The UL wire flame test is a test method used to evaluate the flame resistance of wire and cable materials, and the UL standard is one of the most commonly used standards. UL (Underwriters Laboratories) is an independent third-party certification body whose flame retardant test methods and ratings are widely accepted and used in the wire and cable industry. The following is the detailed information about UL wire flame resistance test grades and test methods:
1. UL wire flame retardant test grade:
UL wire flame retardant test grades divide wires and cables into different grades according to the flame retardant properties of the materials. The following are common UL wire flame retardant test grades:
- VW-1: The lowest rating, indicating that a wire or cable can extinguish itself without spreading flame when burned in a vertical position.
- FT1: Medium rating, indicating that the wire or cable is self-extinguishing when burned in a vertical position, with a limited distance for the flame to travel.
- FT2: A higher rating, meaning that the wire or cable can self-extinguish when burned in a vertical position, and the distance the flame will travel is less.
- CT: the highest rating, indicating that the wire or cable can extinguish itself when burned in a vertical position, with a very short distance for the flame to travel.
These grades represent the different flame resistance properties of the wire or cable material, from low to high to provide greater safety.
2. UL wire flame retardant test method:
UL wire flame retardant test methods mainly include vertical burning test and horizontal burning test. Here is an overview of the two testing methods:
- Vertical Flame Test (UL 1581): This test method is used to evaluate the flame resistance of wires or cables when burned in a vertical position. In the test, the wire or cable sample is placed in a vertical position and ignited under a specific combustion source. Then, evaluate indicators such as flame propagation speed, burn time and residue.
- Horizontal Flame Test (UL 1666): This test method is used to evaluate the flame resistance of wires or cables when they are burned in a horizontal position. During the test, the wire or cable sample is placed in a horizontal position and ignited under a specific combustion source. Then, evaluate indicators such as flame propagation speed, burn time and residue.
Measurements of other parameters such as dripping after burning, smoke production and gas release may also be included in these tests.
3. Steps for UL wire flame test:
The general steps for conducting a UL wire flame test are as follows:
- Prepare samples: select wire or cable samples that meet the requirements of UL standards, and perform sample preparation and size adjustments according to the requirements in the standards.
- Carry out tests: According to the test methods and requirements in UL standards, conduct vertical burning test and horizontal burning test. Make sure to set up the combustion source and test conditions as specified in the standard, and make the necessary measurements and observations.
- Evaluate test results: Evaluate the flame retardant performance of the sample according to the indicators such as flame propagation speed, burning time and residue observed in the test. Compare the test results with the requirements in the UL standard to determine the flame retardant grade of the sample.
- Recording and Reporting: Record all details and results of the test, including sample information, test conditions, observation and measurement data, etc. As required, generate detailed test reports for subsequent reference and review.
Please note that the specific methods and requirements of UL wire flame test may vary with different UL standards and product types. Therefore, be sure to read the applicable UL standards and guidelines in detail and follow the relevant testing procedures and requirements before conducting the test.