Cpe 615 process safety notes unedited mo

CHAPTER 1: INTRODUCTION TO HAZARD AND RISK CHAPTER 1.1: INTRODUCTION TO PROCESS SAFETY 1.1.1 Safety and Loss Prevention  Safety  The older strategy of accident prevention through the use of PPEs and a variety of rules and regulations  Emphasis is on the worker safety  Loss prevention  Replaced safety  Includes hazard identification, technical evaluation and the design of new engineering features to prevent loss  Both  Definition: Prevention of accidents through the use of appropriate technologies to identify hazards of a chemical plant and eliminate them before accident occurs 1.1.2 Hazards versus Risk  Hazard  A condition that has the potential to cause human injury or fatality, damage to property, damage to the environment or some combination of these  Category of hazards  Risk  A measure of human injury, environmental damage, or economic loss in terms of both the incident likelihood and the magnitude of the loss or injury  A chance of injury or loss or bad consequences to happen 1|Page 1.1.3 Safety versus Health  Safety  The absence of physical or psychological injury or harm and often extends to the absence of damage or property  Deals with acute effects of hazards  Health  A state of physical and mental well-being  Including the absence of disease or infirmity  Deals with chronic effects of hazards  Definition  Chronic  Persistent  Prolonged  Repeated  Acute  Immediate  Short Term 1.1.4 Engineers and Safety  Health and safety issues must be a given great emphasis starting from the design stage  Non-compliance with safety standards can severely affect a company’s bottom line, such as  Penalties and fines  Worker compensation  Engineers who design the workplace and its equipment or who manage and supervise workers need to have an understanding of the safety and health regulation 1.1.5 Major Process Industry  Accidents  Fires  Explosions  Toxic Releases  Consequences  Fatalities  Injuries  Environmental damage  Property damage  Plant closings  Fines and lawsuit 2|Page 1.1.6 Major Industrial Accidents in the Past  Bhopal  1984  Release of toxic gas  40 tons of Methyl Isocynate escaped from Union Carbide Plant  Thousands more died in weeks that followed  More than 500,000 suffered  Chernobyl  26 April 1986  Chernobyl Nuclear Reactor, Ukraine  Large area of Russia, Ukraine and Belarus was evacuated  336,000 people resettled  Fewer than 50 direct death, but thousands of cancer-related cases  Severe damage to the environment  Piper Alpha  World’s most famous oil rig disaster  167 out of 229 people died  Initial explosion followed by a fierce fire which, in turn, triggered off a further series of explosions  Flames could be seen 100 km away  Bright Sparkles  1991  Fire ignited from product testing activities  Fire and explosion destroyed the factory completely  23 people died and 103 other sustained injuries  BP Texas City Refinery  23 March 2005  Fire and Explosion  Killing 15 workers and injuring more than 170 others  Deep Water Horizon Platform  Gulf coast of United States  Platform explosion and sinking, killed 11 workers  Leaking of hundreds of thousands of barrels of oil into the Gulf of Mexico that is making it probably the worst industrial environmental disaster in US history 3|Page CHAPTER 1.2: THEORIES OF ACCIDENT CAUSATION 1.2.1 Incident versus Accident  Incident  All undesired circumstances that have the potential to cause accidents  Near miss  An unplanned event that did not result in injury, illness or damage – but had the potential to so  Or called close call  Accident  A sequence of events that produce unintended injury, damage to property or the environment, production losses, or increased liabilities  Refers to event, not the results of the event  Accident Pyramids:  Development of accident: 4|Page C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an 1.2.2 Why Do Accidents Occur?  We choose to handle dangerous processes, materials, energies  To make a living  To provide society with desirable products  A potential for loss events exist 1.2.3 How Do Accidents Occurs 1) Domino theory  From Herbert W Heinrich  An early pioneer of accident prevention and industrial safety  Studied 75000 reports of accidents for insurance claims and concluded  88% caused by unsafe acts committed by workers  10% of industrial accidents are caused by unsafe conditions  2% of industrial accidents are unavoidable  Heinrich’s axiom of industrial safety  Injuries result from a complete series of factors  An accident can occur as a result of unsafe act and/or unsafe conditions  Most accidents are the result of the unsafe behaviour by people  An unsafe act or an unsafe conditions does not immediately result in accident/injury  The reasons why people commit unsafe acts can serve as helpful guides in selecting corrective actions  The severity of an