REVISION
NO.
1A
1B
DESCRIPTION
ISSUED FOR REVIEW
ISSUED FOR
CONSTRUCTION
DATE
ORIGINATOR
REVIEWER
APPROVER
11/10/19
AFA
KK
RV
22/11/19
AFA
KK
RV
Page 2 of 18
TITLE
DOCUMENT NO.
REVISION NO.
LIGHTNING PROTECTION ASSESSMENT
REQUIREMENT
0591-8530-CA-0007
1B
DSN NO.:
1048
Contents
1.0
SCOPE
4
2.0
REFERENCE DOCUMENTS
4
3.0
BASIS OF STUDY
4
4.0
LIGHTNING PROTECTION CALCULATION FOR COLUMN C-2753
4
5.0
LIGHTNING PROTECTION CALCULATION FOR COLUMN C-2751
9
6.0
LIGHTNING PROTECTION CALCULATION FOR VESSEL V-2751
13
7.0
CONCLUSION
18
Page 3 of 18
TITLE
DOCUMENT NO.
REVISION NO.
1.0
LIGHTNING PROTECTION ASSESSMENT
REQUIREMENT
0591-8530-CA-0007
1B
DSN NO.:
1048
SCOPE
The purpose of this study is to evaluate the lightning risk of LPG4 project in order to keep the
risk of human-life loss (labelled “R1” in SS 555 Standard) below the tolerable value, fixed by SS
555 Standard.
2.0
REFERENCE DOCUMENTS
No
1
Document No
SS 555: Part 1: 2018
2
SS 555: Part 2: 2018
3
0591-8530-71-0002
Description
Code of practice for protection against lightning (general
principles)
Code of practice for Protection against lightning (risk
management)
LPG4- Area classification layout
3.0
BASIS OF STUDY
3.1
Lightning ground flash density is considered as 15 flashes/Sq.km/year as per SS-555-1. (As per
Figure ZB.2-Singapore ground flash density map given in SS-555 part-1, Bukom Plant location
falls under 10 to 15 flashes/sqkm/year, hence conservative value has been considered for the
study).
3.2
For the structure, the risks are calculated for loss of human life (R1) as per Clause no. 6 of the SS
555-Part 2.
3.3
Factor for Loss of Human Life “R1” shall be less than the tolerable risk factors RT (1X10-5) as per
Table-4 of SS 555-Part 2.
3.4
The following equipment are considered in this lightning protection study report.
No
Equipment
Material
Height (m)
Diameter (m) Thickness (mm)
1
Column C-2753
Carbon steel
19.6
1.85
23
2
Column C-2751
Carbon steel
15.3
1.2
26
3
Vessel V-2751
Carbon steel
8.3
2
38
This equipment are located by surrounding objects of the same height or smaller and provided
with fire fighting equipment (fire water sprinkler) surrounding them.
4.0
LIGHTNING PROTECTION CALCULATION FOR COLUMN C-2753
4.1
Composition of Risk Component (R1: Risk of loss of human life in structure)
For loss of human life, following risk components are identified,
RA: Risk component (injury to living beings – flashes to a structure)
RB: Risk component (physical damage to structure -flashes to the structure)
RU: Risk components (injury to living beings -flashes to a connected service)
RV: Risk Component (physical damage to structure-flashes to a connected service)
Page 4 of 18
TITLE
DOCUMENT NO.
REVISION NO.
LIGHTNING PROTECTION ASSESSMENT
REQUIREMENT
0591-8530-CA-0007
1B
DSN NO.:
1048
Hence, total Risk of loss of human life is calculated as below,
R1 = RA + RB + RU + RV
4.2
To Calculate RA (Risk component injury to living beings – flashes to a structure)
4.2.1
As per Cl. 6.2 of SS-555-Part 2,
RA = ND X PA X LA
Where,
ND: Number of dangerous events due to flashes to a structure.
PA: Probability of injury to living beings (flashes to a structure)
LA: Loss related to injury to living beings
4.2.2
To Calculate ND (Number of dangerous events due to flashes to a structure),
ND = NG x AD x CD x 10-6 (As per Cl. A.2.4 of SS-555-Part 2)
Where,
NG : Lightning ground flash density (1/km2 x year)
AD: Collection area of the isolated structure (m2)
CD: Location factor of the structure
In above equation,
NG=15 flashes/Sq.km.
