Inspection requirements and standards for children's tables and chairs

Children need children's tables and chairs, whether studying at home or attending school. Domestic and international studies have shown that poorly designed children's tables and chairs can directly impact adolescents' physical health and learning outcomes, causing nearsightedness, hunchbacks, and affecting bone development. To protect children's back health and improve learning and entertainment outcomes, the European Union has introduced a new set of "Guidelines for Children's Tables and Chairs," recommending that schools purchase tables and chairs that adhere to ergonomic principles. Children's tables and chairs designed with ergonomic considerations in mind create a comfortable learning and entertainment environment, helping children focus on their studies while mitigating the impact of tables and chairs on their physical and mental health. So, what are the technical requirements and inspection standards for children's tables and chairs? How do third-party inspection companies inspect children's tables and chairs?

1. Scope of application of children's tables and chairs inspection

GB/T 39223 stipulates: Ergonomic technical requirements and test methods for children's tables and chairs. It is applicable to adjustable learning tables and chairs for children aged 4 to 14 years old that meet basic performance, quality, safety and environmental protection standards.

2. Inspection size requirements for children's tables and chairs

2.1 Children's table size requirements

• Tabletop width <br>Tabletop width B should provide suitable space for children to sit, study and entertain. Inspection requirements for children's tables and chairs require that the tabletop width should be no less than 700mm.

• Tabletop depth <br>Tabletop depth T1 should take into account the arm working area for sitting learning or entertainment activities. The tabletop depth should not be less than 450 mm.

• Table top height <br>The table top height H1 should meet the support height of children's elbows when sitting, studying and playing. The adjustable range of the table top height should be 540 mm.

• Under-table clearance height <br>H2 should refer to a child's knee clearance height and sitting knee height. The adjustable range of the under-table clearance height should be 320 mm to 570 mm.
  Taking the clearance height under the table as the benchmark, the difference between the table height and the clearance height under the table should not be greater than 220 mm.

• The clearance depth under the table <br>The clearance depth T2 under the table should refer to the depth of the child's knee space. The clearance depth under the table is designed based on the length of the sitting thigh. The requirements are as follows:
  a) Baffles that affect the leg's forward extension should not be installed in the depth direction under the table. If baffles are required, they should not affect the effective space for leg movement;
  b) The clearance depth under the table should be no less than 450mm;
  c) If the clearance depth under the table is affected by structural safety design, the clearance depth under the table should at least be guaranteed for the lower limb activity area, and the clearance depth under the table should not be less than 380 mm.

• Tabletop inclination angle <br>The tabletop inclination angle should be adjustable, and the adjustment mechanism should have a safety lock or other anti-pinch mechanism. The adjustable range of the tabletop inclination angle should be no less than 24°.
  During measurement, an inclinometer with an accuracy of not less than 1° is required to measure the angle between the surface under the load and the horizontal plane.

2.2 Children's Chair Size Requirements

• Seat Height <br>The seat height SH should be consistent with the child's sitting height, ensuring comfortable learning and entertainment in a seated position. The seat height is the vertical distance between the seat base and the ground when the seat is loaded with the weight of a 50cm child (see GR/T 26158 for the 7-10 age group). The design range of the seat height should meet the following requirements:
  a) The seat height should range from 220mm to 460mm;
  b) For seats that do not take preschool children into consideration, the seat height range may be 320 mm to 460 mm.

• Seat width <br>The seat width SW is the distance between the left and right edges at half the seat depth, which should match the width of the child's sitting hips to ensure comfortable learning and entertainment in a sitting position.
  The seat width should not be less than 400 mm.

• Seat Depth <br>The seat depth (SD) should be consistent with the child's hip distance when sitting, ensuring comfortable learning and entertainment in a sitting position. The seat depth is the horizontal distance from the midpoint of the front edge of the seat to the midpoint of the lower edge of the backrest. The seat depth should be within 230mm-470mm.

• Seat inclination angle <br>The seat inclination angle a is the angle between the horizontal and the line connecting the vertical intersection of the backrest point and the seat reference plane and the uppermost edge of the seat front. The seat inclination angle should meet the requirements of children's sitting comfort and safety and stability when studying or playing.
  The seat inclination should be between 0° and 4°.

• chair back

  • Backrest Point Height <br>The seat back should effectively support the child's back area when sitting, providing comfortable and safe sitting conditions. The backrest point PB is the point on the midline of the seat back where the backrest protrudes most forward. The backrest point height is the vertical distance from this point to the seat base plane. The backrest point height range should be 160 mm to 220 mm.

  • Backrest Width <br>The backrest should be able to effectively support the child's back. The backrest width BW is the horizontal width of the backrest within the backrest height range and should be greater than or equal to 350mm.

  • Backrest Recline Angle <br>Backrest recline angle β is the angle between the horizontal plane and the line connecting the vertical intersection of the backrest point and the seat base plane, and the upper edge of the backrest. When the angle between the seat and backrest is adjustable, the backrest recline angle should be greater than or equal to 80°. In normal operation, the backrest recline angle should be between 90° and 95°. When the user moves from the forwardmost sitting position to the rearmost sitting position, the backrest recline angle should increase by at least 15%.

• Body pressure distribution requirements <br>The seat surface's hardness should meet the child's buttocks pressure comfort requirements. The maximum pressure in the ischial tuberosity area corresponding to the child's seat surface should not exceed 30kPa.

-Other ergonomic requirements

• Contact surface hardness <br>The contact surface of children's tables and chairs should have appropriate hardness to provide users with good contact pressure comfort and support.
  Example: The contact area of a child's seat includes the child's seat, the back of the seat, etc. The contact area of a person's seat.

• Contact surface feel <br>The material, material temperature, contact surface texture, and design of children's tables and chairs should give users a good tactile feel. They should not feel rough enough to make users feel uncomfortable, nor should they have obvious hot or cold stimulation.

• Adjustability <br>The operation of the adjustment function of children's tables and chairs should be simple, convenient and safe, and the adjustment results should achieve the expected effect, giving users a good operating experience.
  Example: Adjustment functions, such as height adjustment, backrest tilt adjustment, desktop tilt adjustment, etc.

• Structure and Shape <br>The functional structure of children's tables and chairs, designed to support specific body parts, should be safe and stable, ensuring a comfortable user experience. The chair should not tip over or fall over during normal posture adjustments and leaning forward or backward.
  The structural design should take into account cleaning and maintenance as well as the comfort and convenience when used with regular chairs.
  Example: Specific functional structures such as the structural shape of a chair back.

• Appearance safety <br>The inner and outer surfaces, folding mechanisms, holes and gaps, moving wheels, etc. of children's tables and chairs should be considered for usage risks. Structural components with safety hazards should be handled safely to avoid accidental injuries to users during use.

• Accessories <br>Accessories with special functions for children's tables and chairs should be reasonably designed and laid out to facilitate effective use and provide a good comfortable experience.
  Examples: Accessories include drawers, shelves, storage pockets, etc.