accident is largely fortuitous and the factors that cause it are largely preventable  The prevention technique are analogous with the best quality and productivity techniques  Management should assume responsibility for safety because it is in the best position to get results  The supervisor is the key person in the prevention of industrial accidents  In addition to the direct costs of an accident, there are also hidden or indirect cost  factors in the sequence of events leading up to an accident Social Environment and Ancestry  Negative character traits that might lead people to behave in an unsafe manner can be inherited or acquired as a result of the social environment Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn 5|Page C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an Fault of person (carelessness)  Negative character traits, whether inherited or acquired are why people behave in unsafe manner and why hazardous conditions exist Unsafe act or condition  Unsafe act committed by people  Unsafe conditions due to the presence of mechanical / physical hazards Accident Injury  Heinrich’s theory has two central points  Injuries are caused by the action of preceding factors  Removal of the central factor (unsafe acts/hazardous conditions) negates the action of the preceding factors and, in so doing, prevents accidents and injuries 2) Human factors theory  Attributes accidents to a chain of events that were ultimately the result of human error  Human factors  Overload  An imbalance between a person’s capacity at any given time and the load that a person is carrying in a given state  A person’s capacity is the product of such factors as his/her ability, training, state of mind, fatigue, stress and physical conditions  Resulting from  Environmental factors o Noise o Distractions  Situational factors o Level of risk o Unclear instructions  Internal factors o Personal problems o Emotional stress o Worry  Inappropriate response  How a person responds in a given situation can cause or prevent an accidents  Detecting hazard but not correcting it  Removing safeguards from machines and equipment  Ignoring safety Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn 6|Page C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an  Include  A person detects a hazardous condition but does nothing to correct it  A person removes a safeguard from a machine in an effort to increase output  A person disregards an established safety procedure  Inappropriate activities  Performing task without the requisite training  Misjudging the degree of risk involved with a given task 3) Accident/Incident theory  Developed by Dan Peterson  Extension of the human factors theory  Introduced such new elements as ergonomic traps, the decision to err (mistake) and system failure  Important contribution: system failure  Some ways that a system fails  Management does not establish a comprehensive safety policy  Responsibility and authority with regard to safety are not clearly defined  Safety procedures such as measurement, inspection, correction and investigation are ignored or given sufficient attention  Employees not receive proper orientation  Employees are not given sufficient safety training  Summary Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn 7|Page C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an 4) Sociotechnical system framework  Every fault in an incident scenario will have been affected by root causes  Failures in large industrial system cannot be considered solely in technical terms  The sociotechnical system approach emphasis the individual, organizational, management and technical aspects which affect a system’s performance  Summary 1.2.4 Causes of Accidents 1) Immediate cause  The most apparent cause  Represent the initiators of the incidents  The symptom  Normally called either unsafe acts or unsafe conditions  Example of unsafe acts  Horseplay  Defeating safety devices  Failure to secure or warn  Operating without authority  Working on moving equipment  Taking an unsafe position or posture  Operating or working at an unsafe speed  Unsafe loading, placing, mixing, combining  Failure to use PPE Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn 8|Page C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an  Example of unsafe conditions  Improper PPE  Improper tools  Improper guarding  Poor housekeeping  Improper ventilation  Improper illumination  Unsafe dress or apparel  Hazardous arrangement 2) Root cause  Exists because of lack of management control such as commitment to safety policy  Either  Personal related  Lack of knowledge or skills  Poor motivation  Physical difficulties  Job related  Inadequate work standards  Poor maintenance  Design of equipment  Example  Safety policy not defined and communicated  Responsibility, authority and accountability not assigned  