Guide to Exam Preparation for Special Equipment Safety Technology (continuously being updated)
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Safety Technology for Special Equipment, Section 1: Basic Knowledge of Special Equipment Safety. A. Examination content, its position in the textbook, and its importance. Question number, examination content, position in the textbook, importance. I. Special equipment: (1) The types and classifications of special equipment, the working principles and characteristics related to the safety of such equipment, the concept of safety strength for special equipment, as well as the materials used in pressure-bearing equipment and the safety aspects related to welding; the safety characteristics of the media handled by pressure-bearing equipment； P230-P243 P252-PP256 Understanding (II): The uses and locations of special equipment, as well as the safety accessories of such equipment and their functions ； P230-P243 Familiar (III): Master the accident characteristics and hazards of various types of special equipment, as well as the control of urban hazard sources. P230-P243 Mastering Detection Techniques: The basic principles, inspection methods, and purposes of various detection techniques used for the safety inspection of special equipment. P244-P251 Getting to Know the Summary of Answer B I. Special Equipment (1) The types and classifications of special equipment, the working principles and characteristics related to the safety of such equipment, the concept of safety strength in special equipment, as well as the materials used in pressure-bearing equipment and the safety aspects related to welding; the safety characteristics of the media handled by pressure-bearing equipment ； Types and classifications of special equipment: There are seven categories in total, including boilers, pressure vessels (including gas cylinders), pressure pipelines, elevators, lifting machinery, passenger cableways, and large-scale amusement facilities. Among them, boilers, pressure vessels (including gas cylinders) and pressure pipelines fall under the category of pressure-bearing equipment, while elevators, lifting machinery, passenger cableways, large-scale amusement facilities, etc. belong to the mechanical and electrical category. Working principles and characteristics of safety in special equipment: Safety characteristics of boilers: (1) The hazards of explosions. (2) Vulnerability to damage. (3) Widespread use. (4) Continuous operation. Safe operating characteristics of pressure vessels: They share similarities with boilers, such as the risk of explosion and susceptibility to damage due to exposure to high temperatures and pressures. Furthermore, due to the medium’s flammability, toxicity, or corrosiveness, leaks can lead to serious accidents such as fires and widespread poisoning. Safe operating characteristics of elevators: The common dangers that can occur with elevators include people being crushed, sheared, impacted, or falling ； People are electrocuted, and the car crashes due to exceeding its maximum travel distance ； Car speeding or falling due to a broken rope ； Structural failure due to material degradation and loss of strength, etc. Safety operating characteristics of lifting machinery: Lifting machinery includes three categories – lightweight lifting equipment, cranes, and elevators. Its operating characteristics can be summarized in the following 7 points: (1) Lifting machinery usually has a large structure and relatively complex mechanisms, capable of performing one lifting movement as well as one or several horizontal movements. (2) The loads being lifted are diverse, and the load capacity varies. (3) Most lifting machinery needs to operate over a large area, requiring significant movement space. (4) Some lifting machinery is required to directly transport people for vertical movement on guide rails, platforms, or wire ropes (such as elevators and lift platforms), and its reliability has a direct impact on personal safety. (5) There are many exposed and moving components that often come into direct contact with lifting operators (such as hooks, steel cables, etc.), posing numerous potential accidental hazards. (6) The working environment is complex. (7) Tasks often require multiple people to work together to carry out an operation. The presence of these various risk factors contributes to a high incidence of lifting injury accidents. Large-scale entertainment facilities and cable cars: Since they are designed to carry people and move over large distances, any electrical or mechanical failure that causes changes in their operating conditions can lead to accidents resulting in injuries or deaths. Materials for pressure equipment: steel, which can be classified into carbon steel and alloy steel based on their chemical composition; and into pearlitic steel, bainitic steel, austenitic steel, and ferritic steel based on their microstructural characteristics. Safety features of welding: The book discusses fusion welding methods such as manual arc welding, automatic submerged arc welding, manual tungsten inert gas welding, automatic gas shielded welding, and electroslag welding, as well as pressure welding methods like friction welding. It does not provide specific details regarding their safety characteristics. Generally speaking, it is required that the weld be thorough, free from pores, have a uniform structure, and exhibit low residual stress. Furthermore, welding work itself poses certain risks; it is considered a special type of work that requires certification to carry out. Safety characteristics of the media carried by pressure equipment: The media carried by pressure equipment can be classified by their physical state into liquids, gases, liquefied gases, elements, and mixtures ； Based on chemical properties, they are classified into four types: flammable, highly flammable, inert, and oxidizing ； Classified by their toxicity to humans, they are categorized as extremely hazardous, highly hazardous, moderately hazardous, and mildly hazardous. Some media are corrosive to containers or pipes. (II) The uses and locations of special equipment, as well as the safety accessories of such equipment and their functions (familiarity required) ● Boilers: They provide energy and power for production and daily life throughout society, which is why they are used in a very wide range of applications. Boiler safety accessories: 1) Safety valve: It plays an important role in controlling the maximum pressure inside the boiler and ensuring its safety. 2) Pressure gauge: The pressure gauge is used to accurately measure the pressure of the parts that need to be monitored in the boiler. 3) Water level gauge: The water level gauge is used to indicate the level of water inside the boiler. 4) Temperature measurement device: Measures the temperature of media such as feedwater, steam, and flue gas, to monitor the boiler’s thermal system. 5) Protection devices: (1) Over-temperature alarm and interlock protection devices, which can automatically cut off the fuel supply and stop the blower and exhaust fan when an over-temperature alarm is triggered, thereby preventing damage or explosion of the hot water boiler due to excessive temperature. (2) High and low water level alarms and low water level interlock protection devices. (3) Boiler flame-out protection device. When the boiler furnace goes out, the fuel supply is cut off and a corresponding signal is sent. 6) Drain valve or water discharge device: To remove the scale, sludge, and other harmful substances that remain after the water in the boiler has evaporated. 7) Explosion-proof doors: Explosion-proof doors are installed in the explosive areas of the furnace and flue to prevent furnace explosions. 8) Boiler automatic control device: Ensures the boiler operates under the safest and most economical conditions. (Among them, safety valves, pressure gauges, and level gauges are also known as the three essential components of boilers.) ● Pressure vessels refer to sealed containers used in industrial production for carrying out processes such as reactions, mass transfer, heat transfer, separation, and storage, and which are capable of withstanding pressure. It is widely used in industrial fields such as petroleum, chemicals, energy, metallurgy, machinery, light textiles, pharmaceuticals, and national defense. Safety accessories for pressure vessels 1) Safety valve: It automatically releases a certain amount of fluid when the pressure inside the vessel becomes too high, thereby reducing the pressure ； When the pressure inside the container returns to normal, the valve closes automatically. 