True or False Questions on Risk Identification and Analysis [Daily Question 090218]

1. The results of hazard identification, risk assessment, and risk control do not need to be ranked in order of priority. (Yes) 2. Fault tree analysis requires investigating all cause events and various factors related to the accident. (Yes) 3. The preliminary hazard analysis method can identify the causes of hazards in a system. (Yes) 4. The safety checklist method can provide a grading of accident consequences. (Yes) 5. The HAZOP analysis method can only be used for the safety analysis of continuous systems. (Yes) 6. The minimum path set represents the hazard of a system; the greater the number of minimum path sets in an accident tree, the higher the hazard level of the system. (Yes) 7. In the DOW fire and explosion hazard index method, the general process hazard factor is the main factor determining the extent of damage from an accident. (Yes) 8. Quantitative FTA can be used to estimate the frequency of occurrence of top events. Yes ( ) 9. The event tree diagram represents the nodes of various events, with branches for successful events extending downward and those for failed events extending upward. (Yes) 10. The Dao chemical method is suitable for evaluating machining workshops. (right)

1. The results of hazard identification, risk assessment, and risk control do not need to be ranked in order of priority. (×). The results of hazard identification, risk assessment, and risk control need to be ranked by priority. 2. Fault tree analysis requires investigating all cause events and various factors related to the accident. (√) 3. The preliminary hazard analysis method can identify the causes of hazards in a system. (√) 4. The safety checklist method can provide a grading of accident consequences. (×). The safety checklist only checks whether the items comply with laws and regulations, and does not provide an analysis of accident consequences. 5. The HAZOP analysis method can only be used for the safety analysis of continuous systems. (×), it can also be used in batch systems. 6. The minimum path set represents the hazard of a system; the greater the number of minimum path sets in an accident tree, the higher the hazard of the system. (×). On the contrary. 7. In the DOW fire and explosion hazard index method, the general process hazard factor is the main factor determining the extent of damage from an accident. (×) There are not only general process risk factors but also special process risk factors. 8. Quantitative FTA can be used to estimate the frequency of top-event occurrences. (×). It’s not frequency, but probability. 9. The event tree diagram represents the nodes of various events, with branches for successful events extending downward and those for failed events extending upward. (×). On the contrary. 10. The Dao chemical method is suitable for evaluating machining workshops. (×). The Dow Chemical fire and explosion method is generally used for fire and explosion systems.

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1. The results of hazard identification, risk assessment, and risk control do not need to be arranged in order of priority. (×): To control risks, it is first necessary to identify the hazards present in all operations carried out by the employer. Then, the risk level of each hazardous event must be assessed. Unacceptable risks are determined based on the occupational safety and health regulations and policies applicable to the employer, and controls are then implemented for those unacceptable risks. 2. Fault tree analysis requires investigation of all cause events and various factors related to an accident. (√) 3. Preliminary hazard analysis can help identify the reasons behind potential dangers in a system. (√) 4. Checklists can be used to determine the severity of potential accident consequences. (√) 5. HAZOP analysis can only be used for the safety analysis of continuous systems. (√) 6. The minimal path set represents the danger level of a system; the more minimal path sets there are in a fault tree, the higher the system’s danger level. (√) 7. In the DOW fire and explosion hazard index method, the general process hazard factor is the main factor determining the extent of potential damage from an accident. (×) 8. Quantitative FTA can be used to estimate the frequency of occurrence of top-level events. (√) 9. In event tree diagrams, nodes represent various events, with branches for successful events extending downward and branches for failed events extending upward. (×) 10. The Dow chemical method is suitable for evaluating mechanical processing workshops. (×) This post was last edited by lyhh9024 on 2009-2-18 at 10:02

1. The results of hazard identification, risk assessment, and risk control do not need to be ranked in order of priority. (×). 2. Fault tree analysis requires investigating all cause events and various factors related to the accident. (√) 3. The preliminary hazard analysis method can identify the causes of hazards in a system. (√) 4. The safety checklist method can provide a grading of accident consequences. (×) 5. The HAZOP analysis method can only be used for the safety analysis of continuous systems. (×) 6. The minimum path set represents the hazard of a system; the greater the number of minimum path sets in an accident tree, the higher the hazard level of the system. (×) 7. In the DOW fire and explosion hazard index method, the general process hazard factor is the main factor determining the extent of damage from an accident. (×) 8. Quantitative FTA can be used to estimate the frequency of occurrence of top-event scenarios. (×) 9. The event tree diagram represents the nodes of various events, with branches for successful events extending downward and those for failed events extending upward. (×) 10. The Dao chemical method is suitable for evaluating machining workshops. (×)

