ENVIRONMENTAL RISK ANALYSIS AND RISK MANAGEMENT SYSTEM OF A TEXTILE MILL IN TURKEY

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1 ENVIRONMENTAL RISK ANALYSIS AND RISK MANAGEMENT SYSTEM OF A TEXTILE MILL IN TURKEY Meral Mungan 1, Ertuğrul Alp 2, Ulku Yetis 1 1 Department of Environmental Engineering, Middle East Technical University Ankara, TURKEY 2 Alp & Associates Incorporated, Richmond Hill, Ontario, CANADA ABSTRACT Risk analysis and risk management system in industries towards IPPC Directive is very important in terms of preventing industrial accidents which might come up with catastrophic results. It is also vital to maintain sustainable production in the industry. This study is carried out so as to identify, assess and analyze the existing risk with regards to hazardous chemicals inside a textile mill and to conduct advanced studies to diminish the risk level of the facility. 1. INTRODUCTION It is of great importance to prevent accidents which might interfere with public health and safety, safety and health at work, environment; safety of property, products and reputation of companies and industries. The paper investigates the risk of an explosion or fire involving hazardous materials inside a textile mill and also analyses the results of this probability. This paper deals with the prevention of accidents aspect of Integrated Pollution Prevention and Control Directive. Among all EU Directives on environmental issues; Integrated Pollution Prevention and Control Directive (IPPC Directive 96/61/EC) is the most extensive regarding the environmental concerns related to industries. 2. IPPC DIRECTIVE The Regulatory System places an integrated approach to control the environmental impacts of certain industrial activities. The Directive does not only consider one aspect of environmental effects of industries, but also covers the matter in all its bearings. It means that the permits of the Directive must handle all aspects of environmental performance of an industrial plant, considering e.g. emissions to air, water and land, generation of waste, use of raw materials, energy efficiency, noise, prevention of accidents, and restoration of the site upon closure [1]. The study covers the risk analysis and risk management study which was conducted within the scope of Turkey s IPPC adoption project. 1

2 2.1. IPPC Adoption Project The project is executed by the Middle East Technical University and a textile mill in Kayseri, a province in Central Anatolia. It is conducted to ensure that the textile mill is fully prepared, before the legal transposition of IPPC Directive into Turkish Legislation. Studies in the facility include multidimensional studies including water and energy minimization, water reuse and alternative treatment techniques to be in concordance with the Directive. This study is conducted as a branch of this extensive project. Risk analysis covering investigation of the potential for large scale industrial accidents is a must for the IPPC permit. 3. TEXTILE MILL The textile mill which is declared among top the 5 in Europe produces 20,000 tons of cotton fiber and 40 million meters denim fabric per year. The factory contains more than 140 different types of chemicals; many of which are hazardous. One of these chemicals is an explosive liquid, 33 of them are explosive solids and 13 of them are flammable liquids. Four departments are examined for the risk analysis and 47 chemicals which are used in these departments are either explosive or flammable. This means that 36% of all chemicals inside the mill are potential fire or explosion hazards There is another factory and an industrial zone which are both 20 meters away from the factory. Residential area is approximately 350 meters to the mill. Hence, any sort of industrial accidents due to these chemicals may affect a large population. Also, when it is considered that another factory resides near the textile factory and there is an industrial zone 20 meters away from the facility, it can be said that knock-on effect is likely to occur in case of a major industrial accident at the mill. In other words, the effects of a potential accident may be larger because of a chain of accidental events Process The denim fabric production process (Figure 1) starts with cotton in the integrated facility. First, different types of cotton are blended and turned into fiber. By spinning the fibers, yarn is produced. Yarns are dyed according to the color desired before weaving. Yarns should be strengthened to be weaved, otherwise they can easily detach. Hence, sizing is applied to yarns. During sizing, yarns are washed with cellulose and amylase solution. Yarns which are stronger are then weaved. The finishing process then gives the desired quality and characteristics to denim fabric. With the aid of numerous chemicals the fabric is made more resistant to crease and shrinkage, water and fire. The denim fabric is now ready for the customers. Figure 1: Process for Denim Fabric 2