2) Pressure relief disc: It is pressed and ruptured by imported static pressure to release the medium and reduce pressure; once it ruptures, it can no longer be used and must be replaced, meaning it does not have self-reclosing capability. 3) Combination of safety valve and rupture disc device: There are three combination methods – a parallel combination of the safety valve and the rupture disc device, a rupture disc device installed in series between the inlet of the safety valve and the container, and a rupture disc device installed in series on the outlet side of the safety valve. 4) Blasting cap: When overpressure occurs, its weak surface breaks, allowing the medium to be released in order to reduce pressure. It cannot be used after blasting and must be replaced. 5) Fusible plug: It belongs to the “melting-type” (“temperature-type”) safety relief device; it activates when the temperature of the container wall exceeds a certain limit. It is mainly used in small pressure vessels under medium and low pressures (such as liquefied gas cylinders). 6) Emergency shut-off valves, pressure relief valves: Emergency shut-off valves are usually installed in series with globe valves on the pipeline leading out of the container, so as to enable immediate shutdown of the leak in case of a severe leakage in the pipeline ； They generally also have the capabilities of overcurrent shutdown and overtemperature shutdown. The pressure relief valve has a small clearance; as the fluid passes through it, throttling occurs and the pressure drops, allowing high-pressure fluids to be delivered to low-pressure pipelines. 7) Pressure gauges, thermometers, level gauges (1) Pressure gauge: It indicates the pressure of the medium inside a container and is an important safety device for pressure vessels. (2) Level gauge: Also known as a liquid level meter, it is used to observe and measure changes in the liquid level within a container. Especially for containers holding liquefied gas, a level gauge is an essential safety device. (3) Thermometer: Used to measure the temperature of the medium inside the pressure vessel; for vessels where it is necessary to control the wall temperature, a thermometer for measuring the wall temperature must also be installed. ● Elevators are used in high-rise buildings. Elevator safety accessories: 1. Protection against overtravel. 2. Protection against elevator overspeed and rope breakage. 3. Protection against personnel being cut or falling. 4. Buffer devices. 5. Alarm and rescue devices. 6. Stop switches and maintenance operation devices. 7. Fire-fighting functions. 8. Protective devices against mechanical injuries. 9. Electrical safety protection devices: (1) Protection against direct electric shock, (2) Protection against indirect electric shock, (3) Protection against electrical faults, (4) Electrical safety devices. For the specific functions of these various accessories, please refer to pages P237–P240 in the book. ● Lifting machinery includes: lightweight lifting equipment (used for lifting smaller weights and performing simple lifting and moving tasks, such as cranes installed in workshops), cranes (used on construction sites and in factories to lift heavier objects and move them in multiple directions), and elevators (in which the heavy objects and lifting devices can only move up and down along tracks, and are used on construction sites and in factories). Crane safety devices: 1) Position limiting and adjusting devices: including upward limit position limiters, operational limit position limiters, tilting adjustment and display devices, buffers, etc. 2) Wind and climbing prevention devices: rail clamps, anchoring devices, and shoe blocks. 3) Safety hook, anti-tilt device, and swing locking device. 4) Lifting capacity limiter: provides overload protection. 5) Torque limiter: Functions as an overload protection device. 6) Collision prevention device: There are direct-type and reflective-type versions. 7) Hazard voltage alarm (detects high voltages in the vicinity and issues an alarm to prevent electric shock). (III) Accident characteristics and hazards of various types of special equipment, as well as the control of urban hazard sources (must be understood). Accident characteristics and hazards of boilers: Boiler explosions can lead to serious consequences, including multiple casualties and substantial financial losses. Pressure vessels and pressure pipelines: Fires and explosions can occur similar to those in boilers, and if toxic substances are released, it can lead to serious accidents resulting in multiple casualties from poisoning. Characteristics and hazards of elevator accidents: people being crushed, sheared, impacted, and falling ； People are electrocuted, and the car crashes due to exceeding its maximum travel distance ； Car speeding or falling due to a broken rope ； Structural failures caused by material degradation or loss of strength can lead to severe casualties, while operational failures can trap people. Characteristics and hazards of lifting machinery accidents: overturning, falls of people or heavy objects from heights, electric shocks, etc., which can result in multiple casualties and property losses. Accidents involving large amusement rides and passenger cable cars can result in multiple casualties. Urban hazard sources and their control: Not covered in this chapter. II. Inspection Techniques: Describes the basic principles, inspection methods, and purposes of various inspection techniques used for the safety inspection of special equipment. (Familiar) (I) Macroscopic inspection: Visual inspection and measurement using tools are commonly referred to as macroscopic inspection, and they are used to directly identify and examine relatively obvious defects on the inner and outer surfaces of containers. 1. Visual inspection: Using the sensory organs of the inspector, the inner and outer surfaces of the container are examined to determine whether there are any defects. 1) Inspection items (Page 244 of the book) 2) Inspection tools: flashlight, 5–10x magnifying glass, mirror, endoscope, a pointed hammer weighing about 0.5 kg, etc. 3) Inspection methods: visual inspection, inspection by inserting a reflector or endoscope into the container, observation under a magnifying glass, inspection by touching the inner surface with hands, inspection by hammering with a hammer, etc. 2. Gauge inspection: Simple tools and gauges (rulers, templates, vernier calipers, feeler gauges, etc.) are used to measure the defects identified through visual inspection, in order to determine the severity of those defects. For the inspection contents, tools, and methods, see pages P244–P245 of the book. (II) Non-destructive testing: 4 objectives – ensuring product quality, guaranteeing safe use, improving manufacturing processes, and reducing production costs. 1. Radiographic testing 2. Ultrasonic testing 3. Magnetic particle testing 4. Penetrant testing 5. Eddy current testing 6. Acoustic emission testing 7. Magnetic memory testing (III) Thickness measurement: Special physical methods are required, with ultrasonic testing being the most commonly used. (IV) Chemical composition analysis: The methods for analyzing the elements in steel materials include atomic emission spectroscopy and chemical analysis methods. (V) Metallographic examination. (VI) Hardness testing. (VII) Fracture analysis. (VIII) Pressure resistance test. (IX) Airtightness test – Inspection method: ① Apply (spray) soapy water to the area to be inspected, and check whether bubbles form in the soapy water ； ②Check whether the gauge installed on the test system and the container shows a decrease in reading ； ③Ammonia gas with a volume fraction of 1% was added to the test medium, and the surface of the area to be inspected was covered with a paper strip soaked in a 5% mercuric nitrate solution; if there were any areas that were not dense, the ammonia gas would pass through, leaving black marks on the corresponding parts of the paper strip. (10) Blasting tests (11) Mechanical property tests (12) Stress-strain testing (13) Stress analysis (14) Fracture mechanics analysis (15) Risk assessment. The principles, methods, and characteristics of the above methods are described on pages 244–251 of the book.