CD = 0.5, As per Table A.1 of SS-555-Part 2 (Structure surrounded by structure of same heights or
smaller)
Collection area of a Column, AD = π (R+3H)2
For Column with 1.85 metres diameter & 19.6 metres Height, AD = 11206 m2
Therefore, ND = 15 X 11206 X 0.5 x 10-6 = 0.084
4.2.3
To Calculate PA (Probability of injury to living beings by electric shock)
As per equation B.1 in Annexure B of SS-555-Part 2,
PA = PTA X PB
Where,
PTA: Probability of reducing PA depending on protection measures against touch and step voltages
(Values to be selected as per Table B.1 of Annexure B SS-555-Part 2)
PB: Probability of physical damage to structure - Flashes to structure. (Values of PB depends on
the protection measure provided to reduce physical damage. Values shall be selected as per Table
B.2 of Annexure B of SS-555-Part 2)
Page 5 of 18
TITLE
DOCUMENT NO.
REVISION NO.
LIGHTNING PROTECTION ASSESSMENT
REQUIREMENT
0591-8530-CA-0007
1B
DSN NO.:
1048
Values Selected,
PTA = 1
No protection measures are provided
PB = 1
No protection measures are provided.
Therefore, PA = 1 X 1 = 1
4.2.4
To calculate LA (Loss related to injury to living beings)
As per equation C.1 of Annexure C of SS-555-Part 2
LA = rt X LT X nz / nt X tz/8760
Where,
rt : Factor reducing loss if human life depending on the type of soil or floor (Values to be selected
as per Table C.3 of Annexure C of SS-555-Part 2)
LT :Typical mean relative numbers of victims by physical damage due to one dangerous event
(Values to be selected as per Table C.2 of Annexure C of SS-555-Part 2)
nz : Number of persons in the Zone.
nt : Number of persons in the structure
tz : Time in hours per year for which the person are present in the Zone.
Values Selected,
rt = 10-2
Since, type of surface in case of Column C-2753 is concrete.
LT = 10-2
Since, for all types of structure 10-2 shall be selected.
nz/nt = 1,
Considered that number of persons in the Zone and number of persons in the structure are
equal
tz = 8760
Considering person present as worst case for 24 hours 365 days
Therefore , LA = 10-2 X 10-2 X 1 X (8760/8760)
Page 6 of 18
TITLE
DOCUMENT NO.
REVISION NO.
LIGHTNING PROTECTION ASSESSMENT
REQUIREMENT
0591-8530-CA-0007
1B
DSN NO.:
1048
Value of LA = 1 X 10-4
4.2.5
Substituting all the calculated values in following equation of RA,
RA = ND X PA X LA
RA = 0.084 X 1 X 1 X 10-4
Therefore , RA = 8.4 X 10-6
4.3
To Calculate RB (Risk component physical damage to structure -flashes to the structure)
4.3.1
As per Cl. 6.2 of SS-555-Part 2,
RB = ND X PB X LB
Where,
ND: Number of dangerous events due to flashes to a structure.
PB: Probability of physical damage to structure (flashes to a structure)
LB: Loss in a structure related to physical damage (flashes to structure)
4.3.2
Value of ND shall be 0.084 as Calculated in Cl. No. 4.2.2 above.
4.3.3
To Calculate PB
As per Table B.2 in Annexure B of SS-555-Part 2,
PB = 1,
No protection measures are provided.
4.3.4
To Calculate LB
As per equation C.3 of Annexure C of SS-555-Part 2
LB = rp X hz X rf X LF X nz / nt X tz/8760
Where,
rp : Factor reducing the loss due to provision against fire (Value to be selected as per Table C.4
of Annexure C of SS-555-Part 2)
hz : Factor increasing the loss when special hazard is present (Value to be selected as per Table
C.6 of Annexure C of SS-555-Part 2)
rf : Factor reducing loss depending on risk of fire or on the risk of explosion of the structure
(Value to be selected as per table C.5 of Annexure C of SS-555-Part 2)
LF = Typical mean relative numbers of victims by physical damage due to one dangerous event
(Value to be selected as per table C.2 of Annexure C of SS-55-Part 2)
nz : Number of persons in the Zone.
Page 7 of 18
TITLE
DOCUMENT NO.
REVISION NO.
LIGHTNING PROTECTION ASSESSMENT
REQUIREMENT
0591-8530-CA-0007
1B
DSN NO.:
1048
nt : Number of persons in the structure
tz : Time in hours per year for which the person are present in the Zone.