3 4. SCOPE OF THE RISK ANALYSIS Before conducting a risk analysis, its scope should be defined accurately. IPPC requires a risk analysis towards large scale industrial accidents which is likely to affect vicinity of the industry negatively. Hence, preliminary analysis is necessary in terms of detecting the source which could lead to such an accident Preliminary Analysis Investigation visits were paid to the textile mill to understand the hazardous conditions/sections/activities. The hazardous chemicals inside the plant were identified as having the potential to result in serious explosion events. Due to the nature of long and complex production chain, numerous chemicals are used during production including surfactants, dyes, pigments, chelating agents, dispersing agents, etc. In the textile mill, about 140 chemicals are used. Most of them are laid up within the main warehouse besides depositories of different departments in the facility. Chemicals are also transported and used inside the factory. The greatest financial value and frequency of loss in industries are due to explosions which include runaway reactions of chemicals [2]. Hence, in the present study, the potential for an explosion which involves these chemicals is inspected. Hazardous materials form the focal point of this study, because the most destructive accident would result from an explosion or fire which involves hazardous materials. 5. RISK ANALYSIS There are three general approaches for carrying out a risk analysis: qualitative, semi-quantitative and quantitative. This paper uses a semi-quantitative approach involving a risk matrix for analyzing the risks of explosion and fire events in the facility involving hazardous materials. The intrinsic hazards of the chemicals used in the facility are first established. Any potential hazardous events that can occur are then identified through site inspection, study of past incidents in similar industries, and brainstorming with personnel familiar with the process and hazards of the chemicals involved. The consequences and likelihood of potential hazardous events are examined using the risk matrix, for establishing the risk levels and risk ranking of the different areas of the mill. Armed with the risk ranking information, the factory management board can then take risk control action regarding the highest risks. This is discussed further below under Risk Management Plan Brief Description of Potential Explosion and Fire Events: In the proceeding paragraphs, literature is reviewed so as to understand the mechanisms of explosions resulting from chemicals. It is important to comprehend how an explosion involving a chemical can occur before assessing the risks associated with chemical explosion hazard. Vapor Cloud Explosion: Any liquid which is flammable may vaporize. Gas form of the substance develops vapor cloud. The vapor cloud, oxygen and ignition source triple results in fire or explosion. Vapor cloud explosion brings forth potential injuries, fatalities and structural damage to buildings [3]. The behavior of vapor cloud explosion is similar to that of a gas explosion. Explosion is based on development of a vapor cloud in which enough flammable gas and oxidant are present 3

4 to carry out the explosion. Thus, a vapor cloud explosion can be considered as a volumetric explosion with a possible propagation until the mixture is fully consumed [4]. Dust Explosion: Many solid materials are combustible. The ease of combustion depends on the nature and dimensions of the solids. Finely divided solids are burned more easily and more rapidly. Two main reasons can be explained as: access to oxygen is abundant in dust form due to increased surface area and heat cannot be withdrawn into the interior part of the burning body when this body is small dust particle [5]. The dusts of combustible materials are explosive to a certain degree. Grain dust, coal, wood flour, starch, sugar, cereals, sulfur are known to be explosive. The factors to affect the likelihood of an explosion and its violence may be stated as; size of dust particles, moisture content, the quantity present, the containing room and the size or temperature of the source of ignition [6]. Expansion effects in dust explosions occur as a result of the heat produced during combustion. In addition to that, some gases are evolved from the dust due to high temperatures. A dust explosion should be considered as a spontaneous build-up of pressure or in uncontrolled expansion effects [5]. The expansion effect of dust explosion then causes damage in the surroundings. The explosion usually occurs in two stages, first a primary explosion from a spill which shakes the building creating more airborne dust from previous accumulations. Then, a secondary explosion occurs due to the airborne dust. Secondary explosions are much destructive generally, spreading throughout the facility. For both of these phenomena to emerge, an ignition source is needed. Hot surfaces and sparks are the most frequent ignition sources in the industry. Contact with hot surfaces can give the substance a lag period before its temperature raises till ignition temperature. Sparks, on the other hand can be produced by electricity, friction, or by welding [5] Identification of Hazardous Events In this study, a detailed investigation is first carried out to identify potential hazardous event that can occur at the mill. This investigation involved a review of literature and historical accident data, and interviews with employees of the mill. The application of the risk matrix to the hazardous events results in a risk inventory for the facility, providing a risk ranking of the different areas of the plant. The risk ranking then forms the basis of the risk management plan. The matrix method was selected for semi-quantitative risk analysis because it is a simple yet very powerful technique. It can readily lead to decisions in terms of actions required immediately and further studies required for more detailed understanding The Risk Matrix Used In Study An important step in the semi-quantitative risk analysis approach is the development of a risk matrix, which establishes the definitions of consequence and likelihood (frequency) categories to be used in the analysis, and which combinations of consequence and likelihood would be defined as high, medium, low or very low risk. The risk matrix used in the study is shown in Figure 2. 4

5 Figure 2: The risk matrix used in the study In the matrix above, the risk level for each cell is determined with the aid of the well-established risk equation. (Risk = Frequency * Consequence). 5.4 Risk Inventory and Risk Map for the Facility The risk inventory for the facility shows a list of the potential hazardous events that can occur at the facility, their potential consequences and their likelihood, and suggested additional actions/risk control measures to keep the risk at acceptable levels. A sample portion of the risk inventory for each area of the facility is shown in Figure 2. The risk level for each hazardous event is established after literature review and interviews with the facility employees. Figure 3: Sample risk inventory table for the plant Figure 3 does not represent the whole study, but it gives an overall idea about how risk matrix is shaped. 12 risk items are written in risk tables for main warehouse. 9 for dyeing, 5 for sizing and 22 items for finishing are present in risk tables. Overall, 48 risk items are investigated for this study. Frequencies and consequences of risk items are ranked according to the literature research, historical data and employee interviews. Then, risk items are placed in risk matrix where they are going to be ranked in terms of their hazards. The risk matrix is in Figure 2. The full risk inventory for the mill consists of 12 types of hazardous events (that could occur at the plant and that fall within the scope of major accidents ) for the main warehouse. Additionally, 9 5