Section 2: Safety Technologies for Special Equipment A. Examination Content, Position in the Textbook, and Importance Question Number Examination Content Position in the Textbook Importance I. Safety technologies for the use of special equipment (1) Safety usage techniques and management requirements for special equipment such as boilers, pressure vessels, pressure pipelines, elevators, lifting machinery, amusement facilities, and passenger cableways P256-P289 Basic understanding (2) Operating procedures for using special equipment, major hazards, and preventive control measures P256-P289 Good understanding (3) Safety aspects of hazardous facilities such as power station boilers, liquefied petroleum gas storage areas, and gas cylinder filling stations, as well as common accidents that occur during the use of various types of special equipment and the corresponding emergency measures to take. P256-P289 Mastering Safety Techniques for the Maintenance of Special Equipment (I) Professional Knowledge on Maintenance Safety Techniques: 1. Preparatory work before maintenance, steps for shutting down equipment and relevant precautions, as well as methods for identifying and controlling hazards during the maintenance of various types of special equipment. P290-P291 Understanding: 2. Regulations regarding the use of fire, electricity, water, and communication during maintenance, as well as requirements for entering equipment and working at heights ； P290-P291 Be familiar with the use of 3 types of personal protective equipment as well as measures for ensuring personal safety. P290-P291 Master: (II) Causes of accidents involving boilers and pressure vessels and preventive measures; 1. Causes of leaks in the pressure-bearing components of boilers and preventive measures ； P291-P299: Understand the causes of explosions in pressure vessels and preventive measures. P299-P301: Understand the causes of reignition at the rear of boilers and preventive measures. P298: Master the causes of explosions in boiler furnaces and preventive measures. P297-P298: Master the causes of explosions in coal grinding systems and preventive measures; understand the causes of insufficient or excessive water levels in boiler drums. Understand the causes of damage to boiler structural components and preventive measures. Master. Summary of answers for B: I. Safety technologies for the use of special equipment (1) Safety usage technologies and management requirements for special equipment such as boilers, pressure vessels, pressure pipelines, elevators, lifting machinery, amusement facilities, and passenger cable cars (understanding): 1. Management requirements for boilers and pressure vessels: 1) Use products from qualified manufacturers ； 2) Registration and file establishment ； 3) Dedicated management ； 4) Work with a valid license ； 5) Operate in accordance with regulations ； 6) Regular inspection ； 7) Monitor water quality ； 8) Report the accident. 2. Safety operation techniques for boilers 1) Boiler startup steps (1) Inspection and preparation: Inspect the internal and external surfaces of the heating surfaces and pressure-bearing components, examine all parts of the combustion system, as well as various doors, baffles, safety devices and measuring instruments. Also check the boiler frame, stairs, platforms, and all types of auxiliary equipment, especially rotating machinery. (2) Water supply: Be careful not to let the temperature difference between the water supply temperature and the wall temperature of the cylinder be too large, and ensure that the water supply speed is not too fast. (3) Oven drying: Dry the moisture in the furnace chamber and flue ducts and preheat them to prevent cracks, deformation, or even collapse. (4) Boiler boiling: For newly installed, relocated, overhauled, or long-term unused boilers, it is necessary to boil them before starting up operation, in order to remove rust, oil, and other contaminants from the evaporative heating surfaces, reduce corrosion of these surfaces, and improve the quality of the boiler water and steam. (5) Ignition and voltage rise: The ignition method varies depending on the combustion method and combustion equipment. Layered combustion furnaces are generally ignited using wood; the use of highly volatile oils or flammable materials is strictly prohibited to avoid explosion accidents. (6) Pipe warming and steam synchronization: Pipe warming involves using steam to slowly heat components such as pipes, valves, and flanges, thereby increasing their temperature gradually to reduce thermal stress. It also helps to drive out condensation water from the pipes, preventing water hammer. Parallel operation, also known as combined operation or parallel firing, refers to the situation where a newly commissioned boiler supplies steam to a common steam header, and this must be carried out in accordance with specific procedures. 2) Safety precautions during the ignition and voltage-raising phase: (1) To prevent furnace explosion, the main measure is to start the exhaust fan before ignition to ventilate the furnace for 5–10 minutes; if there is no fan, natural ventilation for 5–10 minutes should be used to remove combustible substances from the furnace and flue.
(2) Control the rate of temperature and pressure increase: The pressure increase process in the boiler must proceed slowly to reduce thermal stress. (3) Closely monitor and adjust the instruments: Determine whether the startup process is proceeding normally based on the indications from the instruments, and make any necessary adjustments. (4) Ensure reliable cooling of the surfaces subject to forced flow: During startup, there is no continuous flow of water and steam in the economizer and superheater, and they may be damaged by the externally flowing flue gas; therefore, protection is necessary. The protection measures for the superheater are: during the pressure increase process, activate the drain valve of the superheater outlet header and the vent valve. The protection measure for the economizer is to install a recirculation pipe between the economizer and the boiler drum; during the ignition and pressure-raising phase, the valve on this recirculation pipe is opened, allowing the water in the economizer to flow back to the economizer via the boiler drum and the recirculation pipe (which remains unheated), thus enabling circulation. 3) Monitoring and control during normal boiler operation (1) Monitoring and control of boiler water level. The boiler water level should always be maintained at the normal level, with fluctuations allowed within 50 mm above or below this normal level. During low-load operation, the water level should be slightly higher than the normal level ； During high-load operation, the water level should be slightly lower than the normal level. (2) Supervision and adjustment of boiler pressure: Operators adjust the amount of fuel, air, and water supplied to the boiler in accordance with changes in load, thereby changing the boiler’s evaporation rate and maintaining relatively stable pressure. (3) Temperature regulation (4) Monitoring and adjustment of combustion. To adapt fuel combustion for heating to the requirements of the load, and to reduce losses due to incomplete combustion, etc. (5) Waste discharge and soot blowing to keep the interior of the heated surfaces clean. 4) Shutdown and shutdown maintenance (1) Shutdown: The main issue to be addressed during a normal shutdown is to prevent too rapid a drop in pressure and temperature, in order to reduce thermal stress. The order specified in the regulations can be found on page P261 of the book. The conditions for emergency shutdown and the sequence of operations for emergency shutdown are listed on pages P261–P262 of the book. (2) Shutdown maintenance. Shutdown maintenance mainly refers to maintenance inside the boiler, that is, the protective measures taken within the steam and water system to prevent or reduce corrosion. Common maintenance methods include pressure maintenance, wet maintenance, dry maintenance, and inerting maintenance. 