Value Selected,
rp = 0.5
For C-2753 column, the fire fighting equipment (fire water sprinkler) is provided
surrounding them. (Table C.4 of SS 555)
hz = 1 (as per table C.6 of Annexure C of SS-555-Part 2)
Since no special hazard applicable for Column C-2753.
rf = 10-3
Since, Hazardous Area Classification for Column C-2753 is considered as Zone 2 area
and risk of fire is considered as low. (Table C.5 of SS 555)
LF = 2 X 10-2
Since, Column C-2753 falls under Industrial type. (Table C.2 of SS 555)
nz/nt = 1,
Considered that number of persons in the Zone and number of persons in the structure are
equal
tz = 8760
Considering person present as worst case for 24 hours 365 days
Therefore, LB = 0.5 X 1 X 10-3 X 2 X 10-2 X 1 X (8760/8760)
Value of LB = 1 X 10-5
4.3.5
Substituting all the calculated values in following equation of RB
RB = ND X PB X LB = 0.084 X 1 X 1 X 10-5 = 8.4 X 10-7
4.4
To calculate RU - Risk components (injury to living beings -flashes to a connected service)
The column structure to be protected in this case, the concrete circular column is not connected
to any other service and hence Ru is considered as not applicable.
4.5
To calculate RV
Page 8 of 18
TITLE
DOCUMENT NO.
REVISION NO.
LIGHTNING PROTECTION ASSESSMENT
REQUIREMENT
0591-8530-CA-0007
1B
DSN NO.:
1048
The column structure to be protected in this case, the concrete circular column is not connected
to any other service and hence Ru is considered as not applicable.
4.6
CALCULATION OF R1
Substituting all the calculated values of RA and RB obtained from above equations,
R1 = 8.4 X 10-6 + 8.4 X 10-7
R1 = 9.24 X 10-6
Hence Total R1(Risk of loss of human life in structure) is less than tolerable risk factor RT
(1X10-5), column C-2753 is protected.
5.0
LIGHTNING PROTECTION CALCULATION FOR COLUMN C-2751
5.1
Composition of Risk Component (R1: Risk of loss of human life in structure)
For loss of human life, following risk components are identified,
RA: Risk component (injury to living beings – flashes to a structure)
RB: Risk component (physical damage to structure -flashes to the structure)
RU: Risk components (injury to living beings -flashes to a connected service)
RV: Risk Component (physical damage to structure-flashes to a connected service)
Hence, total Risk of loss of human life is calculated as below,
R1 = RA + RB + RU + RV
5.2
To Calculate RA (Risk component injury to living beings – flashes to a structure)
5.2.1
As per Cl. 6.2 of SS-555-Part 2,
RA = ND X PA X LA
Where,
ND: Number of dangerous events due to flashes to a structure.
PA: Probability of injury to living beings (flashes to a structure)
LA: Loss related to injury to living beings
5.2.2
To Calculate ND (Number of dangerous events due to flashes to a structure),
ND = NG x AD x CD x 10-6 (As per Cl. A.2.4 of SS-555-Part 2)
Where,
NG : Lightning ground flash density (1/km2 x year)
AD: Collection area of the isolated structure (m2)
CD: Location factor of the structure
In above equation,
NG=15 flashes/Sq.km.
Page 9 of 18
TITLE
DOCUMENT NO.
REVISION NO.
LIGHTNING PROTECTION ASSESSMENT
REQUIREMENT
0591-8530-CA-0007
1B
DSN NO.:
1048
CD = 0.5, As per Table A.1 of SS-555-Part 2 (Structure surrounded by structure of same heights or
smaller)
Collection area of a Column/Tank, AD = π (R+3H)2
For Column with 1.2 metres diameter & 15.3 metres Height, AD = 6793 m2
Therefore, ND = 15 X 6793 X 0.5 x 10-6 = 0.051
5.2.3
To Calculate PA (Probability of injury to living beings by electric shock)
As per equation B.1 in Annexure B of SS-555-Part 2,
PA = PTA X PB
Where,
PTA: Probability of reducing PA depending on protection measures against touch and step voltages
(Values to be selected as per Table B.1 of Annexure B SS-555-Part 2)
PB: Probability of physical damage to structure - Flashes to structure. (Values of PB depends on
the protection measure provided to reduce physical damage. Values shall be selected as per Table
B.2 of Annexure B of SS-555-Part 2)
Values Selected,
PTA = 1
No protection measures are provided
PB = 1
No protection measures are provided.
