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Nat. Hazards Earth Syst. Sci., 14, 891–900, 2014 www.nat-hazards-earth-syst-sci.net/14/891/2014/ doi:10.5194/nhess-14-891-2014 © Author(s) 2014. CC Attribution 3.0 License. Natural Hazards and Earth System Sciences Open Access Risk assessment study of fire following an earthquake: a case study of petrochemical enterprises in China J. Li 1,2 , Y. Wang 1,2 , H. Chen 1,2 , and L. Lin 1,2 1 Key Laboratory of Environmental Change and Natural Disaster of MOE, Beijing Normal University, No.19, XinJieKouWai St., HaiDian District, 100875, Beijing, China 2 Academy of Disaster Reduction and Emergency Management, Beijing Normal University, No.19, XinJieKouWai St., HaiDian District, 100875, Beijing, China Correspondence to: Y. Wang ([email protected]) Received: 13 January 2013 – Published in Nat. Hazards Earth Syst. Sci. Discuss.: 29 April 2013 Revised: 6 November 2013 – Accepted: 11 November 2013 – Published: 16 April 2014 Abstract. After an earthquake, the fire risk of petrochemi- cal enterprises is higher than that of other enterprises as it involves production processes with inflammable and explo- sive characteristics. Using Chinese petrochemical enterprises as the research object, this paper uses a literature review and case summaries to study, amongst others, the classifi- cation of petrochemical enterprises, the proportion of daily fires, and fire loss ratio. This paper builds a fire following an earthquake risk assessment model of petrochemical en- terprises based on a previous earthquake fire hazard model, and the earthquake loss prediction assessment method, cal- culates the expected loss of the fire following an earth- quake in various counties and draws a risk map. Moreover, this research identifies high-risk areas, concentrating on the Beijing–Tianjin–Tangshan region, and Shandong, Jiangsu, and Zhejiang provinces. Differences in enterprise type pro- duce different levels and distribution of petrochemical enter- prise earthquake fire risk. Furthermore, areas at high risk of post-earthquake fires and with low levels of seismic fortifica- tion require extra attention to ensure appropriate mechanisms are in place. 1 Introduction Petrochemical enterprises produce products under complex process conditions and can be described as having the follow- ing characteristics: airtight environments, high temperatures, high pressure, deep cooling and pipelining in most cases, and involve raw materials and products that are inflammable, explosive, toxic, and corrosive. Further, such processes are prone to catch fire in daily production because of a number of factors including operation errors and equipment failure. After a destructive earthquake strikes, fires are likely to occur in petrochemical enterprises with the leakage of inflammable and explosive substances, ignited by friction sparks or open flames as a result of earthquake damage to workshops, equipment, containers, and other structures. For example, during the Tangshan earthquake in China in 1976, a fire occurred in a synthetic fat factory in Tianjin, which totally destroyed the workshop after the sudden ex- plosion of the synthetic tower resulting from a rise in tem- perature and pressure due to a power failure after workshop frames collapsed. A fire also broke out in a chemical plant in Hangu because of the spontaneous combustion of sili- con dichloride following pipeline equipment damage with the collapse of buildings. Furthermore, a fire started in a fac- tory in Hangu when a violent shake threw glycerin into a strong oxidant potassium permanganate and caused a chem- ical reaction (Business Community, 2008). During Japan’s 2011 earthquake, numerous fires started in refineries in cities such as Sendai and Chiba, leading to a significant interrup- tion of factory production (Sohu News, 2011a, b). Therefore, post-earthquake fires (secondary fires) constitute the great- est threat and harm to petrochemical enterprises (Hui and Jiang, 2002). In 1976, fires in petrochemical enterprises ac- counted for 24 % of the total post-earthquake fires in Tianjin as a result of the Tangshan earthquake in China (Business Community, 2008). Published by Copernicus Publications on behalf of the European Geosciences Union.

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Page 1: Risk assessment study of fire following an earthquake: a ... · PDF filesparks or open flames as a result of earthquake damage to workshops, equipment, containers, ... in Hangu because

Nat. Hazards Earth Syst. Sci., 14, 891–900, 2014www.nat-hazards-earth-syst-sci.net/14/891/2014/doi:10.5194/nhess-14-891-2014© Author(s) 2014. CC Attribution 3.0 License.

