Tables of Assumptions

This section summarizes the assumptions adopted in the QRA study. These are broadly categorised as population, meteorological, frequency, consequence and plant data assumptions.

1 Terminal

1.1 Population

Table 1.1 Residential Population

Location	Approx. Distance from Terminal Site	2011 Population	2021 Population
Fan Lau Tai Long Wan Tseun Shek Pik Prison Tung Wan School Shui Hau Ma Po Ping Prison Tong Fuk Cheung Sha Villas Cheung Sha San Shek Wan Pui Wo Ham Tin Mong Tung Wan Sea Ranch Tai Long Shek Kwu Chau South Lantau Hospital	7km 7km 7km 6km 6km 6km 7km 9km 9km 10km 11km 11km 11km 10km 11km 8km 9km	52 293 824 152 375 1,728 1,133 665 597 156 2,628 859 43 313 34 43 90	52 293 824 152 375 1,728 1,133 665 597 156 2,628 859 43 313 34 43 90

Table 1.2 Road Population

Location	Approx. Distance from Terminal Site	2011 Population	2021 Population
South Lantau Road	7km	5/km	5/km

Table 1.3 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 1.4 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 1.5 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 (excluding fast ferries)

Figure 1.2 Marine Population at Risk by Grid, Year 2021 (excluding fast ferries)

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*, 2021

* 75% in daytime, 25% in night time

Table 1.6 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 1.7 Helicopter Population

Population	Daytime Flights	Night time flights
12 per flight	2 return flights per hour	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 Helicopters	0.1 1 0.5 0.1 0.3 0.3 0.9 0.9 1

1.2 Meteorological Data

Table 1.9 Weather Data Adopted from Cheung Chau Weather Station (2003)

1.3 Frequency Analysis

Table 1.10 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 1.11 LNG Storage Tank Release Ignition Probabilities

	Ignition Probability
Immediate ignition Delayed ignition 1 Delayed ignition 2	0.3 0.1 0.6

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.

1.4 Consequence Analysis/Plant Data

Table 1.12 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/m^3)	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 Battery Limit	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

2 Pipeline

2.1 Segmentation of Route

Figure 2.1 Segmentation of Route

Table 2.1 Pipeline Segmentation

Section		Gate [2]		Kilometre Post		Length (km)	Typical water depth (m)	Trench type
		From	To	From	To
1 2 3 4 5 6 7 8 9 10 11 12	South Soko Approach West Soko Adamasta Channel West Lantau Tai O North Lantau Sha Chau North Lung Kwu Chau Urmston Road West Urmston Road central Urmston Road East Black Point Approach	LP2 IP1 IP2 IP4 IP5a IP7 IP7a IP10 IP10a	IP1 IP2 IP4 IP5a IP7 IP7a IP10 IP10a LP1	0 1.6 4.5 9.8 14.2 19.5 22.2 31.6 33.5 34.7 37.0 37.8	1.6 4.5 9.8 14.2 19.5 22.2 31.6 33.5 34.7 37.0 37.8 38.3	1.6 2.9 5.3 4.4 5.3 2.7 9.4 1.9 1.2 2.3 0.8 0.5	5 8 25 20 17 7 6 4 20 20 5 4	2A 1 3B/3A 3A 3B 1 1 1 3B/3A 3A/3B 1 2B

2.2 Marine Vessel Classification

Table 2.2 Vessel Classes Adopted for Assessment

2.3 Marine Traffic

Table 2.3 Traffic Volume Assumed for Base Case 2011

		Traffic volume (ships per day)
Section		Fishing	River-trade	Ocean-going	Fast Launch	Fast ferry	Other	Total
1 2 3 4 5 6 7 8 9 10 11 12	Soko Approach West Soko Adamasta Channel West Lantau Tai O North Lantau Sha Chau North Lung Kwu Chau Urmston Road West Urmston Road Central Urmston Road East Black Point Approach	0 21 126 11 42 37 79 21 21 250 11 2	0 0 16 2 1 12 22 3 2 265 13 3	0 0 7 3 4 0 0 0 6 144 0 0	1 2 83 4 7 5 28 24 23 117 5 2	0 6 260 9 12 11 44 31 30 150 7 0	0 4 4 4 4 6 27 8 2 5 2 0	1 33 496 33 70 71 200 87 84 931 38 7
	Total	621	339	164	301	560	66	2051