3. Technologies for the safe use of pressure vessels 1) Safe operation of pressure vessels (1) Basic requirements ① Smooth operation: Loading and unloading should be carried out slowly, and the load should remain relatively stable during operation to prevent sudden increases in pressure. Heating and cooling should also take place gradually in order to reduce thermal stresses in the vessel walls. ②Preventing overloading: Preventing overloading of pressure vessels mainly involves preventing excessive pressure; the operating temperature of such vessels must also be strictly kept within the range specified in their design. (2) Inspections during the operation of the container, including checks on process conditions, equipment status, and safety devices. In terms of process conditions, the main aspects to check are operating pressure, operating temperature, liquid level, and the chemical composition of the working medium. Regarding the condition of the equipment, it is necessary to check for any leaks or seepages at the various connection points, as well as to examine whether there is plastic deformation, corrosion, or other defects or suspicious signs in the components and accessories of the container. Additionally, it is important to check for vibrations or wear on the container and its connecting pipes. Regarding safety devices, it is primarily necessary to check whether the safety devices and safety-related measuring instruments are in good condition. (3) Emergency shutdown of the container. The operation of pressure vessels must be stopped immediately in the following situations: when the operating pressure or wall temperature of the vessel exceeds the limits specified in the safety operating procedures, and these conditions cannot be brought under control even by taking measures, with a tendency for further deterioration ； Signs that endanger the safety of the container, such as cracks in its pressure-bearing components, bulging or deformation, and leaks at welds or detachable joints ； All safety devices have failed, connection fittings are broken, fasteners are damaged, etc., making it difficult to ensure safe operation ； A fire broke out at the operating station, threatening the safe operation of the containers ； Leakage from the signal hole or alarm hole of the high-pressure vessel. 2) Container maintenance mainly includes the following 5 aspects. (1) Maintain an intact anti-corrosion coating. (2) Eliminate the factors that cause corrosion. (3) Eliminate ‘leakage, emission, dripping, and seepage’ in containers. (4) Strengthen the maintenance of the container during periods of inactivity: The internal medium must be completely removed to keep the container dry and clean. (5) Always maintain the container in good condition, including safety devices and measuring instruments, as well as the container’s accessories and parts. 4. Operation and management of pressure pipelines (see pages P274–P277 in the book for details) ● Pre-operational inspections 1) Inspection of completion documents Completion documents refer to the final drawing and documentation related to the design, procurement, and construction of a facility (unit); they mainly consist of three categories: design completion documents, procurement completion documents, and construction completion documents. 2) On-site inspection: The on-site inspection can be divided into three aspects: design and construction omissions, unfinished work, and construction quality. 3) Documentation, labeling, and data collection (1) Contents of documentation: pipeline number, start and end points, medium (including various corrosive media along with their concentration or partial pressure), operating temperature, operating pressure, design temperature, design pressure, main pipe diameter, pipe material, pipe grade (including nominal pressure and wall thickness grade), pipe category, insulation requirements, heat treatment requirements, pipe grade code, date of commissioning of the regulated pipeline, record of relevant matters, etc. (2) Identification and data collection. Pipeline markings can be divided into two main categories: regular markings and special markings. Special markings are designed based on the characteristics of each pressure pipeline; they are used to identify certain weak points or hazardous areas of the pipeline, as well as typical points where instability may occur under thermal conditions (such as creep or fatigue), key areas for corrosion inspection, key areas for non-destructive testing, and other points that require special attention during inspections. At locations that affect the safety of pressure pipelines, monitoring points should be established and marked; careful observation should be carried out during operation, records should be kept, and initial data (before construction) should be collected. ●. Inspection and monitoring during operation Inspection and monitoring during operation include three parts: initial inspection at the start of operation, online monitoring, final inspection, and life expectancy assessment. 1) During the initial operation phase, inspections should focus on aspects such as the displacement of pipes, vibration levels, support conditions, and the tightness of valves and flanges; any issues identified must be resolved promptly. 2) Line inspection and on-line monitoring: Regular or irregular inspections are carried out to detect early signs of problems and take measures to address them. In addition to comprehensive inspections, attention should also be paid to aspects such as the displacement of pipelines, vibration, support conditions, and the tightness of valves and flanges. For important pipelines or critical sections of pipelines, modern inspection techniques can also be used for online monitoring. 3) Final inspection and life assessment: After prolonged operation, pressure pipelines suffer damage due to corrosion by the medium, wear, fatigue, aging, creep, etc. Some of these pipelines are in an unstable state or are nearing the end of their useful life; therefore, it is even more necessary to strengthen online monitoring, and to establish emergency measures and rescue plans to be ready for any emergency situations. Life assessment: The evaluation of the service life of pressure pipelines should be based on the condition of damage to those pipelines as well as the data obtained from inspections. In general, the assessment focuses on aspects such as creep, fatigue, phase changes, uniform corrosion, and cracks that occur in the pipeline materials. 5. Safety Management for Elevator Use 1) Instructions for Using the Elevator (1) Safety in operation: Ensure proper power supply for the elevator and lighting; when the elevator is not in use, it should be stopped on the lowest floor, with the power turned off as well as all floor doors closed. (2) Handling of emergency situations in elevators (see page P277 in the book for details). 2) Elevator management measures: (1) Legal management requirements: approval of design, and production license as well as safety certification from the manufacturing unit ；
Qualification certification for installation and maintenance companies, elevator inspection certificates issued by the provincial **competent authorities； Operator’s job-specific operation qualification certificate ； Regular inspections are carried out by units recognized as having the necessary legal qualifications. (2) Establishment of management records: ① Technical documents of the elevator, ② Record cards for the elevator. (3) Establish management systems: including training systems for elevator operators and maintenance personnel, elevator duty record systems, systems for elevator inspection, maintenance, and repair, operating procedures for various positions, and emergency rescue plans. (4) Establish an automated, 24/7 remote management system. 6. Safety management of lifting machinery 1) Safety management measures for lifting machinery (1) Safety management system: The elements of safety management regulations include: driver guidelines and safety operating procedures for lifting machinery ； Maintenance, upkeep, inspection, and testing system for lifting equipment ； Management System for Safety Technical Archives of Lifting Machinery ； Safety training and assessment system for operators and maintenance personnel of lifting machinery ； The entities that operate lifting machinery shall apply to the competent authorities in their jurisdiction on a regular basis for safety technical inspections of the machinery in use, as well as for handling matters related to the renewal of the permits allowing such machinery to be used. (2) Technical records: The items included in the safety technical records of lifting machinery are: the equipment’s technical documents issued at the time of manufacture ； Installation, repair records, and acceptance documents ； Records of use, maintenance, upkeep, inspection, and testing ； Safety Technology Supervision and Inspection Report ； Records of equipment and personal accidents ； Analysis of equipment problems and cost records. (3) Regular inspection system: The periodic safety supervision inspection cycle for in-use lifting machinery is 2 years (the periodic safety supervision inspection cycle for elevators and passenger lifts is 1 year). In addition, the user unit should also conduct self-inspections of the crane, including daily inspections, monthly inspections, and annual inspections. (4) Training of operators: Crane operators must pass specialized assessments and obtain a certificate before they can operate the crane independently. Commanders, drivers, and riggers should also receive professional technical training and safety skill training, be aware of the dangers and risks associated with their work, and possess the ability to protect themselves and others. 2) Safety protection for work at heights: On cranes, all reasonable working positions at a height of 2m or more must be protected. The structure and dimensions of the safety protection should be determined based on human body parameters ； The requirements for strength and stiffness shall be determined based on the most adverse loads that may act on walkways, platforms, stairs, and handrails. 