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1. The results of hazard identification, risk assessment, and risk control do not need to be ranked in order of priority. (×) The priority reflects the quantification of risk level. 2. Fault tree analysis requires investigating all cause events and various factors related to the accident. (√ ) This is the principle of system safety analysis. 3. The preliminary hazard analysis method can identify the causes of hazards in a system. ( √ ) The pre-hazard analysis method aims to identify potential hazards within a system, determine their risk levels, and prevent those hazards from developing into accidents. Of course, it is necessary to identify the reasons why the system poses a danger. 4. The safety checklist method can provide a grading of accident consequences. (×) The safety checklist is primarily used to qualitatively identify non-conformities. 5. The HAZOP analysis method can only be used for the safety analysis of continuous systems. (×) 6. The minimum path set represents the hazard of a system; the greater the number of minimum path sets in an accident tree, the higher the hazard level of the system. (×) 7. In the DOW fire and explosion hazard index method, the general process hazard factor is the main factor determining the extent of damage from an accident. (√) 8. Quantitative FTA can be used to estimate the frequency of occurrence of top events. (√) 9. The event tree diagram represents the nodes of various events, with branches for successful events extending downward and those for failed events extending upward. (×) 10. The Dao chemical method is suitable for evaluating machining workshops. ( × )

1. The results of hazard identification, risk assessment, and risk control do not need to be ranked in order of priority. (×) Required. 2. Fault tree analysis requires investigating all cause events and various factors related to the accident. (√) 3. The preliminary hazard analysis method can identify the causes of hazards in a system. (√) 4. The safety checklist method can provide a grading of accident consequences. (×) It is not possible to grade the consequences of accidents. 5. The HAZOP analysis method can only be used for the safety analysis of continuous systems. (×) 6. The minimum path set represents the hazard of a system; the greater the number of minimum path sets in an accident tree, the higher the hazard level of the system. (×) 7. In the DOW fire and explosion hazard index method, the general process hazard factor is the main factor determining the extent of damage from an accident. (×) 8. Quantitative FTA can be used to estimate the frequency of occurrence of top events. (√) 9. The event tree diagram represents the nodes of various events, with branches for successful events extending downward and those for failed events extending upward. (×) 10. The Dao chemical method is suitable for evaluating machining workshops. (×) Not applicable

1.× 2.√ 3.√ 4.× 5.× 6.× 7.× 8.√ 9.× 10.×

1.(×)2.(√)3.(√)4.(×) 5.(×)6. (×)7.(√)8.(√)9.(×)10.(×)

1. The results of hazard identification, risk assessment, and risk control do not need to be ranked in order of priority. (Yes). (The reason is: the results of hazard identification, risk assessment, and risk control need to be ranked in order of priority, so this is incorrect). 2. Fault tree analysis requires investigating all cause events and various factors related to the accident. (Yes) 3. The preliminary hazard analysis method can identify the causes of hazards in a system. (Yes) 4. The safety checklist method can provide a grading of accident consequences. (Wrong). (The reason is: safety checklists only verify compliance with laws and regulations and do not provide an analysis of accident consequences, hence they are incorrect). 5. The HAZOP analysis method can only be used for the safety analysis of continuous systems. (Wrong), (Reason: The HAZOP analysis method is suitable for safety analysis of the entire chemical production system; therefore, this statement is incorrect.) 6. The minimal path set represents the hazard level of a system – the greater the number of minimal path sets in an accident tree, the higher the hazard level of the system. (Wrong). (The reason is: the minimum set of paths represents the hazard of the system, and the greater its size and hazard level, the higher they are.) 7. In the DOW fire and explosion hazard index method, the general process hazard factor is the main factor determining the extent of damage from an accident. (Wrong), (Reason: The DOW fire and explosion hazard index method also includes a risk factor for special processes.) ) 8. Quantitative FTA can be used to estimate the frequency of occurrence of top events. (Wrong). (The reason is: quantitative FTA can be used to estimate the probability of occurrence of top events.) 9. The event tree diagram represents the nodes of various events, with branches for successful events extending downward and those for failed events extending upward. (Wrong). (The reason is that the event tree diagram represents the nodes of various events, with branches for successful events pointing upward and those for failed events pointing downward.) 10. The Dao chemical method is suitable for evaluating machining workshops. (Wrong). (The reason is: the Dao Chemical Fire and Explosion Law is generally used for fire and explosion systems.)

