School Uniform Inspection

School uniform inspection mainly conducts scientific testing and analysis on key performance indicators, objectively assessing the product quality grade and issuing a detailed test report, providing a basis for manufacturers' quality control and downstream users' product acceptance.

Testing Scope and Objects

Fibre composition and content: In accordance with the product labelling and standard requirements, qualitative and quantitative analysis is carried out on the types and mass percentages of the various fibres (such as cotton, polyester and spandex) in the school uniform fabric. This is the basis for evaluating the wearing comfort, durability and price of the school uniform, and is also the key item for preventing the adulteration of inferior products and safeguarding the rights and interests of consumers.

Formaldehyde content: Detects the content of free and hydrolysed formaldehyde in the school uniform fabric. Formaldehyde is commonly used for the anti-wrinkle finishing of textiles, but an excessive amount will irritate the human skin and respiratory tract, and may even cause allergies. According to the mandatory standards GB 18401 and GB 31701, strict limits are set for infant products and textile products in direct contact with the skin.

pH value: Determines the acidity and alkalinity of the aqueous extract of the school uniform fabric. The surface of human skin is weakly acidic. An excessively high or low pH value of the textile may destroy the skin barrier, causing itching or dermatitis. The pH value of a qualified school uniform should be controlled within the range from slightly acidic to neutral, to ensure safe and comfortable wearing.

Decomposable carcinogenic aromatic amine dyes: Detects whether the school uniform uses prohibited azo dyes that can decompose to release carcinogenic aromatic amines under certain conditions. This type of dye, when absorbed through the skin, may cause serious harm to human health, and is an item strictly prohibited by the national mandatory standards. The test result must be "not detected".

Colour fastness: Evaluates the fastness of the school uniform colour under the action of various external factors. It mainly includes the colour fastness to soaping, rubbing (dry/wet), perspiration, light and water. School uniforms with poor colour fastness not only affect the appearance, but the shed dyes may also transfer to the skin, posing a safety hazard.

Odour: Judges whether the school uniform has abnormal odours such as musty smell, high-boiling-point petroleum smell, fishy smell and aromatic hydrocarbon smell through the sense of smell. These odours may originate from the chemical residues in the processing process, indicating that the product may be contaminated, directly affecting the wearing health. The standards stipulate that no abnormal odour can be detected.

Physical and mechanical safety: The cords, drawstrings, buttons and decorations on the school uniform are tested. Their length, position, tensile strength and the adhesion of the small parts are evaluated, to prevent mechanical injuries such as entanglement, strangulation and accidental swallowing caused by improper design. This is the key content of the children's clothing safety standards.

Core Testing Items

Breaking strength and tearing strength: Simulates the tensile and tearing forces suffered during wearing and use, testing the durability of the fabric. The breaking strength reflects the ability of the fabric to resist tensile damage, and the tearing strength reflects the ability to resist local tearing. High-quality school uniforms need to have sufficient strength to ensure that they are not easily damaged in daily activities and washing.

Seam performance: Evaluates the quality of the sewn parts of the school uniform, including the degree of yarn slippage (seam slippage) at the seams and the seam strength. An excessively large seam slippage will cause the sewn parts to open, affecting the appearance and wearing; an insufficient seam strength will easily cause thread breakage under force. This item is directly related to the process quality and service life of the school uniform.

Pilling performance: By simulating friction, the degree of pilling formed on the surface of the school uniform fabric due to the entanglement of the fibre ends is assessed. Frequently rubbed parts (such as cuffs and elbows) are prone to fuzzing and pilling, affecting the appearance and touch. This test can objectively reflect the anti-pilling grade of the fabric, especially the blended fabrics containing chemical fibres.

Composite colour fastness to light and perspiration: Examines the colour retention ability of the school uniform fabric under the combined action of light and human perspiration. Students have many outdoor activities, so this item is particularly important. Poor colour fastness may cause the school uniform colour to fade under sunlight and perspiration, or stain the skin and underwear. It is a key indicator of high-quality school uniforms.

Burning performance: Determines the burning rate and state of the school uniform fabric after contact with a fire source. Although the school uniform is not directly required to be flame retardant, understanding its burning characteristics is still meaningful for evaluating the potential risks. For certain specific uses (such as stage performance costumes) or fabrics (such as pure polyester), this performance may need attention.

