Analytical Research of the Container Ships Cargo Area Fires in the Period From 2010 to 2020

Container transport by sea has almost doubled in the last decade. Accordingly, container ships’ size has increased signifi cantly, and the latest container ships carry up to 24000 Twenty-foot Equivalent Units (TEU). In the near future, the appearance of container ships with a capacity of 25000 TEUs can be expected on the market, because the design is already available. It is known that 10-12% of transported containers contain International Maritime Dangerous Goods (IMDG) cargo. The above stated reasons directly impact the frequency of container ship fi res in cargo spaces. According to the Insurance Companies, fi res occur on average every two months, and this is a growing problem of container transport by sea. In this paper, 23 fi res in the cargo area, either in cargo holds or on deck, were analysed. The analysis results determined the most common causes of fi res and have shown that the current fi re protection systems on container ships are ineff ective. It is unacceptable that fi refi ghting systems’ ineffi ciency results in the loss of human lives, abandonment of vessels, environmental pollution, and extensive property losses related to cargo and ship structure. Due to all the above, it is necessary to continuously work on new regulatory and technical solutions to improve the fi re safety of cargo areas on container ships.


INTRODUCTION / Uvod
Container ships' size and design have remarkably changed over the last decade. It is standard for large container ships to carry 22 -24 rows and 8 -11 container tiers on deck. In addition to bringing benefi ts, an increase in size and container carrying capacity brings certain issues along. One of the more signifi cant problems is related to fi res and explosions in the cargo area. Increased ship size and capacity result in concentrating more boxes on a smaller number of ships. A higher number of containers on one ship increases fi re risk. Fires and explosions incur massive losses, which, in the worst-case scenario, can reach up to one to two billion USD on mega container ships [1].
As part of multimodal transport, containerization has played an essential role in seaborne trade over the last fi ve decades. The standard-sized 20 and 40-foot containers are mostly carried by purpose-built container ships. The fi rst purpose-built container ship, named American Lancer, with a 1210 TEUs capacity, was delivered in 1968 in the USA. The world's largest container vessel HMM Algeciras, having 23964 TEUs capacity, was delivered on 23. April 2020 at the DSME shipyard in South Korea. Another 11 sister vessels were delivered during 2020. In the last 52 years, container ships' capacity has increased by almost 2000% [2]. Container ships' capacity in the last decade has increased from 15000 TEUs to 24000 TEUs. In 2018, newly built container vessels represented 23.5% of the world's total deadweight tonnage (dwt) delivered [3]. Most of the tonnage was attributed to the Neopanamax and Ultra Large Container Ships (ULCS), whose capacity grew by 33% in 2018 [4]. ULCS achieved the lowest fuel consumption per TEU per mile and reduced Greenhouse Gases (GHG) emission per TEU per mile.
The total container ships fl eet in January 2019 accounted for 5152 ships with an aggregate capacity of 266 million metric tons, which represented 13.4% of the entire world fl eet. The capacity since 2018 has increased by 4.9% [5]. In 2018, 1875 billion tons of goods were carried by containers, which accounted for 17% of the total seaborne trade [3]. In 2019, global container throughput reached 802 million TEUs and had increased by 2.3% compared to 2018 [5], while comparing to the 2010 fi gures of 531.4 million TEUs [6], the aggregate increase in the last ten years is above 50%. A large share of container trade is carried across the major East-West trading routes: Asia -Europe, the Trans-Pacifi c, and the Trans-Atlantic. These three routes account for more than 40% of the global containerized trade. The largest container vessels are utilized on these routes. Asia has a major role in container handling traffi c and in 2018 accounted for 64% of the world's total, Europe 15%, North America 8%, Latin America and Caribbean 7%, Africa 4%, and Oceania 2% [5]. As can be seen, nearly two-thirds of the global container handlings were in Asian ports. China, Taiwan, and Hong Kong accounted for one half of the total regional traffi c. In 2019, 7 out of the 10 world top container ports were located in China [7] with the container throughput over 106 million TEUs. Out of China in top 10 there were Singapore, Busan and Dubai.
