This
section summarizes the assumptions adopted in the hazard assessment. These are
broadly categorised as population, meteorological, frequency, consequence and
plant data assumptions.
Table
1.1 Estimated
Residential Population Data
Location |
Approx. Distance from Terminal Site |
2011 Population |
2021 Population |
Lung
Kwu Tan village Ha Pak
Nai village Lung
Kwu Chau |
3km 3.7km 4km |
753 216 0 |
1,297 372 0 |
Table 1.2 Industrial Facility
Population
Location |
Approx. Distance from Terminal Site |
2011 Population |
2021 Population |
Black Point Site Surrounding WENT
Landfill Shui
Wing Steel Plant Siu Lang
Shui Landfill Site Office |
1km 3km 3.5km 4.5km 4.8km 4.9km |
100 194 1,102 177 390 7 |
100 194 1,102 177 390 7 |
Table 1.3 Road
Population
Location |
Approx. Distance from Terminal Site |
2011 Population |
2021 Population |
Lung |
1.2km |
22/km |
22/km |
Table 1.4 Population
Time Periods Definitions
Time Period |
Description |
Night
time Weekday Peak
hours Weekend
day |
7:00pm until 7:00am 9:00am till 5:00pm, Monday through Friday 7:00am to 9:00am and 5:00pm to 7:00pm, Monday to Friday 7:00am to 9:00am and 1:00pm to 3:00pm, Saturdays 3:00pm to 7:00pm Saturdays, and 7:00am to 7:00pm Sundays |
Table 1.5 Land
Population Occupancy and Indoor/Outdoor Fractions
Population |
Occupancy |
%
Outdoors |
||||||
Type |
Night |
Peak |
Weekday |
Weekend day |
Night |
Peak |
Weekday |
Weekend day |
Residential Prison Hospital School Road |
100 % 100 % 100 % 0 % 10 % |
50 % 110 % 120 % 10 % 100 % |
20 % 100 % 110 % 100 % 50 % |
80 % 110 % 120 % 10 % 20 % |
0 % 5 % 0 % 0 % 0 % |
30 % 100 % 30 % 100 % 0 % |
10 % 50 % 10 % 20 % 0 % |
20 % 50 % 30 % 20 % 0 % |
Table 1.6 Marine Vessel Population
Type of Vessel |
Average Population per Vessel |
% of Trips |
Ocean-Going
Vessel Rivertrade
Coastal vessel Fast
Ferries Tug
and Tow Others |
21 5 450
(largest ferries with max population) 350
(typical ferry with max population) 280
(typical ferry at 80% capacity) 175
(typical ferry at 50% capacity) 105
(typical ferry at 30% capacity) 35
(typical ferry at 10% capacity) 5 5 |
3.75 3.75 22.5 52.5 12.5 5.00 |
Figure
1.1 Marine
Population at Risk by Grid, Year 2011
Figure 1.2 Marine Population at
Risk by Grid, Year 2021
Figure 1.3 Number of Fast Ferries
Per Day*, 2011
* 75% in
daytime, 25% in night time
Figure 1.4 Number of Fast Ferries
Per Day*, 2011
* 75% in