Natural Hazards and Earth System

SciencesO

pen Access

Risk assessment study of fire following an earthquake: a case studyof petrochemical enterprises in China

J. Li 1,2, Y. Wang1,2, H. Chen1,2, and L. Lin 1,2

1Key Laboratory of Environmental Change and Natural Disaster of MOE, Beijing Normal University, No.19,XinJieKouWai St., HaiDian District, 100875, Beijing, China2Academy of Disaster Reduction and Emergency Management, Beijing Normal University, No.19, XinJieKouWai St.,HaiDian District, 100875, Beijing, China

Correspondence to:Y. Wang ([email protected])

Received: 13 January 2013 – Published in Nat. Hazards Earth Syst. Sci. Discuss.: 29 April 2013Revised: 6 November 2013 – Accepted: 11 November 2013 – Published: 16 April 2014

Abstract. After an earthquake, the fire risk of petrochemi-cal enterprises is higher than that of other enterprises as itinvolves production processes with inflammable and explo-sive characteristics. Using Chinese petrochemical enterprisesas the research object, this paper uses a literature reviewand case summaries to study, amongst others, the classifi-cation of petrochemical enterprises, the proportion of dailyfires, and fire loss ratio. This paper builds a fire followingan earthquake risk assessment model of petrochemical en-terprises based on a previous earthquake fire hazard model,and the earthquake loss prediction assessment method, cal-culates the expected loss of the fire following an earth-quake in various counties and draws a risk map. Moreover,this research identifies high-risk areas, concentrating on theBeijing–Tianjin–Tangshan region, and Shandong, Jiangsu,and Zhejiang provinces. Differences in enterprise type pro-duce different levels and distribution of petrochemical enter-prise earthquake fire risk. Furthermore, areas at high risk ofpost-earthquake fires and with low levels of seismic fortifica-tion require extra attention to ensure appropriate mechanismsare in place.

1 Introduction

Petrochemical enterprises produce products under complexprocess conditions and can be described as having the follow-ing characteristics: airtight environments, high temperatures,high pressure, deep cooling and pipelining in most cases,and involve raw materials and products that are inflammable,

explosive, toxic, and corrosive. Further, such processes areprone to catch fire in daily production because of a numberof factors including operation errors and equipment failure.

After a destructive earthquake strikes, fires are likelyto occur in petrochemical enterprises with the leakage ofinflammable and explosive substances, ignited by frictionsparks or open flames as a result of earthquake damageto workshops, equipment, containers, and other structures.For example, during the Tangshan earthquake in China in1976, a fire occurred in a synthetic fat factory in Tianjin,which totally destroyed the workshop after the sudden ex-plosion of the synthetic tower resulting from a rise in tem-perature and pressure due to a power failure after workshopframes collapsed. A fire also broke out in a chemical plantin Hangu because of the spontaneous combustion of sili-con dichloride following pipeline equipment damage withthe collapse of buildings. Furthermore, a fire started in a fac-tory in Hangu when a violent shake threw glycerin into astrong oxidant potassium permanganate and caused a chem-ical reaction (Business Community, 2008). During Japan’s2011 earthquake, numerous fires started in refineries in citiessuch as Sendai and Chiba, leading to a significant interrup-tion of factory production (Sohu News, 2011a, b). Therefore,post-earthquake fires (secondary fires) constitute the great-est threat and harm to petrochemical enterprises (Hui andJiang, 2002). In 1976, fires in petrochemical enterprises ac-counted for 24 % of the total post-earthquake fires in Tianjinas a result of the Tangshan earthquake in China (BusinessCommunity, 2008).

Published by Copernicus Publications on behalf of the European Geosciences Union.

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892 J. Li et al.: Risk assessment study of fire following an earthquake

The total output value of the Chinese petrochemical indus-try makes up more than 12 % of the gross industrial outputvalue (China Petroleum and Chemical Industry Association,2009). However, in terms of site selection, petrochemical en-terprises’ main concern is given to raw materials, producttransport, and industrial basis, with little or no considerationfor earthquakes. For example, a great many petrochemicalenterprises, such as the Jianfeng enterprise, Youxin chemi-cal plant, Hongda chemical plant, and Huafeng phosphoruschemical plant, are located along the Longmenshan Moun-tain fault belt where the Wenchuan earthquake occurred in2008. Furthermore, the layout of most petrochemical enter-prises significantly increases post-earthquake fire hazards.