6 events for dyeing, 5 for sizing and 22 events for finishing are identified. Overall, 48 types of potential hazardous events are investigated for this study. Frequencies and consequences of risk items are ranked using the risk matrix definitions of Figure 2, based on the literature review, historical data and employee interviews. The event types are then placed in the risk matrix for developing a visual risk map for the facility. In the risk map, risk items are coded from risk inventory tables. The numbers indicate the identification number of the event/additional precaution in the risk inventory table and the letters indicate the mill area where the event can occur. The risk map for the facility is shown in Figure 4. Figure 4: Chemical fire and explosion risk map of the selected textile mill In the risk map, risk items are coded from risk inventory tables. The numbers indicate the identification number of the event/additional precaution in the risk inventory table and the letters indicate the mill area where the event can occur. The matrix method helps to classify the present risks inside the facility so that the highest risks are set apart for the highest attention. The highest risk events and areas are identified as: Explosion in tanks in the finishing section. A tank explosion could result in a blast wave to disturb any previously accumulated starch dust and a dust explosion may also occur. Vapor cloud explosion in the main warehouse; lack of sufficient ventilation is a main contributor to the high frequency assignment to the event. Any kind of flammable or combustible vapors remain inside for a long time and accumulate. The contributors to the high consequence and/or high frequency assignments to these events are the following: Potential knock-on effect on other industries in case of an accident. If an accidental explosion occurs in the main warehouse, the scale of this explosion may enlarge spontaneously, resulting in higher consequences. Electrical appliances are not insulated. Ignition source may be introduced to the main warehouse that way. This is a contributor to the high likelihood assessment for explosions. The high likelihood of escalation of any accidents that do occur, because the walls are not fire or explosion resistant in the main warehouse. The potential for delay in appropriate response or implementation of inappropriate responses in case of an accident due to lack of an emergency plan for the textile mill. Any accidents that do occur may therefore escalate rapidly. 6

7 6. RISK MANAGEMENT PLAN A risk management plan includes the risk control measures for controlling the risks at acceptable levels. A contingency plan forms part of a risk management plan and describes how the facility and local emergency responders would respond to an emergency. The risk inventory developed above is a primary input to the risk management plan. Other inputs include: (i) Quantitative consequence analysis involving mathematical modeling for establishing explosion hazard zones, to confirm the qualitative consequence estimates used in the risk matrix, and to feed into contingency plans; and (ii) cost/benefit analysis of risk control measures. These tasks are also within the scope of the IPPC project and currently being undertaken by the project team. 7. CONCLUSION After this semi-quantitative risk assessment study, highest risk items and additional precautions are determined and conveyed to the facility management. The high risk events are identified as vapor cloud explosion, dust explosion and knock-on influence of an explosion on nearby industries and residential areas. The highest risk level is observed in the chemical warehouse of the facility. This is closely pertinent to the location of the main warehouse and amount of flammable and combustible materials stored inside the warehouse. Un-grounded electrical appliances, forklifts and lack of adequate ventilation in the main warehouse are primary contributors to this finding. In case such an explosion occurs, it is vital that the explosion radius is known. This powerful tool for decision makers would help to reduce the risk level via observing the cost-benefit relationship towards investment for risk reducing actions. It is also important to revise risk management system and emergency plans of the mill. This study is important as it is a first implementation in Turkey of risk analysis for industrial accidents within the framework of IPPC directive of EU. It is also substantial to show what sort of risks the facility may pose due to chemicals stored and used for their processes. To conclude; various chemicals located in industries may carry high risks for the health of public and environment. Determining and diminishing this risk is very important for the sake of public health and environmental safety which is a requirement of IPPC, the Seveso Directive and the upcoming legislation in Turkey on industrial accidents. REFERENCES 1. Council Directive on Integrated Pollution Prevention and Control 96/61/EC. 2. S. Banerjee (2003) Industrial Hazards and Plant Safety, Taylor & Francis. 3. E. Alp (2007) Consequence Analysis Methods for Hazards Associated with Releases of Hazardous Materials, Risk Assessment and Management Short Course Notes, presented at the Middle East Technical University, August. 4. David L.Y. Louie, and Louis F. Restrepo, Analytical Approach for Gas Explosions for DOE Nuclear and Non-Nuclear Facilities, Omicron Safety and Risk Technologies, Inc. 5. K.N. Palmer (1973) Dust Explosions and Fires, Chapman & Hall. 6. G.W. Underdown (1973) Practical Fire Precautions 7