In the U.S. market, the flammability of UL1581 is probably the most widely used standard for evaluating the flammability of wires and cables. It is used to evaluate the extinguishing ability of the cable after being ignited, and is generally divided into vertical combustion and horizontal combustion. UL 1581 VW-1 is a flame test used to check how flame propagates on wires and cables. Two clips hold a sample vertically. The burner is mounted at a 20° angle and applied for 15 seconds, then four more times each time the wire stops burning. If the sample is not lit for more than 60 seconds after any of these burning events, or if less than 25% of the indicators are lit, or if the batt is ignited during the test, the wire will pass. “Tray level” cables must also pass this test.
With the wide application of cable materials in various fields, the possibility of fire has greatly increased, and fire has great harm to people and the economy. UL 1581, UL 2556, UL 1685 and other flame resistance tests for wire and cable are helping major wire and cable companies to understand the performance and quality of their products, so that their products can better meet fire safety standards, open market channels, and gain more market opportunities .
Test Method
UL 1581 Part 1080 → VW-1 (Vertical Specimen) Flame Test
UL 2556 Part 9.4 → FV-2/VW-1
Description
The cable is secured vertically. A burner is used to apply the flame and it is secured at an angle of 20° in respect to the vertical.
Duration
15 seconds of flame application and 15 seconds of pause for 5 cycles. When flaming of the specimen persists longer than 15 seconds after removal of the burner flame, the burner flame shall not be re-applied until immediately after the flaming ceases.
Compliance
The paper indicator flag (P) shall not be burned more than 25% and the specimen shall not continue to burn for more than 60 seconds. Dripping material shall not ignite the cotton wool underneath (B).
Test Method
UL 1581 Part 1060 → Vertical Flame
UL 2556 Part 9.5 → FV-1/Vertical Flame
Description
The cable is secured vertically. A burner is used to apply the flame and it is secured at an angle of 20° in respect to the vertical.
Duration
15 seconds of flame application and 15 seconds of pause for 5 cycles. The burner flame shall be reapplied after 15 seconds, regardless of whether flaming of the specimen persists longer than15 seconds.
Compliance
The paper indicator flag (P) shall not be burned more than 25% and the specimen shall not continue to burn for more than 60 seconds. Dripping material shall not ignite the cotton wool underneath(B).
Test Method
UL 1581 Part 1060 → FT1
UL 2556 Part 9.3 → FT1
Description
The cable is secured vertically. A burner is used to apply the flame and it is secured at an angle of 20° in respect to the vertical.
Duration
15 seconds of flame application and 15 seconds of pause for 5 cycles. The burner flame shall be reapplied after 15 seconds, regardless of whether flaming of the specimen persists longer than15 seconds.
Compliance
The paper indicator flag (P) shall not be burned more than 25% and the specimen shall not continue to burn for more than 60 seconds. Dripping material or the ignition of the cotton wool underneath (B) are ignored for the compliance of this test.
Test Method
UL 1581 Part 1061 → Cable Flame Test
Description
The cable is secured vertically. A burner is used to apply the flame and it is secured at an angle of 20 in respect to the vertical.
Duration
60 seconds of flame application and 30 seconds of pause for 3 cycles. The burner flame shall be reapplied after 30 seconds, regardless of whether flaming of the specimen persists longer than30 seconds.
Compliance
The paper indicator flag (P) shall not be burned more than 25% and the specimen shall not continue to burn for more than 60 seconds. Dripping material shall not ignite the cotton wool underneath(B).
Test Method
UL 1581 Part 1090 → Horizontal Specimen Appliance → Wire Flame Test
Description
The cable is secured horizontally. A burner is used to apply the flame and it is secured vertically.
Duration
30 seconds of flame application.
Compliance
The flame propagation speed must not exceed 25 mm/min. Dripping material shall not ignite the cotton wool(B) placed next to the burner.
