Testing a glow wire involves subjecting a material or product to a standardized heat source to assess its resistance to ignition and flame spread. The glow wire test is commonly used in industries such as electrical and electronics, automotive, and furniture manufacturing to evaluate the fire safety performance of materials. Here's an overview of the procedure:
1. Setup and Equipment:
- Glow Wire Test Apparatus: This consists of a heating element (the glow wire) made of a specific alloy, typically nichrome, with a loop shape. The glow wire is heated to a specified temperature during the test.
- Specimen Holder: A fixture or holder is used to position and secure the test specimen during the test.
- Control System: A control system is used to regulate the temperature of the glow wire and maintain it at the desired level.
- Safety Equipment: Safety measures, including fire extinguishers and protective gear, should be readily available during the test.
1. Test Procedure:
- Sample Preparation: The test specimen, which could be a component, material sample, or finished product, is prepared according to the specified dimensions and requirements of the test standard.
- Conditioning: The specimen may need to be conditioned in a controlled environment, such as specific temperature and humidity conditions, prior to testing.
- Placing the Specimen: The specimen is mounted securely onto the specimen holder, ensuring proper alignment and contact with the glow wire during the test.
- Test Parameters: The test parameters, such as the temperature of the glow wire and the duration of the test, are set according to the applicable standard. Commonly used temperatures range from 500°C to 1,000°C, depending on the specific requirements.
- Test Execution: The glow wire is heated to the specified temperature, and the specimen is exposed to the wire for a predetermined duration, typically ranging from a few seconds to a minute. During this time, the specimen is observed for any signs of ignition, flame spread, melting, or dripping.
- Evaluation: After the test, the specimen is examined to determine if it meets the specified criteria. This may include assessing factors such as whether ignition occurred, the duration of flaming, the extent of charring, melting, or dripping, and any damage to the glow wire.
1. Test Standards:
- The glow wire test is governed by various international standards, such as IEC 60695-2-10, UL 746A, and DIN EN 60695-2-12. These standards define the test setup, procedure, performance criteria, and acceptance levels for different materials and products.
1. Reporting:
- Test results, including observations, measurements, and any deviations from the standard requirements, are documented in a test report. The report should include details about the specimen, testing conditions, equipment used, test parameters, and the outcome of the test.
It is important to note that the glow wire test is just one of many fire safety tests and should be used in conjunction with other relevant tests to obtain a comprehensive understanding of a material's or product's fire behavior and resistance to ignition and flame spread. Additionally, it is crucial to adhere to safety protocols and follow the specific requirements outlined in the applicable standards during the testing process.