3) Safety operation techniques for lifting operations (1) Preparations before lifting. Including: proper use of personal protective equipment ； Inspect and clean the work area, determine the transport route, and remove obstacles. For outdoor work, it is necessary to check the weather forecast for the day. Mobile cranes need to secure and level the supporting ground to prevent settlement of the foundation during operation ； Conduct safety inspections on the cranes, lifting equipment, and accessories used ； Based on the conditions of the load to be lifted, organize relevant personnel to jointly develop work plans and emergency response plans. (2) General operating requirements for crane operators. (See pages P282–P283 in the book for details.) (3) Safety operation requirements for riggers. (For details, see pages P283–P284 in the book.) 7. Safety management of amusement facilities 1) Organizational structure 2) Qualifications of personnel 3) Conditions required for operation 4) Management systems 5) Environmental conditions. For specific details, see pages P284–P286 in the book. 8. Key points for the safety management of passenger cable cars 1) Safety management measures for passenger cable cars. (1) Establish and improve various safety management systems centered on the responsibility system for safe production (operation). (2) Safety technical records, to ensure the authenticity, completeness, and value of the information for preservation. (3) Qualities of safety management personnel: sense of responsibility, experience, educational level, and proportion of engineering and technical personnel. 4) Training and education for workers: They must pass examinations, work with valid certificates, and receive safety education on a regular or irregular basis. (5) Safety inspections: include various forms such as regular, periodic, surprise, specialized, and seasonal inspections. Record, rectify, and recheck the identified potential hazards ； After reinspection and rectification meet the requirements, the case is closed. 2) Safety characteristics of passenger aerial cable cars (1) Work at heights in the open air. (2) Steel wire ropes have a significant impact on safety. (3) Natural conditions vary greatly and lack regularity. (4) There are many safety aspects, with poor interconnections. (5) There are many cases of employee errors, as well as incorrect behaviors on the part of passengers and people in the surrounding area. (6) The rescue is difficult and has a significant social impact. 3) Safety rescue for passenger cable cars (1) Establish a rescue organization and organize regular rescue drills for the rescuers; the components of such an organization are listed on page P288 of the book. (2) Rescue methods and facilities: In the first scenario, when the power supply from the external power circuit is interrupted or there is a fault in the main motor control system, the backup power source, such as a diesel generator set, should be activated to provide power, and auxiliary motors should be used to pull the passenger train back to the station at a slow speed. Second scenario: When major failures occur in mechanical equipment, station systems, traction cables, etc., rendering it impossible for the cable car to continue operating, it is necessary to use the simplest methods to evacuate passengers from the cars to the ground in the shortest possible time. The method of evacuation depends on the type of cable car, topographical features, weather conditions, and the height of the passenger car above the ground. Equipped with appropriate rescue equipment, such as winches, ladders, first-aid kits, etc. (3) Rescue using a single-track loop cable car: Release the winch of the pulley system in the tail tensioning device to lower the height of the chair above the ground, and use ground ladders and rescue safety belts (bags) to evacuate passengers. II) Operating procedures for the use of special equipment, major hazards, and preventive control measures (familiarity required). (The basic requirements for this question are similar to those of the previous question, so they will not be repeated.) III) Safety aspects of hazardous facilities such as power station boilers, liquefied petroleum gas storage areas, and gas cylinder filling stations, as well as common accidents that occur during the use of various special equipment and the corresponding emergency measures to take. (Mastery) The book provides more details on gas cylinder filling stations; for specific information, see pages P265–P274 of the book – details are omitted here. II. Safety Techniques for the Maintenance of Special Equipment (I) Professional knowledge related to safety techniques for maintaining special equipment 1. Preparatory work before maintenance, steps for shutting down the equipment and precautions to take, as well as methods for identifying and controlling hazards during the maintenance of various types of special equipment. ● Preparatory work before boiler maintenance: (1) Before maintaining a boiler, it should be shut down following the standard procedures for shutting down boilers, with slow cooling being employed. Methods such as water circulation within the boiler and ventilation inside the furnace are used to gradually reduce the temperature inside the boiler and furnace. When the temperature of the water in the boiler drops below 80°C, open all the doors and openings on the boiler being inspected. Be careful to avoid burns from steam, hot water, or smoke when opening the door aperture. (2) Isolate the pathways of pipes such as steam, feedwater, and blowdown on the boiler under inspection from the corresponding pipes of other operating boilers. The blind plates used for partitioning must have sufficient strength to prevent them from being punctured by the high-pressure medium under operation. The location of the partition must be clearly indicated. (3) The combustion chamber and flue of the boiler under inspection shall be isolated from the main flue or flues connected to other operating boilers. The flue gates must be closed tightly, and ventilation should be carried out after sealing them off. ● Precautions before inspecting pressure vessels (1) Before inspecting the vessel, it is necessary to completely disconnect the pipes that connect it to other devices still under pressure or containing gases, especially those connected to devices handling flammable or toxic substances. Not only must the valves be closed, but these connections must also be sealed tightly using blind flanges. (2) All the medium inside the container must be completely drained. Containers holding flammable, toxic, or asphyxiating media must also undergo technical treatments such as cleaning, purging, or disinfection, and sampling analysis must show satisfactory results. The power supplies related to the container, such as those for the container’s mixing device and turning mechanism, must be disconnected, and there must be clear warning signs indicating that power connection is prohibited.
● Methods for identifying and controlling hazard sources during the maintenance of special equipment; Safety precautions during the maintenance of boilers and pressure vessels. 1) Pay attention to ventilation and supervision. Before entering the boiler drum or vessel, it is necessary to open all access holes in the drum or vessel as well as the manholes on the headers, allowing air to circulate for a certain period of time to ensure adequate ventilation. When entering the boiler drum or container for inspection, there must be someone outside to supervise. Ventilation must also be carried out before entering the flue or combustion chamber for inspection. 2) Pay attention to electrical safety. When using lamps for lighting during inspections in the boiler drum and humid flues, the lighting voltage should not exceed 24V ； In relatively dry flues, with proper safety measures in place, an illumination voltage of no more than 36V can be used. When entering the container for inspection, low-voltage explosion-proof lamps with a voltage not exceeding 12V or 24V should be used. When the power voltage of testing instruments and repair tools exceeds 36V, well-insulated flexible cables and reliable grounding wires must be used. The use of open flames for lighting is strictly prohibited inside boilers and containers. 3) It is prohibited to disassemble or assemble connected components while under pressure: if it is necessary to remove or tighten the fasteners of components that are under pressure, this must be done only after all pressure has been released. 4) It is prohibited to use pressure testing with gas as a substitute for hydraulic testing. For pressure testing of boilers and pressure vessels, water is generally used as the medium for applying pressure; gases cannot be used as such a medium, as it is extremely dangerous. 