.


Coal Mill Rs

= 100

ρ Log e

2π L

2L

2

wt


: 52000cm


: 50 x 6 mm


:

Rs

= 100 x 312

Log

e

2 x 52000

2x3.14x52000

60 cm 2

=

60x5


=

Re /2 =

41.36 / 2= 20.68 Ω

0.64 Ω

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Rt

=

Re

x Rs

=

Re + Rs

20.68X0.64

=

0.62 Ω

20.68+0.64.


earth

5.1 Power plant 5.2.1 DG Set Rs

= 100

ρ Log e

2π L

2L

2

wt


: 63800cm


: 50 x 6 mm


:

Rs

= 100 x 312

Log

e

2 x 63800

2x3.14x63800

60 cm 2

=

0.578 Ω

60x5


Rt

=

=

Re /3 =

Re

x Rs

41.36 / 3= 13.78 Ω

=

Re + Rs

13.78X0.578

=

0.55 Ω

13.78+0.578

Thus the Total resistance is less than 3 ohms . 50x6 G.I Flat strip is selected for vertical down conductor and horizondal conductor. 5.2.2 T.G CPP Building Rs

= 100

ρ Log e

2π L

2L

2

wt

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: 81802.2cm


: 50 x 6 mm


:

Rs

= 100 x 312

Log

e

60 cm

2 x 81802.2

2x3.14x81802.2

2

0.588 Ω

=

60x5


Rt

=

=

Re /4 =

Re

41.36 / 4= 10.34 Ω

x Rs

=

Re + Rs

10.34X0.588

=

0.5532 Ω

10.34+0.588


5.2.3 Chimney-1 Rs

= 100

ρ Log e

2π L

2L

2

wt


: 23659cm


: 50 x 6 mm


:

Rs

= 100 x 312

Log

e

2 x 23659

2x3.14x23659

60 cm 2

=

60x5


=

Re /2 =

41.36 / 2= 20.68 Ω

1.379 Ω

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Rt

=

Re

x Rs

=

Re + Rs

20.68X1.379

=

1.285 Ω

20.68+1.379.


earth

Chimney-2 Rs

= 100

ρ Log e

2π L

2L

2

wt


: 24899cm


: 50 x 6 mm


:

Rs

= 100 x 312

Log

e

2 x 24899

2x3.14x24899

60 cm 2

=

1.379 Ω

60x5

There are 2 Nos of earth pits are used, therefore

Re

Rt

=

=

Re

Re /2 =

x Rs

Re + Rs

=

41.36 / 2= 20.68 Ω

20.68X1.379

=

1.285 Ω

20.68+1.379.


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5.3

Colony

5.3.1 Water Tank (454000 Litres) Rs

= 100

ρ Log e

2L

2π L

2

wt


: 15875.2cm


: 50 x 6 mm


:

Rs

= 100 x 312

Log

e

60 cm

2 x 15875.2

2x3.14x15875.2

2

=

1.94 Ω

60x5


=

=

Re

Re /2 =

x Rs

=

Re + Rs

41.36 / 2= 20.68 Ω 20.68X1.94

=

1.764 Ω

20.68+1.94.


Water Tank (227000 Litres) Rs

= 100

ρ Log e

2π L

2L

2

wt


: 13329.2cm


: 50 x 6 mm


:

60 cm

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Rs

= 100 x 312

Log

e

2 x 13329.2

2x3.14x13329.2

2

2.26 Ω

=

60x5


Rt

=

=

Re

Re /2 =

x Rs

=

Re + Rs

41.36 / 2= 20.68 Ω

20.36X2.26

=

2.0 Ω

20.36+2.26.


Kagina Guest house Rs

= 100

ρ Log e

2π L

2L

2

wt


: 22100cm


: 50 x 6 mm


:

Rs

= 100 x 312

Log

e

60 cm

2 x 22100

2x3.14x22100

2

=

1.46 Ω

60x5


Re

Rt

=

=

Re

Re /2 =

x Rs

Re + Rs

=

41.36 / 2= 20.68 Ω

20.36X1.46 20.36+1.46.

=

1.35 Ω

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earth

V.P Bungalow Rs

= 100

ρ Log e

2π L

2L

2

wt


: 14194m


: 50 x 6 mm


:

Rs

= 100 x 312

Log

e

60 cm

2 x 14194

2x3.14x14194

2

=

2.14 Ω

60x5


Re

Rt

=

=

Re

Re /2 =

x Rs

Re + Rs

=

41.36 / 2= 20.68 Ω

20.36X2.14

=

1.925 Ω

20.36+2.14.


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Sports Club Rs

= 100

ρ Log e

2π L

2L

2

wt


: 33200m


: 50 x 6 mm


:

Rs

= 100 x 312

Log

e

2 x 33200

2x3.14x33200

60 cm 2

=

1.027 Ω

60x5


Re Rt

=

=

Re

Re /2 =

x Rs

Re + Rs

=

41.36 / 2= 20.68 Ω 20.36X1.027

=

0.97 Ω

20.36+1.027.


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6.0

RESULTS

a) 38 mm ID,3 M long pipe suggested for earth pit refer drg. No. E-ECBA565-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 the drawing. d) The Lightning conductor shall be placed at the topmost height of every Building. 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 inorder to reduce the leakage current. h) All the down conductors shall have a test Link arrangement between the arrestor and Earthpit. Old Wadi plant Area: Location of Lightning Conductor

the

No.of Lightnin g Conduct or. 2

No.of Earth Pits

2

3

One Arrestor at each silo.

Packing plant

1

2

Shall be placed at the topmost structure.

Cement storage silo

2

2

Arrestor Shall be placed at the topmost structure.

Cement mill building 4&5

2

2

Arrestor Shall be placed at topmost structure.

Raw mill 4&5

2

2


Coal mill

2

2

Arrestor Shall be placed at the topmost

KilnNo-1&2 Preheater Bulk loading cement silo

Remarks

2


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structure. Kiln No.3 preheater

2

2


Cement expansion

4

4

4 silo in a line.In each silo one arrestor shall be placed.

2

2


silo

Cement mill building

Colony Area Note: The Horizotal Air terminations to be Placed as marked in the drawing for Water Tanks and Gust houses. Description

No.of Earth Pit 2

Remarks

Water Tank (2 Nos)

No.of Arrestor 2

Kagina guest house

1

2

One Arrestor is already existing No need to provide additional arrestor.

Management hostel

1

2

One Arrestor is already existing No need to provide.

V.P Bungalow

1

2

One Arrester is already existing No need to provide.

Sports club

2

2

One Arrestor is placed, one more should be placed.

trainee

One Arrestor is placed in each Tank. So no need to provide additional arrestor.


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Power plant Area Note: The Horizotal Air terminations to be Placed as marked in the drawing for D.G set building & T.G building. As the Chimneys are provided with the 2 nos of 25x3 GI Flat as down conductor, the same shall be retained as it is and the required earth value of less than 3 ohms should be confirmed. Description

No.of Earth Pit 3

Remarks

D.G Set

No.of Arrestor 2

T.G CPP building

10

4

7 Arrestor is already existing remaining 3 should be placed as per drawing.

Chimney 2Nos

2

4

One Arrestor is existing in each chimney. No need to provde.

Two Arrestor is existing. No need to provide.

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.

Lightning Calculations

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