For a long time, how to objectively and scientifically evaluate the protective performance of special clothing such as military uniforms, fireproof suits, firefighting suits, and flame-retardant high-temperature work clothes has been a difficult problem for the industry. Currently, this evaluation is generally based solely on combustion or flame-retardant tests of the clothing fabric, failing to reflect the actual effects of the clothing's structure and human movement, and may even lead to insufficient or excessive protection of the overall clothing in actual working environments. Standard Group, in collaboration with renowned international companies, has developed a combustion dummy system. This system features a combustion dummy that can accurately sense high-temperature heat flow and predict the degree of skin burns in different activity postures, as well as a combustion simulation environment laboratory that highly simulates the high-risk environment of a fire scene.
The Flame Test Manikin is a crucial testing method for ensuring worker safety under fire and heat radiation conditions. For a long time, my country has mainly used the vertical burning test method for textiles and the oxygen limiting index method to evaluate the flame-retardant protective performance of clothing. Both of these methods only indicate whether the clothing fabric is flame-retardant, not its resistance to the high temperatures and heat generated by flames or electric arcs. The combustion dummy testing system, however, uses dummies in simulated testing environments to test the survival limits under various harsh conditions.
The combustion dummy testing system is a computer-controlled testing system comprised of a combustion dummy, a thermal sensor array, a flame generating device, a computer control module, a data acquisition and processing module, and a burn analysis module. The first four parts are primarily implemented by corresponding hardware, while the latter four are solved using software programming and model building.
The combustion dummy model is a 1:1 adult male model made of stable, flame-inert, and high-strength fiberglass, with a thickness of 2-3 mm and a surface area of 1.72 m². A certain number of sensors are evenly distributed on the surface of the dummy's head, torso, legs, and arms. The outer surface of the dummy is coated with black flame-retardant and high-temperature resistant paint. The dummy's head has processed sensor data output lines for easy data signal acquisition and processing by the instrument.
The sensor array includes thermal sensors and pressure sensors. The thermal sensor system consists of over 120 heat flow sensors evenly distributed across the dummy's surface. Each sensor represents a specific area of skin's physical condition. Each sensor is numbered, and if the temperature value calculated by that sensor, based on burn estimation, meets the criteria for second- or third-degree burns, it is marked with a different color on the simulated digital human body model. Since the temperature change of the flame is a dynamic process, the test sensors must have a high temperature measurement range and a short response time to accurately measure the dynamic changes in the flame. Pressure sensors are primarily used to measure the gas pressure within the gas containers and pipelines, ensuring the experiment's safety and controllability.
The flame generation device consists of 12 propane flame generators arranged in 6 groups around the dummy. Each flame generator group comprises a high-pressure liquefied gas tank, a buffer tank, pressure pipelines, a gas pressure sensor, a flame nozzle with adjustable flame size, and a guide flame. The duration of the flame generated by the flame generation device is controlled by a computer-controlled simulation module, maintaining a uniform and stable flame intensity within this time.
The computer control module consists of pre-programmed software. Its main function is to automatically check the status of all relevant sensors before the experiment begins, and issue a ready command once the status is confirmed to be normal. During the experiment, the computer control program controls the duration and intensity of the flame generator and automatically guides the data processing module to record the data changes of each sensor. In the experimental results phase, the recorded data is downloaded and saved as a file, and the exhaust ventilation system is guided to cool and ventilate the combustion test chamber.
The data acquisition and processing simulation, with the assistance of the computer control module, controls the acquisition, amplification, conversion, and storage of data from temperature and heat flux sensors. Signal preprocessing is performed, converting the heat flux signal into corresponding temperature values through a model, and then temporarily storing the results for use by the burn estimation module.
The burn estimation module estimates the extent and degree of burns caused by the flame. Information on the change in dummy surface temperature over time obtained from sensors is input into the burn estimation model. Burn estimation calculations yield burn integral values and burn program values. Combined with the mapping of the digital human body model, a distribution map of second- and third-degree burns on the dummy surface is obtained.
The clothing to be tested is worn on an instrumented dummy and placed in a laboratory environment simulating flashover conditions where heat flux, duration, and flame distribution are controlled. Data from the thermal sensors on the dummy's skin surface is used to calculate the potential second- and third-degree burns and the total burn area. A larger burn area indicates a more severe burn, and consequently, poorer thermal protection from the clothing; conversely, smaller burn areas indicate better thermal protection.
The maintenance and care of the combustion test dummy requires a multi-dimensional approach, encompassing hardware, software, environmental safety, and long-term management. Specific methods are as follows:
Hardware system maintenance is fundamental to ensuring test accuracy. The dummy itself must be thoroughly cleaned after each experiment. Use a soft brush or vacuum cleaner to remove residual combustion particles and ash to prevent sensor clogging. If contaminated with oil or chemicals, wipe with a neutral detergent, avoiding the use of corrosive solvents that could cause material aging. Additionally, regularly check moving joints (such as shoulders, elbows, and knees) and apply a high-temperature lubricant to ensure the flexibility of simulated movements. As a core component, the sensor requires in-depth maintenance: Before experiments, check for loose connections and surface cracks, and calibrate it every 3 months or after every 50 experiments using a standard heat source (such as a blackbody radiation source) to ensure temperature measurement error ≤ ±1℃; if the sensor responds slowly or data is abnormal, it must be replaced immediately and the fault conditions recorded. The burner system maintenance is equally critical. The nozzle should be purged weekly with compressed air to prevent carbon buildup, the gas pipeline should be checked for leaks monthly, and the ignition system should be manually tested before each experiment to ensure spark intensity and ignition success rate meet standards.
Software system maintenance directly affects data reliability. The data acquisition module needs regular software updates to fix vulnerabilities, increase the sampling frequency to ≥100Hz, and clean the historical data repository to optimize system efficiency. The burn assessment model needs to be validated every six months by comparing the model output with theoretical values using standard heat flux data; the error must be controlled within ±5%. If it exceeds this limit, the algorithm needs to be retrained or parameters adjusted. Backups of the control program are also crucial. Code and configuration files must be stored on a dedicated hard drive or in the cloud monthly. When updating logic, a 24-hour simulated test run must be performed to ensure no anomalies before deployment.
Environmental and safety maintenance are critical aspects of risk prevention. After each experiment, the forced ventilation system must be activated immediately. The combustion chamber walls should be wiped with a damp cloth to remove soot, and fire-resistant materials (such as ceramic fiber panels) should be checked regularly for detachment. Gas storage requires strict management. Propane cylinders should be stored in a cool, ventilated place, away from heat sources and open flames, with the temperature controlled between -20°C and 50°C. Pressure gauges should be checked monthly, and replaced immediately if the pressure drops below 80% of the rated value. Furthermore, emergency shutdown scenarios (such as power outages or gas leaks) must be simulated quarterly to test system response time and safety linkage functions, ensuring a shutdown time of ≤2 seconds.
Long-term storage and transportation must adhere to regulations to extend equipment lifespan. When not in use for extended periods, dummies should be placed on dedicated supports to prevent joint deformation. The storage environment temperature should be controlled between 10°C and 30°C, and humidity ≤60% to prevent mold growth. Before transportation, movable parts need to be disassembled, the main body secured with foam boards, and shock-absorbing devices provided to prevent damage to the sensors from severe bumps. A systematic maintenance process ensures the long-term stable operation of the combustion test dummy, providing reliable data support for experiments.