Residual metal needle detection: Metal detection equipment is used to check whether the finished school uniform has residual sharp metal objects such as broken needles and staples. This is an important link in the quality control of the production process, aiming to eliminate the risk of serious physical injury caused by management negligence, and ensure the safety of the product before leaving the factory.

Accessory sharp points and edges: Strictly checks whether the edges and points of the accessories on the school uniform, such as zipper heads, metal buttons and decorative plates, have sharp points that may scratch the skin. Objective evaluation is carried out through professional testing instruments (such as sharp edge testers and sharp point testers), ensuring no injury risk.

Main Testing Methods and Standards

GB 18401 "National general safety technical code for textile products": The Chinese mandatory national standard, stipulating the basic safety technical requirements of all textiles (including school uniforms) in five aspects: formaldehyde, pH value, colour fastness, odour and decomposable carcinogenic aromatic amine dyes. The school uniform inspection must first comply with this standard.

GB/T 31888 "School uniforms for primary and middle school students": The Chinese recommended national standard, and is the comprehensive technical requirement specification for school uniform products. It specifies in detail the size system, safety, quality, inspection rules and other contents of school uniforms, and directly cites the safety requirements of GB 18401. It is the core basis for the quality assessment of school uniforms.

GB 31701 "Safety technical code for infants and children textile products": The mandatory safety standard for textile products for infants aged 36 months and below and children aged 14 and below. Its requirements are stricter than those of GB 18401, adding detailed provisions on the physical safety of cords and small accessories, and it is applicable to the vast majority of primary and middle school student uniforms.

Quantitative analysis of fibre composition (GB/T 2910 series, etc.): In accordance with the series of national standards, the composition ratio of different fibres in the school uniform fabric is precisely determined through the chemical dissolution method, microscope method and so on. The selection of the test method depends on the fibre types, and the results need to be strictly compared with the product labelling. It is an important technical means for combating counterfeit and shoddy products.

Colour fastness test methods series (GB/T 3920, 3921, 3922, 5713, etc.): Respectively corresponding to the standard test methods of different items such as the colour fastness to rubbing, soaping, perspiration and water. Each method strictly specifies the test instruments, reagents, conditions (such as the temperature, time and number of frictions) and the rating methods, ensuring the accuracy and comparability of the test results.

Physical property test methods (GB/T 3923, 3917, 13772, 13773, etc.): These standards respectively specify the test methods of the breaking strength, tearing strength, seam slippage and seam strength. By using equipment such as electronic fabric strength testers, the specimens of the specified size are tested under standard atmospheric conditions, obtaining objective mechanical property data.

Burning performance test (GB/T 14644): The vertical method is adopted to determine the burning performance of the textile. By measuring the afterflame time, afterglow time and damaged length of the specimen of the specified size after contact with a standard flame for a certain time in a vertical state, its burning characteristics are evaluated.

Testing Instruments and Equipment

Gas chromatography-mass spectrometer (GC-MS): Used to precisely detect the formaldehyde content and decomposable carcinogenic aromatic amine dyes in school uniforms. This equipment has strong separation ability, high sensitivity and accurate qualitative analysis, and is the core equipment for the analysis of trace hazardous chemicals, effectively ensuring the reliability and repeatability of the test results.

pH meter and extraction device: Used to determine the pH value of the aqueous extract of the fabric. The precision pH meter needs to be regularly calibrated to ensure the measurement precision; the extraction device oscillates and extracts the specimen under the specified conditions (such as a specific liquor ratio, temperature and time), simulating the influence of body fluids such as perspiration on the textile, and providing a standard sample solution for the pH value determination.

Colour fastness tester series: Including washing fastness testing machines, rubbing fastness testers, perspiration fastness testers and xenon lamp weathering testing machines. These equipment can simulate and precisely control the conditions such as washing, friction, perspiration immersion and sunlight exposure, objectively evaluating the stability of the school uniform colour in various environments.

