In the safety standards of children's wear, all countries have specific provisions on the flame retardant performance of fabrics.  There are two kinds of standards for textiles. One is product standards, which mainly stipulate the minimum requirements of the quality of specific products or the index of limited value. For example, the flame retardant standards for children's wear in various countries stipulate the minimum requirements of the combustion performance of fabrics.  Another type of standard is the test standard, which specifies the test method to obtain various quality parameters, but does not judge the quality of the results.  For the same fabric combustion performance index, the results obtained by different testing methods are not comparable, so when we look at the flame retardant performance requirements of children's wear in various countries, we can not only look at the required flame retardant value, but also look at what method is used to test the value.

1. Main flame retardant test methods

The burning performance of the fabric is mostly judged by the burning rate of the fabric. The burning rate is to judge the fabric according to the specified method and the flame contact for a certain time, and then remove the flame, determine the flame burning time and non-flame burning time of the fabric, and the degree of damage to the fabric.

There are a variety of combustion test methods, according to the relative position of the sample and flame, can be divided into vertical method, inclined method and horizontal method.  Vertical method provides that the sample is placed vertically (the length direction of the sample is perpendicular to the horizontal line), and the combustion source is under the sample or on the surface of the sample, which is mainly used for the flame retardant performance of clothing fabric, decorative fabric, tent fabric, etc.  45° inclination method provides that the sample is placed 45° inclination (the length direction of the sample is 45° Angle with the horizontal line), and the combustion source is on the upper or lower surface of the sample below to ignite the sample, which is suitable for the decoration cloth of various transportation vehicles;  Horizontal method is to fire the sample placed horizontally, determine the flame spread distance and time on the sample, suitable for the bedding fabric such as carpet sheets.

The flame test is inseparable from the flame, so the accurate control of the flame is the most important point in this kind of test.  Precise flame control includes ignition source, ignition time and flame length.  Ignition source is different, that is, the type of gas is different, so the calorific value of the flame is different;  The ignition time is different, the calorific value of the flame is different, the longer the ignition time is, the higher the calorific value is;  Finally, the length of the flame should meet the requirements of the standard, the longer the length and the greater the contact area of the fabric, the easier the fabric burns.

The data obtained by the traditional evaluation methods of flame retardant performance of textiles have great limitations, sometimes the results obtained by different testing methods for the same material are very different, and a single flame retardant testing method often cannot reflect the combustion performance of materials, so several testing methods should be combined as far as possible.

2. Introduction of flame retardant test methods in various countries

The United States CFR 16 Part 1615 and 1616 "flammability standard of children's pajamas" uses vertical method to test the flame retardant performance of children's pajamas, mainly testing the length of carbonization of samples of children's pajamas with fabrics within 3 seconds.  The standard stipulates that children's clothing shall be flame retardant tested on both materials and garments.

EN 1103 "Textile-Clothing Textile-Detailed Procedure for the determination of flammability" uses the vertical method to test the flame retardant performance of children's pajamas, mainly measuring the surface flaring and burning rate of the fabric.  According to EN 14878 "Flammability of Pyjamas for Children", 3 test samples shall be tested for warp and weft direction of the fabric, and the samples shall not be washed before testing.

British BS 5438 "Flammability test method for Textile Fabrics when the surface or bottom edge of a vertically oriented sample is subjected to a small flame" the vertical method is used to test the flame retardant performance of children's pajamas, mainly to test the burning rate of the fabric.  According to the standard, the warp and weft of the fabric should be tested separately by 3 test samples.

AS/NZS 1249-2014 standard "Children's Pajamas and Limited Daily Clothing for Reducing fire Risk" stipulates that the ignition method is step A (surface ignition), the igniter is 20mm away from the bottom of the sample, the flame level is close to the test sample, the flame length is 25±2mm, and the horizontal distance between the igniter and the test sample surface is 17±1mm.  Record the burning time of the first and third marker wires, whether the filter paper is ignited, and record the burned length if the filter paper is ignited.

