Vol. 5, No. 6, June 2024
E-ISSN: 2723-6692
P-ISSN: 2723-6595
http://jiss.publikasiindonesia.id/
Journal of Indonesian Social Sciences, Vol. 5, No. 6, June 2024 1370
Quantitative Fire Risk Assessment of Crude Oil Tank at
Company A
Andralisa Febriani, Fatma Lestari
Universitas Indonesia, Depok, Indonesia
Email: andralisafebr[email protected], fat[email protected]
Correspondence: andralisafebrian[email protected]m
*
KEYWORDS
ABSTRACT
Quantitative Risk Assessment;
Fire; Tank; Crude Oil
The oil and gas industry has a high risk of losses due to fire. There have
been several fire incidents in the oil industry involving fires in crude oil
tanks. The objective of this research is to assess the level of fire risk in
Crude Oil Tank T32 at Company. The research method used is to analyze
the frequency of fire occurrences using event tree analysis and modeling
the consequences of fires using ALOHA software. After conducting
frequency analysis and consequence modeling, individual risk and social
risk are calculated. Results: Based on the results of consequence modeling,
the furthest distance for heat radiation with a 100% risk of death is 84
meters. The largest risk calculation result is in the leaky tank scenario with
a hole size of 100 mm with an individual risk value of 1,84 x 10-
8
and a
social risk value of 3,13 x 10-
7
. The results of the T32 tank fire risk
assessment at Company A's oil collection tank facility show that individual
and social risks are still within the acceptable risk category according to
the UK HSE Risk Acceptance Criteria. Even though the risk of a fire incident
is still within acceptable limits, risk control efforts still need to be carried
out so that the risk remains within acceptable tolerance limits.
Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)
1. Introduction
Fire is a problem that is often faced in Indonesia and other countries. As industrialization
develops, the risk of fire increases, especially in the oil and gas sector (Lestari et al., 2021). In the last
century, a series of major accidents, such as the Flixborough, Bhopal, and Piper Alpha, have been in
the spotlight on the potential dangers posed by the chemical industry and the impact of those hazards
on the surrounding communities (FIChemE & Richardson, 2018; Pitblado et al., 1990). In the 2018-2019
period, there were 4 fire cases whose losses were included in the top 20 in the 30 years since 1988
(Robb, 2020).
Some fires in the oil and gas industry involve crude oil tanks. For example, the case of the
Huangdao depot fire in Qingdao in 1989 which caused 19 people to die with losses of up to 35.4
million yuan (Dong, 2013; Yuan et al., 2021). In addition, the Gulf Oil refinery fire in Philadelphia in
1975 which lasted for 10 days caused 8 fire brigades to die (Quivik, 2015; Yoshida, 2019).
Facilities that are more than 30 years old have the potential to suffer losses. In the first 10 years
of factory operation, most of the losses are caused by operation-related failures, such as not following
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operating procedures or work permits. As the facility's operating experience grew, the number of
losses due to these things decreased. Failures related to mechanical integrity cause 65% of losses.
Deterioration in equipment/piping integrity becomes more common as plants age, which can
increase the risk of fire.
Company A has a final oil gathering facility, a place where all crude oil is collected before being
distributed to the Port for transportation by oil tankers. This failure stores crude oil in the form of
heavy oil and light oil which have a risk of burning. Company A's oil collection facility has been
operating for more than 50 years, so the potential for losses is quite high.
In order to fulfill compliance with Law No. 1 of 1970, Company A highly upholds the aspect of
occupational safety to protect workers, the environment, assets and the reputation of the company.
Because this facility is a facility where crude oil flows, this facility is very critical and needs to be kept
safe to avoid fires. If there is an operational disruption, the production and distribution of crude oil
from this company will result in losses for both the Company and the State.
In the concept of risk management, conducting assessments related to risks that can occur is
important to be able to control risks. For this reason, studies related to fire risk are carried out as a
basis for risk control. The purpose of this study is to look at the potential for fires in crude oil tanks
in companies using ALOHA software.
2. Materials and Methods
This study is a non-experimental quantitative study. Data analysis is processed using software
based on possible fire scenarios. This quantitative study framework uses the reference of The Centre
for Marine and Petroleum Technology (Sponge, 1999) presented in Figure 1.
Figure 1 Quantitative Study Framework
Data collection related to the research object is carried out as input data to conduct this
quantitative study. The data is in the form of geographic, meteorological data, tank specifications, fuel
characteristics, operational process conditions, and the environment around the research object.
