Assessing Fire Safety in Maritime Composite Superstructures A Risk-Based Approach - PDF

Please download to get full document.

View again

of 119
All materials on our website are shared by users. If you have any questions about copyright issues, please report us to resolve them. We are always happy to assist you.
Information Report
Category:

Biography

Published:

Views: 5 | Pages: 119

Extension: PDF | Download: 0

Share
Related documents
Description
Assessing Fire Safety in Maritime Composite Superstructures A Risk-Based Approach Franz Evegren Department of Fire Safety Engineering and Systems Safety Faculty of Engineering Lund University, Sweden Avdelning
Transcript
Assessing Fire Safety in Maritime Composite Superstructures A Risk-Based Approach Franz Evegren Department of Fire Safety Engineering and Systems Safety Faculty of Engineering Lund University, Sweden Avdelning för Brandteknik och Riskhantering Lunds Tekniska Högskola Lunds Universitet Report 5327, Lund 2010 2 Assessing Fire Safety in Maritime Composite Superstructures A Risk-Based Approach Franz Evegren Lund Title / Titel Assessing Fire Safety in Maritime Composite Superstructures A Risk-Based Approach / Bedömning av Brandsäkerheten i Marina Kompositöverbyggnader En Riskbaserad Approach Author / Författare Franz Evegren Report / Rapport 5327 Number of pages: 117 Illustrations: If not specified, by author ISSN: ISRN: LUTVDG/TVBB 5327 SE Copyright: Brandteknik och Riskhantering, Lunds Tekniska Högskola, Lunds universitet, Lund 2010 Abstract Reduced weight and maintenance make it advantageous to replace steel with Fibre Reinforced Polymer (FRP) composites in maritime applications, but being combustible makes fire safety a burning issue. A new methodology in regulations has opened up for innovative design solutions if they can be regarded as safe as a design complying with all prescriptive requirements. However, an uneven safety level in regulations and unclear connections with objectives and functional requirements make it problematic to distinguish the level of fire safety in prescriptive requirements. This report provides an approach to clarify effects to the implicit fire safety when implementing an FRP composite superstructure to a passenger ship. FRP composites were considered with thermal insulation as a basic requirement for all interior surfaces, which keeps it thermally insulated for 60 minutes in case of fire. In order to establish how this conceptual design affects the prescribed level of fire safety, five qualitative analyses were performed, investigating (1) the fire safety regulations, (2) the fire safety objectives and functional requirements, (3) the fire safety structure, (4) the fire safety properties and (5) the fire development. The analyses showed on possible improved containment of fire and enhanced evacuation conditions within the first 60 minutes of a fire in the novel structure. After 60 minutes there may, however, be negative effects necessary to consider, such as an increased production of toxic smoke. Furthermore, if exterior surfaces are considered in the design, these will need special attention since they are combustible and outside the scope of current regulations. With the verification needs established, the report presents a riskbased approach to assess the fire safety in FRP composite designs. It consists of a risk analysis process in line with the methodology required when deviating from prescriptive fire safety requirements. It considers the previously revealed effects to fire safety and is adaptable to the intended scope of the novel design. Keywords Composite, fire safety, ship, risk-based, risk analysis, maritime, risk assessment. Sökord Komposit, brand, fartyg, riskbaserad, riskanalys, säkerhet, riskbedömning, marin. Department of Fire Safety Engineering and Systems Safety Lund University P.O. Box 118 SE Lund, Sweden Telephone: +46 (46) Telefax: +46 (46) Brandteknik och Riskhantering Lunds Tekniska Högskola Lunds Universitet Box Lund Telefon: Telefax: Sammanfattning Fiberarmerad plastkomposit (FRP) är ett lättviktsmaterial med styva och starka kvaliteter (se figur 