In ISO 10047 "Textile burning Properties - Determination of fabric Surface burning Time" standard, fabric longitudeand weft four test samples were respectively measured, each test sample size 170*75mm, the sample was vertically suspended on the gripper.  The combustion gas of the burner is propane or propane butane mixture gas, and the ignition time is 1.0±0.1s.  The vertical length of the flame is 40±2mm. Place the igniter horizontally and slowly approach the test sample. Ensure that the horizontal distance of the igniter from the surface of the test sample is 15mm, observe whether there are villous flames spreading or being ignited.

AS/NZS 1249-2014 Standard children's Pyjamas and Limited Daily Wear to Reduce Fire Risk divides children's wear into 4 categories:

Flame retardant requirements of a class of children's wear, the flame spread time of fabric from the first sign line to the third sign line is not less than 12s, and the ignition time of each test sample is not less than 10s;  If the fabric in the process of combustion melting drip down lit the filter paper, then the length of the filter paper burned shall not be greater than 20mm;  For suede fabrics, the surface burning time of washed fabrics shall not be less than 10s.

The flame retardant requirements of the second type of children's wear, for suede fabric, the surface burning time of the fabric after washing is not less than 10s.

The flame retardant requirement of the third class of children's wear is that the surface burning time of suede fabric after washing should not be less than 10s.

The flame retardant requirements of the four categories of children's wear are as follows: for suede fabric, the surface burning time of the fabric after washing should not be less than 10s.  Cellulose fiber, acetate fiber, acrylic fiber products are restricted to use in this kind of children's clothing;  For the fabric that did not pass the burning rate test of the fabric in children's wear, the content of cellulose fiber, acetate fiber and acrylic fiber in the fabric composition was less than 50%.

According to GB/T 14644-2014 "Textile Fabrics - Combustion -45° Direction Combustion Rate Determination" method, China adopts tilt method to test the burning performance of children's wear fabrics, mainly testing the burning rate of fabrics placed at 45°C tilt.  According to the standard, the direction with the fastest burning rate of the fabric is used as the length direction of the sample. If the direction with the fastest burning rate of the fabric is unknown, the direction with the fastest burning rate determined in the pre-test is used as the length direction of the sample.  The warp direction should be used as the length direction for non-suede fabrics with no difference in warp and weft burning rate in pre-test.

The test sample size is 160*50mm, and the sample is tilted on the gripper at 45°C.  The gas of the burner is butane, the ignition time is 1.0±0.05s, and the flame length is 16mm.  The ignition point is 19mm from the bottom of the sample, and a marker line is placed at the distance of 127mm from the ignition point.  The flame acts vertically on the surface of the sample, and the burning time of the marking line is recorded after ignition.  For suede fabrics, the sample shall continue to burn to determine whether the base cloth is burnt and fused.

3. Differences in flame retardant performance tests of children's wear in different countries

(1) Different combustion methods: American standard, European standard, British standard and Australian standard are vertical combustion, while Chinese standard is inclined combustion.

(2) Ignition methods are different: the same is vertical combustion, the American standard uses the bottom ignition, while the European Union, Britain and Australia standard uses the surface ignition.

(3) the combustion source is different: the American standard is methane, the European standard is propane, the British standard and the Chinese standard is butane, the Australian standard is propane or propane/butane mixture.

(4) different post-processing requirements: American standard and Australian standard clear requirements in accordance with the provisions, washing procedure before washing and after washing is tested, oubiao specify only test sample before washing, the British standard requirements as stipulated in the clothing washing label of washing process after washing test, provisions in China standard for washing before combustion performance for level 1 or level 2 should be measured after washing a combustion performance.

(5) Different sampling procedures:  The American standard clearly stipulates that samples must be taken from both fabric and clothing, the EU standard requires samples to be taken from the warp and weft direction of fabric, the British standard requires samples to be taken from the warp and weft direction and the test report indicates whether the samples are taken from fabric or clothing, the Australian standard only requires samples to be taken from the warp direction of fabric or the length direction of clothing.  Our standard only requires that the sample be taken from the direction of the most easy to burn and does not require whether it is taken from the fabric or clothing.

(6) Different investigation indicators: The American standard investigated the carbonization length after combustion, the European standard investigated the combustion rate and surface flasticity, the British standard investigated the flame spread degree and combustion rate, the Australian standard investigated the combustion rate and surface combustion time, and the Chinese standard investigated the combustion rate.

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