From the perspective of the post-earthquake fire-causingmechanism of petrochemical enterprises, by summarizingthe regular pattern of general fire occurrence in differenttypes of enterprises, this paper can build a petrochemicalenterprise post-earthquake fire risk assessment model basedon the post-earthquake fire risk model put forward by ZhaoZhendong (Yu et al., 2003; Zhao et al., 2003) and earthquakeloss prediction assessment methods. A macroanalysis willfollow, with comments on the post-earthquake fire risk ofChinese petrochemical enterprises, and thus this paper canprovide a scientific basis for regional economic developmentand industrial planning.

2 Previous research

Currently, the most common analysis model to determine therate of post-earthquake fires is the empirical statistics regres-sion model. Its aim is to find the expression between the post-earthquake fire rate and post-earthquake fire factors using aregression analysis method based on statistics regarding his-torical earthquake damage.

Kobayashi (1984) performed a statistical regression anal-ysis with historical earthquake secondary fire data and ob-tained expressions between the earthquake secondary fire in-cidence rate and house collapse rate. The expressions are re-gression models built in linear, logarithmic, and index formswith the number of post-earthquake fires per square me-ter of building as dependent variables and building collapserates as independent variables. Scawthorn put forward a re-gression model (Scawthorn, 1986, 1996; Scawthorn et al.,1981), looking for a relationship between post-earthquakefire rates and earthquake intensity on the basis of collectingand analyzing data on 20th century post-earthquake fires inthe United States. His results have been applied to the soft-ware package HAZUS developed by the Federal EmergencyManagement Agency (FEMA) to assess loss under the ef-fect of multiple disasters, and to predict the number of post-earthquake secondary fires in the United States.

In studying the fire after the Northridge earthquake in Cal-ifornia, Trifunac and Todorovska (1997, 1998) found thatfire ignition rate models correlated with site intensity, peak

horizontal ground velocity, the number of red-tagged build-ings, and breaks in water pipes. Based on the Monte Carlosimulation and physics-based fire-spread/evacuation simula-tion, Nishino et al. (2012) considered a number of factors(number and location of fire outbreaks, firefighting at the ini-tial stages, weather, earthquake-related structural damage tobuildings, initial evacuee locations, and the obstruction ofroads) to simulate the burn-down risk and fire-fatality riskafter an earthquake. Zhao (2010) built an integrated soft-ware system for the dynamic simulation of fires followingan earthquake based on GIS; fire ignition, fire spread, andfire suppression were also considered in this system.

Tanaka (2012) studied the characteristics and problemsof fires following the Great East Japan Earthquake inMarch 2011, and he classified post-earthquake fires into threetypes: conventional types of fires unrelated to tsunami waves,conflagrations in coastal areas inundated by the tsunami, andthe peculiarities of tsunami-related fires. Fire characteristicsare different from fire types. Fire ignition rates should be doc-umented to determine the relative occurrence of gas, electri-cal, chemical and other types of fires (Trifunac and Todor-ovska, 1997).

The DOW Fire and Explosion Index method and the ICIMOND method, which was developed from the DOW Fire& Explosion Index by personnel at the Imperial Chemical In-dustries Mond division (Cai et al., 2009; Wang and Xu, 2009)have been adopted in petrochemical enterprise fire safety as-sessment studies for the quantitative study of the degree andloss of chemical fire risk on the basis of previous accidentstatistics, material potential energy, and the situation of cur-rent safety measures.

However, in view of there being relatively few studieson post-earthquake fires in petrochemical enterprises, Xu etal. (2002) presented methods to calculate the petrochemicalenterprise post-earthquake fire probability via research on therelationships among the probability of petrochemical enter-prise post-earthquake secondary fires, level of combustiblehazard classification, and the level of equipment damagefrom earthquakes. Chen (2010) researched the risk of in-dustrial enterprise secondary accidents in a natural disaster,based on energy transfer and fire dynamics energy theories,combined with a hazard and operability analysis (HAZOP)method.