Table 2.4 Traffic Volume Assumed for 2021 “No Tonggu” Case

		Traffic volume (ships per day)
Section		Fishing	River-trade	Ocean-going	Fast Launch	Fast ferry	Other	Total
1 2 3 4 5 6 7 8 9 10 11 12	Soko Approach West Soko Adamasta Channel West Lantau Tai O North Lantau Sha Chau North Lung Kwu Chau Urmston Road West Urmston Road Central Urmston Road East Black Point Approach	0 22 132 11 44 39 83 22 22 262 11 2	0 0 17 2 1 13 24 3 2 290 14 3	0 0 1 0 0 0 0 0 1 197 0 0	1 2 91 5 8 6 31 26 25 128 6 2	0 7 307 10 14 13 52 36 35 177 8 0	0 5 5 5 4 7 30 9 2 6 2 0	1 36 560 36 76 78 220 96 93 1102 41 7
	Total	650	369	263	331	659	76	2346

Table 2.5 Traffic Volume Assumed for 2021 “With Tonggu” Case

		Traffic volume (ships per day)
Section		Fishing	River-trade	Ocean-going	Fast Launch	Fast ferry	Other	Total
1 2 3 4 5 6 7 8 9 10 11 12	Soko Approach West Soko Adamasta Channel West Lantau Tai O North Lantau Sha Chau North Lung Kwu Chau Urmston Road West Urmston Road Central Urmston Road East Black Point Approach	0 22 132 11 44 39 83 22 22 262 11 2	0 0 17 2 1 13 24 3 2 290 14 3	0 0 162 3 4 0 0 0 7 85 0 0	1 2 91 5 8 6 31 26 25 128 6 2	0 7 307 10 14 13 52 36 35 177 8 0	0 5 5 5 5 7 30 9 2 6 2 0	1 36 714 36 76 78 220 96 93 948 41 7
	Total	650	369	199	331	659	76	2346

2.4 Marine Vessel Population

Table 2.6 Vessel Population and Population at Risk

Class	Population	% of trips	Fatality Probability	Population at Risk
Fishing vessels Rivertrade coastal vessels Ocean-going vessels Fast launches Fast ferries* Other	5 5 21 5 450 (largest ferry at 100% capacity) 350 (typical ferry at 100% capacity) 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	3.75 3.75 22.5 52.5 12.5 5	0.9 0.3 0.1 0.9 0.3 0.3 0.3 0.3 0.3 0.3 0.9	5 2 2 5 135 105 84 53 32 11 5
* A distribution was assumed for the fast ferry population to reflect the occupancy at different time periods so that on average, the population is similar to the average load factor published by the Marine Department.

2.5 Frequency Analysis

Table 2.7 Anchor Damage Frequencies used in this Study

Pipeline section	Frequency (/km/year)	Comment
South Soko Approach West Soko Adamasta Channel West Lantau Tai O North Lantau Sha Chau North Lung Kwu Chau Urmston Road West Urmston Road Central Urmston Road East Black Point Approach	1.37 x 10^-5 1.37 x 10^-5 8.6 x 10^-4 1 x 10^-4 8.6 x 10^-4 1 x 10^-4 1 x 10^-4 1 x 10^-4 8.6 x 10^-4 8.6 x 10^-4 1 x 10^-4 1 x 10^-4	Low marine traffic Low marine traffic High marine traffic Medium marine traffic Next to anchorage Medium marine traffic Medium marine traffic + some anchoring Medium marine traffic High marine traffic High marine traffic Medium marine traffic Medium marine traffic

