This package prepares candidates for 消防設備士 甲種第5類, the class covering metal escape ladders, rescue chutes, and slow-descent devices. It focuses on identification, mechanical principles, installation and maintenance, inspection, and safety/legal responsibilities, with supporting MCQs and open-task practice. The class-specific technical material is a subject review; confirm current examination scope, exemptions, fees, schedule, question format, and legal requirements with the 消防試験研究センター. Automatic fire alarm and leakage fire alarm content is not the target of this class. Class Ko 5 is about mechanical evacuation equipment—metal escape ladders, rescue chutes, and slow-descent devices—not automatic fire alarm systems. A 甲種 licence covers construction, maintenance, and inspection for the class. Study identification, load and descent calculations, installation and inspection, safe deployment, and documentation; confirm current examination details with the 消防試験研究センター.
Scope, Credential Boundaries, and Exam Mindset
Center Class Ko 5 study on mechanical evacuation equipment, the 甲種 work scope, and the written and practical skills used to assess it.
The class-specific equipment is metal escape ladders (金属製避難はしご), rescue chutes (救助袋), and slow-descent devices (緩降機). A 甲種 licence permits 工事, 整備, and 点検 for the class; 乙種 is limited to 整備 and 点検. The written examination framework includes fire service law, basic mechanical knowledge, and the structure, function, construction, and maintenance methods of the class equipment; the practical component assesses identification and drawing. Class 5 preparation should centre on mechanical basic knowledge and mechanical structure/function, not an electrical paper. Confirm current question counts, time limits, exemptions, fees, schedule, and exact administration with the 消防試験研究センター before finalizing your plan.
If your study material begins with smoke detectors, heat detectors, or alarm control panels, check whether it belongs to a different class. Detector and automatic fire alarm topics are not the focus of Class Ko 5. For this class, practice recognizing devices from their support and descent mechanism, reading simple layout information, explaining installation and inspection sequences, and recognizing when a defect must be removed from service.
Prioritize in this order: equipment identification and scope; load, energy, and descent calculations; installation, inspection, and maintenance; safe deployment and documentation; then drawing and written explanation. This order keeps mechanical concepts connected to real checks rather than isolated vocabulary. The treatment here is subject review, not a substitute for current examination instructions or legal advice.
Equipment Identification: Ladder, Chute, and Slow-Descent Device
Identify each device by how it supports the user and controls descent, and connect identification to installation and inspection checks.
A metal escape ladder uses rigid rails and rungs; the user climbs down and is supported by the ladder structure. Installation and inspection focus on rails, rungs, welds, wall or anchorage connections, standoff from the building, access at the top, and the landing area. A rescue chute uses a fabric sleeve, entry collar, and internal friction or braking action; the user enters the sleeve and descends within it. A slow-descent device uses a controlled-rate mechanism—such as a governor, brake, or friction system—with a harness or connector and a descent line.
Installation matters as much as the device. For a ladder, verify the designated anchor or wall fixing, standoff, access, and landing; for a chute, verify the anchor, entry position, suspension, and clear vertical path; for a slow-descent device, verify the anchor, connector compatibility, and clear descent line. The 甲種 scope includes construction/installation as well as maintenance and inspection, so study the sequence: confirm the equipment and location, verify the supporting structure and anchor, check clearances, secure the installation, then test and record. Do not infer structural adequacy from appearance alone.
A useful identification scenario: an inspector opens a rooftop cabinet and finds a folded fabric sleeve with an entry collar and suspension strap, but no rigid rungs. That is most likely a rescue chute. If the same cabinet contained a rope, harness, and a braking unit, it would suggest a slow-descent device. If it contained rigid metal rails and rungs, it would suggest a metal escape ladder. The first action is not to throw or deploy the device; it is to check the label, service record, anchorage, storage condition, and deployment path.
Do not infer equipment class from a cabinet label alone. Confirm the device type, rated use, and instructions from the equipment marking and maintained records. In an exam answer, state the identifying features plainly: rigid rungs for the ladder, enclosing fabric for the chute, and controlled braking with a connector for the slow-descent device.