3 Mechanism and assessment models of petrochemicalenterprise fire following an earthquake

Figure 1 shows the post-earthquake fire-causing mechanismof petrochemical enterprises. The earthquake first damagesworkshops and equipment (this loss is called earthquake di-rect loss) in petrochemical enterprises, then triggers the leak-age of flammable, explosive, toxic, and corrosive objects,which result in fire once they meet with an open flameor a spark caused by friction of some kind. Furthermore,

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22

1

2

Figure 1. Post-earthquake fire causing mechanism of the petrochemical enterprises. 3

Earthquake direct loss Fire loss

Fire

Aggravate

Earthquake

Reduction of fire-fighting capacity

Open flame or

spark by friction

Chemical reaction

Workshops damage

Equipment damage

……

Leakage of

flammable and

explosive objects

Total loss of the

fire following

earthquake

disaster chain

Petrochemical

enterprise

Source: Authors Fig. 1. Post-earthquake fire-causing mechanism of the petrochemi-cal enterprises.

the earthquake can cause damage to fire-fighting facilities,pipelines, and roads, which reduces fire-fighting capacity.Thus, it accelerates the spread of fire and fire loss is greater(loss is referred to as fire loss). The sum of the above twolosses is the total loss of the fire following an earthquake.

According to the above analysis, the calculation formulaof post-earthquake fire total loss EFL is shown as Eq. (1),where EL denotes the direct loss of the earthquake and FLthe fire loss.

EFL = EL + FL. (1)

It is necessary to classify the earthquake fire loss accordingto the petrochemical enterprise types that are susceptible tofire. The calculation formula of the direct earthquake loss ELin a certain petrochemical enterprise is shown in Eq. (2).

(ELRi

)k=

5∑j=1

P(Dj |Ri

)· lDj

· Wk. (2)

In Eq. (2), Dj refers to the damage level andP(Dj |Ri)

to the probability of the damage levelDj with the seismicground motion parameterRi . Furthermore,lDj

denotes theearthquake loss ratio of the damage levelDj , k the petro-chemical enterprise type, andWk the total fixed assets ofk-type petrochemical enterprises.

The calculation formula of a petrochemical enterprise’sfire loss FL is shown in Eq. (3).

(FLRi

)k=

1

5∑j=1

[P(Dj/Ri) · P (Fk/Dj)] · lf · W′

k. (3)

In Eq. (3), 1/C stands for safety measure failure coef-ficients,P(Fk/Dj ) for the post-earthquake fire occurrenceprobability ofk-type petrochemical enterprises,lf for the fireloss ratio, andW ′

k for the value ofk-type petrochemical en-terprises before the fire occurs.

Where a fire occurs after an earthquake,W ′

k stands forthe surplus value after the earthquake damage, as shown inEq. (4).

W ′

k = Wk − EL. (4)

In terms of the DOW Fire and Explosion Index assessmentmethod, because process control, physical isolation, and fireprevention measures can reduce fire loss, security compen-sation coefficientC is usually adopted to revise the index toensure that the final loss assessment value better conformsto reality. An earthquake often reduces the local fire-fightingcapacity, thus aggravating fire loss. In this case, the safetymeasure failure coefficient 1/C can be used to revise fire losswhen fire-fighting capacity has been reduced because of theearthquake.

Consulting the best safety measure compensation coef-ficient in the DOW Fire and Explosion Index assessmentmethod,C is established:C = 0.489 and 1/C = 2.05.

4 Macro-risk assessment of China petrochemicalenterprise fire following an earthquake

4.1 Earthquake hazard probability P(Dj |Ri) and lossratio lDj

The 2000 seismic ground motion zonation map of China(China Earthquake Administration, 2001), as shown inFig. 2, has seven levels:< 0.05g, 0.05g, 0.10g, 0.15g,0.20g, 0.30g and ≥ 0.40g, according to the seismic peakground acceleration (PGA) in each region and the 10 % ofprobability of exceedance in the class (medium hard) siteover 50 yr.

