2026 Industrial Safety Engineer Written Exam: All-in-One Pass Course Summary (6 Hours Continuous Play)

The video introduces the 'Construction Safety Engineering' section, emphasizing that it's the easiest to master among the six subjects. It focuses on frequently tested questions and answers, highlighting essential points for quick memorization. Reviewing this speed memorization note two or three times before the exam is expected to be highly beneficial.

Key construction equipment for excavation and loading are discussed. Power shovels are identified for simultaneous excavation and loading, while backhoes are suitable for excavating areas below the machine's ground level. Power shovels are used for areas above ground level, like in mountainous terrain or for various soil types from rock to clay. The importance of understanding these distinctions for exam questions is highlighted.

Regulations for excavation slopes are covered, specifying gradients for sand (1:1.8), general soil (1:1.2), soft rock/weathered rock (1:1), and hard rock (1:0.5). It emphasizes that 1:1 for soft/weathered rock is a frequently tested revised regulation. The 'Bain Test' is introduced as a field test to determine the cohesiveness of soft clay soil. 'Front backfilling' is mentioned as a method to prevent slope collapse.

This section explains various phenomena related to earth retaining wall construction. 'Heaving' describes soil swelling due to pressure differences, 'Boiling' involves water and sand rising from the ground, 'Piping' refers to the formation of water channels, and 'Frost Heaving' is the swelling of ground due to freezing water. Regular inspection points for earth retaining walls are also outlined, including checking for damage, deformation, corrosion, displacement, and the condition of bracing and settlement.

Safety regulations for loading and unloading operations are discussed. This includes the requirement for ladders and safety nets for cargo trucks with a 2m or higher bed, and for ships over 300 tons. The maximum speed for construction vehicles that do not require speed limits is 10 km/h. For wharf and quay loading,通路の幅 must be at least 90 cm. Fall protection measures are also covered, such as safety nets with specific mesh sizes (under 10 cm and 5 cm) and strength requirements.

Lifting equipment (Yangjunggi) includes hoists, cranes, mobile cranes, lifts, gondolas, and elevators. Lifts for moving household goods are considered lifting equipment if they have a loading capacity of 0.1 tons or more. Passenger/cargo elevators and escalators are also classified as lifting equipment. Key safety devices for cranes include overload prevention, emergency stop, overwinding prevention, and hook unfastening devices. The importance of these devices is highlighted.

Specific safety regulations are detailed. Tower crane operations must cease if wind speeds exceed 15 m/s. Running cranes installed outdoors require a derailment prevention device activated at wind speeds over 30 m/s. Construction lifts need additional supports if wind speeds exceed 35 m/s. Temporary passages must have a slope of 30 degrees or less (with exceptions) and non-slip surfaces if over 15 degrees. Stair landings are required every 7m for scaffolds over 8m high (10m for vertical shafts over 15m), and illumination must be at least 75 lux.

Ladder safety standards include durable construction, consistent rung spacing, a minimum 15 cm gap from the wall, and a width of at least 30 cm. The angle of inclination must be 75 degrees or less (90 degrees for fixed ladders). Backrests are required starting from 2.5m for ladders 7m or taller. For ladders over 10m long, landings must be installed every 5m. The top of the ladder must extend at least 60 cm above the landing point. The necessity of structural calculations and detailed drawings for temporary structures like scaffolding over 31m, bracket scaffolds, formwork over 5m, tunnel supports over 2m, and power-operated structures is also discussed.

Structures requiring safety assessments include those with severely degraded structural integrity due to fire, cracks/deformation from earthquakes, or those being reused after long periods of disuse, or structures at risk due to nearby excavation. The 'Five Principles of Material Handling' focus on direct, continuous, concentrated, and mechanized transport, minimizing manual labor. The 'Three Principles of Material Handling' emphasize minimizing distance, mechanization, and careful handling.

This section covers requirements for submitting hazardous risk prevention plans. The plan must be submitted before construction begins or 15 days before specific work, in duplicate, to the Korea Occupational Safety and Health Agency. It needs to be reviewed every 6 months to ensure it aligns with the actual work. Industries requiring such plans include bridge construction (over 50m span), tunnel construction, excavation (over 10m deep), buildings over 31m tall, and specific facilities over 3,000 to 5,000 square meters. Required documents include construction outline, site map, equipment layout, schedule, safety budget, and emergency response plans.

Industrial accident prevention costs apply to projects over 20 million won, excluding electrical and telecommunication works. Contractors must check the usage records every 6 months with the client or supervisor. They also need to report expenses monthly and retain records for one year after project completion. The video highlights revised rates and basic amounts for different construction types and project values, with critical figures for projects between 500 million and 5 billion won being 2.28% and 4.325 million won, respectively. If the project value is unclear, 70% of the total cost is used. Safety costs must be used progressively with project completion.