Emphasis on production, rather on safety  Lack of direct communication with management  Unsafe design and selection of equipment, chemicals, process and facilities  Inadequate safety inspection procedures  Insufficient procedures for normal and emergency situations  Lack of training  Inadequate employee selection, supervision and rewards Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn 9|Page C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an 1.2.5 The ‘Accident Weed’ 1.2.6 Cost of Accidents 1) Direct cost  Expenses incurred because of an accident  Include medical expenses and compensation paid to an injured employee for time away from work  Costs for repair and replacement of damaged items 2) Indirect cost of accidents  Real expenses associated with accident  Example  Lost time of injured employee  Time lost by other employees to assist injured co-workers  Time lost by supervisor to investigate accident, prepare report and make adjustment of work arrangements  Time spent by company first aid, medical staff  Lost of profit  Paper works for insurance claim  Production losses 1.2.7 To Keep Accident from Happening?     Design of process Management of process Operation of process Regulations Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn 10 | P a g e C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an 3) Control  Application of appropriate technology to reduce workplace exposures to acceptable levels  After potential health hazards are identified and evaluated, the appropriate control techniques must be developed and installed  Requires the application of appropriate technology for reducing workplace exposures  major control techniques  Environmental control o Enclosures o Ventilations o Wet methods o Good housekeeping  Personal protection o Safety glasses o Face shields o Aprons o Space suits o Ear plugs Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an CHAPTER 3.4 FIRE AND EXPLOSION 3.4.1 What Engineers Need to Know?  To prevent accidents resulting from fires and explosions, engineers must be familiar with  The fire and explosion properties of materials  The nature of the fire and explosion process  Procedures to reduce fire and explosion hazards 3.4.2 Fire and Explosion  Fire  The combustion process (fire)  A chemical reaction in which a substance combines with an oxidant and heat is released (exothermic oxidation)  Combustion always occurs in the vapour phase  Liquids are volatised and solids are decomposed into vapour upon heating  If the concentration of vapour is high enough it forms a flammable mixture with the oxygen of the air  If this flammable mixture is heated further to its ignition point, the combustion starts  Normally, the heat required is initially supplied by an external source and then provided by the combustion itself  The amount of heat needed to cause ignition depends on the form of the substance  A gas / vapour may be ignited by a spark or small flame while a solid may require a more intense heat source Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an  Ignition of a combustible gas may occur in two ways a) The energy for ignition is supplied by a local source at a point within the mixture  Spark or small flam b) The bulk gas mixture is heated up to its ignition temperature  Autoignition temperature: A fixed temperature above which adequate energy is available in the environment to provide an ignition source  Differences between fires and explosions  Major factor: Rate of energy release  Fire  Release energy slowly  Can result from explosions  Explosions  Release energy rapidly (in the order of microseconds)  Can result from fire 3.4.3 Flammability Characteristics of Liquids  Terms  Flash point of liquid  The lowest temperature at which a liquid gives off enough vapour to form an ignitable mixture with air  At the flash point, the vapour will burn but only briefly because inadequate vapour is produced to maintain combustion  Fire point  The lowest temperature at which a vapour above a liquid will continue to burn once ignited  The fire point is higher than the flash point  Instrument Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an  Flash point temperatures  For pure materials correlate well with the boiling point of the liquid  Formula Tf: The flash point temperature (K) a, b and c are constants Tb is the boiling point temperature of the material  Table  Can be estimated for multicomponent mixtures if only one component is flammable and if he flash point of the flammable component is known Experimentally determined flash points are recommended for multicomponent mixtures with more than one flammable component For a single flammable component mixture, the flash point temperature is estimated by determining the temperature at which the vapour pressure of the flammable component in the mixture is equal to the pure component