Mechanical Basics: Load, Work, Energy, and Descent Time
Use mass, weight, height, time, and energy relationships to check descent performance and explain risk.
Weight is mass times gravitational acceleration: W = mg, with g approximately 9.8 m/s². Gravitational potential energy for a vertical descent is approximately mgh. Average descent speed is distance divided by time. Average power dissipated during descent is energy divided by time, mgh/t. For a simple constant-speed model, the net force is near zero, so the upward braking force balances the user’s weight, mg, while other losses are ignored. These calculations are planning checks; actual device forces depend on the mechanism and manufacturer’s design.
Worked scenario one: a 75 kg person descends 16 m. The potential energy is 75 × 9.8 × 16 = 11,760 J, or about 11.8 kJ. If the descent takes 20 s, average power is 11,760 ÷ 20 = 588 W, and average speed is 16 ÷ 20 = 0.8 m/s. This does not establish a regulatory limit; it checks whether the stated scenario is internally consistent.
Worked scenario two: a total mass of 90 kg descends 12 m in 18 s. The energy is 90 × 9.8 × 12 = 10,584 J. Average power is 10,584 ÷ 18 = 588 W. Average speed is 12 ÷ 18 = 0.67 m/s. In multiple-choice calculations, keep mass and weight separate: a 60 kg person has a weight of about 588 N, not 60 N.
Anchorage, Clearance, and Deployment Geometry
Treat anchorage, clear descent path, and landing zone as parts of one system.
A sound device can fail in practice through a poor anchor, an obstructed path, or an unsafe landing zone. The anchor should be the designated, verified point, compatible with the connector, and free from sharp edges or corrosion. Load direction matters. If two symmetrical vertical slings share a total static load equally, each carries half. For a 1,200 N total load with equal vertical sharing, each sling carries 600 N. As sling angle increases, tension can rise; do not assume that a visually strong point is adequate without design information.
Clearance means that the descent path is free of projections, open windows, railings, power lines, and stored objects, and that the landing area is clear. For a training scenario with an 18 m descent, check the full vertical route and the ground area before anyone enters the device. The device length, user height, and landing space must be considered together. A clear path at the top does not guarantee a clear path lower down.
Worked planning scenario: a 70 kg user descends 15 m. The static weight is 70 × 9.8 = 686 N. If a hypothetical planning factor of 5 is applied to the static weight, the target design load is 3,430 N. This is an exercise in consistent reasoning, not an official rating. Always use the manufacturer’s rated capacity and the current site instructions. Never substitute a handrail, pipe, or tree for a designated anchor unless it has been verified for that purpose.
Inspection, Maintenance, and Functional Testing
Combine visual checks, functional checks, and records; any defect removes the equipment from service.
Pre-use inspection should confirm the equipment identity, service record, anchor condition, connectors, rope or fabric condition, brake or governor condition, locking arrangements, corrosion status, storage condition, deployment path, and communication plan. For a rescue chute, look for cuts, abrasion, seam damage, moisture, mildew, heat damage, or contamination. For a metal ladder, inspect rails, rungs, welds, anchors, and wall clearance. For a slow-descent device, inspect the descent line, brake surfaces, connector, and harness according to the manufacturer’s information.
After a drill or use, do not simply return the equipment to storage. Follow the manufacturer’s and authority’s instructions for inspection, cleaning, drying, repacking, and possible replacement. A wet fabric chute should not be sealed away damp. Oil or chemicals on a braking surface may reduce or alter braking performance; remove the equipment from service and follow maintenance instructions. Corrosion at a ladder rung, weld, or anchor can reduce load capacity and requires assessment before reuse.
Functional testing with people requires trained personnel, competent supervision, the manufacturer’s instructions, fall protection where appropriate, and a rescue plan. Never test alone, disable a brake to observe speed, or use an untrained volunteer. Record the date, equipment ID, findings, actions taken, and tester. A record without findings is not useful; a finding without an action is incomplete.