1). I kombination med minskat underhållsbehov och förenklade reparationer gör materialets egenskaper att det blir gynnsamt att ersätta stålkonstruktioner i marina tillämpningar. En ny metodik i marina regelverk har öppnat upp för innovativa designlösningar om de kan visas vara minst lika säkra som designer som uppfyller alla normativa krav. Att materialet är brännbart gör brandsäkerhet till den centrala frågan vid bedömningen av säkerhet i FRP-konstruktioner. En grundförutsättning i rapporten är därför att alla invändiga ytor värmeisoleras (se figur 2). Det gör att det nya byggnadsmaterialet ges värmebeständighet och isoleras från en fullt utvecklad brand i 60 minuter. En svårighet i jämförelsen av säkerhet ligger i att marina förordningar ofta följden av allvarliga olyckor istället för resultatet av proaktivt regelfattande. En ojämn nivå av säkerhet i förordningar samt otydliga kopplingar till mål och funktionskrav gör det svårt att urskilja brandsäkerhetsnivån i normativa krav (se figur 3). Denna rapport tillhandahåller en metod för att klargöra effekterna på den implicita nivån av brandsäkerhet när FRP introduceras i överbyggnader på passagerarfartyg. För att fastställa hur en överbyggnad i isolerad FRP förändrar den föreskrivna brandsäkerheten undersöktes dess inverkan på: 1. brandskyddsföreskrifter; 2. syften och funktionella krav; 3. brandskyddets struktur; 4. brandskyddets egenskaper; och 5. brandens utveckling. Figur 1. Illustration av en FRP-konstruktion med starka och fasta fiberarmerade laminat fästa på en lättviktig kärna. Figur 2. Isoleringen som är markerad i figuren ger FRP konstruktionen värmebeständighet. Figur 3. Illustration av hur det marina regelverket är uppbyggt. Analyser genom dessa fem kvalitativa perspektiv visade på möjliga förbättringar, gällande isolering av branden från övriga utrymmen samt gällande utrymningsförhållandena under de första 60 minuterna av en brand. Efter 60 minuters brand kan den nya designen dock ge upphov till negativa effekter som är nödvändiga att beakta, såsom en ökad produktion av giftiga brandgaser. Vidare kommer utvändiga ytor, om sådana är inkluderade i utformningen av FRPkonstruktionen, att kräva särskilt beaktande eftersom dessa är brännbara (oisolerade) och inte omfattas av nuvarande regelverk. När verifieringsbehoven har fastställts presenterar rapporten också en riskbaserad metod för att uppskatta brandsäkerheten i en FRP-konstruktion. Tillvägagångssättet är i linje med den föreskrivna metod som krävs när avsteg görs från normativa brandsäkerhetsföreskrifter (IMO, 2001). Metoden tar även hänsyn till, enligt ovan, klargjorda effekter på brandsäkerheten och kan anpassas till den planerade omfattningen av designen. Det första steget i processen är, liksom i de flesta andra riskanalyser, en faroidentifiering (A). Därefter följer en uppskattning av risken på en av tre nivåer, baserade på Pate-Cornell (1996), enligt figur 4. De olika nivåerna representerar olika förfinade analyser, varav föreskrifter kräver en analys på den minst krävande nivån (B), en analys av värsta troliga scenarion. Risken återspeglas i denna analys genom uppskattningar av de värsta 5 rimliga brandscenarierna som kan inträffa, vilka även anger den erfordrade funktionsnivån hos konstruktionen. Även om säkerhetsnivån hos designen antas klara det värsta troliga scenariot finns dock en okänd sannolikhet för att så inte blir fallet. Den faktiska säkerhetsnivån i konstruktionen är därmed inte uppenbarad. Trots det kan en analys på denna nivå vara tillräcklig; om omfattningen av den avsedda FRP-överbyggnaden är begränsad och inte innefattar några utvändiga (oisolerade) ytor. I annat fall kommer effekterna på brandsäkerheten att vara mer komplicerade och behovet av verifiering är större. Nästkommande nivå (Γ) innebär att en probabilistisk riskanalys utförs för att illustrera riskerna. I motsats till föregående angreppssätt tar en analys på denna nivå inte bara hänsyn till konsekvenser utan även till sannolikheter. Analysen är avsedd att beskriva en fullständig fördelning av potentiella förluster, vilket vanligtvis framställs genom en risk kurva. En