daytime, 25% in night time
Table 17 Fast
Ferry Population Distribution for Day and Night Time Periods
Population |
Population at Risk |
% of Day Trips |
% of Night Trips |
% of All Trips (= 0.75 x day + 0.25 x night) |
450 350 280 175 105 35 |
135 105 84 53 32 11 |
5 5 30 60 - - |
- - - 30 50 20 |
3.75 3.75 22.5 52.5 12.5 5.0 |
Table 1.8 Fatality Factors
Population Type |
Fatality Probability |
Land
Population Indoor Outdoor Road vehicles Marine
Population Ocean-Going Vessel Rivertrade Coastal Vessel Fast Ferries Tug and Tow Others |
0.1 1 0.5 0.1 0.3 0.3 0.9 0.9 |
Table 2.1 Data
for Sha Chau Weather Station (2003)
|
Day |
Night |
||||||
Wind
Speed (m/s) |
2.5 |
2 |
3 |
7 |
2.5 |
2 |
3 |
7 |
Atmospheric
Stability |
B |
F |
D |
D |
B |
F |
D |
D |
Wind
Direction |
Percentage of
Occurrence |
|||||||
0° |
2.48 |
0.92 |
1.37 |
13.75 |
0.00 |
2.08 |
0.89 |
9.93 |
30° |
0.72 |
0.61 |
0.76 |
4.38 |
0.00 |
1.78 |
0.84 |
7.12 |
60° |
0.55 |
0.61 |
0.59 |
0.55 |
0.00 |
1.89 |
0.76 |
0.95 |
90° |
2.00 |
1.57 |
2.43 |
6.07 |
0.00 |
6.69 |
2.97 |
9.53 |
120° |
1.68 |
0.90 |
1.32 |
15.98 |
0.00 |
3.82 |
1.84 |
20.08 |
150° |
1.06 |
0.61 |
0.36 |
3.12 |
0.00 |
2.28 |
0.60 |
3.83 |
180° |
2.43 |
0.71 |
0.65 |
3.64 |
0.00 |
1.81 |
0.74 |
3.88 |
210° |
3.35 |
0.86 |
1.39 |
9.04 |
0.00 |
2.06 |
1.01 |
6.91 |
240° |
0.07 |
0.16 |
0.05 |
0.02 |
0.00 |
0.23 |
0.02 |
0.04 |
270° |
0.08 |
0.09 |
0.01 |
0.01 |
0.00 |
0.11 |
0.00 |
0.01 |
300° |
1.58 |
0.35 |
0.21 |
0.07 |
0.00 |
0.62 |
0.04 |
0.05 |
330° |
3.78 |
0.74 |
1.09 |
5.22 |
0.00 |
1.59 |
0.53 |
2.45 |
Table 3.1 Ignition
Probabilities
|
Immediate Ignition |
Delayed Ignition 1 |
Delayed Ignition 2 |
Delayed Ignition Probability |
Total Ignition Probability |
Liquid small leak |
0.01 |
0.035 |
0.005 |
0.04 |
0.05 |
Liquid large leak/rupture |
0.08 |
0.18 |
0.02 |
0.2 |
0.28 |
Gas small leak |
0.02 |
0.045 |
0.005 |
0.05 |
0.07 |
Gas large leak/rupture |
0.1 |
0.2 |
0.02 |
0.22 |
0.32 |
* Small leak = 10 and 25mm. Large leak = 50 and 100mm holes
Table 3.2 LNG Storage Tank Release
Ignition Probabilities
|
Ignition Probability |
Immediate
ignition Delayed
ignition 1 Delayed
ignition 2 |
0.7 0.2 0.1 |
Release Size
For piping and equipment, a range of release sizes are
considered, including 10mm, 25mm, 50mm, 100mm holes and full bore ruptures.
For LNG storage tanks, all failures are modelled at
catastrophic failures.