Therefore, PA = 1 X 1 = 1
5.2.4
To calculate LA (Loss related to injury to living beings)
As per equation C.1 of Annexure C of SS-555-Part 2
LA = rt X LT X nz / nt X tz/8760
Where,
rt : Factor reducing loss if human life depending on the type of soil or floor (Values to be selected
as per Table C.3 of Annexure C of SS-555-Part 2)
LT :Typical mean relative numbers of victims by physical damage due to one dangerous event
(Values to be selected as per Table C.2 of Annexure C of SS-555-Part 2)
nz : Number of persons in the Zone.
Page 10 of 18
TITLE
DOCUMENT NO.
REVISION NO.
LIGHTNING PROTECTION ASSESSMENT
REQUIREMENT
0591-8530-CA-0007
1B
DSN NO.:
1048
nt : Number of persons in the structure
tz : Time in hours per year for which the person are present in the Zone.
Values Selected,
rt = 10-2
Since, type of surface in case of Column C-2751 is concrete.
LT = 10-2
Since, for all types of structure 10-2 shall be selected.
nz/nt = 1,
Considered that number of persons in the Zone and number of persons in the structure are
equal
tz = 8760
Considering person present as worst case for 24 hours 365 days
Therefore , LA = 10-2 X 10-2 X 1 X (8760/8760)
Value of LA = 1 X 10-4
5.2.5
Substituting all the calculated values in following equation of RA,
RA = ND X PA X LA
RA = 0.051 X 1 X 1 X 10-4
Therefore , RA = 5.1 X 10-6
5.3
To Calculate RB (Risk component physical damage to structure -flashes to the structure)
5.3.1
As per Cl. 6.2 of SS-555-Part 2,
RB = ND X PB X LB
Where,
ND: Number of dangerous events due to flashes to a structure.
PB: Probability of physical damage to structure (flashes to a structure)
LB: Loss in a structure related to physical damage (flashes to structure)
5.3.2
Value of ND shall be 0.051 as Calculated in Cl. No. 5.2.2 above.
5.3.3
To Calculate PB
As per Table B.2 in Annexure B of SS-555-Part 2,
PB = 1,
Page 11 of 18
TITLE
DOCUMENT NO.
REVISION NO.
LIGHTNING PROTECTION ASSESSMENT
REQUIREMENT
0591-8530-CA-0007
1B
DSN NO.:
1048
No protection measures are provided.
5.3.4
To Calculate LB
As per equation C.3 of Annexure C of SS-555-Part 2
LB = rp X hz X rf X LF X nz / nt X tz/8760
Where,
rp : Factor reducing the loss due to provision against fire (Value to be selected as per Table C.4
of Annexure C of SS-555-Part 2)
hz : Factor increasing the loss when special hazard is present (Value to be selected as per Table
C.6 of Annexure C of SS-555-Part 2)
rf : Factor reducing loss depending on risk of fire or on the risk of explosion of the structure
(Value to be selected as per table C.5 of Annexure C of SS-555-Part 2)
LF = Typical mean relative numbers of victims by physical damage due to one dangerous event
(Value to be selected as per table C.2 of Annexure C of SS-55-Part 2)
nz : Number of persons in the Zone.
nt : Number of persons in the structure
tz : Time in hours per year for which the person are present in the Zone.
Value Selected,
rp = 0.5
For C-2751 column, the fire fighting equipment (fire water sprinkler) is provided
surrounding them. (Table C.4 of SS 555)
hz = 1 (as per table C.6 of Annexure C of SS-555-Part 2)
Since no special hazard applicable for Column C-2751.
rf = 10-3
Since, Hazardous Area Classification for Column C-2751 is considered as Zone 2 area
and risk of fire is considered as low. (Table C.5 of SS 555)
LF = 2 X 10-2
Since, Column C-2751 falls under Industrial type. (Table C.2 of SS 555)
nz/nt = 1,
Page 12 of 18
TITLE
DOCUMENT NO.
REVISION NO.
LIGHTNING PROTECTION ASSESSMENT
REQUIREMENT
0591-8530-CA-0007
1B
DSN NO.:
1048
Considered that number of persons in the Zone and number of persons in the structure are
equal
tz = 8760
Considering person present as worst case for 24 hours 365 days
Therefore, LB = 0.5 X 1 X 10-3 X 2 X 10-2 X 1 X (8760/8760)
Value of LB = 1 X 10-5
5.3.5
Substituting all the calculated values in following equation of RB
RB = ND X PB X LB = 0.051 X 1 X 1 X 10-5 = 5.1 X 10-7
5.4
To calculate RU - Risk components (injury to living beings -flashes to a connected service)
The column structure to be protected in this case, the concrete circular column is not connected
to any other service and hence Ru is considered as not applicable.