Then, the researcher identified the fire hazard on the research object (T32 tank). The results of hazard
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identification continued to be analyzed for frequency analysis and analysis of fire modeling
consequences. Event tree analysis is used to analyze the frequency of fires, while ALOHA software is
used to analyze the consequences of fire modeling. After conducting frequency and consequence
analysis, a risk analysis was carried out by calculating individual risk and societal risk. The concept of
as low as reasonably practicable (ALARP) is used to evaluate whether the risk is still acceptable or not.
The upper limit of individual risk for ALARP is 1 x 10-3, while the lower limit is 1 x 10-6 (HaSPA, 2012).
Figure 2 Risk Levels and ALARP (modified from HSE, 1988)
3. Results and Discussions
Company A's Crude Oil Collecting Facility is the largest facility where all crude oil produced is
stored before being distributed to customers through a port that is also operated by Company A. The
facility, which has an area of 400,000 m2, consists of 16 crude oil collection tanks which are divided
into 2 types of crude oil, namely light oil and heavy oil. This facility operates for 24 hours with 2 shifts
(morning and night), and the number of workers is 17 people at any time.
The T32 tank is an oil collection tank (hydrocarbon) located at the final crude oil collection
facility in Company A. This tank holds crude oil of the light oil type, which is a class 1-C flammable
liquid based on the category in NFPA 30 (2021). The T32 tank is a vertical tank type atmospheric tank
with a fixed cone roof with a height of 17.07 m and a diameter of 90.53 m. The storage capacity of this
tank is around 674,840 bbls. This tank is located in an area close to other facilities besides company
facilities, such as other company facilities and public facilities. The following is the distance from the
T32 Tank and other facilities around it.
Table 1 Distance of the T32 Tank to the Surrounding Facilities
Facilities
Distance
(m)
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Control Room Building
380
Main Office
540
Fire Station
680
Product Oil Depot Facilities
355
Gas Metering Facilities
600
Highway
655
Residential Areas
800
Fire Hazard Identification
Although there is no history of fires at this facility, the potential danger in the operation of the
crude oil collection tank cannot be ignored. The potential for oil spills and fires can occur if not
controlled. Process failures such as declining equipment integrity and overpressure or overfilling
have the consequence of fuel leakage that has the potential to cause fires that have an impact on
workers, communities, the environment, and company assets. The worst possible scenario for the
T32 tank that is used as the object of this study is a fire in the embankment (dike), which functions as
the secondary containment of the T32 tank. The identification of this scenario is intended so that the
company can ensure that the readiness of this fire control equipment can be met according to its
needs.
Table 2 Fire Hazard Identification
Early Events
Consequences
Leakage
Pool fire in tank
Pool fire in a dike
Analysis of Fire Frequency
Referring to the Risk Assessment Data Directory OGP RADD 434-3 of 2010 for the frequency of
leaks in atmospheric tanks, the frequencies for leaking and ruptured tank failures are presented in
Table 3. (OGP, 2010a)
Table 3 Frequency of Leaks
Initiating Event
Hole Size
(mm)
Failure Mode
Release
Frequency (per
tank per year)
Leak (continuous
release)
Small
5
Minor
3.0 x 10
-4
Medium
25
Major
1.0 x 10
-4
Large
100
Major
1.0 x 10
-4
Cracked (instantaneous release)
> 250
Catastrophic
5.0 x 10
-6
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The results of the analysis of the frequency of pool fires using the event tree analysis (ETA)
method in the Bevi Risk Assessments version 3.2 – Module B Reference Manual with a probability of
direct ignition of 0.065 are as follows (RIVM, 2009).
Table 4 Pool Fire Scenario Frequency Analysis
Scenario
Pool Fire
frequency per
year
Leak
5 mm
1,95 x 10
-5
25 mm
6,5 x 10
-6
100 mm
6,5 x 10
-6
Cracked
>250 mm
3,25 x 10
-7
Fire Consequence Modeling Analysis
The results of modeling the consequences of the Pool Fire event are presented in Table 5. The
heat radiation generated by the pool fire incident produces varying exposure distances. This is
affected by the size of the leak and the speed of the wind. The release of heat radiation with the worst
impact, which is 35 KW/m2, can result in death at a rate of 100% if exposed to humans (OGP, 2010b).
The worst consequence value is at a distance of 84 meters, namely a scenario where the tank ruptures
(holes of more than 250 mm) with a wind speed of 20 m/s. Referring to Table 5, the distance
generated from heat radiation does not affect other facilities presented in Table 1.
