What is the Vertical Flame Test?

With increasing global awareness of fire safety, the fire resistance of materials has become a focus across various industries. A vertical flame tester is a device specifically designed to measure the flame retardancy of materials. It is primarily used for measuring the flame retardancy of fabrics such as clothing, decorative fabrics, and tent fabrics requiring flame retardancy. It is also suitable for measuring the flame retardancy of rubber, plastic, and other materials requiring flame retardancy. The vertical flame test for wires and cables is a key method for evaluating the flame retardancy of wires and cables. It primarily determines their fire rating by simulating the flame spread of materials in a vertical installation. As a key assessment technique, the vertical flame test plays a vital role in the field of fire safety. So, what is a vertical flame test?

What is a vertical flame test?

The vertical flame test is a method for evaluating the combustion characteristics of a material by simulating burning in a vertical position. This test is typically used to assess a material's flame retardancy, burning time, burning rate, and droplet generation. The testing process is conducted in a laboratory environment in strict accordance with international standards to ensure accurate and reliable results.

During the test, the sample is typically mounted on a frame, a fire source is ignited from below or to the side, and the combustion process is recorded. For example, whether the flame spreads rapidly, whether molten droplets are generated, and whether the material self-extinguishes are all important evaluation indicators. Using this data, testers can determine whether a material meets certain fire rating requirements.

Why is the vertical burn test so important?

In practical applications, materials face a variety of complex environments, with high temperatures and fire being particularly dangerous. Using scientific experimental methods, the vertical burn test helps companies predict material performance in advance, providing a reliable basis for product design and development. Furthermore, this test is directly related to consumer safety and property protection.

Furthermore, many international markets have strict fire protection standards. Companies that cannot provide compliant test reports face difficulties entering these markets. The vertical burn test is not only a technical evaluation tool but also a key factor in commercial competition.

Principle

The vertical combustion test simulates the burning of a material in a vertical position to evaluate its combustion characteristics. The test process is conducted in a laboratory environment in strict accordance with international standards to ensure the accuracy and reliability of the results. The sample is fixed to a frame, and a fire source is ignited from below or to the side. The combustion process is recorded. Key test indicators include burning time, burning rate, droplet formation, and char length. These indicators are not only fundamental data for evaluating the fire resistance of materials, but also serve as important reference for companies designing and producing fire-resistant products.

Operational Procedure

1. Connect the gas pipe to the burner, control box, and gas tank. Check the gas pipe connections for leaks.

2. Turn on the power switch. Set the flame time1， after flame time 2, and afterburn time 3 as required (they can be set to a shorter time during commissioning).

3. Clamp the sample, tilt the burner to a specific angle (0°, 20°, or 45°), and adjust the fixture 30 and sample to the test position.

4. Set the gas flow control valve to the minimum setting.

5. Open the main valve of the gas tank, connect the gas source, and press the gas supply button 10. Simultaneously, use a lighter or match to ignite and adjust the gas pressure regulating valve to 0.1 MPa. Adjust the gas flow regulating valve 14. Simultaneously, ensure that the gas back pressure (U-type pressure gauge 26) reaches the appropriate pressure and the flame reaches the standard height. The burner should be in a vertical position during ignition. (If using a premix burner, you must also connect a compressed air source and adjust the pressure to 0.1 MPa. Adjust the air flow control valve 15 to achieve the desired flame.)

Core Indicators of the Vertical Burning Test

Core indicators of the vertical burning test include the following:

1. Burning Time: Records the duration of the flame on the material to assess its self-extinguishing ability.

2. Burning Rate: Measures the speed of flame spread, reflecting the material's flame retardant properties.

3. Melt Droplet Status: Observes whether the material produces melt droplets during combustion and their condition (e.g., whether they are flaming).

4. Charring Length: Measure the length of the charred area after the test to assess the extent of flame spread.

These indicators are not only fundamental data for evaluating a material's fire resistance performance, but are also crucial for companies designing and producing fireproof products. Reference.

Application Scenarios

Vertical flame testing plays an important role in multiple industries:

1. Construction Industry: Building materials such as insulation boards and wall materials must undergo vertical flame testing to ensure they meet fire protection standards and reduce fire risks.

2. Electronics Industry: The casing materials of many electronic devices must possess certain flame retardant properties to protect internal components from fire damage.

3. Transportation Industry: Car seats, interior materials, and aircraft cabin decoration materials all require vertical flame testing to ensure passenger safety.

4. Textile Industry: Vertical flame testing is also essential for evaluating the flame retardancy of textiles such as clothing, curtains, and carpets.

These industries use vertical flame testing to better select materials that meet standards, improving product safety and market competitiveness.

Daily Maintenance of the Test Instrument (Required After Each Use)

1. Cleaning the Combustion Chamber

After each test, immediately open the instrument door or cover to remove ash, charred debris, and smoke generated by combustion. Use a soft brush or low-power vacuum cleaner to carefully clean the specimen clamp, combustion base, windshield, and chamber walls to prevent residue from affecting the next test result or corroding the equipment.

2. Cleaning the Specimen Clamps

Inspect the horizontal and vertical clamps for looseness, deformation, or carbon deposits. Wipe the clamp surfaces with a clean cotton cloth dampened with anhydrous ethanol to ensure a clean clamping position to prevent specimen slippage or abnormal heat transfer.

3. Inspect and Clean the Flame Observation Window

The high-temperature resistant glass window on the front of the instrument is prone to accumulation of smoke and dust, which can obstruct flame observation. Use a soft lens cloth or cotton cloth dampened with a small amount of alcohol to gently wipe it to maintain clarity. Avoid scratching or cracking with hard objects.

4. Ventilation System Inspection

Confirm that the exhaust fan is operating properly and that the exhaust duct is unobstructed. If the equipment is equipped with an activated carbon filter, its adsorption performance should be checked regularly. If ventilation is reduced or odor is detected, the filter element should be replaced promptly.

5. Gas Pipeline and Source Inspection

After the test is completed, be sure to close the external gas cylinder valve and confirm that the internal gas line of the instrument is disconnected. Inspect the gas hose for signs of aging, cracks, or loose joints to prevent gas leaks and accidents.

Market Prospects

With increasing awareness of fire safety, the market demand for vertical combustion testers is also increasing. In the future, with continuous technological advancements and expanding application areas, vertical combustion testers will become more intelligent, automated, and convenient, providing even more effective protection for fire safety.

As a key method for evaluating the fire resistance of materials, the vertical combustion test is of great significance in ensuring product safety in various industries and protecting the lives and property of consumers. Its rigorous testing principles, standardized procedures, clear core indicators, and wide range of application scenarios all demonstrate its irreplaceable role in the fire safety field. Routine maintenance of the tester ensures accurate and reliable test results, and its broad market prospects continue to fuel its development. I believe that in the future, vertical combustion testing and its related instruments will continue to evolve, building a solid line of defense for global fire safety.