Allowable expenses for industrial accident prevention costs include wages and travel expenses for full-time safety managers (50% for part-time), wages for safety-only workers like guides, safety education costs (facilities, materials, uniforms), safety equipment (guardrails, nets, PPE), safety and health diagnostics, and worker health prevention costs (AEDs, mental health, infection control, rest area conditions). This part provides a comprehensive list of what safety funds can be used for.

Wire ropes consist of strands, core, and individual wires. A 6x30 designation means 6 strands with 30 wires each. Boiler safety standards include having two or more pressure relief devices, with one activating below maximum operating pressure and another below 1.05 times max pressure. Lead is used to seal safety valves after inspection. Boiler explosion prevention devices include pressure limit switches, pressure relief devices, high/low water level controls ('Jebang Gosu'), and flame detectors.

Boiler malfunctions such as 'priming' (water and steam not separating, causing water level instability), 'foaming' (excessive bubbles due to impurities), and 'carryover' (water droplets moving with steam) are explained. A 'stack switch' is mentioned as a device using bimetal expansion to detect flames and prevent boiler explosions. Lathe safety includes chip breakers to manage metal chips, as well as chuck covers, shields, emergency brakes, and guards. A 'steady rest' is used to prevent vibration for long workpieces.

Permissible noise exposure limits are outlined. For continuous noise, 90dB allows 8 hours of exposure, with exposure time halving for every 5dB increase (e.g., 115dB allows 15 minutes). For impulse noise, 120dB allows 10,000 exposures, 130dB allows 1,000, and 140dB allows 100. This section provides detailed numerical limits for noise exposure.

Six major mechanical hazards are identified: shearing, entanglement, crushing, nip points, drawing-in, and cutting. Cutting points are specifically noted for milling cutters and circular saws. Crane safety devices ('Gwabigwon Hook') include overload protection, overwinding prevention, emergency stop, and hook unfastening devices, with collision prevention and stoppers also added. 'Fail-safe' mechanisms ensure safety even when machines malfunction, categorized into passive, active, and operational modes. 'Fool-proof' designs prevent accidents even due to human error.

Maintenance types include preventive maintenance (time-based, condition-based, adaptive) and corrective maintenance (planned, emergency). Plant layout involves a three-stage process: site selection, building layout, and equipment arrangement ('Jijigye'). This ensures optimal workflow and safety. The height for safety fences around industrial robots is 1.8m.

Machine failure rates follow a 'bathtub curve' with early failure, random failure, and wear-out failure phases. Guarding mechanisms for hazardous areas include isolation guards, fixed guards, interlocked guards, and adjustable guards. 'Two-hand control' is a type of fixed guard. Different types of machinery, including metalworking machines (lathes, milling, drilling) and pressing machines, are discussed along with their respective guarding mechanisms.

Press guarding includes 'sweep-away' guards to remove hands from the danger zone (with specific oscillation angles and stroke rates). Other guards include photo-electric, two-hand control, and enclosure guards. 'No-hand-in-die' principles apply to inherently safe designs like barrier guards. Safety blocks are used to prevent unintended slide descent during die attachment/removal. Lifting equipment (cranes, lifts) are defined by capacity (e.g., 0.1 tons for lifts). Safety markings must include rated load, operating speed, and warnings.

Woodworking circular saws require anti-kickback devices and blade contact prevention guards. The gap between the saw blade and the splitter must be within 12mm. The splitter thickness must be at least 1.1 times the saw blade thickness. Non-destructive testing methods include eddy current, ultrasonic, penetrant, and magnetic particle testing, all used to detect flaws without damaging the material. Tension, fatigue, and impact tests are destructive and not part of non-destructive testing.

Magnetic particle testing (NDT) uses magnetic fields to detect surface and subsurface flaws in ferromagnetic materials, employing techniques like magnetic flux methods ('chooktong' methods). Ultrasonic testing is suitable for detecting internal cracks and weld defects. Grinding wheels have three main components: abrasive grains, bonding material, and pores. Causes of grinding wheel breakage include excessive speed, cracks, impact, and improper flange diameter. Flange diameter must be at least 1/3 of the wheel diameter. Gap between workbench and wheel: 1-3mm; between cover and wheel: 3-10mm. Covers must protect the top of the wheel. Training includes 1-minute test runs daily and 3 minutes after wheel replacement.

Grinding machine covers have specific opening angles (60° for top use, 125° below horizontal, up to 150° for cutting/surface grinders, 180° for portable grinders). Shapers (heng-sa-gi) need fences and splash guards. Roller machines require emergency stop devices (hand, belly, knee operated) with specific stop distances based on roller speed. Rope specifications for these devices include minimum diameters and breaking strengths. The ILO standard for roller machine guards specifies a maximum opening gap based on a formula.

Conveyors require anti-reverse devices to prevent cargo from moving backward during power outages. These can be mechanical (ratchet, roller-band) or electrical (brake). For lever hoists and chain blocks, hooks must be discarded if the opening gap increases by more than 10% from the manufacturer's specification. Rupture discs require specific markings, including nominal size, application, rated rupture pressure, temperature, and discharge capacity.