Common Errors and False Assumptions
The highest-risk errors are scope confusion, uncontrolled deployment, and returning damaged equipment to service.
A common study error is preparing alarm-system content for Class Ko 5. Another is assuming that a new-looking device needs no inspection. In installation and deployment, common errors include using an unverified anchor, ignoring lower-level obstructions, crowding the entry, skipping communication, and failing to secure the landing zone. In maintenance, common errors include storing a chute wet, applying unauthorized lubricants, painting over corrosion, and treating a drill use as proof that the equipment is ready for immediate reuse.
Calculation errors also cluster predictably: mixing mass in kilograms with weight in newtons, forgetting g, using height in centimeters without converting, dividing by the wrong time, or treating average braking force as if it were the mass. In written answers, vague terms such as “strong enough” are weaker than a stated check: anchor identified, load direction considered, capacity confirmed, path clear, landing zone controlled.
For exam preparation, make a three-column error log: what I missed, why the reasoning failed, and the corrected rule or check. Review the log before the next practice set. Do not memorize a single numeric threshold as a substitute for understanding the equipment and the current instructions.
Integrated Practice Task and Self-Check Rubric
A complete answer links identification, mechanics, installation, inspection, safe deployment, and documentation.
Practice task: a six-story training building has an 18 m descent to a controlled ground area. A rescue chute is stored in a marked roof cabinet beside a designated anchor. A 78 kg trainee is expected to descend in about 25 s. Identify the likely equipment; calculate the trainee’s weight; calculate the change in gravitational potential energy; calculate average speed and average power; list five pre-deployment checks; state two stop criteria; and describe the record you would complete.
Model calculations: weight = 78 × 9.8 = 764.4 N. Potential energy = 78 × 9.8 × 18 = 13,759.2 J, or about 13.8 kJ. Average speed = 18 ÷ 25 = 0.72 m/s. Average power = 13,759.2 ÷ 25 = 550.4 W. These calculations use only the stated data. They do not replace the manufacturer’s rated capacity or the current site procedure.
Self-check rubric: (1) correct equipment identification and class scope; (2) calculations with units and clear working; (3) anchor, connector, and clearance checks; (4) inspection items specific to fabric, rope, brake, ladder, or harness as relevant; (5) stop criteria such as damaged fabric, contaminated brake, insecure anchor, obstruction, or uncontrolled landing zone; (6) record with date, ID, findings, actions, and tester; (7) clear communication and exclusion of unauthorized persons. Score each item 0–3 and redo any item scoring below 2. For drawing practice, produce a labeled elevation showing anchor, device, descent path, landing zone, access, and exclusion area. This open task is representative practice, not a simulation of the official practical examination.
A Practical Study Sequence
Build in four passes: scope, mechanics, installation and inspection, then integrated practice.
First pass: scope and identification. Make a table with device, identifying features, support/descent mechanism, installation points, common defects, and inspection points. Confirm the current examination scope and administration with the 消防試験研究センター. Second pass: mechanics. Solve ten short calculations for weight, potential energy, time, average speed, average power, and equal load sharing. Write units at every step and check whether answers are plausible.
Third pass: installation, inspection, and maintenance. Create a pre-use checklist and an after-use checklist. Practice explaining why a wet chute, corroded ladder, or contaminated brake is removed from service. Practice a labeled drawing with anchor, path, landing zone, and access. Fourth pass: integrated scenarios. Answer the MCQ set, then write two open responses using the self-check rubric. Review errors by category rather than by question number alone.
A four-week plan works well: week 1 scope and identification; week 2 mechanics and calculations; week 3 installation, inspection, maintenance, and drawing; week 4 integrated scenarios and timed written practice. Keep sessions short and active: retrieve, calculate, explain aloud, and correct. Use current official information for legal and administrative requirements, and treat all class-specific technical notes here as subject review.
References and further reading
Use these references to explore the concepts and check the latest information from the relevant organizations.