begränsning i uppskattningen av risker på denna nivå är att effekterna av olika osäkerhetsfaktorer inte kan särskiljas. En djupare analys av osäkerheter kan beskriva sekundära sannolikheter eller osäkerhet rörande sannolikhet, vilket definierar den mest avancerade nivån av dem som beaktas i rapporten. På denna nivå (Δ) är det möjligt att t.ex. särskilja spridning orsakad av bristande kunskap från den på grund av naturlig variation. Detta görs genom att presentera risken som en familj av riskkurvor. En analys på denna nivå är dock mycket krävande och bör endast eftersträvas vid exceptionellt höga verifieringsbehov, t.ex. om säkerheten optimeras genom att minska den termiska isoleringen. Figur 4. Beroende på hur brandsäkerheten påverkas av en föreslagen FRP-konstruktion rekommenderas att uppskatta effekterna genom en riskanalys på en viss nivå. Figur 5. Beskrivning av den rekommenderade riskanalysprocessen som inkluderar en utredning av effekterna på brandsäkerheten och är i linje med IMO (2001). Ett steg till nästkommande nivå i figur 4 bör endast tas i den mån som krävs för att få tillräckligt med information för att kunna ta ett beslut (Bridges, 2000). En djupare analys tar itu med specifika brister i de tidigare nivåerna, men att gå vidare till nästa nivå gör också informationen mer komplex och ökar kostnaderna för insamling och bearbetning av ytterligare data. Detta symboliseras av den växande arean för nivåerna nedåt i triangeln. Den ökade arbetsbelastningen gör att det är aktuellt att söka en balans vad gäller utvärderingen av osäkerheter. Det föregående beskrivna angreppssättet för att klargöra verifieringsbehov kan inkluderas i den beskrivna riskanalysen och bildar då en process som exemplifieras översiktligt i rapporten och sammanfattas i figur 5. 6 Preface This project has indeed been an interesting journey. I hope this report will be of some help and bring as much knowledge and ideas to someone else out there as it has brought me. I am very glad for the opportunity to study within this field, provided by Tommy Hertzberg, PhD, Department of Fire, Risk and Safety, SP Technical Research Institute of Sweden. I am also thankful for all the advice and hospitable treatment when visiting Borås. As the apprentice, I would also like to give many thanks to my allknowing master, Håkan Frantzich, PhD, Department of Fire Safety Engineering and Systems Safety, Lund University, Lund, Sweden, for the patience and the many long discussions. Finally, I would like extend my most loving gratitude to Kristie; for all the self-sacrificing love you heave over me, Franz May 2010 Everything is in fact combustible the question is only at what temperature. 7 Abbreviations ALARP CCF Circ. COSO DNV ETA ETSC Fe FMEA FN FRD FRP FSA FTA GBS HAZOP HRA HSC HSE IACS IEC IMO ISM ISO LÄSS LSA LTH MSC NFPA PHA PLL PRA PVC QRA RCM RCO RFR RO SLA SOLAS SOU THERP UK As Low As Reasonably Practicable Common Cause Failures Circular Committee of Sponsoring Organizations of the Treadway Commission Det Norske Veritas Event Tree Analysis European Transport Safety Council Steel Failure Modes and Effects Analysis Frequency of accidents versus Number of fatalities Fire Resisting Division Fibre Reinforced Polymer Formal Safety Assessment Fault Tree Analysis Goal Based Design Hazard and Operability Study Human Reliability Analysis High Speed Craft Health & Safety Commission (UK) International Association of Classification Societies International Electrotechnical Commission International Maritime Organization International Safety Management International Organization of Standards Light Weight Construction Applications at Sea (Lättviktskonstruktioner till sjöss) Life-Saving Appliances Faculty of Engineering, Lund University Marine Safety Committee (commission within the IMO) National Fire Protection Association Process Hazards Analysis Potential lives lost Probabilistic Risk Assessment Polyvinyl Chloride Quantitative Risk Assessment Risk Control Measure Risk Control Option Regulation Functional Requirement Regulation Objective Safety Level Approach International Convention for the Safety of Life at Sea Swedish Government Official Reports (Statens Offentliga Utredningar) Technique for Human Error Rate Prediction United Kingdom SOLAS chapter II-2 is also sometimes written SOLAS II-2 and refers to the second subchapter of SOLAS chapter II. SOLAS II-2/ means SOLAS chapter II-2 Regulation 9 paragraph If not specified, the chapter regarding fire safety, SOLAS II-2, is implied. Further explanations of some of the abbreviations are found in Appendix A. Definitions. 