2. Regulations regarding the use of fire, electricity, water, and communication during maintenance work, as well as requirements for entering equipment and working at heights ； 3. Master the use of safety protection equipment and personal safety monitoring, etc. (II) Causes of accidents involving boilers and pressure vessels and preventive measures 1. Causes of leaks in the pressure-bearing components of boilers and preventive measures ； Several causes of boiler explosion accidents: 1) Steam explosion: The container ruptures, causing the pressure above the liquid in the container to drop instantly to atmospheric pressure. The saturated water, which was at a temperature above 100°C under the original operating pressure, becomes extremely unstable and difficult to exist at atmospheric pressure; part of this water vaporizes instantaneously, resulting in a dramatic increase in volume that leads to an explosion in the space surrounding the container. 2) Overpressure explosion: An explosion of a boiler that occurs when, for various reasons, the pressure acting on the boiler’s main pressure-bearing components such as the cylinder, head, tube sheet, and furnace shell exceeds their capacity to withstand such pressure. Preventive measures mainly involve strengthening operational management. 3) Defects leading to explosion: This refers to a situation where the pressure exerted on the boiler does not exceed the rated pressure, but due to cracks, severe deformation, corrosion, or changes in the structure of the boiler’s main pressure-bearing components, these components lose their capacity to bear load, resulting in sudden large-scale rupture and explosion. Preventive measures mainly involve strengthening boiler inspections to prevent the main pressure-bearing components of the boiler from operating with defects. 4) Explosions caused by severe water shortage: The main pressure-bearing components of a boiler, such as the drum, head, tube sheet, and furnace chamber, are often directly heated by the flames. Once a boiler suffers from a severe water shortage, the aforementioned main pressure-bearing components cannot be cooled properly and may even be burned, causing the metal temperature to rise sharply or even turn red-hot. Under such water shortage conditions, it is strictly prohibited to add water; the furnace must be shut down immediately. Filling a boiler that is severely short of water often leads to explosion accidents. Boilers that run dry due to a lack of water for an extended period can also explode. The main measure to prevent such explosions is also to strengthen operational management. 2. Causes of pressure vessel explosion accidents and preventive measures: Causes of accidents include overpressure, overheating, local damage to the vessel, and failure of safety devices. Harm: a. Shock waves and their destructive effects: The overpressure from shock waves can cause casualties and damage to buildings. b. Damage caused by shrapnel: It can cause severe injuries or death, damage nearby equipment and pipelines, and lead to secondary accidents. c. Medium-induced damage: Medium-induced damage mainly includes poisoning by toxic media and burns caused by high-temperature water vapor. d. Secondary explosion and combustion: When the medium contained in the container is a flammable liquefied gas, the rupture and explosion of the container generate large amounts of flammable vapor at the scene; these vapors quickly mix with air to form an explosive mixture. Upon encountering an open flame during their dispersion, a secondary explosion occurs, often turning the area around the scene into a sea of flames and causing severe damage. Prevention: (1) In terms of design, a reasonable structure should be adopted. (2) During manufacturing, repair, installation, and modification, strengthen welding management, improve welding quality, and carry out heat treatment and flaw detection in accordance with standard requirements ； Strengthen material management to avoid using defective materials or the wrong types of steel and welding materials. (3) Strengthen usage management to avoid operational errors, as well as situations such as overheating, overpressure, overloading, lack of inspection, poor maintenance, and malfunctioning safety devices. (4) Strengthen inspection work to detect defects in a timely manner and take effective measures. 3. Causes and preventive measures for afterburning at the boiler tail. Secondary combustion in the tail flue mainly occurs in fuel-fired boilers. When combustion is incomplete during boiler operation, some of the combustible materials enter the tail flue along with the flue gases, accumulating within the flue or adhering to the heated surfaces at the tail end. Under certain conditions, these combustible materials catch fire on their own; the conditions for this are: ① accumulation of combustible materials, ② reaching a certain temperature, and ③ an adequate supply of air. Harm: It often damages air preheaters and economizers. Methods to prevent secondary combustion at the rear of the boiler: Minimize losses due to incomplete combustion and reduce the number of times the boiler is started and stopped ； Enhance soot blowing of the heated surfaces at the tail end: Ensure good sealing of all doors and flue dampers ； A fire extinguishing device should be installed in the rear flue of the fuel boiler. 4. Causes and preventive measures for boiler furnace explosions. Phenomena and conditions of furnace explosions: A furnace explosion occurs when a combustible mixture accumulated inside the furnace ignites simultaneously, resulting in a sudden increase in the pressure on the smoke side of the furnace. This increased pressure exceeds the limits tolerated by the design structure, leading to damage to the water wall, rigid beams, as well as the furnace roof and walls – this is what is known as a positive-pressure explosion. There is also negative pressure explosion, which occurs when the supply fan stops suddenly while the exhaust fan continues to operate, resulting in a sharp drop in pressure on the flue gas side and causing damage to the furnace chamber, rigid beams, and furnace walls. Three conditions are required for a furnace explosion (external explosion): first, the fuel must be present in the furnace in gaseous form; second, the mixture of fuel and air must reach an explosive concentration; third, there must be sufficient ignition energy. The main causes of furnace explosions are: first, the design lacks a reliable ignition system as well as effective shutdown protection mechanisms, along with interlock, alarm, and trip systems; the furnace and its rigid beam structure have poor explosion resistance, and there are defects in the coal grinding system and fuel atomization system ； Secondly, errors in judgment or misoperations by operators during operation account for over 90% of all furnace explosion incidents. Sometimes explosions occur due to the use of the ‘deflagration method’ for ignition. In addition, there have been furnace explosion incidents caused by the closure of the flue gate. Methods to prevent furnace explosion accidents: ① Reliable furnace safety protection devices should be installed based on the capacity and size of the boiler. ②Strive to improve the blast resistance of the furnace chamber and rigid beams. ③Usage management should be strengthened to improve the technical skills of boiler operators. 5. Causes of explosions in the powder grinding system and preventive measures: No specific details are provided in the book. 6. Causes of low water level in the boiler drum and preventive measures 1) Water shortage accidents (1) Consequences of low water level in the boiler: Severe water shortage can cause the tubes in the boiler’s evaporation surfaces to overheat and deform, or even burn out; leaks may occur at the joints, the tubes may come loose, the steel used in the heating surfaces can overheat or be damaged, resulting in a reduced or lost load-bearing capacity, tube ruptures, and damage to the furnace walls. If a boiler runs out of water and is not handled properly, it can even lead to a boiler explosion. (2) Common causes of water shortage: ① Carelessness on the part of operators ； ②A malfunction in the water level gauge caused an incorrect water level reading, which was not detected in time by the operators ； ③The water level alarm or automatic water supply regulator fails and is not detected in time ； ④Fault in the water supply equipment or pipes, resulting in no water supply or insufficient water flow ； ⑤The operator forgets to close the discharge valve after discharging waste, or the discharge valve leaks ； ⑥The water wall, convective tube bank, or economizer tubes burst and leak. (3) Handling of boiler water shortage: First, determine whether it is a mild or severe water shortage. The method is “call for water”. “The procedure for \"draining water\" is as follows: open the drain valve on the water level gauge to flush the steam connection pipe and the water connection pipe, close the valve on the steam connection pipe of the water level gauge, and then close the drain valve. If there is a water level shown on the gauge at this time, it indicates a slight water shortage. If no water level appears in the gauge even after asking for water, it indicates that the water level has dropped below the water connection pipe or even further, representing a severe water shortage.