Electronic fabric strength tester: Integrating multiple test functions such as tensile, tearing and bursting, it is the key equipment for testing the physical and mechanical properties of the school uniform fabric such as the breaking strength, tearing strength and seam performance. Its high-precision sensors and computer control system can automatically record and analyse the force-displacement curve, outputting accurate test data.

Martindale abrasion and pilling tester: Through the planar friction motion with a specified pressure and trajectory, it simulates the friction of the parts such as the elbows and hips of the school uniform in daily wearing. This instrument is widely used to test the abrasion resistance, pilling performance and appearance retention of the fabric, evaluating its durability grade.

Metal detector/needle detector: Used for the pre-shipment safety screening of the finished school uniforms. When the school uniform containing metal foreign objects such as broken needles passes through its detection area, the instrument will sound an alarm and automatically stop or mark, and is the essential production and inspection equipment for preventing the injury of metal residues and ensuring the physical safety of the product.

Sharp edge tester and sharp point tester: Specially used to objectively evaluate whether the accessories of the school uniform (such as metal buttons and zipper heads) have injury risks. The sharp edge tester judges by measuring the cut depth of the silicone strip, and the sharp point tester checks whether the point can be inserted into a specific aperture under a specified force, quantitatively evaluating the safety.

Conformity Judgement and Report Interpretation

One-vote veto of mandatory items: For the mandatory items specified in GB 18401 and GB 31701, such as formaldehyde, pH value, decomposable carcinogenic aromatic amine dyes, odour and physical safety (cords and small parts), if any one item is unqualified, the whole batch of school uniforms is judged to be unqualified, and sales and wearing are not allowed.

Comprehensive assessment of recommended items: For the recommended items such as the fibre content deviation, colour fastness grade and breaking strength, the judgement needs to be made in accordance with the product declared standards (such as GB/T 31888 or the enterprise standards). A single unqualified item may affect the product grade (such as the reduction of the excellent grade to the first grade or the qualified grade), and the specific handling is carried out according to the standard provisions.

Verification of the core information of the inspection report: A complete school uniform inspection report should include the sample information, inspection basis, inspection items, inspection results, judgement conclusion and the seal of the inspection institution. It is necessary to focus on checking whether the inspection basis standards are the latest valid versions, and whether the inspection items cover the key safety and quality requirements.

Understanding of the result data: When interpreting the report, the numerical meanings of the various indicators need to be understood. For example, the pH value of 4.0-8.5 is qualified; the formaldehyde content needs to be lower than the limit of the corresponding product category (such as ≤20 mg/kg); the colour fastness grade is usually divided into grades 1-5, and the higher the grade, the better, generally required to be grade 3 or above.

Sampling rules and report validity: The inspection conclusion is based on sampling inspection, and the report is only responsible for the submitted samples. The batch judgement needs to follow the sampling plan specified in the product standard. The report usually has a validity period (such as one year), but it only represents the state of the submitted batch of products at the time of testing, and cannot guarantee the quality of the subsequent production batches.

The role of the report in the supply chain: The school uniform inspection report is the "physical examination certificate" for the manufacturer to prove the compliance of the product, an important basis for the education departments and schools in the procurement acceptance, and the judgement basis for the market supervision departments to carry out quality supervision spot checks. A complete quality file should include the inspection reports of the fabric and the finished products.

Risk tracing of unqualified items: If there are unqualified items in the report, risk tracing needs to be carried out according to the items. The unqualified chemical items may originate from the dyes or finishing agents; the unqualified physical items may be related to the fabric quality or the production process; and the unqualified safety items directly reflect the defects in the design or production control, which must be immediately rectified.

Testing Standards

Domestic Standards:

1. GB 18401-2010, National general safety technical code for textile products

2. GB 31701, Safety technical code for infants and children textile products

3. GB/T 31888, School uniforms for primary and middle school students

4. GB/T 2910, Textiles — Quantitative chemical analysis

5. GB/T 3920-2024, Textiles — Tests for colour fastness — Colour fastness to rubbing

International Standards:

1. ISO 13934-1, Textiles — Tensile properties of fabrics — Part 1: Determination of maximum force and elongation at maximum force using the strip method

2. ISO 105, Textiles — Tests for colour fastness

Note: The applicable standard can be selected according to the product use and customer trade requirements; standards agreed in the contract take precedence over general standards.