vapour pressure at its flash point   3.4.4 Flammability of gases and vapours  A flammable gas burns in air only over a limited range of composition  The vapour-air mixture  Don’t burn as the composition lower than lower flammability limit (LFL)  The mixture is too lean for combustion  Not combustible when the composition is too rich (above the upper flammability limit)  Only flammable when the composition is between LFL and UFL Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an 3.4.5 Flammability Diagram 3.4.6 Flammability Limit  For vapours, flammability limits are determined experimentally  For mixture, LFL and UFL are computed using Le Chatelier’s equation  Formula  Lower flammability limit (LFL) LFL: The lower flammability limit for component i (in volume %)  Upper flammability limit (UFL) yi: The mole fraction of component I on a combustible basis n: The number of combustible species 3.4.7 Estimating flammability limit 3.4.8 Estimating LOC  LFL is based on fuel in air  However, oxygen is the key ingredient and there is a minimum oxygen concentration required to propagate a flame  Fires and explosions can be prevented by reducing the oxygen concentration regardless the concentration fuel  This concept is the basis for a common procedure called inerting  Below the LOC, the reaction cannot generate enough energy to heat the entire mixture of gases to the extent required for the self-propagation of the flame  LOC is estimated using the stoichiometry of the combustion reaction and the LFL LOC = z(LFL) Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an 3.4.9 Relationships between Various Flammability Properties 3.4.10 Ignition Sources Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an 3.4.11 Fire 1) Flash fire  Definition: An unexpected, sudden, intense fire caused by ignition of flammable solids (including dust), liquids or gases  A combustion event with little or no overpressure  Proceeds in a very fast time scale until the fuel is consumed  As fuel gas is released into air  Typically its concentration is very high near the release points  It is not well mixed in the air  If the gas ignites at that time, generally the result is a flash fire  Consume escaping fuel so it is not available for further mixing in air  Characterized by  High temperature  Short duration  Rapidly moving flame front  Flame spreads at subsonic velocity  So the overpressure damage is usually negligible  The bulk of the damage comes from  Thermal radiation  Secondary fires  When inhaled  The heated air can cause serious damage to the tissue of the lungs  Possibly leading to death by asphyxiation  Can lead to smoke burn  Particular danger in enclosed spaces  Even a relatively small fire can consume enough oxygen and produce enough smoke to cause death of the persons present, whether by asphyxiation or by smoke inhalation 2) Pool fire  Definition: The combustion of flammable vapour evaporating from a layer of liquid at the base of the fire  Occurs on ignition of an accumulation of liquid as a  Pool on the ground or  On water  Other liquid  A storage tank fires are usually treated as pool fires  A steadily burning fire is rapidly achieved as the vapour to sustain the fire is provided by the evaporation of the liquid by heat from the flames  Pool fire are less dangerous to human life than flash fire  However, their longer duration results in greater structural and equipment damage Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an 3) Jet fire  The combustion of material emerging with significant momentum from an orifice, from a source under pressure (example: a flammable liquid or gas is ignited after its release from a pressurized, punctured vessel or pipe)  The pressure release generates a long flame which is stable under most conditions  The duration of a jet fire is determined by  Release rate  Capacity of the source  Flame length increase directly with flow rate 3.4.12 Effects of Fire on People  Main hazard present from large open fires are due to radiation  A first degree burn  At a mild level causing reversible reddening, erythema  No blisters are form  Only the epidermis is affected  The skin usually reverts to normal within 24 hours  A second degree burn  Is characterized by formation of blisters  The blister depth may be shallow with only the surface layer of the skin damaged  In more severe cases the whole of the dermis is damaged  A third degree burn  A deep burn characterized by the destruction of the skin layers and part of the subcutaneous tissue 3.4.13 Thermal Radiation  The thermal radiation effects on people depend upon the length of time the people are exposed to a specific thermal radiation level  Longer exposure durations, even at a lower thermal radiation level, can produce serious physiological effects  Thermal radiation levels of concern (LOC)  Definition: A threshold