Table 5 Results of Modeling the Consequences of Pool Fire Events
Initiating
Event
Hole Size
(mm)
Wind
Speed
(m/s)
Thermal Radiation Distance (m)
35 kW/m2
12,5 kW/m2
6,3 kW/m2
Leaks
(continuous
release)
5
1B
< 10
< 10
< 10
5D
< 10
< 10
< 10
20D
< 10
< 10
< 10
25
1B
< 10
< 10
14
5D
< 10
15
19
20D
11
14
17
100
1B
19
38
56
5D
29
50
67
20D
38
49
59
Rupture
(instantaneous
release)
>250
1B
52
97
139
5D
61
108
149
20D
84
111
137
An illustration of the results of modeling the consequences of pool fire events in ALOHA
software is shown in Figure 3. The thermal radiation threat zone is displayed with three color
contours, namely, yellow, orange and red. The contour shown in yellow indicates a radiation exposure
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Journal of Indonesian Social Sciences, Vol. 5, No. 6, June 2024 1375
area of 6.3 KW/m2, then the contour shown in orange indicates a radiation exposure area of 12.5
KW/m2, while the contour shown in red (innermost) indicates a radiation exposure area of 35
KW/m2.
Figure 3 Thermal Radiation Threat Zone yang Dihasilkan Software ALOHA
Risk Analysis
Results from individual risk calculations (CCPS, 1999) presented in table 6. The individual risk
value in the leak tank scenario with a hole size of 25 mm is 1.54 x
10-9
while for a hole size of 100 mm
is 1.84 x 10-8. Then the individual risk value in the leak tank scenario with a hole size of 250 mm is
4.50 x 10-9. By looking at the results of this individual risk value, the incidence of pool fires in the T32
tank shows that it is still within acceptable limits.
Table 6 Individual Risk Calculation Results
Scenario
Area
Terdampak
(m
2
)
Consequenc
e Impact
Fatality
Probabilit
y
Event
Frequency
(per year)
Individual
Risk
(per year)
Conclusion
Leaks
5 mm
0
0
1,95 x 10
-5
1,95 x 10
-5
0
Acceptable
25 mm
94,9
2,37 x 10
-4
6,5 x 10
-6
6,5 x 10
-6
1,54 x 10
-9
Acceptable
100 mm
1.133,5
2,83 x 10
-3
6,5 x 10
-6
6,5 x 10
-6
1,84 x 10
-8
Acceptable
Crack
ed
>250 mm
5.538,9
1,38 x 10
-2
3,25 x 10
-7
3,25 x 10
-7
4,50 x 10
-9
Acceptable
After calculating individual risks, societal risk calculations are carried out to see the risks that
may occur in a community, in this case, the group of workers in facilities that may be affected. The
number of permanent daily workers at this facility is 17 people. By looking at the results of the
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consequence modeling for pool fire occurrences, the worst thermal radiation value is 35 kW/m2
(which can result in death at a rate of 100% if exposed to humans), then the possibility of affected
workers does not exist. However, in this calculation of societal risk, it is assumed that these 17
workers are in the worst thermal radiation range . The results of the social risk assessment are as
follows:
Table 7 Societal Risk Calculation Results
Scenario
Jumlah
Orang
Societal Risk
Kesimpulan
Bocor
5 mm
17
0
Negligible
25 mm
17
2,62 x 10
-8
Negligible
100 mm
17
3,13 x 10
-7
Negligible
Pecah
>250 mm
17
7,65 x 10
-8
Negligible
The societal risk value in the leak tank scenario with a hole size of 25 mm is 2.62 x 10-8, while
for a hole size of 100 mm, it is 3.13 x 10-7. Then, the societal risk value in the leak tank scenario with
a hole size of 250 mm is 7.65 x 10-8. Based on these results, the incidence of pool fires in T32 tanks is
still within acceptable limits.
Figure 4 Societal Risk Criteria (modified from NSW Government, 2011)
4. Conclusion
The T32-tank fire risk assessment results at Company A's oil collection tank facility show that
individual and social risks are still within the acceptable risk category according to HSE UK's Risk
Acceptance Criteria. Although the risk of fire events is still within acceptable limits, risk control efforts
still need to be carried out so that the risk is still within acceptable tolerance limits. Some of the efforts
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Journal of Indonesian Social Sciences, Vol. 5, No. 6, June 2024 1377
that can be made to control risks include identifying hazards in each work process, ensuring that the
workers involved have appropriate qualifications and competencies, ensuring that the equipment
used is in good condition and in accordance with the work being done, ensuring the completeness of
documents in carrying out each work, ensuring the integrity of equipment/instruments in the work
process, ensuring the preparedness of emergency resources fire and integrity of the fire protection
system, ensuring access control into the facility is carried out properly to maintain safety in the
facility, providing education to workers regarding all hazards in the facility, evaluating the work
process including contractor performance.
5. References
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