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1. The results of hazard identification, risk assessment, and risk control do not need to be ranked in order of priority. (×). 2. Fault tree analysis requires investigating all cause events and various factors related to the accident. (√) 3. The preliminary hazard analysis method can identify the causes of hazards in a system. (√) 4. The safety checklist method can provide a grading of accident consequences. (×). 5. The HAZOP analysis method can only be used for the safety analysis of continuous systems. (×), it can also be used in batch systems. 6. The minimum path set represents the hazard of a system; the greater the number of minimum path sets in an accident tree, the higher the hazard of the system. (×). 7. In the DOW fire and explosion hazard index method, the general process hazard factor is the main factor determining the extent of damage from an accident. (×) 8. Quantitative FTA can be used to estimate the frequency of occurrence of top events. (×). 9. The event tree diagram represents the nodes of various events, with branches for successful events extending downward and those for failed events extending upward. (×). 10. The Dao chemical method is suitable for evaluating machining workshops. (×)

1. The results of hazard identification, risk assessment, and risk control do not need to be ranked in order of priority. (×). The results of hazard identification, risk assessment, and risk control need to be ranked by priority. 2. Fault tree analysis requires investigating all cause events and various factors related to the accident. (√) 3. The preliminary hazard analysis method can identify the causes of hazards in a system. (√) 4. The safety checklist method can provide a grading of accident consequences. (×). The safety checklist only checks whether the items comply with laws and regulations, and does not provide an analysis of accident consequences. 5. The HAZOP analysis method can only be used for the safety analysis of continuous systems. (×), it can also be used in batch systems. 6. The minimum path set represents the hazard of a system; the greater the number of minimum path sets in an accident tree, the higher the hazard of the system. (×). On the contrary. 7. In the DOW fire and explosion hazard index method, the general process hazard factor is the main factor determining the extent of damage from an accident. (×) There are not only general process risk factors but also special process risk factors. 8. Quantitative FTA can be used to estimate the frequency of top-event occurrences. (×). It’s not frequency, but probability. 9. The event tree diagram represents the nodes of various events, with branches for successful events extending downward and those for failed events extending upward. (×). On the contrary. 10. The Dao chemical method is suitable for evaluating machining workshops. (×). The Dow Chemical fire and explosion method is generally used for fire and explosion systems.

My answer: 1×； 2√ ； 3√ ； 4× ； 5× ； 6 × ； 7√ ； 8√ ； 9× ； 10×

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1. The results of hazard identification, risk assessment, and risk control do not need to be ranked in order of priority. (×). 2. Fault tree analysis requires investigating all cause events and various factors related to the accident. (√) 3. The preliminary hazard analysis method can identify the causes of hazards in a system. (√) 4. The safety checklist method can provide a grading of accident consequences. (×) 5. The HAZOP analysis method can only be used for the safety analysis of continuous systems. (×) 6. The minimum path set represents the hazard of a system; the greater the number of minimum path sets in an accident tree, the higher the hazard level of the system. (×) 7. In the DOW fire and explosion hazard index method, the general process hazard factor is the main factor determining the extent of damage from an accident. (×) 8. Quantitative FTA can be used to estimate the frequency of occurrence of top-event scenarios. (×) 9. The event tree diagram represents the nodes of various events, with branches for successful events extending downward and those for failed events extending upward. (×) 10. The Dao chemical method is suitable for evaluating machining workshops. (×)