Acetylene welding requires safety devices on each torch and between the generator and gas cylinder to prevent flashback. Flashback causes include faulty torches, pressure regulators, or clogged tips, but not excessive acetylene supply. Acetylene pressure must not exceed 127 kPa. Generators should be on the top floor, 3m from open flames, and 1.5m from other buildings. Forklifts must have backrests (unless not needed due to cargo position). Overhead guards must withstand twice the maximum load (up to 4 tons).

Gas cylinders must be handled with valves closed slowly, caps on during transport, and kept below 40°C. Gas cylinder colors indicate contents: green for oxygen, gray for argon/nitrogen, blue for carbon dioxide, orange for hydrogen, yellow for acetylene. Welding flame temperatures vary: methane (2700°C), propane (2820°C), hydrogen (2900°C), and acetylene (3430°C), with acetylene being the hottest.

Rated load for lifting equipment is defined as the maximum lifting capacity minus the weight of the lifting accessories. Safety factor is calculated as maximum load divided by rated load (or ultimate load divided by allowable load, or breaking load divided by design load). Examples show how to calculate safety factors and ultimate strengths. The video emphasizes memorizing the formulas for safety factor calculations.

Static electricity is defined as an electric charge that accumulates on an object's surface due to friction or separation, with minimal spatial movement of charge. Preventing static electricity involves controlling generation, preventing accumulation, and safely discharging. Various generation mechanisms include friction, separation, collision, fluid flow (flow electrification, significantly influenced by fluid velocity), injection, and induction. Industries with high static electricity risks include dry cleaning, volatile substance drying, and explosives manufacturing.

Flow velocity limits for liquids in pipes are given: e.g., for pipe diameters of 25mm, the limit is 4.9 m/s. Highly flammable substances like diethyl ether and carbon disulfide require flow velocities below 1 m/s. Measures to prevent human electrification include anti-static shoes and clothing, wrist straps (with 1 ohm resistance), and using low-resistivity floor materials (10^8 to 10^5 ohms). Static eliminators (electric field, self-discharge, ion spray, radiation types) are used to neutralize charges, with an efficiency target of over 90%.

Discharge phenomena include spark, brush, corona, and surface discharges, as well as lightning. Ozone (O3) is generated during corona and spark discharges. Voltage categories are defined: low voltage (up to 1000V AC, 1500V DC) with 1m isolation, high voltage (1000V-7000V AC, 1500V-7000V DC) with 1.2m isolation, and extra-high voltage (over 7000V AC/DC) with 2m isolation distance. Arc discharge voltage and current show an inverse relationship. Test pencils (low/high voltage testers) are used to check for charge.

Insulation resistance for low-voltage circuits is evaluated based on supply voltage and circuit type, with thresholds of 0.5 MΩ for non-earthed/earthed circuits (SELV/PELV) and 1.0 MΩ for safety-earthed/non-earthed circuits (FELV). For hazardous environments with dust or explosive materials, either metal conduit or cable wiring (excluding rubber-sheathed cables) must be used. Junctions between conduits or with equipment typically require at least five full turns of a threaded connection. For extra-high voltage equipment, fences must be erected, with the sum of fence height and distance to live parts being at least 5m.

Underground high-voltage power lines buried directly under roads should use combined duct cables (CD cables). For arc-generating high/extra-high voltage circuit breakers, the separation distance from flammable materials must be at least 1m (high voltage) or 2m (extra-high voltage). Lightning arresters for high/extra-high voltage circuits must have an earth resistance of 10 Ω or less. Installation locations for lightning arresters include substations, overhead line entry/exit points, high/extra-high voltage sides of distribution transformers, customer main entry points, and where overhead lines connect to underground lines.

Various types of grounding include system grounding (for protection against high-voltage shorting to low-voltage, preventing shock and fire), fault detection grounding (for reliable circuit breaker operation), functional grounding (for electrical anti-corrosion systems), and equipotential bonding (for medical equipment safety in hospitals). The video also mentions TN, TT, and IT systems as types of grounding systems, citing NTI as a common acronym in exams. The earth is used as ground due to its large area and near-zero resistance. Ground electrodes are buried at least 75 cm deep to reduce contact voltage and avoid freezing issues.

Grounding resistance is determined by conductor resistance, soil resistance, and contact resistance. Petersen coil grounding (reactor grounding) offers stable operation with near-zero fault current and uninterrupted power transmission. Equipotential bonding conductors should have a cross-sectional area of at least 6 mm² for copper (16 mm² for aluminum, 50 mm² for steel), aiming to equalize electrical potential and reduce shock hazards. Electrical components like circuit breakers (CB), disconnectors (DS), and lightning arresters (LA) are explained by their function. Circuit breakers interrupt fault currents, disconnectors isolate circuits for maintenance, and lightning arresters protect against lightning damage. Disconnectors primarily open/close no-load circuits.