This paper aims to identify the main causes of fi res and explosions in the cargo spaces of container ships, to evaluate the eff ectiveness of a fi xed fi re extinguishing system, the ability of overall fi refi ghting measures and the loss of life caused by fi res and explosions. To achieve this, 23 fi re accidents between 2010 and 2020 were thoroughly investigated and analysed, although during this period there were many more.
The paper is structured in 4 sections. Section 2 presents literature review related to cargo fi re problems on container vessels. The reviewed literature can be divided into three categories: articles published in scientifi c journals, accident investigation reports issued by the various fl ag state administrations, and various initiatives undertaken by the shipping industry stakeholders. In section 3, reports on the major fi re cases that occurred in the last decade are analysed. Section 4 describes activities initiated by the container-shipping companies, the International Union of Marine Insurance (IUMI), the International Maritime Organization (IMO), and the Classifi cation Societies as a response to the frequent container fi res. The fi nal section contains research results and certain technical solutions which can be considered for installation on newly built container ships to enhance fi re safety and reduce risk of fi re. The results of the analytical research provide insight into the most common locations of fi re outbreaks. The most common causes of fi res have been revealed, and the assessment of the eff ectiveness of fi re extinguishing systems in cargo space, and overall fi refi ghting activities on container ships has been made.

LITERATURE REVIEW / Pregled literature
Previous papers published in various journals have concentrated on the analysis of accidents related to the transport of containers on deck, the impact of IMDG cargo on fi res, the share of cargo fi res in total container ship fi res, loss of human lives caused by container ship fi res, etc.
Langerbecker at al. [8] in 2008 made a risk model for the operation of container vessels. The risk model was made based on the reported accident categories on fully cellular container ship in the period 1993 -2004. In this period there were 1582 reported accidents onboard container vessels with 80 dead and 28 missing crew members. The accidents were broken down to the diff erent accident categories. Fire and explosion were recognized as one of the top-ranked hazard categories. This category is with the largest loss of human life and it resulted in 42 fatalities.
In 2010 Moctar at al. [9] concluded that fi re and explosions on container vessels contribute to one third of all recorded fatalities onboard container vessels and that the fi re accidents are second-largest cost contributor of all encountered accidents. The fi res onboard container vessels are diffi cult to handle due to inadequate fi re detection and fi refi ghting capabilities, especially on deck. They conducted a series of full-scale tests with two loaded Twenty-foot containers. Their research aimed to estimate cargo fi re risk for the container ships by measuring gas temperature in the container, temperature of the container steel structure, and gas concentration inside the box under various conditions regarding the temperature and ventilation.
Ellis [10] in her study in 2011 was focused to the factors leading to the accidental release of containerized dangerous goods carried onboard container ship. Records of dangerous goods cargo accidental release in an 11-year period (1998 -2008) in UK and USA were analysed to recognize and categorize main contributing factors. According to this study it was estimated that the incidents relating to packaged dangerous goods account to 15% of all fatalities. Self-ignition and misdeclared packaged dangerous goods are main contributing factors for the fatal accidents.
Chen at al. [11] in 2013 reviewed fi re and explosion safety related regulations, investigated main contributing factors to the explosions and fi res on container ships based on the statistical date published by the Marine Incident Investigation Branch (MAIB). For the assessment of fi res and explosion in container line supply chain they used the Intelligent Decision System tool.
Gafero and Sunaryo [12] in 2018 made container ship accident analysis due to container stacked on deck. One of the factors that are recognized in this paper as a trigger for fi re accidents is connected to the placement of containers with IMDG cargo and the container packaging incompatibility with the IMDG code.
Callesen at al. [13] at the Technical University Lyngby, Denmark recognized a problem with container ship fi res. In 2019 they did extensive research where the focus was put on analysis of four types of IMDG cargoes (calcium hypochlorite, compressed charcoal briquette, rechargeable batteries, and divinylbenzene) that initiated most fi res in the period between 1996 -2017. The authors studied 39 fi re accidents in the given period and they conclude that calcium hypochlorite and charcoal briquette caused almost 50% of all fi res.
