Furuno WR2120 Installation Manual page 55

2.3. Risk Assessment Conclusion
Values of the risk components for the unprotected structure are reported in the regulation.
The public service loss (L2) and the economic loss (L4) are relevant for this type of structure. It is
required to evaluate the need for protection. This implies the determination of the risk
risk for L4 with the risk components
tolerable risk
the tolerable risk.
According to the IEC 62305-2, calculation of the risk parameters is shown as follows:
Table A-4: Risk components for different types of damage and source of damage (IEC 62305-2)
Damage
S1
D2
D3
Calculation of the risk components requirement is as shown in the Table A-5.
Table A-5: Weather radar at CWRP: Environment and structure characteristics
Input parameter
Ground flash density
Number of over voltages [1/year]
Structure dimensions [m]
Location factor of structure
Use the エラー! 参照元が見つかりません。A-4 and the Table A-5, risk assessment result will be
calculated. The result is shown in the Table A-6. Therefore considering current condition, the
weather radar is not protected by existing lightning rods. Total risk value is exceeded of the
tolerable risk value.
We'll propose solution for this later, protecting the radar by additional lightning rod and adapt LPL
Class IV. Assessment for this solution is also shown in the Table A-6. According to the result is
almost half of the tolerable risk value, so the condition of the radar turned into safe.
Type of damage
D2: Physical Damage
D3 failure of
internal systems
Total
Tolerable
. Suitable protection measures will be selected to reduce the risk to or below
Source of damage
S2
Table A-6: Risk assessment result at CWRP
Symbol Current Condition
13
and
S3
Symbol
L, W, H
Protected by LPL IV
0
0
0.01
0.1323
-6
3.36 x 10
-4
3.36 x 10
0.134
NG
S2E-17-0209_IM_WR2120_C
for L2 and
and to compare it with the
S4
Value
16.8
-3
2.709 x 10
0
13.227
-4
3.36 x 10
-2
3.36 x 10
0.95, 0.95, 3.177
0.5
0
0
0.0005
-6
1.37 x 10
-7
1.68 x 10
-5
1.68 x 10
0.00052
Safety