Earthquake loss assessment in China classifies the damagelevels of buildings into five levels: collapse, serious dam-age, medium damage, slight damage, and basically intact.Further, the assessment also provides (based on historicalearthquake damage and experimental data) the probabilityP(Dj |Ri) and loss ratiolDj

corresponding to different dam-age levels (earthquake loss prediction research team of ChinaEarthquake Administration, 1990; Institute of EngineeringMechanics, 2005), as shown in Table 1.

As industrial factory buildings are the main assets of petro-chemical enterprises, this paper takes the factory buildingloss ratio as the earthquake loss ratiolDj

of petrochemicalenterprises. In Eq. (2), thelDj

is the loss ratio of petrochem-ical enterprises suffering from different degrees of seismicdamage, and its range refers to the industrial factory build-ing damage loss ratio in post-earthquake field works – Part4: assessment of direct loss (GB/T 18208.4-2005) (Instituteof Engineering Mechanics, 2005), as shown in Table 2.

4.2 Petrochemical enterprise classificationk and assetvalueWk

A post-earthquake fire is subject to uncertainty due to numer-ous factors including the existence of combustibles, flamma-bility of combustibles, and earthquake damage levels. Pro-duction equipment, technological processes, raw materials,and semi-finished and final products vary among petrochem-ical enterprises, which result in different fire probabilities.

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894 J. Li et al.: Risk assessment study of fire following an earthquake

Fig. 2.Seismic ground motion parameter zonation map of China.

Table 1.The vulnerability matrix of industrial factory buildings.

Collapse Serious damage Medium damage Slight damage Basically intact

P(Dj |Ri = 0.05) 0 0 0.07 0.2 0.73P(Dj |Ri = 0.1–0.15) 0 0.03 0.12 0.28 0.57P(Dj |Ri = 0.20–0.3) 0.02 0.15 0.31 0.28 0.24P(Dj |Ri >= 0.4) 0.05 0.25 0.4 0.2 0.1

Source: earthquake loss prediction research team of China Earthquake Administration (1990).

In accord with the Industrial Classification For NationalEconomic Activities (GB/T 4754-2011) (National Bureau ofStatistics of China, 2011), this paper divides petrochemi-cal enterprises into four types: PE1, oil, natural gas drilling,petroleum processing, coking and nuclear fuel processing en-terprises; PE2, chemical raw materials and chemical productmanufacturing enterprises; PE3, chemical fiber manufactur-ing enterprises; PE4, rubber and plastic product manufactur-ing enterprises.

Considering the complexity of the value components ofpetrochemical enterprises and the availability of data, thefixed asset valueWk is taken as the total values of petrochem-ical enterprises.

The fixed asset dataWk for the four types of petrochem-ical enterprises were sourced from China’s 2008 economiccensus data (Leading Group Office of the Second China Eco-nomic Census of the State Council, 2010), with the provinceas the basic statistical unit. In view of the lack of related

county or city data regarding the fixed assets of petrochem-ical enterprise, this paper assigns province-level values forfixed assets to all cities and counties according to the indus-try output value ratio of every city or county to the wholeprovince. Therefore, the distribution of the fixed assets ofpetrochemical enterprises for counties or cities is obtained inthis paper. Figure 3 shows the distribution of the fixed assetsper unit area of petrochemical enterprises.

4.3 Fire hazard probability of different types ofpetrochemical enterprises

The fire occurrence probabilityP(Fk/Dj ) of petrochemicalenterprise depends on the probabilityP(Cj |Dj ) of leakageand diffusion of flammable materials in factories, the proba-bility P(Sj |Dj ) of ignition, and the fire proportionFk of thepetrochemical enterprise, as shown in Eq. (5) below.

P (Fk/Dj) = P(Cj/Dj

)· P

(Sj/Dj

)· Fk. (5)

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Table 2. Industrial factory building damage loss ratio.

Collapse Serious damage Medium damage Slight damage Basically intact

81–100 % 46–80 % 17–45 % 5–16 % 0–4 %

Source: Post-earthquake field works – Part 4: assessment of direct loss (GB/T 18208.4-2005).

Fig. 3.Fixed assets per unit area of petrochemical enterprises.