5.5
To calculate RV
The column structure to be protected in this case, the concrete circular column is not connected
to any other service and hence Rv is considered as not applicable.
5.6
CALCULATION OF R1
Substituting all the calculated values of RA and RB obtained from above equations,
R1 = 5.1 X 10-6 + 5.1 X 10-7
R1 = 5.61 X 10-6
Hence Total R1(Risk of loss of human life in structure) is less than tolerable risk factor RT
(1X10-5), column C-2751 is protected.
6.0
LIGHTNING PROTECTION CALCULATION FOR VESSEL V-2751
6.1
Composition of Risk Component (R1: Risk of loss of human life in structure)
For loss of human life, following risk components are identified,
RA: Risk component (injury to living beings – flashes to a structure)
RB: Risk component (physical damage to structure -flashes to the structure)
RU: Risk components (injury to living beings -flashes to a connected service)
RV: Risk Component (physical damage to structure-flashes to a connected service)
Hence, total Risk of loss of human life is calculated as below,
R1 = RA + RB + RU + RV
Page 13 of 18
TITLE
DOCUMENT NO.
REVISION NO.
LIGHTNING PROTECTION ASSESSMENT
REQUIREMENT
0591-8530-CA-0007
1B
DSN NO.:
1048
6.2
To Calculate RA (Risk component injury to living beings – flashes to a structure)
6.2.1
As per Cl. 6.2 of SS-555-Part 2,
RA = ND X PA X LA
Where,
ND: Number of dangerous events due to flashes to a structure.
PA: Probability of injury to living beings (flashes to a structure)
LA: Loss related to injury to living beings
6.2.2
To Calculate ND (Number of dangerous events due to flashes to a structure),
ND = NG x AD x CD x 10-6 (As per Cl. A.2.4 of SS-555-Part 2)
Where,
NG : Lightning ground flash density (1/km2 x year)
AD: Collection area of the isolated structure (m2)
CD: Location factor of the structure
In above equation,
NG=15 flashes/Sq.km.
CD = 0.5, As per Table A.1 of SS-555-Part 2 (Structure surrounded by structure of same heights or
smaller)
Collection area of a Vessel, AD = π (R+3H)2
For Vessel with 2 metres diameter & 8.3 metres Height, AD = 2107 m 2
Therefore, ND = 15 X 2107 X 0.5 x 10-6 = 0.016
6.2.3
To Calculate PA (Probability of injury to living beings by electric shock)
As per equation B.1 in Annexure B of SS-555-Part 2,
PA = PTA X PB
Where,
PTA: Probability of reducing PA depending on protection measures against touch and step voltages
(Values to be selected as per Table B.1 of Annexure B SS-555-Part 2)
PB: Probability of physical damage to structure - Flashes to structure. (Values of PB depends on
the protection measure provided to reduce physical damage. Values shall be selected as per Table
B.2 of Annexure B of SS-555-Part 2)
Values Selected,
PTA = 1
Page 14 of 18
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DOCUMENT NO.
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LIGHTNING PROTECTION ASSESSMENT
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DSN NO.:
1048
No protection measures are provided
PB = 1
No protection measures are provided.
Therefore, PA = 1 X 1 = 1
6.2.4
To calculate LA (Loss related to injury to living beings)
As per equation C.1 of Annexure C of SS-555-Part 2
LA = rt X LT X nz / nt X tz/8760
Where,
rt : Factor reducing loss if human life depending on the type of soil or floor (Values to be selected
as per Table C.3 of Annexure C of SS-555-Part 2)
LT :Typical mean relative numbers of victims by physical damage due to one dangerous event
(Values to be selected as per Table C.2 of Annexure C of SS-555-Part 2)
nz : Number of persons in the Zone.
nt : Number of persons in the structure
tz : Time in hours per year for which the person are present in the Zone.
Values Selected,
rt = 10-2
Since, type of surface in case of Vessel V-2751 is concrete.
LT = 10-2
Since, for all types of structure 10-2 shall be selected.
nz/nt = 1,
Considered that number of persons in the Zone and number of persons in the structure are
equal
tz = 8760
Considering person present as worst case for 24 hours 365 days
Therefore , LA = 10-2 X 10-2 X 1 X (8760/8760)
Value of LA = 1 X 10-4
6.2.5
Substituting all the calculated values in following equation of RA,
Page 15 of 18
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DOCUMENT NO.