The fi re investigation reports analysed in this paper were issued by the casualty investigation departments of the various vessel's fl ag state maritime authorities. Most of these reports are available on the relevant authorities' websites, while some reports were obtained through the author's direct contact with the fl ag state administrations. IUMI in September 2017 released "Position Paper on fi refi ghting on container vessels" [14]. This paper emphasized that large fi res on container ships are among the most serious hazards for the world shipping industry, given the loss of human lives, economic losses, and the threat of environmental pollution. The main reasons of increased number and severity of fi res are the growing sizes of container ships and ineff ective fi re detection and fi refi ghting systems presently installed onboard the vessels.
Allianz Insurance, in its "Safety and Shipping review 2018" [15] emphasized several issues related to the rapid growth of ULCS. Major fi res are identifi ed as one of the most signifi cant safety challenges. Firefi ghting capabilities on board these vessels have not kept pace with the increasing vessel size. Cargo is not being properly declared despite of IMO requirements that shippers declare container contents; there are still many cases where the shippers avoid following these requirements. 12% of global container trade contains dangerous cargo. In 2015 incorrectly declared cargo increased by 65%. The salvage of ULCS, due to their size, it is a problem to fi nd a suitable port that can accommodate them and provide safe refuge following a fi re.
On the International Salvage Union Associate Members' Day in London on 23. April 2019, the challenges that salvor and crew face responding to cargo fi res on large container ships were discussed [16]. One recent check in the USA on the container content showed that 20% of the containers were found with mis-declared cargo. Limited space between boxes makes access to the seat of the fi re very diffi cult for the effi cient fi refi ghting operation. Once the fi re breaks out, the crew is exposed to smoke, noxious gasses, and explosions. There is also a risk of losing control and a need to abandon the ship.
As per literature review, fi res on container ships have been attracting great attention of the global maritime industry. This comes as no surprise considering the possible loss of life, substantial property loss, and possible environmental pollution which are all consequences of fi res on container ships. It is estimated that signifi cant container ship fi res occur every two months. In 2019, there were six such cases [17]. Many fi res that have occurred on container ships have not been registered because of their size. They have not attracted publicity in the maritime world nor the press and, due to lack of data, were not analysed further.

ANALYSIS OF MAJOR FIRE INCIDENTS / Analiza velikih požarnih incidenata
This chapter presents an analysis of major fi re accidents in the period between 2010 and 2020. The purpose of this tabular analysis is to determine what the most common causes of fi re are. Table 1 represents a chronological order of fi re cases in the given period. The fi re locations, the extent of the damage and the fi re causes are also presented in the table. Data on the number of injured and dead persons, the extent of the external assistance in extinguishing the fi re and whether the ship was abandoned after the fi re broke out due to its escalation are shown in Figure 4 for all analysed cases.
As can be seen in Figure 1, 10 fi res broke out on the deck, while 13 in cargo holds. Five of the fi res that started in cargo holds spread to the deck, while eight were contained in cargo holds and extinguished.  Figure 1 Fire locations in analysed cases Slika 1. Lokacije požara u analiziranim slučajevima Figure 2 represents the causes of 23 analysed fi res. It can be noted that the two most common causes of fi res are various forms of calcium chlorite and charcoal. However, the consequences of fi res caused by calcium chloride are much more severe due to this chemical's nature. Calcium hypochlorite Ca(ClO) 2 [43] or calcium chlorite Ca(ClO 2 ) 2 [44] and its forms represent one of the most dangerous IMDG cargoes and were responsible for many container ship fi res in the past. That is why the Cargo Incident Notifi cation System (CINS) issued "Guidelines for the Carriage of Calcium Hypochlorite in Containers" in January 2018 [45]. The document describes this cargo's characteristics, the IMDG classes, the potential risks associated with its transport, the selection of containers, storage, packaging, and inspection before loading the ship. This fi gure shows that 22 out of 23 fi res were caused by IMDG cargo. Only one fi re (highlighted blue) was caused by the non-IMDG cargo, i.e. the self-ignition of the cotton in the container as a result of the heat released due to the friction caused by the collapse of the container stack stow. Ten fi res out of 22 were caused by the IMGD cargo which was either not declared as IMDG or was mis-declared. Given that the total number of fi res