The vertical flame test It is one of the most critical tests in the cable industry, designed to evaluate the flame retardant properties of electrical cables. This test is carried out with the objective of verifying how a cable behaves in front of a vertical flame., thus simulating a fire situation where the fire could spread along the cables. Different vertical flame test methodologies will be analyzed, based on international regulations such as BSEN 60331-1-2, CSA FT1 y UL VW-1, and how these tests guarantee safety in electrical installations.
What is the Vertical Flame Test?
The vertical flame test is a standardized procedure used to evaluate fire spread over a length of vertically installed cable. A sample of cable is subjected to a controlled flame for a certain period to observe its behavior in the face of fire.. This test is essential in the selection and certification of cables, as it ensures that cables used in electrical installations do not contribute to the spread of fires and minimize the risk of damage to people and property.
Vertical Flame Test Methodology According to BSEN 60331-1-2
The norm BSEN 60331-1-2 establishes the procedures for the evaluation of the fireproof properties of electrical cables. This test is aimed at measuring the resistance of a cable to the spread of fire in vertical conditions.. The methodology to perform this vertical flame test includes the following steps:
- Sample Preparation: A representative sample of cable is selected that has a length of approximately 600 mm. This cable is placed vertically between two clamps.
- Flame Application: A lighter flame is applied to the cable sample for a specific time determined in the standard. This time varies depending on the characteristics of the cable and the regulations that are being applied..
- Observation: After flame application, the fire is removed and the cable must self-extinguish. The test is considered successful if the fire spread in the cable does not reach the 50 mm from the point of contact with the clamps.
- Approval Criteria: The cable must meet the requirement of self-extinguishing after flame withdrawal. This means that the cable must stop burning on its own without the intervention of other extinguishing methods..
BSEN vertical flame test 60331-1-2: Tabla 1
| Overall diameter of test piece (mm) | Flame application time (s) |
|---|---|
| D ≤ 25 | 60 ± 2 |
| 25 < D ≤ 50 | 120 ± 2 |
| 50 < D ≤ 75 | 240 ± 2 |
| D > 75 | 480 ± 2 |
The BSEN 60331-1-2 It is one of the most used standards in Europe and has a comprehensive approach to evaluating the fire resistance of cables., ensuring that these are suitable for use in electrical installations where fire safety is critical.
CSA FT1 Vertical Flame Test
In North America, the CSA FT1 It is the standard test for evaluating the fire resistance of finished cables and equipment.. This test is established by the Canadian Standards Agency (CSA) and applies mainly to cables destined for the Canadian and export markets. Like BSEN vertical flame test 60331-1-2, the CSA FT1 It is designed to measure the ability of a cable to resist the spread of a fire under controlled conditions..
CSA FT1 Test Procedure
- Cable Sample: The cable or finished equipment is placed vertically.
- Flame Application: A controlled flame is applied for a set period of time, according to the specifications of the regulations.
- Approval Conditions: For the cable to pass the test CSA FT1, the flame should cease on its own after exposure, and there must be no spread of fire beyond an established limit.
This test is especially important for cables sold in the North American market., as it ensures that cables used in these regions are capable of resisting the spread of fire in a variety of installation conditions.
UL VW-1 Vertical Flame Test
The norm UL VW-1, also known as UL 1581, It is the American standard for testing the fire resistance of cables and wires.. This test is performed on electrical cables and wires that are used in a wide range of applications., from residential to industrial facilities. The UL VW-1 is a test of repeated cycle, which means that the cable sample is exposed to several flame cycles to evaluate its ability to resist fire.
UL VW-1 Test Procedure
- Flame Cycles: The cable is exposed to 5 cycles of 15 seconds application of a direct flame, with breaks between 15 y 60 seconds between each cycle. Break time depends on the specific standard requirements of the cable being tested.
- Observation of Fire Behavior: After each cycle, It should be observed if the cable is self-extinguish in a maximum time of 1 minutes.
- Approval Conditions:
- The paper flag fixed to the top of the sample should not carbonize more than 25%.
- The droplets released during combustion should not ignite the cotton placed under the sample.
The UL VW-1 is a rigorous test that ensures that the cables tested are not only fire resistant, but are also safe in terms of the spread of fire and the release of incandescent droplets that could start other fires.
Differences and Similarities Between Vertical Flame Tests
Although the evidence of BSEN 60331-1-2, CSA FT1 y UL VW-1 have similar goals, What are evaluating the spread of fire in cables, there are key differences in acceptance procedures and criteria:
- BSEN 60331-1-2 It is mainly used in Europa and focuses on evaluating the behavior of the cable in a single length and under more controlled conditions.
- CSA FT1 It is designed for cables intended for Canada and the North American market, and is similar in many ways to the BSEN, but has its own set of criteria for evaluating fire spread.
- UL VW-1 It is an American standard that performs flame tests with repeated cycles, which involves a more thorough evaluation of a cable's ability to resist fire.
In general terms, All of these tests are designed to meet the most stringent safety requirements in the cable industry., which ensures that cables used in electrical installations are sufficiently fire resistant to prevent the spread of fires.
Applications of Vertical Flame Tests
Vertical flame testing is essential to ensure cables are safe for use in a wide range of applications. Some of the areas where these tests are crucial include:
- Construction and Building: In residential and commercial buildings, Cables must meet fire resistance requirements to minimize the risk of fire spreading through electrical systems.
- Industrial Systems: In industrial facilities, where electrical systems are exposed to high temperature conditions, Vertical flame tests ensure cables are able to withstand these extreme conditions.
- Transport: In sectors such as aviation and railways, cables must be highly fire resistant to ensure the safety of passengers and operations.
Conclusion
The vertical flame test It is an essential component in the evaluation of the fire safety of cables. Through regulations such as BSEN 60331-1-2, CSA FT1 y UL VW-1, Ensures that cables used in electrical installations meet the necessary requirements to prevent the spread of fire. These tests are not only essential to ensure security, but also help to comply with international standards, providing users with confidence and increasing safety in a variety of electrical applications.