level of thermal radiation (heat), usually the level above which a hazard may exist  When you run a pool fire, jet fire, BLEVE scenario, thermal radiation is the hazard that is modelled  Unlike toxic LOCs, no well-defined guidelines or standards exist to evaluate the thermal radiation hazard Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an  So, default thermal radiation values (in kilowatts per square meter) that are based on a review of several widely accepted sources on thermal radiation  10 (kW/m2): Potentially lethal within 60 seconds  (kW/m2): Second degree burns within 60 seconds  (kW/m2): Pain within 60 seconds  Thermal radiation effects  Depend upon the length of time they are exposed to a specific thermal radiation level  Longer exposure durations, even at a lower thermal radiation level, can produce serious physiological effects  The threat zones represent thermal radiation levels  The accompanying text indicates the effects on people who are exposed to those thermal radiation levels, but are able to seek shelter within one minute  Time for physiological effects (on bare skin) to occur following exposure to specific thermal radiation levels Radiation intensity (kW/m2) 10 12 Time for severe pain (seconds) 115 45 27 18 13 11 Time for 2nd degree burns (seconds) 663 187 92 57 40 30 20 14 11  Effects of thermal radiation Radiation Intensity (kW/m2) 37.5 12.5 9.5 4.0 1.6 Observed effects   Causes damage to process equipment The minimum energy to ignite wood at indefinitely long exposures Minimum energy for igniting wood and for melting plastic tubing  Pain threshold reached after second  After 20 second of exposure, second degree burns  Cause pain after 20 second exposure  Second degree burns (blisters) are likely Cause no discomfort for long exposures Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an  Protection against fire Category Heat radiation Pool and jet fire Tank fires Flash fire Protection  Seeking protection behind obstacles  Run away from fire  Find shelter  Escapes if possible  Evacuate the area soonest possible  Usually developed slowly  Can be approached by the fire men from cross wind or up wind direction  Usually flame speed  Spread is very fast  Fumes may enter the shelter  Evacuation is not possible  Usually 20-30 minutes before BLEVE  A relief valve can reduce the BLEVE time further 3.4.14 Explosion  Sudden and violence release of energy  The violence of the explosions depends on the rate at which energy is released  The energy release must be sudden enough to cause a local accumulation of energy at the site of the location  This energy is dissipated by a variety of mechanisms, including formation of pressure wave, projectiles, thermal radiation and acoustic energy  The damage from an explosion is caused by dissipating energy  If the explosion occurs in a gas  The energy causes the gas to expand rapidly  Initiating a pressure wave that moves rapidly outward from the blast source  Pressure wave  Contains energy  Results in damage to surroundings Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an Provides a traceable, logical, quantitative representation of causes, consequences and event combinations Top-down approach Top event and intermediate events Rectangle Accident that is being analyzed Represent basic events in a fault tree Circle Lowest level of resolution in the fault tree Logical functions Represent events that cannot be developed further in the fault tree due Diamond to the lack of suitable information Resulting output event requires the simultaneous occurrence of all input events AND Gate Resulting output event requires the occurrence of any individual input event OR Gate Various sets of events that could lead to the top event AND Gate increase the number of events in the cut sets Minimal cut sets OR Gates lead to more sets Determines the probability of the top event Fault tree analysis (FTA) Reliability = 1- Probability Quantitative Probabilities are multiplied across an AND gate Reliabilities are multiplied across an OR Gate Almost every type of risk assessment application Most common uses Effective root cause analysis tool in several applications Narrow focus Quantification requires significant expertise Limitations Forget to address human and organizational issues Define the system of interest Define the top event for the analysis Define the treetop structure Consequences Explore each branch in successive levels of detail Risk assessment Solve the fault tree for the combinations of events contributing to the top event Probability of those events Determination of the events that can produce an accident Lecture 13: FTA and ETA Identify important dependent failure potentials and adjust the model appropriately The identification of unacceptable risks Procedure Results of a hazard analysis The selection of means of controlling Perform