Table 3 shows the data, the probabilityP(Cj |Dj ) of leak-age and diffusion and the probabilityP(Sj |Dj ) of petro-chemical enterprise fire occurrence at different levels ofearthquake damage on the basis of historical data (Yu et al.,2003; Zhao et al., 2003).

Fk is the daily fire occurrence proportion of petrochemicalenterprises. Fire hazard probability varies among petrochem-ical enterprises because the chemical substances used in theirproduction processes and the flammable materials in the fac-tory buildings have different characteristics and are stored invarious quantities (Sinopec Group, 2008; Ministry of Pub-lic Security of PRC, 2006). Therefore, this paper usesFk toadjust their fire hazard probability.

On account of the lack of official statistics regarding firesin petrochemical enterprises, this paper calculatesFk bycollecting data on 233 fires at petrochemical enterprises inChina from January 2005 to July 2011; the data were sourcedfrom China’s most authoritative fire protection websites(China Fire Protection Website, 2005–2011; Huicong FireProtection Website, 2005–2011). According to the China

Fire Services, the incidence of petrochemical enterprise fireswas 579, 429, 532, 382, and 349 (Fire Department of theMinistry of Public Security of PRC, 2006–2010) for the year2005, 2006, 2007, 2008, and 2009, respectively. The 233records are in accord with the minimum sample size demandof the sample survey.

According to enterprise types, this paper divides the abovefires into four categories – PE1, PE2, PE3, and PE4 – and cal-culates daily fire proportion for each category. The results areshown in Table 4; for PE2, the fire proportion of chemical rawmaterials and chemical product manufacturing enterprises ishigher than for the other categories.

4.4 Fire loss ratiolf of petrochemical enterprises

Considering the availability of data, this paper simplified thecalculation of petrochemical enterprise fire loss ratiolf bythe average loss ratio, that is, the ratio of the average fireloss value to the average fixed asset value of petrochemicalenterprises, as shown in Eq. (6) below.

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Table 3.Probability of leakage, diffusion, and fire occurrence of inflammable material.

Collapse Serious damage Medium damage Slight damage Basically intact

Leakage, diffusionP(Cj |Dj )

0.97(0.94–1.00)

0.89(0.84–0.94)

0.80(0.75–0.84)

0.68(0.60–0.75)

0.50(0.40–0.60)

Fire occurrenceP(Sj |Dj )

0.97(0.94–1.00)

0.89(0.84–0.94)

0.80(0.75–0.84)

0.68(0.60–0.75)

0.50(0.40–0.60)

Source: Zhao et al. (2003).

Table 4.Daily fire proportion for petrochemical enterprises.

Enterprise type PE1 PE2 PE3 PE4

Daily fire proportion 0.171 0.438 0.129 0.262

Source: this study.

lf =Lf

W. (6)

In this equation,lf refers to the petrochemical enterprisedaily fire loss ratio,Lf to the petrochemical enterprise dailyfire average loss value, andW to the average fixed asset valueof a single petrochemical enterprise.

According to the average fixed asset value of petrochemi-cal enterprises (Leading Group Office of the Second ChinaEconomic Census of the State Council, 2010) and petro-chemical enterprise fire economic loss data (Fire Depart-ment of the Ministry of Public Security of PRC, 2006–2010)in 2008, the petrochemical enterprise daily fire loss ratiolf = 0.001.

5 Fire following an earthquake risk of petrochemicalenterprises for China’s counties

The seismic ground motion zonation map (Fig. 2) can helpidentify the level of seismic ground motionsRi in eachcounty and then obtain theP(Dj |Ri) andlf . With the aboveloss ratio and fixed asset value, and Eqs. (1), (2), (3), and (4),the post-earthquake fire expected loss value of the four typesof petrochemical enterprises in various counties can be cal-culated, as shown in Fig. 4a, b, c and d. Figure 4e shows apost-earthquake fire risk map of China’s petrochemical enter-prises, showing the loss value of the four types of petrochem-ical enterprises. Taking Heping District of Tianjin City forexample, the PGA of this region is between 0.15g to 0.20g.Table 5 shows the original data and results of this calculatingprocess.