Table 4.1 Process
Conditions used for Calculating Discharge Rate
Code |
Scenario Name |
Fluid Phase |
Nature of Section |
No. of Items |
Length of Section (m) |
Pipe Diameter (mm) |
Pressure (bara) |
Temperature (ºC) |
Density (kg/m3) |
Inventory (kg) |
Pumping Rate (kg/s) |
L01 |
Liquid Piping from Tank to HP Pump |
Liquid |
Piping |
1 |
450 |
500 |
7.50 |
-161.5 |
464 |
40,977 |
248 |
L02 |
Liquid Unloading Arm |
Liquid |
Unloading Arm |
3 |
20 |
400 |
5.50 |
-161.5 |
464 |
1,166 |
601 |
L03 |
Liquid Transfer Pipe from Jetty to Shore End |
Liquid |
Piping |
2 |
300 |
700 |
5.50 |
-161.5 |
464 |
53,543 |
601 |
L04 |
Liquid from HP Pump Discharge to Vaporisers (ORV/SCV) |
Liquid |
Piping |
1 |
30 |
400 |
106 |
-155.2 |
464 |
1,748 |
251 |
L05 |
Liquid Transfer Pipe from Shore End to Tank |
Liquid |
Piping |
2 |
900 |
700 |
5.50 |
-161.5 |
464 |
160,630 |
601 |
L06 |
Liquid in Recondenser |
Liquid |
Process Vessel |
1 |
N/A |
N/A |
6.50 |
-160.5 |
463 |
46,300 |
100 |
G07 |
Gas from Metering Station to |
Gas |
Piping |
1 |
390 |
750 |
102 |
5.0 |
79.4 |
13,680 |
251 |
G08 |
Gas from Vaporisers (ORV/SCV) Outlet to Metering Station |
Gas |
Piping |
1 |
108 |
750 |
104 |
5.8 |
80.8 |
3,851 |
251 |
G09 |
Vapour Piping from Tank to Compressor |
Gas |
Piping |
1 |
450 |
600 |
1.08 |
-110.0 |
1.43 |
182 |
2.93 |
G10 |
Gas Piping from Compressor to Recondenser |
Gas |
Piping |
1 |
24 |
400 |
6.80 |
57.0 |
4.46 |
13 |
2.93 |
G11 |
Recycle Gas Piping from Compressor to Ship (till Shore
End) |
Gas |
Piping |
1 |
720 |
500 |
1.05 |
-120.2 |
1.49 |
211 |
4.74 |
G12 |
Recycle Gas Piping from Compressor to Ship (Shore End to
Jetty) |
Gas |
Piping |
1 |
300 |
500 |
1.05 |
-120.2 |
1.49 |
88 |
4.74 |
G13 |
Gas Piping from HP Compressor Discharge to Vaporiser
Outlet |
Gas |
Piping |
1 |
30 |
150 |
104 |
5.8 |
80.8 |
43 |
0.78 |
G14 |
Vapour Unloading Arm |
Gas |
Unloading Arm |
1 |
20 |
400 |
1.05 |
-120.2 |
1.49 |
4 |
4.54 |
P15 |
Ship Compressor |
Gas |
Pump |
1 |
1 |
450 |
23.0 |
35.0 |
16.2 |
51 |
3.00 |
P16 |
BOG Compressor |
Gas |
Pump |
1 |
1 |
400 |
6.80 |
57.0 |
4.46 |
11 |
1.50 |
P17 |
SCV Inlet/Outlet Piping |
Gas |
Piping |
5 |
10 |
400 |
106 |
5.8 |
82.3 |
103 |
25.0 |
P18 |
ORV Inlet/Outlet Piping |
Gas |
Piping |
5 |
10 |
400 |
106 |
5.8 |
82.3 |
103 |
50.3 |
P19 |
HP Pump Suction/Discharge Piping |
Liquid |
Piping |
10 |
10 |
400 |
106 |
-155.2 |
464 |
583 |
51.6 |
P20 |
In-Tank Pump Discharge Piping (on Tank Roof up to ESD
Valve) |
Liquid |
Piping |
1 |
150 |
400 |
7.30 |
-161.5 |
464 |
8,742 |
87.0 |
P21 |
Piping at Jetty between ESD Valves |
Liquid |
Piping |
1 |
300 |
600 |
5.50 |
-161.5 |
464 |
39,338 |
601 |
P22 |
HPBOG Compressor |
Gas |
Pump |
1 |
1 |
450 |
102 |
35.0 |
71.7 |
228 |
0.78 |
T23 |
LNG Storage Tank |
Liquid |
Tank |
3 |
N/A |
N/A |
1.08 |
-161.5 |
464 |
83,520,000 |
N/A |