Table 2.8 Failure Frequencies and Pipeline Protection Factors

Pipeline section	Trench type	Corrosion /defects (/km/year)	Anchor/Impact			Others /km/year	Total /km/year
			Frequency (/km/year)	Protection factor (%)
				anchor<2	Anchor>2
South Soko Approach West Soko Adamasta Channel West Lantau Tai O North Lantau Sha Chau North Lung Kwu Chau Urmston Road West Urmston Road Central Urmston Road East Black Point Approach	2A 1 3B/3A 3A 3B 1 1 1 3B/3A 3A/3B 1 2B	1.18 x 10^-6 1.18 x 10^-6 1.18 x 10^-6 1.18 x 10^-6 1.18 x 10^-6 1.18 x 10^-6 1.18 x 10^-6 1.18 x 10^-6 1.18 x 10^-6 1.18 x 10^-6 1.18 x 10^-6 1.18 x 10^-6	1.37 x 10^-5 1.37 x 10^-5 8.6 x 10^-4 1 x 10^-4 8.6 x 10^-4 1 x 10^-4 1 x 10^-4 1 x 10^-4 8.6 x 10^-4 8.6 x 10^-4 1 x 10^-4 1 x 10^-4	99 99 99.9 99.9 99.9 99 99 99 99.9 99.9 99 99	50 50 99 99 99 50 50 50 99 99 50 50	1.34 x 10^-6 1.34 x 10^-6 1.34 x 10^-6 1.34 x 10^-6 1.34 x 10^-6 1.34 x 10^-6 1.34 x 10^-6 1.34 x 10^-6 1.34 x 10^-6 1.34 x 10^-6 1.34 x 10^-6 1.34 x 10^-6	2.66 x 10^-6 2.66 x 10^-6 3.49 x 10^-6 2.70 x 10^-6 3.82 x 10^-6 3.52 x 10^-6 3.52 x 10^-6 3.52 x 10^-6 3.93 x 10^-6 4.58 x 10^-6 3.52 x 10^-6 3.52 x 10^-6

2.6 Scenario Development

Table 2.9 Hole Size Distribution for Corrosion and Other Failures

Table 2.10 Hole Size Distribution for Anchor Impact

Table 2.11 Ignition Probability

3 Gas Receiving Station

3.1 Population

3.1.1 Land Population

Table 3.1 Land Population

Location	Approx. Distance from GRS	2011 Population	2021 Population
Residential Population Industrial Population Black Point Site Surrounding Road Population Lung Kwu Tan Road	1km 1.3km	- 100 22/km	- 100 22/km

Table 3.2 Population Time Periods

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 3.3 Land Population Occupancy and Indoor/Outdoor Fractions

Population	Occupancy				% Outdoors
Type	Night	Peak	Weekday	Weekend day	Night	Peak	Weekday	Weekend day
Industrial Residential Road	10 % 100 % 10 %	10 % 50 % 100 %	100 % 20 % 50 %	10 % 80 % 20 %	5 % 0 % 0 %	10 % 30 % 0 %	10 % 10 % 0 %	10 % 20 % 0 %

3.1.2 Marine Population

Table 3.4 Vessel Population and Population at Risk

Class	Population	% of trips	Fatality Probability	Population at Risk
Fishing vessels Rivertrade coastal vessels Ocean-going vessels Fast launches Fast ferries* Other	5 5 21 5 450 (largest ferry at 100% capacity) 350 (typical ferry at 100% capacity) 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	3.75 3.75 22.5 52.5 12.5 5	0.9 0.3 0.1 0.9 0.3 0.3 0.3 0.3 0.3 0.3 0.9	5 2 2 5 135 105 84 53 32 11 5

Figure 3.1 Marine Population at Risk by Grid, Year 2011 (excluding fast ferries)

Figure 3.2 Marine Population at Risk by Grid, Year 2021 (excluding fast ferries)

Figure 3.3 Number of Fast Ferries Per Day by Grid, Year 2011

Figure 3.4 Number of Fast Ferries Per Day by Grid, Year 2021

Table 3.5 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

Figure 3.5 Stationary Marine Population at Risk (2011)

Figure 3.6 Stationary Marine Population at Risk (2021)

3.2 Meteorological Data

Table 3.6 Data for Sha Chau Weather Station

3.3 Frequency Analysis

Table 3.7 Ignition Probabilities

	Immediate Ignition	Delayed Ignition 1	Delayed Ignition 2	Delayed Ignition Probability	Total Ignition Probability
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

3.4 Consequence Analysis/Plant data

Table 3.8 Process Conditions Used for Discharge Rate Calculations

Code	Scenario Name	Fluid Phase	Nature of Section	No. of Items	Length of Section (m)	Pipe Diameter (mm)	Pressure (bara)	Temperature (ºC)	Density (kg/m^3)	Inventory (kg)	Normal Flow Rate (kg/s)
G01	Gas piping from shutdown valve through gas filter to control valve	Gas	Piping	1	25.5	750	91.18	11.93	92.73	1044	356.40
G02	Gas Heater Piping	Gas	Piping	4	4.5	250	90.68	43.39	73.9	16	54.84
G03	Pressure Control Assembly	Gas	Piping	2	3.9	450	88.68	77.49	61.84	38	135.31