1. The results of hazard identification, risk assessment, and risk control do not need to be ranked in order of priority. (×). 2. Fault tree analysis requires investigating all cause events and various factors related to the accident. (√) 3. The preliminary hazard analysis method can identify the causes of hazards in a system. (√) 4. The safety checklist method can provide a grading of accident consequences. (×). No analysis of the consequences of accidents is provided. 5. The HAZOP analysis method can only be used for the safety analysis of continuous systems. (×), an intermittent system is also acceptable. 6. The minimum path set represents the hazard of a system; the greater the number of minimum path sets in an accident tree, the higher the hazard of the system. (×). The minimum set of paths represents the hazard level of a system; the greater its number and severity, the higher the hazard level. In the DOW fire and explosion hazard index method, the general process hazard factor is the main factor determining the extent of potential damage from an accident. (×) 8. Quantitative FTA can be used to estimate the frequency of occurrence of top events. (×). Quantitative FTA can be used to estimate the probability of occurrence of top-event 9. An event tree diagram represents the various events, with branches for successful events extending downward and branches for failed events extending upward. (×). The branch for successful events points upward, while the branch for failed events points downward. 10. The Dao Chemistry method is suitable for evaluating machining workshops. (×) The Dao Chemical Fire and Explosion Method is generally used for fire and explosion systems