quantitative analysis Use the results in decision making Determine types and locations of potential safety problems Bottom-up approach Allow us Identify corrective measures Define the system or activity of interest Preplan emergency actions Identify the initiating events of interest Hazards of the process Identify lines of assurance and physical phenomena Must address Define accident scenarios Engineering and administrative controls Procedure Consequences of failure Analyze accident sequence outcomes A list of possible problems and areas to be checked Summarize results Quick and simple to perform Use results in decision making Advantages Helps check compliance with standard practice Process hazards checklists The occurrence of some failure with the potential to produce an undesired consequence Known hazards are fully explored Initiating event Also called an inicident Depend upon the quality of the checklist Event tree analysis (ETA) A protective system or human action that may respond to the initiating event Line of assurance (LOA) Chapter 4: Hazard Analysis Terminology Lecture 12: Process hazard analysis Limitations Likely to miss some potential problems Introduction Only provides qualitative information Graphical illustration of two potential outcomes when a line of assurance is challenged Branch point Identify all potential hazards and accidental events One specific pathway through the event tree from the initiating event Accident sequence or scenario Is a semi-quantitative analysis that is performed to to an undesired consequence To determine the probability of an event based on the outcomes of each event in the chronological sequence of events leading up to it Goal Rank the identified accidental events according to their severity and frequency Identify required hazard controls and follow up actions Process Hazard Analysis (PHA) Limited to one initiating event Focus an identifying weaknesses early in the life of a system Limitations Can overlook subtle system dependencies Provides a qualitative ranking Generates qualitative descriptions of the hazards Quantitative evaluations of recommendation effectiveness Qualitative descriptions of potential problems Ranking can be used to prioritize recommendations An analysis technique that generates Quality and availability of documentation Quantitative estimates of event frequencies or likelihoods Preliminary hazard analysis (PrHA) Quality of the evaluation Training of the review team leader with respect Identify possible deviations from normal operations Experience of the review teams Uses a systematic process to Ensure that appropriate safeguards are in place Define the activity or system of interest No Define the accident categories of interest and severity categories Procedure More Conduct review Identify the major hazards and associated Higher accidents that could result in undesirable consequences Uses special guidewords Use the results in decision making Less Guidework + Process parameter = Deviation Requires additional follow-up analyses Formula Limitations Specific location in the process which the deviations Quality of the results is highly dependent on the knowledge of the team Choose a study node of the process/design intention are evaluated Postulate potential upsets Flow A brainstorming approach that uses Pick a process parameter broad, loosely structured questioning to Methodology Level etc Ensure that appropriate safeguards against those problems are in place Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn Sooner than Later than Quality of the documentation Applicable to batch processing Apply a guideword What-if-analysis Quality of the evaluation depends on Where else Training of the review team leader Experience of the review teams Pump breaks down Likely to miss some potential problems No flow Line blockage Limitations Difficult to audit for thoroughness C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an Hazard identification Risk assessment process Estimating risk associated with that hazard Decision making Identify the hazard Estimating the risk associated with the hazard Risk assessment and the Principle of Crocodile Eliminate Substitute Decision making Isolate Use PPE Or run away? Proportional to the expected losses which can be caused by an event and to the probability of this event Risk assessment (Probability of Accident) x (Losses per accident) Formula (Likelihood) x (Severity) Falls below some level that is already tolerated Risk is acceptable when Public health professionals say it is acceptable Cost would be better spent on other public health problems Elimination Substitution Hierarchy of controls Engineering controls Administrative controls PPE (least effective) As Low As Reasonably Practicable ALARP Within acceptable limits Risk assessment at workplace Legally required to assess the risks