In the event of mild water shortage, water can be added to the boiler immediately to restore the water level to normal. If the water level does not return to normal after filling water, the boiler should be stopped immediately for inspection. In cases of severe water shortage, the furnace must be shut down urgently. In cases where the degree of water shortage has not been determined or where it is determined to be severe, it is strictly prohibited to supply water to the boiler to avoid boiler explosions. 2) Full water accident (1) Consequences of a boiler being filled with water: Once this occurs, the high water level alarm activates and emits a signal; the temperature of the superheated steam drops, and the flow rate of feedwater becomes abnormally higher than that of steam. In cases of severe overfilling, water from the boiler can enter the steam pipes and superheaters, causing water hammer and scaling in the superheaters. Therefore, the main hazard of full water is the reduction in steam quality, as well as damage or even destruction of the superheater. (2) Common reasons for water filling up ① Carelessness of operators ； ②A malfunction in the water level gauge caused an incorrect water level reading, which was not detected in time by the operators ； ③Failures of the water level alarm and automatic water supply regulator, along with the failure to detect such failures in a timely manner. (3) Handling of a boiler with full water. Upon discovering that the boiler is full of water, the water level gauge should be flushed to check for any faults in it ； Once it is confirmed that the boiler is full of water, the feed water valve should be closed immediately to stop supplying water to the boiler; the economizer recirculation circuit should be activated to reduce combustion, and the blowdown valve as well as the drain valves on the superheater and steam pipes should be opened ； Once the water level returns to normal, close the drain valve and all steam traps ； Identify the cause of the accident and eliminate it to restore normal operation. If water hammer occurs when the tank is full of water, after the water level returns to normal, it is still necessary to inspect the steam pipes, accessories, supports, etc., to ensure there are no abnormalities before normal operation can be resumed. 7. Causes of damage to boiler load-bearing components and preventive measures: No specific details are provided in the book. C. Practice Tests I. Fill-in-the-blank questions 1. According to the Regulations on the Safety Supervision of Special Equipment, special equipment includes seven categories: , , , , , and . 2. The three most important safety accessories of a boiler are , and , which are known as the three treasures of a boiler. 3. The explosion-proof principle of the safety valve in pressure vessels is as follows: when the pressure inside the vessel exceeds a certain limit, the safety valve opens automatically; and when the pressure inside the vessel decreases, the safety valve closes again. 4. The burst disc used for explosion protection in pressure vessels is a non-reclosing pressure relief device, and the term \"non-reclosing\" means . 5. The elevator safety gear is a mechanical device that can stop the elevator car or counterweight. 6. There are mainly three types of wind and climbing prevention devices for cranes, namely , and . 7. The main non-destructive testing techniques used in the inspection of special equipment are seven in total: , , , , , and . 8. The regular inspection cycle for elevators in use is years, and the regular inspection cycle for cranes in use is years. 9. The startup steps for the boiler are: ①, ②, ③, ④, ⑤, ⑥. 10. The forms of lifting injury accidents include: ①, ②, ③, ④, ⑤, ⑥. 11. Boiler explosion accidents include explosion, explosion, explosion, and explosion. 12. The hazards of pressure vessel explosions include: ①, ②, ③, ④. 13. Classified by purpose, boilers can be divided into , , and , , etc. 14. Classified by the heat carrier, boilers can be divided into , , etc. 15. The function of the boiler blowdown valve or drain device is to discharge . 16. Under any circumstances, the surface temperature of the metal components of pressure vessels shall not exceed . 17. The function of the pressure relief valve in a pressure vessel is . 18. The function of the emergency shut-off valve on pressure vessels is . 19. On cranes, all reasonable working positions at a height of not less than a certain level shall be protected. 20. Cranes operating in the open should cease operations when the wind force exceeds a certain level. 21. The on-site inspections before the operation of pressure pipelines include: ①, ②, ③. 22. The safety devices of gas cylinders include: ①, ②, ③. II. Multiple-choice Questions (Single Choice) 1. According to the \"Regulations on the Safety Supervision of Special Equipment\" issued by the State Council, which of the following devices are considered special equipment? ( ) A. Punch press ； B. Excavator ； C. LPG tank ； D. Cars. 2. According to the \"Regulations on the Safety Supervision of Special Equipment\" issued by the State Council, which of the following devices does not fall under the category of special equipment? ( ) A. Boiler ； B. Welding machine ； C. Elevator ； D. Lifting machinery. 3. The special equipment specified in the Regulations on the Safety Supervision of Special Equipment includes a total of [number] types of equipment. ( ) A. Four categories ； B. Category 7 ； C. Category 5 ； D. Category 8. 4. Among the defects in boilers and pressure vessels listed below, the most dangerous one is . ( ) A. Internal sedimentary dirt ； B. Deformation ； C. Uniform corrosion ； D. Cracks. 5. The Safety Technical Inspection Regulations for Steam Boilers apply to fixed steam boilers. ( ) A. Using oil as a medium ； B. Using water or oil as a medium ； C. Using water as a medium ； D. Various media. 6. Ordinary steel, used as a substitute for steel used in boiler and pressure vessels. ( ) A. Yes ； B. No ； C. Increasing the thickness will do ； D. Sometimes it’s possible. 7. Welding cold cracks are cracks that occur. ( ) A. During the welding process ； B. After the weld has cooled ； C. During use ； D. Under transportation. 8. Which of the following procedures should be followed for preparation before lighting the boiler? ( ) A. Drying and protection – Water application – Furnace heating – Steam test ； B. Water filling – furnace drying – furnace boiling – steam test ； C. Water supply – Boiler heating – Oven drying – Steam test ； D. Boiling the furnace – drying the furnace – filling with water – steam test. 9. The boiler water level is an important indicator for ensuring steam supply and safe operation; operators should continuously monitor the water level inside the boiler. ( ) A. Pressure gauge ； B. Safety valve ； C. Water level gauge ； D. Thermometer. 10. The boiler water level should always be maintained at the normal level, with fluctuations allowed within a few millimeters above or below this normal level. ( ) A.30 ； B.50 ； C.200 ； D.100。 11. During boiler operation, the water level gauge should be flushed regularly, at least once per shift. ( ) A.1 ； B.2 ； C.3 ； D.5。 12. Which of the following statements regarding boiler soot blowing is correct? ( ) A. Soot blowing involves using steam or compressed air at a certain pressure to periodically clean the heated surfaces ； B. Soot blowing should be carried out at full load ； C. Soot blowing should be carried out perpendicular to the flue gas flow ； D. Three soot blowers can be used for soot blowing simultaneously. 13. What are the three main aspects of inspection for pressure vessels in operation? ( ) A. Operating pressure, operating temperature, liquid level ； B. Chemical composition, material ratio, dosage amount ； C. Process conditions, equipment status, safety devices ； D. Pressure gauges, safety valves, level gauges 14. Liquefied petroleum gas cylinders that have been in use for no more than 20 years should be inspected once a year. ( ) A.2 ； B.3 ； C.5。 15. Only cylinders that have passed the inspection can be used further. ( ) A. Visual inspection ； B. Audio check ； C. Internal inspection ； D. Hydrostatic test. 16. Common faults of gas cylinder valves during use are or shaft idling. ( ) A. Frosting ； B. Freeze ； C. Wear ； D. Air leakage. 17. When filling gas cylinders, which of the following is incorrect? ( ) A. Check whether there is any residual pressure in the bottle ； B. Pay attention to the paint color and markings on the gas cylinder ； C. Mix the two gases in one bottle ； D. The gas cylinders to be used should be thoroughly inspected before filling. 18. Which of the following measures should be taken first when a gas cylinder is heated or on fire? ( ) A. Try to pull out the gas cylinder and throw it away ； B. Spray water on the gas cylinder ； C. Approach the gas cylinder and try to close the valve on it. 19. To ensure the proper and safe operation of pressure vessels, which of the following requirements regarding their safety valves is incorrect? ( ) A. Compact structure, easy to adjust ； B. It has sensitive and reliable operation; when the pressure reaches a certain level, it will automatically disconnect to release the gas ； C. It can be closed promptly after exhaust, but does not maintain a seal. 20. Cylinders in the warehouse should be placed neatly, with their caps on ； When standing upright, secure it properly ； When placed horizontally, with the heads in the same direction, the stack height shall not exceed layer ( ). A.5 ； B.4 ； C.3。 