In each picture of Fig. 4, the colors (from dark to light)show the post-earthquake fire risk from high to low. Figure 4eshows that the high-risk post-earthquake areas are mainlydistributed in central China, including the Beijing–Tianjin–Tangshan region, Shandong, Jiangsu, Zhejiang provinces,

and parts of Henan, Shanxi, Shaanxi, Sichuan, Yunnan, Xin-jiang, and Guangdong provinces. Cause analysis shows, be-cause of the post-earthquake fire risk chain, that high-risk ar-eas of petrochemical enterprises are closely related to the dis-tribution of seismic fault belts. For example, northern China,containing the north–south seismic belt, has historically ex-perienced significant earthquakes and has a relatively highrisk. In contrast, there is a close correlation between risk lev-els and output value of petrochemical enterprises. For exam-ple, the risk in Shandong and Jiangsu provinces is the high-est because the petrochemical industry there is flourishing.In those two provinces, the total amount of fixed assets oflarge-scale (over RMB 5 million in annual sales) petrochem-ical enterprises accounted for over 10 % of all fixed assets ofpetrochemical enterprises in China in 2008, and ranked firstand second in China.

From the perspective of the specific risk distribution ofthe four types of petrochemical enterprises, as the fixed as-set value of PE1 and PE2 enterprises are relatively high, sotoo are the corresponding risk levels, as shown in Fig. 4a andb. In contrast, the risk levels of PE3 and PE4 enterprises arerelatively low, as shown in Fig. 4c and d. The distribution ofhigh-risk areas for all types of petrochemical enterprises isbasically the same as the distribution in Fig. 4e.

The above expected loss is calculated in county unit, andif the expected loss in county is added up to the provinceunit, the result is shown in Table 6, which is the top 10 ex-pected loss of earthquake fire for provinces. The high lossareas are mainly concentrated in the Bohai Rim (Shandong,Tianjin, Liaoning, Hebei), the Yangtze River delta (Jiangsu)and Shanxi–Henan–Shaanxi region. But there are large dif-ferences between provinces in four types of enterprises, andthe provinces should adopt different risk prevention mea-sures according to their own development features of thepetrochemical industry. For example, Shandong should payattention to PE1 and PE2 earthquake-fire prevention; how-ever, Jiangsu only needs to focus on PE2.

6 Discussion

The seismic ground motion zonation map (Fig. 2) is usedto determine the seismic fortification of buildings in China.The seismic PGA= 0.05g is the minimum seismic fortifica-tion level, and PGA< 0.05g is the non-seismic fortification

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Fig. 4.Earthquake-fire risk map of petrochemical enterprises.

Table 5.Expected loss of earthquake-fire for the petrochemical enterprises in Heping District of Tianjin City.

Petrochemical enterprises PE1 PE2 PE3 PE4 Total

Fixed assets in Tianjin City (RMB 10 000)* 7 432 100 2 179 400 30 300 1 390 700 11 032 500Fixed assets in Heping DistrictWk (RMB 10 000)

201 806.96 59 178.17 822.75 37 762.27 299 570.15

Earthquake loss in Heping DistrictEL (RM 10 000)

49 018.91 14 374.38 199.85 9172.45 72 765.59

Residual values in Heping DistrictW

k(RMB 10 000)

152 788.0 44 803.79 622.90 28 589.81 226 804.5

Fire loss in Heping DistrictFL (RMB 10 000)

28.86 21.68 0.089 8.27 58.90

Total loss in Heping DistrictEFL (RMB 10 000)

49 047.77 14 396.06 199.9344 9180.729 72 824.49

Expected loss per unit area in Heping District(10 000 RMB km−2)

4619.57 1355.89 18.83 864.69 6858.98

Source: this study; the item marked by an asterisk is collected from Leading Group Office of the Second China Economic Census of the State Council(2010).

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898 J. Li et al.: Risk assessment study of fire following an earthquake

Fig. 5.Expected loss per unit area above RMB 20 000 in seismic PGA< 0.05 area.

Table 6.The top 10 expected loss of earthquake fire for provinces.

