This standard consists of 7 chapters, including scope, normative references, terms and definitions, technical requirements, test methods, inspection rules, identification, usage instructions, packaging, transportation, and storage. The main content includes the following aspects:
1. Technical Requirements
(1) Appearance
Requirements for the appearance of wooden components, painted surfaces of wooden components, metal components, plastic components, and soft covers are specified.
(2) Dimensions
a) A nap chair has two functions: one is the function of a student's classroom chair during class time, and the other is the rest and nap function during break times for students.
b) Currently, height-adjustable seat technology is mature and widely applied; to facilitate school procurement, management, and student use, this standard recommends that the nap chairs be adjustable in height, not fixed at a certain height. Therefore, only the functional dimension requirements of the height-adjustable nap chair are specified in this standard.
c) For the comfort of students during naps, the nap chair needs to have headrests and footrest components. Because the seat surface height of the nap chair is adjustable, suitable for students of different heights, the headrests and footrests also need some degree of adjustability.
d) The nap chair will be used in primary and secondary school classrooms, constrained by classroom space dimensions; it needs to be paired with desks and comply with the specifications in GB/T3976. To meet the comfort requirements for sitting and lying down, it is subject to constraints related to human body dimensions.
(3) Weight
The highest weight requirement for elementary school A-type nap chairs is specified.
(4) Physical and Chemical Properties
It follows the principles of corrosion resistance, anti-aging, acid and alkali resistance, and no deformation after exposure to wind, sun, rain, and snow.
(5) Safety Requirements
In addition to the safety requirements in QB/T 4071—2021 for desks and chairs, folding mechanism safety requirements are added to ensure that there are no burrs or sharp edges. It uses slot locks and screws to secure components tightly, ensuring insulation. Crossbars are installed between the legs of the chair to reinforce it, and anti-slip and noise-reducing pads are attached to the bottom of the feet to reduce movement noise and eliminate safety hazards.
(6) Mechanical Properties
In addition to the mechanical properties in QB/T 4071—2021 for desks and chairs, requirements for overall load-bearing capacity, leg endurance, angle adjustment mechanism endurance, lifting mechanism endurance, sufficient backward tilt stability of the seat, and static load test on legs are added.
(7) Limitations of Harmful Substances
In addition to the limitations of harmful substances in QB/T 4071—2021 for desks and chairs, requirements for limits on harmful substances in textiles are added.
2. Test Methods
Based on the QB/T 4071—2021 desk and chair standard, test methods for appearance, main dimensions and dimensional deviations, shape and position tolerances, physical and chemical properties, safety requirements, mechanical properties, and limitations of harmful substances are specified.
3. Inspection Rules
Based on the QB/T 4071—2021 desk and chair standard, requirements for inspection classification, factory inspection, type testing, result determination, and re-inspection rules are specified.
T/JYBZ 031-2024 history
2024T/JYBZ 031-2024 Chair for lunch break of primary and middle school students