8 Table of Contents 1. INTRODUCTION PROBLEM PRESENTATION PROSPECT AND OBJECTIVES METHOD DISPOSITION LIMITATIONS DEFINITIONS FIRE SAFETY REQUIREMENTS AND THE DEVELOPMENT IN SOLAS IMO AND SOLAS ESTABLISHMENT OF SOLAS CHAPTER II CURRENT PERFORMANCE-BASED SOLAS-REGULATIONS Damage Stability Regulation Circular DEVELOPMENT IN IMO RULE-MAKING Formal Safety Assessment Moving from compliance to safety Explicit criteria An opening for risk-based design INTRODUCTION TO THE CONCEPT OF RISK RISK IS INEVITABLE ON THE DEFINITION OF RISK RISK MANAGEMENT AND RISK ASSESSMENT RISK ANALYSIS RISK EVALUATION AND THE CURRENT APPROACH UNCERTAINTY SAFETY CULTURE AND HUMAN ERROR Organization and management Human error in a safety culture Safety culture affects the risk Management systems Risk management systems as an input to risk analysis RISK PERCEPTION STRUCTURAL REQUIREMENTS AND THE FRP COMPOSITE SHIP FIRES EVACUATION SPECIFIC REQUIREMENTS FOR STRUCTURES A class B class divisions C class divisions A note on combustibility THE COMPOSITE BASE DESIGN Structure of an FRP composite panel The necessary insulating qualities Foundational arrangements in an FRD design 46 9 4.5 PROPERTIES REVEALED FROM TESTS TESTS AS A METHOD FOR COMPARISON ANALYZING THE NEEDS FOR VERIFICATION THE FIRE SAFETY REGULATIONS Regulation Regulation Regulation Regulation Regulation Regulation THE FIRE SAFETY OBJECTIVES AND FUNCTIONAL REQUIREMENTS Fire safety objectives Functional requirements THE FIRE SAFETY STRUCTURE Different types of fire protection Multi-purpose complexities Matrix describing the universal effects Marking changes in the matrix Using the matrix to analyze a change to FRD THE FIRE SAFETY PROPERTIES Human intervention Complexity in the fire protection strategy Fire protection complexity Flexibility Sensitivity Reliability Vulnerability THE FIRE DEVELOPMENT Ignition and the first stages of an enclosure fire Structural divisions within the first 60 minutes Structural divisions after propagation or deterioration ( 60 min) Exterior surfaces SUMMARY OF THE PRECEDING ANALYSES RISK ANALYSIS FOR VERIFICATION UNCERTAINTIES IN A SHIP DESIGN UNCERTAINTIES FROM THE DESIGN PROCESS MANAGING UNCERTAINTIES ON DIFFERENT LEVELS IN RISK ANALYSIS Level 0: identification of hazards and failure modes Level 1: the worst-case approach Level 2: plausible worst-case Level 3: best estimates and central values Level 4: probabilistic risk assessment and single risk curve Level 5: display of risk uncertainties Discussion on the levels of verification Choosing a simple or sophisticated approach THE METHODOLOGY OUTLINED IN CIRCULAR Preliminary analysis in qualitative terms Quantitative analysis 84 10 6.4.3 Discussion on the approach outlined in Circular RECOMMENDED APPROACH FOR THE FIRE SAFETY ANALYSIS Level A: identification of hazards and preliminary analysis Level B: plausible worst-case analysis Level Γ: probabilistic risk analysis Level Δ: evaluation of risk uncertainties SYNOPTIC APPLICATION OF THE APPROACH NORWEGIAN GEM AND THE PROPOSED FRD DESIGN THE PRELIMINARY ANALYSIS Identification and enumeration of hazards Analysis of the effects to fire safety Selection of fire hazards and specification of fire scenarios RISK ESTIMATION Fire scenario development Quantification of fire scenarios Presentation of the risk The illustrated process CONCLUSIONS FULFILMENT OF OBJECTIVES FUTURE WORK REFERENCES 105 APPENDIX A. DEFINITIONS 113 APPENDIX B. THE PURPOSES OF SOLAS II APPENDIX C. THE NORWEGIAN GEM 12 1. Introduction This is a degree project that favourably will cover the two fields that have been studied; Master of Science in Risk Management and Safety Engineering as well as Bachelor of Science in Fire Safety Engineering. The education has been a process of obtaining deeper understandings in engineering and now the goal is that a measure of maturity within the particular disciplines has been developed. The overall objective with this project is first and foremost to gain experience and knowledge on how to adequately apply the former education to a subject of importance. Another goal is to develop and demonstrate independent research skills of an engineer, which is to be expressed by the student in diverse manners throughout the project. 