What are the methods of risk assessment?

This paper introduces five risk assessment methods. These methods have their own advantages and disadvantages. According to different risk identification objects, they can be used flexibly, only one of them or in combination. The main consideration should be its effectiveness and employees' acceptability. The ultimate goal is to accurately identify all possible valuable risks and provide reliable basis for subsequent risk assessment and risk control.

1 on-the-spot observation method Through on-the-spot observation of the working environment, the existing hazards are found, which has wide applicability.

Advantages: On-site observation method is suitable for all places and operation links; Disadvantages: ① Personnel engaged in on-site observation are required to have safety technical knowledge and master perfect occupational health and safety regulations and standards; ② Not suitable for large-scale observation.

2. Safety checklist SCL: It is composed of personnel who are familiar with technological process, mechanical equipment and working conditions and have rich experience in safety technology and safety management. According to the relevant norms, standards, processes and systems, analyze and fully discuss the analysis objects in advance, list the inspection items and key points, and make a table. Based on field observation, reading system documents, talking with operators and personal understanding, the analyst answers the questions listed in the safety checklist, finds that the system design and operation are inconsistent with standards and regulations, and records the differences.

Advantages: The safety checklist is the result of qualitative analysis and is established on the basis of the original safety inspection. It is easy to learn and master, especially suitable for post employees to identify hazard factors, which plays a good role in prompting and is convenient for comprehensive identification of hazard factors. Disadvantages: list constraints limit people's initiative, and problems that are not reflected in the list may be ignored. So using this method may miss some new hazards that have not appeared before.

Scope of application: The safety checklist is generally applicable to the identification of hazard factors in relatively mature (or traditional) industries and fields, and a checklist needs to be prepared in advance for comparative identification. The safety checklist method is especially suitable for front-line employees to identify hazard factors, such as before the start of work activities or before the inspection of equipment and facilities. Only existing or traditional business objects and activities can be checked, and this method is not applicable to the identification of hazard factors in new business activities and new industry fields.

The checklist for hazard identification and the checklist for safety inspection are not exactly the same, but they are roughly the same, but each has its own emphasis. Therefore, the checklist used for safety checklist should not be directly used for hazard identification, but should be modified and supplemented on the basis of it, and it is best to re-compile.

3 Pre-hazard analysis PHA: Pre-hazard analysis, also known as preliminary hazard analysis, is a system safety analysis method for macro and general analysis of various risk factors (categories and distribution), accident occurrence conditions and possible consequences in the system before a certain engineering activity (including design, construction, production and maintenance, etc.) begins. ).

Advantages: At the initial conception of product design, we can point out the main dangers, and take measures to eliminate, reduce and control them from the beginning to avoid the losses caused by thoughtlessness. When identifying the hazard factors of a huge and complex system, we can first analyze and judge the main hazards of the system through pre-hazard analysis, so as to make a targeted and in-depth analysis of the main risks. Disadvantages: easily influenced by subjective factors of analysts. In addition, pre-hazard analysis is generally a rough analysis, which can only provide preliminary information and has low accuracy. Complex or high-risk systems need to be further analyzed by other methods. PHA can only provide preliminary information, which is not comprehensive enough, nor can it provide detailed information about risks and their best preventive measures.

Scope of application: Pre-hazard analysis is generally used in the initial stage of project evaluation, which screens out some low-risk links and regions, and also creates conditions for other methods to further identify the hazard factors of other high-risk links and regions. It is suitable for the risk assessment of adopting new methods and contacting new materials and equipment in the inherent system. PHA can also be used to analyze the built devices when only a rough analysis of hazards and potential accidents is needed.

4 Job Hazard Analysis Method JHA: Job Hazard Analysis (JHA), also known as Job Safety Analysis (JSA), is the most commonly used operation in safety management of European and American enterprises. The management tool of safety analysis and control is a preventive workflow to identify and control operational hazards. Through the gradual analysis of the working process, redundant and dangerous working steps and working equipment/facilities are found out, and control and improvement measures are formulated to control risks and reduce and eliminate accidents.

Advantages: This method is simple and easy to understand, especially the JSA/JHA method standard has been formulated, which is easy to operate and implement. Make the operators more aware of the risks in the operation process and make the preventive measures more targeted and operable. Disadvantages: This method does not have many advantages in hazard identification. It is not a special method recommended for hazard identification, but it is generally used for risk management of unconventional operation activities because of its simplicity and operability.

Scope of application: Job hazard analysis is generally applicable to some operational activities, such as new operations, unconventional (temporary) risk management (including identification of hazardous factors, of course), or job hazard analysis when evaluating and changing existing operations. Job hazard analysis is not applicable to the identification of hazard factors in continuous process flow, equipment and facilities.

5 Fault type and impact analysis FMEA: Fault type and impact analysis is to analyze the potential fault types of product components and their impact on product functions during product design. According to the severity of each fault, it is classified and preventive and improvement measures are put forward. It is to divide the working system into subsystems, equipment or original parts, and analyze the possible fault types and their effects one by one, so as to take corresponding preventive measures and improve the security of the system.

Advantages: systematic expression tools; A detailed and auditable hazard identification process was created. Wide applicability, widely applicable to human, equipment and system failure modes, as well as software and hardware.

Disadvantages: this method only considers a single fault situation, and cannot consider these faults together; This method needs to rely on the participation of professionals who have a thorough understanding of systems and equipment; In addition, this method is time-consuming, laborious and expensive.

Scope of application: Fault type and impact analysis is widely used in all stages of product life cycle in manufacturing industry, especially for identifying hazard factors in product or process design stage. If it is necessary to refine the activity steps to identify the hazardous factors of operation activities, then the functional units of equipment and devices should be refined to identify the hazardous factors. On this basis, the risk factors of equipment and devices can be well identified, and FMEA method is an example.