【Personal Protection】Comparison of Standards of Chinese and Foreign Fire Protective Clothing

【Abstract】 Compared with the specific technical indexes of fire protection and flame retardant performance of outer layer materials, protective clothing thermal insulation performance, hydrostatic pressure resistance performance, water vapor permeability and reflective tape performance standards in China's fire protective clothing and the standards of fire protection protective clothing in Europe and America. Analysis, pointed out that China's fire protective clothing standards and the gap between Europe and the United States; proposed China's fire protection clothing standards revision proposals.

【Key Words】 Protective clothing Performance, Standard, Comparative study

1 Introduction

American standard fire protective clothing

With the development of society and economy, the continuous advancement of science and technology, various new materials, new processes, and new technologies are widely used, and the forms of fire accidents also show diversity and complexity. In recent years, the number of firefighters who have been sacrificed or injured due to heat radiation, explosions, etc. has increased significantly in fire fighting and accident handling . The new person in the fire situation for firefighters Fire Rescue seat belt to a certain threat to personal protective firefighters raised new challenges. How to do a good job in protecting firefighters during fire rescue, and what requirements should be reached in the protective performance of fire-fighting protective clothing has become an important issue in the field of personal protective equipment.

2 Fire protective clothing performance parameters comparison

The main performance requirements of fire protective clothing include: outer layer fire-retardant fire-retardant performance, thermal insulation performance, waterproof and air-permeability performance, anti-static performance, reflective tape reflective performance.

2.1 Comparison of Fire-Retardant Performance Requirements of Outer Materials

Extinguishing protective clothing is composed of outer layer, waterproof and breathable layer, thermal insulation layer and comfortable layer multilayer fabric. The outer layer is the layer directly in contact with fire and heat, and it is also the most relevant to the quality of the product. The key layer. Firefighters are generally exposed to high temperatures and flames during fire extinguishing. The fire-retardant performance of protective clothing is an important guarantee for firefighters' work safety.

2.1.1 China's Standard Requirements for Flame Retardant Performance of Protective Clothing Outer Fabrics and Insulation Layers

Of GA10-2002 "firefighters fire protective clothing" on the outer dimensions of the flame retardant materials and a predetermined insulating layer is required to ignite a sample garment damaged length after the test should not exceed 100mm, flame time not greater than 2s, and There should be no melting or dripping. The test method used is the GB/T 5455-1997 "Vertical Testing of Textile Combustion Property Test", which refers to the Japanese Industrial Standard JIS 1091-1992 "Test Methods for Combustion Properties of Textile Products".

2.1.2 European Union requirements for the outer layer of protective clothing fire retardant

Tests were carried out according to the short-term combustion spread test described in the European Union standard EN 533:1997 . The criteria used for this criterion were three-level index criteria. Preparation of test specimens : Six test specimens of length ( 200 ± 1 ) mm x width ( 160 ± 1 ) mm.

Pre-test water wash requirements : A. Washed at 75 °C 12 times (according to the industrial washing method of EN ISO 10528 ) ; It can also be washed 5 times according to customer's request , and then tested.

B. Soak the sample in water ( BS5651:1978 ), then perform dry cleaning five times according to the requirements of ISO 3175 , and then perform the test. The three-level evaluation criteria are shown in Table 1.1 .

Table 1.1 Classification Requirements for ENFR Outer Fire-Retardant Performance

2.1.3 American Standard Requirements for Fire-Retardant Performance of Protective Clothing Outer Materials

The NFPA standard requires the use of the United States ASTM D 6413 "Textile Flame Retardant Testing Methods (Vertical Method)" to test the flame retardant properties of protective apparel outer materials.

The droplets or flammable substances produced after the sample test were collected for testing . The burning time and the burned length were recorded . The burning time and the burned length should be recorded for nearly 0.2 second and nearly 3 mm, respectively . The quality of the sample should be judged by observing the melt, droplets, average burning time, and average burned length. Failure to meet any of the criteria is judged to be unacceptable.

2.1.4 Compared

The standards of China and Europe and the United States are to conduct fire tests on fire protective suits to test their fire-retardant properties. The difference is that the EU standards first wash the protective clothing, so that the experimental results are more reliable, and the EU standard fireproof materials. Fire-retardant properties are graded. The advantage of this classification is that different quality fire-fighting protective clothing has clear criteria for judging the fire-retardant properties of the garment. The NFPA standard in the United States has strict requirements on the fire-retardant and fire-retardant performance of fire-fighting and protective clothing, and the test standards and parameter requirements are all higher than our national standards.