1.1 Problem presentation This degree project is part of the LÄSS-C project, Lightweight Construction Applications at Sea Cruise vessels, directed by SP Technical Research Institute of Sweden. The LÄSS project aims at improving the efficiency of marine transport and to increase the competitiveness of the Swedish shipbuilding industry and the LÄSS-C subproject targets cruise vessels with the same purpose. The project is focused on accomplishing this through development and demonstration of techniques for using lightweight materials for ship construction (SURSHIP; LÄSS). All transport development is today driven by cost effectiveness and optimization of available resources at the same time as improved safety to man, vehicle and environment is of highest concern. By implying fire resisting polymer composites to merchant ships, studies have shown that a structural weight reduction of up to 60 % is achievable (Hertzberg, 2009). The cost may pay back in short time of operation when utilizing the advantages of a more complex design, a less fuel consuming ship or perhaps an additional deck. Addressing the fact that potentially a major part of the load-bearing steel structure in a ship will be replaced by an FRP (Fibre Reinforced Polymer) composite construction, which has some characteristics very different from steel, invokes a holistic approach. Risks to ecology and in shipbuilding, the lifetime and recycling of a ship as well as implicit risks with utilizing the constructions will inevitably be, not necessarily greater but, different. For example, a reduction in topside weight, implied by the lightweight material, could have a positive effect on damage stability and thus reduce the risks entailed with collision and grounding. However, the isolated situation on a ship in case of a fire, and the fact that FRP is combustible, makes fire safety of a design in the novel material the key issue. Therefore, only effects on fire safety will be considered when evaluating the novel material, leaving other risks and benefits out of the scope of this degree project. Laying down a foundation for how fire safety can be assessed for maritime composite constructions, the thesis will focus on passenger ships as it is part of the LÄSS-C project. 1.2 Prospect and objectives In order to make FRP composite a potential maritime construction material, its performance when exposed to fire needs to be analyzed. The involvement of novel material will be different in every application case and the fire safety will be subject to special evaluation in each ship design. The prospect of this project is that methods will be found that can evaluate designs involving FRP composite constructions in order to find solutions for the fire safety that are satisfying to the Administration (International Maritime Organization). Different methods have been used to prove that novel designs surpass prescriptive requirements, but the administration and the maritime classification societies have requested more convincing approaches. The industry is now moving towards further elaborating the methodology outlined in Regulation 17 as well as a risk-based approach involving probabilities. The main objective of this project is therefore to approach the prospect, to reveal
Recommended
View more...
We Need Your Support
Thank you for visiting our website and your interest in our free products and services. We are nonprofit website to share and download documents. To the running of this website, we need your help to support us.

Thanks to everyone for your continued support.

No, Thanks