Test Method
UL 1581 Part 1100 → Horizontal Specimen / FT2 Flame Test
UL 2556 Part 9.1 → FT2/FH/Horizontal Flame
Description
The cable is secured horizontally. A burner is used to apply the flame and it is secured at an angle of 20° in respect to the vertical.
Duration
30 seconds of flame application.
Compliance
The length of the carbonized specimen has to be no greater than 100 mm. Dripping material shall not ignite the cotton wool(B) placed next to the burner.
Test Method
IEC 60332-1-2/ EN 60332-1-2
Description
The cable is secured vertically. A burner is used to apply the flame and it is secured at an angle of 45° in respect to the vertical.
Duration
Based on the cable diameter: 60 seconds (D25 mm), 120 seconds (2575 mm)
Compliance
The fire damage must end at least 50 mm below the upper fixing clamp.The cable must be self-extinguishing.
Flammability tests and determination of combustion products are vital to cable technology. They provide information on how fire spreads along the cables as well as on the potential threats to people and materials in the event of a cable fire. ln order to make sure that a particular cable meets the necessary flammability requirements, a wide range of different testing procedures are often used. These procedures are typically performed in either the vertical or horizontal orientation, on single cables or on group cables.
The cable is secured vertically. A burner is used to apply the flame and it is secured at an angle of 45° in respect to the vertical.
Duration
20 seconds.
Compliance
The fire damage must end at least 50 mm below the upper fixing clamp.The cable must be self-extinguishing.
Test Method
UL 2556 Part 9.6 → Vertical Tray (Method 1)
UL 1581 Part 1160 → Vertical Tray Flame Test
UL 1685
Description
The cables are secured vertically to a ladder in a single layer. A burner is used to apply the flame and it is secured horizontally.
Duration
20 min of flame application for 2 tests.
Compliance
The damage height of all specimens shall be less than 2440 mm when measured from the bottom of the tray.
Test Method
UL 2556 Part 9.6 FT4(Method 2)
Description
The cables are secured vertically to a ladder in a single layer. A burner is used to apply the flame and it is secured at an angle of 20° in respect to the vertical.
Duration
20 min of flame application for 2 tests.
Compliance
The damage height of all specimens shall be less than 1500 mm when measured from the bottom edge of the burner.
Test Method
IEC 60332-3-24 / EN 60332-3-24
Description
The cables are secured vertically to a ladder also in several layers. A burner is used to apply the flame and it is secured horizontally.
Duration
20 min
Compliance
The damage height of all specimens shall be less than 2500 mm when measured from the bottom of the tray.
UI is short for Underwriters Laboratories Inc. The UL Safety Laboratory is the most authoritative in the United States and the largest private institution engaged in safety testing and identification in the world. It is an independent, for-profit professional organization that conducts experiments for public safety. It uses scientific testing methods to study and determine whether various materials, devices, products, equipment, buildings, etc. are harmful and harmful to life and property; determine, write, and issue corresponding standards and help reduce and prevent life-threatening injuries. Information on property damage, and conduct fact-finding business. UL certification is a non-mandatory certification in the United States, mainly testing and certification of product safety performance, and its certification scope does not include the EMC (electromagnetic compatibility) characteristics of products.
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UL1685 is a vertical tray fire test used to determine the cable damage height and smoke release values for cables and fiber optic cables when they encounter a burning ignition source.
Scope of Use of UL 1685
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If the cable is acceptable under the UL test procedure, the following shall be tested:
a) Cable carbonization shall be less than 8 feet 0 inches (244 cm) when measured at the bottom of the cable iron frame.
b) The total amount of smoke released is 95 square meters or less.
c) The maximum smoke release rate shall be 0.25 m2/s or less.
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The purpose of the UL 1685 test is to determine the flame spread and smoke characteristics of these cables to qualify cables with limited smoke marking.
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The UL 1685 test does not study the toxicity of combustion or decomposition products.
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UL 1685 testing does not include structural requirements for cables or any electrical, optical or other performance requirements for cables.