2.2 Comparison of thermal insulation performance requirements of protective clothing

The working environment for firefighters is a high-temperature, high-radiation heat fire. The temperature in the fire is between 60 °C and 1 and 100 °C . The radiant heat is between 115kW/m2 • s and 200kW/m2 • s . High temperature can easily cause burns to firefighters. Therefore , firefighters who adapt to the fire must have good thermal protection performance, including protection against direct burning heat conduction and resistance to radiation heat penetration.

2.2.1 China's Standard Requirements for Insulation Performance of Protective Clothing

In China , the value of thermal protective performance ( TPP ) is used to characterize the thermal insulation performance of fire protective clothing. The principle is to evaluate the relative ability of garment thermal protection by measuring the thermal energy required to cause 2 degree burns (burns) on the surface of the fabric . The TPP value of the fire protective clothing specified in GA10-2002 shall not be less than 28% .

TPP 's formula is as follows:

TPP = F×T

among them:

TPP - thermal protection;

F - Exposure heat flux, cal/ ( cm2 • s );

T - the time that caused the burn, s

2.2.2 European Union requirements for thermal insulation of protective clothing

The EU standard measures the heat transfer capability of fire protective clothing to measure the thermal insulation performance of fire protective clothing under the conditions of direct flame baking and heat radiation .

2.2.2 .1 flame bake heat transfer performance requirements

The method was tested on the determined index (HTI) characterizing heat transfer capacity of heat transfer material, according to the measurement results in Table EN 367 "Test Method for heat transfer capacity of the material is exposed to a flame protective clothing - - heat insulation and fire-retardant" 1.2 for classification.

Table 1.2 Classification of Heat Transfer Capability Under Flame Bake

2.2.2 .2 thermal radiation heat transfer performance requirements

Tested in accordance with the method defined in EN ISO 6942 "Protective clothing - Thermal insulation and flame retardance - Test methods: Evaluation of thermal insulation properties of materials exposed to a single radiant heat source". Radiant heat transfer factor index of material's radiative heat transfer capacity ( RHTI ) Characterization, and the measurement results were ranked according to Table 1.3 .

Table 1.3 Heat transfer capacity classification under radiant heat source

2.2.3 U.S. Standard Requirements for Thermal Insulation of Protective Clothing

In accordance with ISO 17493 "Heat-resistant clothing and equipment - Test method for heat convection using hot air circulation furnace", the test method is the same as the test method for fire protective clothing in China.

2.2.4 Compared

For the insulation performance requirements, the EU standard also uses the method of grading the test material, and the test method is to directly measure the heat transfer capability of the protective clothing material to characterize the absolute thermal insulation performance of the material; while our country adopts indirect Method to use TTP to measure the relative thermal insulation of protective clothing. The fire-retardant protective clothing of the United States requires the same insulation performance as our country.

2.3 Comparing Hydrostatic Pressure Performance and Permeable Steam Performance Requirements

The waterproof breathable layer is a layer of protective clothing fabric used to prevent water from permeating into the thermal insulation layer and discharging water vapor. This layer can make firefighters feel comfortable in the process of fire fighting and facilitate fire fighting and rescue operations.

2.3.1 China's Standard Requirements for Hydrostatic Pressure Resistance and Permeable Steam Performance

China's standards stipulate that the hydrostatic pressure resistance test shall be conducted in accordance with the method specified in GB/4744-1997 "Textile fabrics - Determination of resistance to water seepage - Hydrostatic pressure test". The principle of this method is based on the hydrostatic pressure experienced by the fabric to represent the resistance encountered by water passing through the fabric. Under standard atmospheric conditions, the sample receiving side of a rising pressure, until there is seepage at 3, and the pressure recorded at that time. Pressure may be applied from above or below the sample, the rate of pressure rise should 1.00kPa / min ± 0.05kPa / min ( 10cmH2O / min ± 0.5cmH2O / min), resistance to hydrostatic pressure value should not waterproof breathable layer Less than 17kPa . Permeable steam test is carried out according to the method specified in GB/T 1037-1998 “Plastic Film and Sheet Water Vapor Permeability Test Method”. The water vapor transmission rate should not be less than 5000g / ( m2 • 24h ).