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LIGHTNING PROTECTION ASSESSMENT
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DSN NO.:
1048
RA = ND X PA X LA
RA = 0.016 X 1 X 1 X 10-4
Therefore , RA = 1.6 X 10-6
6.3
To Calculate RB (Risk component physical damage to structure -flashes to the structure)
6.3.1
As per Cl. 6.2 of SS-555-Part 2,
RB = ND X PB X LB
Where,
ND: Number of dangerous events due to flashes to a structure.
PB: Probability of physical damage to structure (flashes to a structure)
LB: Loss in a structure related to physical damage (flashes to structure)
6.3.2
Value of ND shall be 0.016 as Calculated in Cl. No. 6.2.2 above.
6.3.3
To Calculate PB
As per Table B.2 in Annexure B of SS-555-Part 2,
PB = 1,
No protection measures are provided.
6.3.4
To Calculate LB
As per equation C.3 of Annexure C of SS-555-Part 2
LB = rp X hz X rf X LF X nz / nt X tz/8760
Where,
rp : Factor reducing the loss due to provision against fire (Value to be selected as per Table C.4
of Annexure C of SS-555-Part 2)
hz : Factor increasing the loss when special hazard is present (Value to be selected as per Table
C.6 of Annexure C of SS-555-Part 2)
rf : Factor reducing loss depending on risk of fire or on the risk of explosion of the structure
(Value to be selected as per table C.5 of Annexure C of SS-555-Part 2)
LF = Typical mean relative numbers of victims by physical damage due to one dangerous event
(Value to be selected as per table C.2 of Annexure C of SS-55-Part 2)
nz : Number of persons in the Zone.
nt : Number of persons in the structure
tz : Time in hours per year for which the person are present in the Zone.
Page 16 of 18
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DOCUMENT NO.
REVISION NO.
LIGHTNING PROTECTION ASSESSMENT
REQUIREMENT
0591-8530-CA-0007
1B
DSN NO.:
1048
Value Selected,
rp = 0.5
For V-2751, the fire fighting equipment (fire water sprinkler) is provided surrounding them.
(Table C.4 of SS 555)
hz = 1 (as per table C.6 of Annexure C of SS-555-Part 2)
Since no special hazard applicable for Vessel V-2751.
rf = 10-3
Since, Hazardous Area Classification for Vessel V-2751 is considered as Zone 2 area
and risk of fire is considered as low. (Table C.5 of SS 555)
LF = 2 X 10-2
Since, V-2751 falls under Industrial type. (Table C.2 of SS 555)
nz/nt = 1,
Considered that number of persons in the Zone and number of persons in the structure are
equal
tz = 8760
Considering person present as worst case for 24 hours 365 days
Therefore, LB = 0.5 X 1 X 10-3 X 2 X 10-2 X 1 X (8760/8760)
Value of LB = 1 X 10-5
6.3.5
Substituting all the calculated values in following equation of RB
RB = ND X PB X LB = 0.016 X 1 X 1 X 10-5 = 1.6 X 10-7
6.4
To calculate RU - Risk components (injury to living beings -flashes to a connected service)
The vessel structure to be protected in this case, the concrete circular vessel is not connected to
any other service and hence Ru is considered as not applicable.
6.5
To calculate RV
The vessel structure to be protected in this case, the concrete circular vessel is not connected to
any other service and hence Rv is considered as not applicable.
6.6
CALCULATION OF R1
Page 17 of 18
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DOCUMENT NO.
REVISION NO.
LIGHTNING PROTECTION ASSESSMENT
REQUIREMENT
0591-8530-CA-0007
1B
DSN NO.:
1048
Substituting all the calculated values of RA and RB obtained from above equations,
R1 = 1.6 X 10-6 + 1.6 X 10-7
R1 = 1.76 X 10-6
Hence Total R1(Risk of loss of human life in structure) is less than tolerable risk factor RT
(1X10-5), vessel V-2751 is protected.
7.0
CONCLUSION
The calculation result R1 (risk of loss of human life in structure) as per 4.6, 5.6 and 6.6, is less
than tolerable tolerable risk factor RT (1X10-5).
However, one air terminal shall be provided for C-2753, C-2751 and V-2751 as a safety measure
against lightning strike.
Page 18 of 18