Create awareness of hazards and risks Identify who may be at risk Why risk assessment is important Prevent injuries Prioritize hazards and control measures Identify hazards Evaluate the likelihood Consider normal operational situations as well as non-standard event Routine and non-routine activites HIRARC covers How risk assessment is conducted Activities of all personnel including non employees Facilities at workplace Geographical or physical areas within/outside premises Possible ways Stages in production/service process Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn Defined task Methods and procedures used in processing C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an Isolation Phases for separate Main job permits-to-work De-isolation Least effective Closed and locked valve Double block and bleed valve system Isolation Methods available Slip plate Physical disconnection Of vessel and pipe Replacing one gas or vapor with another Purging Water washing Chemical cleaning Steaming Water jetting Methods Cleaning Continue preparation of maintenance in Lecture 16 Solvent jetting The act of maintaining or the state of being maintained Collect necessary maintenance cost information Shot blasting Objectives Manual cleaning Optimize maintenance resources Places where there is inadequate natural ventilation Flammable or explosive Minimize energy usage Corrective maintenance No hazardous concentration residue Diagnosis of the problem Reactive maintenance Class A Steps Repair and/or replacement of faulty component (s) Class B Verification of the repair action Acidic or alkaline chemicals Class C Vertical or maze exit Class D Classification Maintenance philosophies Improved system reliability Decreased cost of Loose dust, replacement fluidised materials or unstable solids Class E Preventive maintenance Long-term benefits Confined space Decreased system downtime Predictive maintenance Flammable substances Better spares inventory Toxic substances Oxygen-deficient atmosphere Lecture 17: Plant Maintenance Chapter 6: Plant Maintainability and Reliability Concerns management Lecture 16: Plant Maintenance Safety maintenance Oxygen-enriched atmosphere Exercise careful control of maintenace work Maintenance procedures Noxious fume Documentation on the procedures themselves Procedures Permit-to-work Maintenance documentation Before entering Systems of control Gas tests The P&ID The instrumentation and electrical system diagram Permit system Controlled by a formal system of permit to work (PTW) Hand-over system Continuous control of the work to be done The work is properly defined Control of workforce Objectives Identification of equipment The precautions to be taken are specified and understood Isolation Company name and address Emptying of liquid Permit title Permit system Preparation of maintenance Removal of solids Permit number Forced ventilation Persons involve in the work to be done Flushing with water and forced ventilation Location of work Gas Freeing Purging Description of work Streaming Isolation requiements Contents of permit Hazards identification Precautions required PPE required Authorization Extension Handback Cancellations Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an Managed at local level Emergency An unexpected event requiring prompt action which is beyond the normal day to day activity in order to ensure the safety of the people, public, environment and equipment Dangerous event that causes significant human and economic losses Disaster Demand a crisis response Internal incident External threat Type Natural disaster Civil disorder Mitigation Chapter 7: Emergency Planning Lecture 18: Emergency response plan and preparedness Emergency vs disaster Malicious damage Planning and preparedness Emergency management Phases Response Establishing policy and organisational structure Reasons to plan for emergency Recovery Hazard analysis and risk assesment Steps in emergency planning process Development of Emergency Response and Action Plan Testing the plan through training and exercise Reviewing the plan Regulation 18: On-site emergency plan Inadequate detection of release Common problems No clear escape procedures CIMAH Regulation 1996 Regulation 21: Off-site emergency plan Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn Emergency response Special team that responds to general and localised team (ERT) emergencies to facilitate personnel evacuation and safety C.vT.Bg.Jy.Lj.Tai lieu Luan vT.Bg.Jy.Lj van Luan an.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj Do an.Tai lieu Luan van Luan an Do an.Tai lieu Luan van Luan an Do an Stt.010.Mssv.BKD002ac.email.ninhd.vT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.LjvT.Bg.Jy.Lj.dtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn.Stt.010.Mssv.BKD002ac.email.ninhddtt@edu.gmail.com.vn.bkc19134.hmu.edu.vn