2.3.2 European Union requirements for hydrostatic pressure resistance and permeability to steam

The EU standard stipulates that the hydrostatic pressure resistance test is carried out in accordance with the method specified in EN 20811-1992 " Testing of Textiles - Water Permeability Resistance - Hydrostatic Pressure Test". The test pressure rate is 0.98 ± 0.05 kPa/min . The European Union uses air impermeability to characterize the water vapour permeability of protective clothing . The measurement of air impermeability is in accordance with EN 31092 “ Testing of heat and steam resistance under conditions of textiles - physiological effects - stability conditions (protected hot plate perspiration test)” The method was tested. The requirements of EU standards for the suitability of hydrostatic pressure resistance and water vapor resistance performance of protective clothing are shown in Table 1.4 .

Table 1.4 European Union Ratings for Hydrostatic Pressure and Permeable Steam Performance of Protective Clothing

2.3.3 U.S. Standard Requirements for Hydrostatic Pressure Performance and Permeable Steam Performance

In the NFPA , the requirements for water penetration resistance are used to determine the waterproof performance of fire protection suits rather than the hydrostatic performance requirements. Requirements are as follows:

Sample requirements, the sample area of ​​at least 1m2 , the number of samples at least 5 ; test pressure 172kPA According to "waterproof fabric hydrostatic pressure test method" requirements. Test method According to the Federal Standard 191A Textile Testing Method, the criterion is: If there is water seepage, the test is judged to have failed.

2.3.4 Contrast

Through comparison, we found that China's requirements for this parameter are lower than the EU standards and the United States NFPA standards. This parameter will affect the combat effectiveness of firefighters. Improving the requirements of this standard is conducive to making our fire protection protective clothing more humane and scientific. The number of frostbite people caused by the poor waterproof performance of fire-fighting and protective clothing in the grassroots fire-fighting units in the northeastern China is high. The reason for this phenomenon is that the waterproof performance of our standards is low, and therefore the water-repellent performance of our fire-fighting protective clothing is increased. Imminent.

2.4 Reflective Tape Performance Requirements Comparison

2.4.1 Requirements of Reflective Signs with Performance in Our Standards

Reflective logo straps should be firmly sewn on protective clothing and trousers. Split protective clothing should be placed on the bust, hem, cuffs, and trousers of the jacket. The width of the stitching of reflective tape should not be less than 50 mm , and the reflective tape should be visible at 360 °. Reflective signs with performance parameters: retroreflectivity, heat resistance, flame retardant, wash performance. The square of the retroreflective index with retroreflective index is called retroreflectivity, so the larger the retroreflective index is, the better the radioactivity can be. The minimum requirements for the retroreflective index of retroreflective markers in Chinese standards are shown in Table 1.5 . The requirement of heat resistance is that the surface of the reflective material should not be charred or peeled after testing at a temperature of 260 °C ± 5 °C for 5 min , and the coefficient of retroreflection should not be less than 70% of that specified in Table 1.5 . Flame resistance is required flame time not greater than 2s, and should not have melted, dripping. Washing performance requirements after washing 25 times according to the standard method , should not appear damaged, off, discoloration phenomenon. High and low temperature performance requirements After the high-low temperature test, the reflective tape should not be broken, wrinkled or distorted.

Table 1.5 Retroreflection coefficient Unit cd/(lx·m2)

2.4.2 European Union requirements for performance of reflective marking tapes

The EU standard requires that the independent reflective material should be attached to the surface of the fire protective clothing with an area of ​​not less than 0.13m2 . The reflective material should surround the arms, legs, and neck of the protective suit so that all parts of the body can be seen. If non-reflective material or mixed reflective material is used, the minimum area of ​​the fluorescent tape is not less than 0.2m2 . Independently reflective materials shall be tested for heat resistance in accordance with ISO 17493 "Thermal Clothing and Apparatus - Convection Heat Test Method for High Temperature Gas Circulating Electric Furnaces" at a temperature of ( 180 ± 5 ) °C and placed in a test box for testing Afterwards, the material did not burn, melt, or shrink the material by more than 5% . It is worth noting that in the EU standards, this test method and requirements are not only aimed at the outer layer of the clothing flame retardant, but also have the same stringent test requirements for reflective marking materials.

2.4.3 American Standard Requirements for Performance of Reflective Signs

The requirements of American standards for reflective tape performance include the reflectance standard and the minimum brightness factor under different light exposures. The photometric properties of retroreflective tapes are performed in accordance with the test method of ASTM E 991 "Standard Practice for Measuring the Fluorescent Characteristics of Reflective Materials." This standard requires the measurement of yellow-green fluorescence, orange-red fluorescence, and the chromaticity coordinates and minimum brightness factor under red light, respectively.

The reflectance test follows the ASTM E 809 Standard Practice for Measuring the Photometric Characteristics of Reflective Materials.

Ra test formula is shown in the following formula

Ra=R1/Ar

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