analysed is 23, this means that 43% of fi res were caused by undeclared or mis-declared IMDG cargo. The evaluation of the fi xed CO 2 fi re extinguishing system and effi ciency of the entire fi refi ghting operations is based on the data obtained from the investigation reports related to the fi re cases analysed in this paper. Cargo holds' fi xed CO 2 fi re extinguishing system effi ciency is presented in Figure 3. As already mentioned, 13 fi res broke out in cargo holds. In one case, the fi re was extinguished very quickly, and there was no need to release a fi xed CO 2 fi refi ghting system. In 12 cases, the crew decided to release a CO 2 fi refi ghting system. In only one case the CO 2 system proved to be eff ective, and the fi re was extinguished, while in the other 11 cases it was partially or entirely ineffi cient. There are several main reasons for the ineffi ciency of the CO 2 system: -limited effi ciency for extinguishing deep-seated fi res inside containers, especially for those types of cargo (e.g., lithiumion batteries, cotton in bales) that smolder for a long time after the fl ame is extinguished and which re-ignite when the oxygen re-enters the scene of the fi re; -CO 2 extinguishes fi re by reducing oxygen content as it is heavier than air, but it has a limited cooling eff ect. This poses a risk of fi re re-ignition once oxygen is re-introduced to the cargo hold; -if the container on fi re is located on higher tiers close to the hatch covers, CO 2 won't have a fi re extinguishing eff ect due to the constant infl ow of fresh air; -some IMDG cargoes are known as oxidizing materials (e.g., calcium hypochlorite), which release oxygen as a result of their instability and decomposition at elevated temperatures; -limited gas tightness of the cargo holds due to the design and construction of the hatch covers. Namely, the covers of large container ships are of lift-away type, consisting of several panels for each cargo hold opening, arranged transversely, and separated by a longitudinal gap of less than 50 mm. The panels rest on bearing pads placed on top of the hatch coamings and do not have rubber packing which makes the cargo hold weather tight. The designed air gap between hatch covers and hatch coamings is 10 -20 mm; -if the fi re spreads rapidly, there is a signifi cant risk that some of the ventilation fl aps and covers won't be accessible due to the smoke on deck; -technical malfunctions of the CO 2 system due to poor maintenance, poor and improper installation of the system, and pipe leakage during system activation.  Figure 4 shows the overall effi ciency of the fi re extinguishing operation. The following four elements were analysed: the extent of damage, whether the ship was abandoned after the fi re broke out due to the sudden escalation of fi re and danger to human lives, whether the fi re was extinguished by the crew or by external assistance (fi refi ghting personnel, tugs, salvage teams, helicopters, etc.), and whether there were any deaths or injuries during fi refi ghting operations.
The extent of damage to the ship and cargo is classifi ed into three categories: minor, severe, and major. The number of damaged containers and the severity of structural damage to the ship was taken as the criteria for determining the degree of total damage caused by the fi re. Damages up to 10 containers and damages to the ship's structure that can be repaired within one week are classifi ed as minor. Damages from 10 to 100 containers and damages to the ship's structure requiring repair from one week to one month are classifi ed as serious, while all damages requiring repair for a period longer than one month and if the number of damaged containers exceeds 100 are classifi ed as major.
The ship was abandoned due to the sudden escalation of fi re and danger to human lives in cases 1, 2, 4, 6, 17, 18 and 19.

Figure 4 Firefi ghting operations effi ciency as elaborated from the investigation reports Slika 4. Učinkovitost vatrogasnih operacija obrađenih iz istražnih izvješća
The fi re was extinguished by the crew without external assistance only in cases 3, 13, 21 and 23. In the cases where the fi re was extinguished with external assistance, various resources were used, such as fi refi ghting tugs, fi refi ghters, fi refi ghting planes, rescue vessels and helicopters, coastguard vessels, towing tugs, and salvage teams. The resources used in these cases range from one fi refi ghting tug and fi refi ghting team (case 5) to several fi refi ghting tugs with fi refi ghting teams, helicopters, two salvage companies and towing tugs (case 18).
Cases 1, 2, 15, 16, 18, 20 and 22 resulted in either dead or injured personnel. In case 2 there were 3 dead and 2 seriously injured crew members. Case 18, fi re on MV Maersk Honam was one of the most devastating fi res on container vessels up to date as it resulted in the loss of 5 crew members' lives and 22 crew members treated in the hospital. In case 22 more than 200 people were treated in the hospital due to respiratory problems. Injuries in cases 1, 15, 16 and 20 were limited to 1 to 3 persons who suff ered burns and respiratory problems.
