Views: 59 Author: Site Editor Publish Time: 2022-12-09 Origin: Site
Children need children's desks and chairs whether they are studying at home or in school. Domestic and foreign studies have shown that poorly designed children's desks and chairs will directly affect the physical health and learning effect of teenagers, resulting in myopia, hunchback, bone development and so on. In order to protect children's back health and improve the effect of learning entertainment. The European Union has introduced a new set of guidelines for children's desks and chairs, advising schools to buy ergonomic ones. The ergonomic requirements of children's desks and chairs are considered in the design process, which will create a good and comfortable learning and entertainment environment for children, which is not only conducive to children's concentration on learning, but also conducive to reducing the impact of tables and chairs on children's physical and mental health. So what are the technical requirements and inspection standards for children's desks and chairs? How does the third party inspection company inspect the children's tables and chairs?
1. Children's table and chair inspection scope
Specification of GB/T 39223: Ergonomic technical requirements and testing methods for children's tables and chairs. Suitable for children aged from 4 to 14 years old to meet the basic performance quality and safety and environmental standards of adjustable size study tables and chairs.
2. Children's table and chair inspection size requirements
3.2.1 Size requirements for children's tables
Table top width
Table width B should provide a suitable space for children's sitting learning and entertainment activities. The width of the table should not be less than 700mm.
Table top depth
Table deep T1 should consider the arm working area under seated learning or recreational activities. The desktop depth should not be less than 450 mm.
The table height H1 should meet the elbow support height of children when they are sitting, learning and playing. The adjustable range of table height should be 540 mm.
High clearance under the table
The headroom height H2 under the table should refer to the knee space height and sitting knee height of children. The adjustable range of the net height under the table should be 320 mm~570 mm.
With the headroom height under the table as the benchmark, the difference between the table height and the headroom height under the table should not be greater than 220 mm.
Deep clearance under the table
The depth of headroom T2 under the table should refer to the knee space depth of children, and the depth of headroom under the table should be based on the length of thigh in sitting position. The requirements are as follows:
a) The baffle plate affecting leg forward movement should not be set in the depth direction under the table. If the baffle plate needs to be set, it should not be declared that it will affect the effective movement space of legs;
b) The headroom depth under the table should not be less than 450mm;
c) If the headroom depth under the table is affected by the structural safety design, the headroom depth under the table should be ensured at least in the lower limb activity area, and the headroom depth under the table should not be less than 380 mm.
Table top Angle
The desktop Angle should be adjustable, and the adjusting mechanism should be safety locking anti-clamping mechanism. The adjustable range of the desktop Angle shall not be less than 24°.
The Angle meter with accuracy of no less than 1° is required to measure the Angle between the surface and the horizontal plane under the load.
2.2 Size requirements for children's chairs
Height of seat surface
The seat height SH should be consistent with the children's sitting height to satisfy the comfortable learning and entertainment under the sitting condition. The seat height is the vertical distance between the seat surface and the ground when the seat is bearing the weight of a child at 50 cm (see GR/T 26158 for ages 7-10). The design range of seat height shall meet the following requirements:
a) The height range of the seat surface shall be 220mm~ 460mm;
b) For seats excluding pre-school children, the height of the seat surface is approximately 320 mm~460.
Width of seat surface
The width SW is the distance between the left and right edges at half of the depth of the seat, which should match the width of the hips of children in sitting position to satisfy the comfort of learning and entertainment in sitting position.
The width of the seat surface should not be less than 400 mm.
Depth of seat surface
The depth SD of the seat surface should be consistent with the hip distance of children in sitting position to satisfy the comfort of learning and entertainment in sitting position. The depth of the seat surface is the horizontal distance between the midpoint of the front edge of the seat and the midpoint of the lower edge of the backrest. The depth of the seat surface should be within 230mm~470mm.
Angle of base surface
Seat surface inclination a is the Angle between the vertical intersection of the backrest point and the datum plane of the seat surface and the line between the upper edge of the front of the seat and the horizontal. The Angle of the seat surface should meet the children's sitting comfort and safety and stability when learning or entertainment.
The orientation of the seat surface should be between 0° and 4°.
Back of the chair
Backrest point height
The back of the chair should be able to effectively support the child's back area while sitting, providing comfortable and secure sitting conditions. Backrest point PB is the point on the center line of the backrest where the backrest protrudes forward. The height of the backrest point is the vertical distance from the datum plane of the backrest point and the height of the backrest point should be 160 mm~220 mm.
Chair back width
The back of the chair should be able to support the child's back effectively. Backrest width BW refers to the horizontal width of the backrest within the height range of backrest point, which should be greater than or equal to 350mm.
Angle of back
The chair back Angle β is the Angle between the vertical intersection of the backrest point and the datum surface of the seat and the line between the upper edge of the chair back and the horizontal plane. When the Angle between the seat and the back is adjustable, the back Angle should be greater than or equal to 80°. When the user changes from the front seat position to the rear seat position, the change in the chair back Angle should be increased by at least 15%
Volume pressure distribution requirements
The seat surface hardness should meet the requirements of children's hip pressure comfort. The maximum pressure in the area where the child seat should face the human sciatic segment should not be greater than 30kPa.
Other ergonomic requirements
Hardness of contact surface
The contact surface of children's table and chair should have appropriate hardness and softness, so that the user has good contact pressure comfort and support.
Example: Child bundle chair contact including child chair use, chair back, etc. The removal of a person's internal contact.
Tactile sensation on the contact surface
The material, temperature sensation, texture and shape design of the contact surface of children's tables and chairs should give the user a good touch. It should not have a rough feeling that makes the user feel uncomfortable, nor should there be obvious cold and hot stimulation.
The operation mode of children's table and chair adjustment function should be simple, convenient and safe, and the adjustment result should be able to achieve the desired effect, and the user has a good operation experience.
Example: adjustment functions, such as height and other dimensions adjustment function, backrest Angle adjustment function, desktop Angle adjustment function, etc
Shape of structure
The functional structure of children's desks and chairs used to support specific parts of human body should be safe and stable to provide users with a good comfortable experience. If the user is performing normal postural adjustments and activities such as leaning forward and back, the child chair should not be at risk of tipping over or falling.
Structural modeling should consider the cleaning and maintenance as well as the comfort and convenience when the chair is used together.
Example: Specific functional structure such as the structural shape of the chair back, etc.
Safety of appearance
The internal and external surfaces, folding mechanisms, holes and gaps, and moving wheels of children's tables and chairs should be considered for the use of risks, and the structural parts with safety risks should be handled safely to avoid accidental injuries during the use of users.