Office Chair Exam

Here are detailed answers to different types of office chair exams:

Office Chair Material Strength Exam

1. Multiple-Choice Questions:
   • The commonly used high-strength engineering plastic for the five-star base of an office chair is glass fiber reinforced polypropylene (glass fiber PP).
   • The standard static load-bearing value for the seat plate of a single-person office chair is usually not less than 1500N.
2. True/False Questions:
   • The strength of the backrest support rod is influenced by both the material and the cross-sectional shape. The statement in the question stem is false.
   • For the same material and thickness, the strength of a rectangular cross-section seat plate is higher than that of a circular cross-section. The statement in the question stem is true.
3. Short-Answer Questions:
   • The wheel base needs to withstand dynamic loads. The design requirements include: strong impact resistance of the material, a stable connection structure, and a tight fit between the wheel axle and the wheel base. Common failure modes include wheel base fracture (due to material fatigue or overload), wheel detachment (due to loose connections), and wheel axle deformation (due to long-term off-center loading).
4. Calculation Questions:
   • According to the compressive strength formula for circular tube cross-sections, the minimum outer diameter of the support leg is calculated as follows:
     Outer diameter ≈ 20.2mm (Calculation process: Yield strength 220MPa, wall thickness 2mm, pressure 800N. Substituting into the formula gives an outer diameter of approximately 20.2mm).
5. Essay Questions:
   • Casters need to have high wear resistance, impact resistance, and low rolling resistance. Low-strength casters are suitable for flat surfaces (such as office carpets), while high-strength casters are suitable for uneven surfaces (such as industrial workshops).
6. Comprehensive Analysis Questions:
   • The fracture may be caused by uneven dispersion of glass fibers leading to insufficient local strength, or improper temperature/pressure control during the injection molding process. Improvement measures include optimizing the glass fiber mixing process, strengthening injection molding parameter monitoring, and adding reinforcing ribs at the connection between the support leg and the central base.

Office Desk and Chair Usage Method Exam

1. Single-Choice Questions:
   • The standard for adjusting the height of the seat is feet flat on the ground, thighs parallel to the ground, and knees at a 90° angle.
   • The cooperation between the desktop and the seat should meet the requirement that when the elbows are hanging down, the forearms are parallel to the desktop.
   • The reasonable range for the angle of the seat backrest is 100°-110°.
   • The top of the monitor should be slightly higher than the line of sight, with the center forming a 10°-15° downward angle.
   • The height of the armrests should be adjusted so that the elbows can rest naturally and the shoulders are relaxed.
   • To prevent lower back strain, one should move for 5-10 minutes every 30-60 minutes.
   • The keyboard and mouse should be placed side by side, 10-15cm away from the edge of the body.

Office Desk and Chair Usage Experience Exam

1. Single-Choice Questions:
   • The ideal adjustable range for the sitting height is 40-50cm.
   • The height of the desktop should be level with the elbows.
   • The core function of the lumbar support design is to support the physiological curve of the spine.
   • The depth of the seat should be adapted to the length of the thighs to avoid the waist hanging in the air.
   • Prolonged sitting can easily lead to cervical and lumbar strain.
2. Multiple-Choice Questions:
   • The characteristics of a high-quality seat include a breathable seat surface, an adjustable backrest, and smooth universal wheels.
   • The functional designs of the desktop include cable holes, rounded corners, and waterproof and scratch-resistant surfaces.
   • To prevent the risks of prolonged sitting, one needs to move regularly and adjust the height of the monitor.
   • The design of the armrests should consider height level with the desktop, soft material, and multi-dimensional adjustment.

Office Chair Training Exam

1. Single-Choice Questions:
   • The current core national standard in China is QB/T 2280-2016.
   • The 2025 version of the new national standard does not add a formaldehyde emission test item.
   • In the EU EN 1335 standard, the seat height of a Type C chair needs to be >480mm.