From the obtained results, it can be concluded that fi res in the cargo area on container ships represent a signifi cant problem that impacts container ship fi re safety. Therefore, classifi cation societies, insurance companies, responsible authorities, and the largest container companies have taken specifi c actions to reduce the risk of fi re outbreaks and reduce their consequences on container vessels. Some of these actions are presented in the following chapter.

INFLUENCE OF THE CONTAINER FIRES FREQUENCY ON INTERESTED PARTIES OF CONTAINER TRANSPORT BY SEA / Utjecaj učestalosti požara kontejnera na zainteresirane strane uključene u pomorski kontejnerski transport
The frequency of container fi res in the last decade and their consequences related to injuries or loss of life, serious damage or loss of assets, and environmental concerns have attracted signifi cant attention among the interested parties of container transport by sea. Consequently, the largest container-shipping lines, insurance companies, IMO, and classifi cation societies have taken certain actions to reduce the risk of fi re and enhance fi refi ghting effi ciency in the event of an outbreak.
Due to many fi res on container ships between 2000 and 2010, the fi ve largest container-shipping lines established a CINS initiative [46] in September 2011. The purpose of this initiative is to collect information on operational cargo-related incidents, analyse all collected information and data on cargo and container related incidents, establish an area of concern and propose actions to improve safety in the container transport chain, and address areas of concern to relevant authorities. Based on the purposes above, relevant authorities can make amendments to the IMDG code and advise on training issues related to packing and securing cargo in containers. Today, the 17 largest containershipping lines are members of the CINS initiative.  [47]. This paragraph applies to ships constructed on or after 01.01.2016, which were designed to carry containers on or above the weather deck. In addition to the standard equipment and arrangements: -ships shall carry at least one water mist lance which shall consist of a tube with a piercing nozzle capable of penetrating a container wall and producing water mist inside a confi ned space when connected to the fi re main; -ships designed to carry fi ve or more container tiers on or above the weather deck shall have mobile water monitors. Ships with breadth less than 30 m at least two monitors and ships with the breadth of 30 m and above at least four mobile water monitors; -the mobile water monitors, hoses, fi ttings, and required fi xing hardware shall be kept ready for use in the area outside of cargo space not likely to be cut off in the event of a fi re in the cargo space; -a suffi cient number of fi re hydrants shall be provided such that all provided monitors can be operated simultaneously for creating an eff ective water barrier forward and aft of each container bay. On 17.10.2019, Norwegian insurer GARD organized a two-day conference with a container ship fi re topic [48]. Representatives from leading container carriers, ship owners, fl ag states, fi re experts, IMO, IUMI, CINS, Baltic and International Maritime Council (BIMCO), International Association of Classifi cation Societies (IACS), and the World Shipping Council attended the conference. The following issues were discussed: root causes of container ship fi res, cargo supply chain, fi re detection, fi refi ghting, innovation in fi refi ghting equipment, proposals on how to reduce risk of container ship fi res, and how to improve fi refi ghting effi ciency.
Classifi cation Society American Bureau of Shipping (ABS) in May 2017 developed and off ered to the ship owners new optional class notation "Firefi ghting on Deck Container" (FOC) for further enhancement of the fi refi ghting capabilities for deck cargo on board container ships [49]. Firefi ghting equipment installed on ships with FOC class notation and fi refi ghting capability is beyond SOLAS's standard equipment.
In 2019 Classifi cation Society Det Norske Veritas Germanische Lloyd (DNV GL) further developed an optional class notation for fi refi ghting on deck container ships and off ered fi ve slightly diff erent class notations: FCS (C) -Extended level beyond SOLAS, FCS (HAZID) -Hazard identifi cation, FCS (FD) -Enhanced fi re detection, FCS (FF) -Enhanced fi refi ghting, FCS (HF) -Firefi ghting by hold fl ooding, to the ship owners [50]. First ULCS MSC Gulsun with a class notation FCS HAZID was delivered on 09 July 2019. Features of this class notation are fi xed fi re monitors, which have a range of over 100 m. Their purpose is to slow and stop the spread of fi re by cooling eff ect. In addition, a system of thermal cameras has been installed, whose goal is to alert the crew of the potential fi re in the event of any irregularity.