1. The results of hazard identification, risk assessment, and risk control do not need to be ranked in order of priority. (×) The results of hazard identification, risk assessment, and risk control should be ranked in order of priority; based on the level of risk, it should be determined which risks need to be maintained as they are and which require improved control measures, and a list of planned risk control measures should be prepared. 2. Fault tree analysis requires investigating all cause events and various factors related to the accident. (√) Fault tree analysis procedure, Step 4: Investigate the cause events. Investigate all cause events and various factors related to the accident, including equipment failures, mechanical defects, operator errors, management and command mistakes, environmental factors, etc., to determine the causes and impacts as thoroughly as possible. 3. The preliminary hazard analysis method can identify the causes of hazards in a system. (√) Through preliminary hazard analysis, four basic objectives are sought to be achieved: ① Generally identifying all major hazards related to the system. The probability of an accident is not considered in the initial identification. ②Identify the causes of the harm. ③Assume that the hazard does occur, and estimate and identify its impact on the system. ④Grade the identified hazards. 4. The safety checklist method can provide a grading of accident consequences. (×) The safety pre-assessment method is a means and tool for analyzing and evaluating the danger and hazard of a system. According to the \"Guidelines for Safety Pre-assessment\" issued by the Production Supervision and Administration Bureau on May 21, 2003, safety pre-assessment methods are divided into three major categories and dozens of types. (1) Safety evaluation methods for accident causation factors include: expert on-site interviews and observation methods, hazard and operability studies, failure mode and effects analysis, fault tree analysis, event tree analysis, safety checklist methods, factor diagram analysis, analysis of accident initiation and development, accident sequence evaluation method, multiple series failure analysis method, paired comparison method, task analysis method, and cause-and-effect (fishbone) diagram analysis method. (2) Safety assessment methods that can provide hazard grading include: Hazard and Operability Studies, Failure Mode and Effects Analysis, Fault Tree Analysis, Logic Tree Analysis, Risk Matrix Assessment Method, Safety Degree Assessment Method, Risk Tolerance Assessment Method, Dow Chemical’s Fire and Explosion Hazard Index Assessment Method, Mond’s Fire, Explosion, and Toxicity Index Assessment Method, Japan’s Ministry of Labor’s six-stage assessment method, the former Soviet Union’s quantitative assessment method for the hazards in chemical processes, Fuzzy Matrix Method, Direct Numerical Estimation Method, Human Cognitive Reliability Analysis Method, China’s hazard grading method for chemical plants, China’s hazard grading method for metallurgical plants, China’s hazard grading method for smelting plants, methods for identifying major hazard sources, Job Condition Hazard Assessment Method (Graham-Kinney Method), the “Safety Checklist – Hazard Index Assessment – System Safety Analysis” assessment method, and statistical chart analysis methods. (3) Safety assessment methods for evaluating the consequences of accidents are available, including: failure type and impact analysis, accident tree analysis, logic tree analysis, probability theory analysis, Markov model analysis, the Dow Chemical Company’s fire and explosion hazard index evaluation method, the Mond fire, explosion, and toxicity index evaluation method, the Japanese Ministry of Labor’s six-stage evaluation method, the former Soviet Union’s quantitative evaluation method for the hazards of chemical processes, the fuzzy matrix method, the success probability index method, the Safeti evaluation method, evaluation methods for highly flammable, explosive, and toxic hazardous sources, the “safety checklist – hazard index evaluation – system safety analysis” evaluation method, statistical chart analysis methods, safety assessment methods for mining projects, tailing pond matrix evaluation methods, liquid leakage models, gas leakage models, adiabatic diffusion models, evaluation models for the flame and radiation intensity of pool fires, models for the damage caused by fireball explosions, models for the damage caused by explosion shock waves, models for the structural damage caused by vapor cloud explosions, models for the dispersion of toxic substances, and the T*T equivalent method for assessing the damage caused by boiler explosions. 5. The HAZOP analysis method can only be used for the safety analysis of continuous systems. (×) The purpose of a HAZOP analysis is to systematically and thoroughly examine the process and operations in order to determine whether deviations in the process could lead to undesirable consequences. This method can be used for continuous or batch processes, and it can also be applied to analyze the established operating procedures. 6. The minimum path set represents the hazard of a system; the greater the number of minimum path sets in an accident tree, the higher the hazard of the system. (×) The set of minimal basic events that cannot lead to the occurrence of a top event is called a minimal path set. In the minimal radicale, removing any single event no longer results in a radicale. An accident tree has a minimum path set, and there is one possibility for the top event not to occur. The more minimal path sets there are, the more ways there are for the top-event not to occur, and thus the safer the system is. 7. In the DOW fire and explosion hazard index method, the general process hazard factor is the main factor determining the extent of damage from an accident. (√) DOW Chemical Company ③ Evaluation process ● Determine the evaluation unit. This includes the determination of evaluation units and the selection of evaluation equipment. ●Calculate the material coefficient MF for the important substances within the unit. Important substances refer to those with high potential for hazard that are present in significant quantities (over 5%) within a unit. The material factor (MF) is an intrinsic property that indicates the amount of energy released by a substance during fires or explosions caused by combustion or other chemical reactions; it is determined by the combustibility Nf of the substance and its chemical reactivity (instability) Nr. ●Based on the process conditions of the unit, appropriate hazard coefficients are used to determine the general process hazard coefficient F1 and the special process hazard coefficient F2 for the unit. The general process hazard factor F1 is the main factor in determining the extent of accident damage. The risk factor F2 for special processes is the main factor affecting the probability of accidents. ●Calculate the process unit hazard factor F3. F3 = F1 × F2. ●Calculate the fire and explosion index F&EI. F&E1 = F3 × MF; it can be used to estimate the damage that accidents may cause during the production process. ●Use the fire and explosion index values to determine the exposure area radius R (m) of the unit, and calculate the exposure area A. A=π×R2 (m2) ●Determine the safety measure compensation coefficient C. The safety measure compensation coefficient C is the product of the process control compensation coefficient C1, the material isolation compensation coefficient C2, and the fire prevention measure compensation coefficient C3; that is, C = C1 × C2 × C3. ● Calculate the fire and explosion index F&E1 after compensating for safety measures. 8. Quantitative FTA can be used to estimate the frequency of top-event occurrences. (√) 2. Development of the accident tree (1) Determine the top event of the accident tree. Determining the top event means identifying the target event to be analyzed. Based on the accident investigation report, the extent of losses and the frequency of accidents are analyzed, and accidents that are likely to occur and have severe consequences are selected as the top events. 3. Qualitative analysis of accident trees: Qualitative analysis of accident trees involves using the structure of the accident tree to determine its minimum cut sets or minimum path sets, as well as the structural importance of the basic events. Based on the results of this qualitative analysis, safety measures can be identified to prevent accidents. 4. Quantitative analysis of accident trees: Quantitative analysis of accident trees involves calculating the probability of occurrence of the top event in the accident tree, based on the probabilities of occurrence of the various basic events that lead to the accident ； Calculate the importance and critical importance of the probabilities of each basic event. Based on the results of quantitative analysis and the potential hazards that may arise after an accident, a risk analysis of the system is conducted to determine the direction for safety investments. 9. The event tree diagram represents the nodes of various events, with branches for successful events extending downward and those for failed events extending upward. (×) The drawing of the event tree is carried out from left to right based on the system schematic. On the nodes representing various events, the branches indicating successful events point upward, while those indicating failed events point downward. The probability of occurrence for each branch is indicated, and finally their product and sum are calculated respectively to serve as the known coefficients of the system. 10. The Dao chemical method is suitable for evaluating machining workshops. (×) This definitely can’t be applied, right? How should the risk factor be determined?