21. A safety valve is a type of device. ( ) A. Measurement ； B. Chain ； C. Alarm ； D. Pressure relief. 22. Which of the following devices is used to heat the saturated steam drawn from the boiler drum to a specified superheated temperature while maintaining constant pressure, in order to meet the requirements of the production process? ( ) A. Superheater ； B. Economizer ； C. Air preheater. 23. The three main safety accessories of a boiler are the pressure gauge and the water level gauge. ( ) A. Meter ； B. Thermometer ； C. Safety valve. 24. One of the main causes of boiler explosions is . ( ) A. Use the boiler continuously for 24 hours ； B. Improper long-term treatment of boiler water ； C. Excessive slag. 25. Special attention should be paid to prevention when working in the boiler room for long periods of time. ( ) A. The hazards of high noise ； B. Heat stroke ； C. Food poisoning. 26. When selecting a safety valve, its discharge capacity must be equal to the device’s safe discharge volume. ( ) A. Greater than ； B. equals ； C. Less than. 27. When the boiler is operating normally, the water level gauge should _____. ( ) A. Stay still ； B. There are slight fluctuations ； C. Large fluctuations. 28. How often at least should a pressure vessel undergo a pressure test? ( ) A.1 ； B.3 ； C.6 ； D. 10. 29. How often are internal and external inspections of boilers conducted? ( ) A.1 ； B.2 ； C.4 ； D.5. 30. The hammer test is _____. ( ) A、Inspection of measuring tools ； B. Visual inspection ； C. Non-destructive testing ； D. Thickness inspection. 31. During the regular inspection of boilers and pressure vessels, _____ is used as the primary method, with _____ methods being added only when necessary. ( ) A. Non-destructive testing, macroscopic inspection ； B. Visual inspection, non-destructive testing ； C. Macro inspection, non-destructive testing ； D. Gauge inspection, non-destructive testing. 32. Surface flaw detection includes ____ and ____. ( ) A. Penetrant testing, radiographic testing ； B. Penetrant testing, magnetic particle testing ； C. Radiographic testing, magnetic particle testing ； D. Ultrasonic testing, penetrant testing. 33. Which of the following phenomena is not a symptom of a boiler water shortage accident? ( ) A. The water level alarm issues a low water level alert ； B. The water level is not visible in the gauge; it appears white and bright inside ； C. Decrease in superheated steam temperature ； D. The boiler exhaust temperature rises. 34. If it is determined that the boiler is severely underwater, then _____ should be done. ( ) A. Immediately increase the water supply volume ； B. Emergency shutdown of the furnace ； C. Stop supplying steam to the load. 35. Which of the following phenomena is not a symptom of a full-water accident? ( ) A. The water level cannot be seen inside the gauge, but the interior of the gauge is dark ； B. The water level alarm issues a high water level alert ； C. The water supply flow rate is abnormally higher than the steam flow rate ； D. The temperature of the superheated steam increases. 36. Measures to be taken in the event of a severe water-overflow accident in a boiler. ( ) A. Change automatic water supply to manual ； B. Close the feed water valve ； C. Reduce fuel and air supply ； D. Emergency shutdown of the furnace. 37. An accident in which the boiler tubes suddenly rupture during operation, resulting in a large release of steam and water, is called ____. ( ) A. Soda supply ； B. Water hammer ； C. Tube rupture ； D. Furnace explosion. 38. Boiler water circulation refers to the circulating flow of water within the _____. ( ) A. Economizer ； B. Superheater ； C. Water wall ； D. Inside the furnace cylinder. 39. The water inside the boiler should be —— while the boiler is in operation. ( ) A. Neutral water ； B. Saline water ； C. Acidic water ； D. Saturated neutral water. 40. The purpose of boiler blowdown is ____. ( ) A. Lower blood pressure ； B. Lower the water level ； C. Reduce the impurity content in the boiler water ； D. Change the saturation of the water in the pot. 41. When the crane is approaching the end point, it should _____. ( ) A. Shut off the power promptly, and try not to use the travel limiters ； B. Wait for the travel limiter to act ； C. Increase the speed of the crane’s movements. Answers to the Practice Tests
I. Fill-in-the-blank questions
1. Boilers, pressure vessels (including gas cylinders), pressure pipelines, lifting machinery, elevators, large-scale amusement facilities, passenger cableways
2. Safety valves, pressure gauges, water level gauges
3. Open, release some fluid, automatically close
4. Get damaged after explosion, cannot close again and must be replaced
5. Move downward
5. Track clamps, anchoring devices, shoe plates
7. Radiographic testing, ultrasonic testing, magnetic particle testing, penetrant testing, eddy current testing, acoustic emission testing, magnetic memory testing
8. 1, 2
9. Pre-start inspection, filling with water, furnace drying, furnace boiling, ignition and pressure building, pipe warming and steam connection
10. Falling heavy objects, crane instability and tipping, crushing, falling from heights, electric shock, other injuries
11. Water vapor, overpressure, defects, severe water shortage
12. Damaging effect of shock waves, damaging effect of explosion fragments, medium hazards (toxic, corrosive or abnormal temperature), secondary explosion and combustion (caused by large-scale leakage of flammable substances)
13. Power station boilers, industrial boilers, domestic boilers, locomotive boilers, ship boilers
14. Steam, hot water, organic heat carriers
15. Scale, sludge and other harmful substances
16. Allowable service temperature of steel
17. Reduce the pressure of the gas flowing out of high-pressure vessels so that it can enter low-pressure pipelines safely
18. Shut down urgently when the pipeline is damaged and leaking to prevent massive leakage of substances inside the vessel
19. 2m
20. Grade 6
21. Omissions in design and construction, unfinished work, construction quality
22. Safety pressure relief devices (safety valves, fusible plugs, etc.), bottle caps, shock-absorbing rings, etc.
II. Multiple-choice questions
The answers are shown in the table below:
Question number: 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Answer: C B B D C B B B C B A A C C
Question number: 15 16 17 18 19 20 21 22 23 24 25 26 27 28
Answer: D D C B C A D A C B B A B D
Question number: 29 30 31 32 33 34 35 36 37 38 39 40 41
Answer: B B C B C B D D C C B C A
I. Fill-in-the-blank questions
1. Boilers, pressure vessels (including gas cylinders), pressure pipelines, lifting machinery, elevators, large-scale amusement facilities, passenger cableways
2. Safety valves, pressure gauges, water level gauges
3. Open, release some fluid, automatically close
4. Get damaged after explosion, cannot close again and must be replaced
5. Move downward
5. Track clamps, anchoring devices, shoe plates
7. Radiographic testing, ultrasonic testing, magnetic particle testing, penetrant testing, eddy current testing, acoustic emission testing, magnetic memory testing
8. 1, 2
9. Pre-start inspection, filling with water, furnace drying, furnace boiling, ignition and pressure building, pipe warming and steam connection
10. Falling heavy objects, crane instability and tipping, crushing, falling from heights, electric shock, other injuries
11. Water vapor, overpressure, defects, severe water shortage
12. Damaging effect of shock waves, damaging effect of explosion fragments, medium hazards (toxic, corrosive or abnormal temperature), secondary explosion and combustion (caused by large-scale leakage of flammable substances)
13. Power station boilers, industrial boilers, domestic boilers, locomotive boilers, ship boilers
14. Steam, hot water, organic heat carriers
15. Scale, sludge and other harmful substances
16. Allowable service temperature of steel
17. Reduce the pressure of the gas flowing out of high-pressure vessels so that it can enter low-pressure pipelines safely
18. Shut down urgently when the pipeline is damaged and leaking to prevent massive leakage of substances inside the vessel
19. 2m
20. Grade 6
21. Omissions in design and construction, unfinished work, construction quality
22. Safety pressure relief devices (safety valves, fusible plugs, etc.), bottle caps, shock-absorbing rings, etc.
II. Multiple-choice questions
The answers are shown in the table below:
Question number: 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Answer: C B B D C B B B C B A A C C
Question number: 15 16 17 18 19 20 21 22 23 24 25 26 27 28
Answer: D D C B C A D A C B B A B D
Question number: 29 30 31 32 33 34 35 36 37 38 39 40 41
Answer: B B C B C B D D C C B C A