In January 2021, Classifi cation Society Bureau Veritas (BV) published the new guidelines developed based on a thorough analysis of container ships' cargo fi re incidents. These guidelines include improved fi refi ghting capabilities on deck with water monitors and water spray systems subdivided into sections, increased protection of accommodation blocks and life-saving equipment, improved fi refi ghting and fi re containment in the cargo hold, and fi re detection appliances in the cargo hold and deck. The guidelines are amended to BV Rules for the Classifi cation of Steel Ships NR 467 [51].

CONCLUSION / Zaključak
Due to the container ships' growing size and number, cargo fi res' frequency and consequences represent a major challenge for all participants in container sea transport. Despite technical improvements of fi refi ghting systems, consequences of fi re accidents are still signifi cant, and it is necessary to work on further improvements of both fi re detection and fi refi ghting systems. From the analysis' results, the following can be concluded: 43% of fi res were caused by undeclared or misdeclared IMDG cargo; current fi re protection systems both in the cargo hold and on deck are ineff ective, as only 17% of fi res were extinguished without external assistance; in 30% of cases the ship was abandoned, and there were injuries or fatalities among crew members; the fi res also caused signifi cant property damage and environmental pollution. Although the CINS initiative and random container inspections contribute to the reduction of mis-declared or undeclared IMDG cargo, this problem will never be completely solved mainly due to the large diff erence in the cost of transporting containers with normal dry cargo and IMDG cargo. It is well-known 10 -12% of containers transported by sea contain hazardous cargo. This means that the largest container ships can carry as many as 2800 TEUs with dangerous goods that increase the possibility of having a single container on board which may cause the fi re or the explosion, especially if the cargo is inadequately stowed or packed inside the container. Once a fi re starts, one can assume that the severity of the fi re damage and fi refi ghting eff orts are enormous due to diffi cult access, distances, and the number of rows and tiers of containers. In addition to the property damage, container ship fi res pose a high risk of personnel injury or death and environmental pollution. Container ships have relatively small accommodation blocks and narrow passages on deck which are frequently obstructed by the container lashing equipment and reefer container electrical cables. This has a negative eff ect on the fi refi ghting effi ciency in case of fi re. Another cumber is that the fi re inside the box develops very quickly and, once discovered by the crew, it might already be too late to fi ght it eff ectively. Due to all of the above, it is necessary to fi nd technical solutions to further improve both the fi re detection system and fi refi ghting in the event of a fi re outbreak in cargo hold or on deck. Installation of optical, thermal, and fl ame detectors and their connection to the central fi re detection system, fi xed-mount thermal cameras for remote monitoring, and video surveillance are possible solutions for earlier fi re detection. Installation of a seawater drencher system in all cargo holds with distributing nozzles in hatch coamings and hatch covers, not just in those designed to transport IMDG cargo is another option for improvement. Permanently connected fl exible hoses to the fi re line during sea passage and the installation of remote-controlled (from the navigation bridge) electro-pneumatic valves will allow rapid activation of the system without exposing the crew to injury risks and loss of life. The installation of the seawater system, fore and aft of all cargo holds, and the creation of water curtains will help prevent the spread of fi re on deck. Newer container ships are equipped with portable water monitors that can be used to extinguish fi res on the higher container tiers. However, given the number of crews on container ships, monitors' weight, and the time required for their deployment, it is evident that their eff ectiveness is limited. Therefore, it is recommended that fi xed monitors be installed on all container lashing bridges. With the ability to be remotely activated and controlled from the navigation bridge, monitors would further contribute to deck fi re protection eff ectiveness. Future research on this topic should focus on the possibility of using other fi re extinguishing agents, such as high expansion liquid foams, and gaseous fi re suppression agents in the cargo holds. As it was shown, CO 2 as a fi refi ghting agent proved to be quite ineff ective. Further, it belongs to the group of greenhouse gases. This is especially signifi cant considering the IMO strategy to reduce respective emissions in shipping by the year 2050 to 50% of emissions as recorded in 2008. From a technical perspective, it will be possible to build a 30000 TEU container ship in this decade. It will be interesting and useful to analyse the respective consequences on container transport and the infrastructure of container terminals as a whole.