Province nameExpected loss (unit: million Yuan RMB)

PE1 PE2 PE3 PE4 Total

Shandong 15 132 15 860 807 5287 37 086Shaanxi 27 426 2741 6 244 30 416Jiangsu 2362 15 931 3686 4840 26 819Tianjin 16 503 4878 70 3091 24 541Xinjiang 20 230 2941 251 209 23 632Shanxi 14 715 7405 12 447 22 580Liaoning 11 060 6881 426 2495 20 863Hebei 9309 5879 294 1930 17 411Guangdong 5036 6647 495 4982 17 160Henan 5137 6089 461 1203 12 890

Source: this study.

area. Using GIS software layer calculation functions, areasof PGA= < 0.05g can be extracted from the seismic groundmotion zonation map and areas with a local expected loss perunit above RMB 20 000 (see Fig. 4e); the two areas can thenbe added together using GIS superposition to show where thetwo meet, as shown in Fig. 5.

The black areas in Fig. 5 show regions with low-level seis-mic fortification and a high risk of petrochemical enterprisepost-earthquake fires; these areas are mainly distributed in

the southern Shandong Peninsula, southern Jiangsu Province,and along the coast of the Hangzhou Bay and the Pearl Riverdelta.

In accordance with the post-earthquake fire risk assess-ment results, the post-earthquake fire loss value per unit areais at a higher level in the above areas, where fire risk is of-ten ignored because of the lower levels of seismic fortifica-tion. Accordingly, the level of fire protection construction inpetrochemical enterprises is especially important in these ar-eas; on the one hand, an appropriate emergency disaster planshould be formulated, and on the other, seismic standardsshould be taken into consideration when petrochemical en-terprises undertake the construction of fire protection equip-ment and pipelines to ensure appropriate fire protection in anearthquake.

Because the occurrence of earthquake and the spread offollowing fire are concerned with many different factors thathave complex relationships among each other, little atten-tion is paid to the matter this paper focuses on, and there-fore a complete research system is still on the way. Consid-ering the capability of fire extinguishing, this study compre-hends those fire hazard models and earthquake loss assess-ing methods and, furthermore, builds up the risk assessmentmodel of fire following an earthquake of petrochemical enter-prises. This paper applies previous research work and, whatis more, makes meaningful academic exploration on the re-search ideas and performing methods of earthquake-fire risk

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J. Li et al.: Risk assessment study of fire following an earthquake 899

assessing. Due to the lack of available data and the limitationof research methods, the model in this paper inevitably sim-plifies some parameters, and thus it has to focus on the dis-cipline on macro-level, namely regional scale. In the comingdays, deeper explorations are in great need on the factors andmethods of earthquake-fire risk assessment.

7 Conclusions

The risk of fire is high for petrochemical enterprises, espe-cially when buildings, chemical equipments, and fire-fightingcapacity are damaged in an earthquake. This paper, based onthe seismic ground motion zonation map, calculates the ex-pected loss in a post-earthquake fire for four types of petro-chemical enterprises in counties of China. The analysis fo-cuses on the probability of flammable material leakage anddiffusion, ignition source, and fire proportion of petrochemi-cal enterprises.

Areas with a high risk of post-earthquake fires have a widedistribution in the Beijing–Tianjin–Tangshan region; Shan-dong, Jiangsu, and Zhejiang provinces; and in a number ofcounties in Henan, Shanxi, Shaanxi, Sichuan, Yunnan, Xin-jiang and Guangdong. The risk of petrochemical enterprisesrequires extra attention and measures in some areas, espe-cially where the level of seismic fortification is low.

In view of the available data, the calculation of some ofthe parameters used in this paper is conducted in a simpli-fied way. Thus, further study is required to conduct a moreprecise risk assessment, including a more detailed classifica-tion based on petrochemical enterprise production processes,and the effect of varying earthquake intensities on chemicalequipments, fire probability, and diffusion probability for alltypes of petrochemical enterprises.

Acknowledgements.This research was primarily supported by theNational Key Technology R & D Program of the 12th Five-YearPlan of China (no. 2012BAK10B03), the National Natural ScienceFunds (no. 41271544), and the Fundamental Research Funds forthe Central Universities (2009SD-20).

Edited by: R. LasaponaraReviewed by: H. Ohtani and four anonymous referees

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