Answer: The above flame resistance and fire propagation tests are often confused with one another on the basis of their very similar designations. However, the test methods employed are quite different. IEC Test for vertical flame propagation for a single insulated wire or cable This flame resistance test is passed by most cables constructed of flame-retardant materials, e. In the test, a single core or cable with a length of approx. The test is deemed passed if, after the flame has been removed, the burning cable extinguishes itself and the fire damage is at least 50 mm from the upper mounting clamp. It is irrelevant how long the cable burns before extinguishing itself.
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IEC and IEC are used to assess the flame propagation characteristics of a single wire. IEC is used to assess the flame propagation characteristics of bundled cables. In this test, a 60cm cable sample is fixed vertically inside a metallic box and a mm long flame is applied at 45C from a gas burner placed at mm from the top at the upper portion.
The specimen is deemed to have passed this test, of after burning has ceased, the charred or affected position does not reach within 50mm of the lower edge of the top clamp which is equivalent to mm above the point of flame application. The test method is not suitable for the testing of some small wires due to the melting of the conductors during the time of application of the flame. In this test, a cable specimen, consisting of number of 3. The cable specimen is deemed to have met the requirements of the standard if, after burning has ceased, the extent of charred or affected portion does not reach a height exceeding 2.
If a cable can pass a specified UL fire standard, an UL performance verification mark can be applied onto the cable jacket, illustrating both the UL class and the number. Cable samples on a horizontal tray in a tunnel type of chamber are burned at To qualify for a plenum rating, the cables must have the flame spread of less than 5 feet or 1.
Cable samples on a vertical shaft are burned at To qualify for a riser rating, the cables must have the flame spread of less than 12 feet beyond the ignition point.
This test does not look at the smoke density or toxicity. Riser cable is suitable for vertical shafts not defined as an environmental air plenum. The cable is deemed to pass the test if the flame spread will not extend to the upper portion and extinguish by itself. The CMG cables are usually used in runs penetrating single floor. This cable cannot be installed in vertical pathways. The test consists of 25 feet long ventilated tunnel.
The CMG cable is suitable for use in. This cable cannot be installed in bundles and must be protected in metal conduit. This type of cable is the minimum requirement in commercial installations. Comparatively speaking, the fire performance requirement for BS is more demanding. Fire is applied for a period of 3 hours. After 3 hours, the fire and the power is switched off.
BS Fire Performance Standard BS specifies the performance requirements for cables required to maintain circuit integrity under fire conditions. It details the following methods to categorize the cables according to cable withstand capacities. Resistance to fire alone — the cables is tested by gas burner flame while passing a current at its rate voltage.
Resistance to fire with water spray — a new sample of cable is exposed to flame at C for 15 minutes while passing a current at its rated voltage and then the spray is turned on to give exposure to both fire and water for a further 15 minutes.
A single survival category W is defined if the cables surpassed the testing requirement. Resistance to fire with mechanical shock — the final requirement is mechanical shock damage. A fresh sample is mounted on a backing panel in an S bend and is exposed flames while the backing panel is stuck with a steel bar with same diameter as the cable under test every 30 seconds for 15 minutes.
Fire Testing Reduced Fire Propagation in accordance with IEC This test is the most common one to verify the behaviour of a cables for the fire propagation. The standard is subdivided in several parts that differ one from the other for the quantity of cable to be installed, the installation mode and the flame application time. Tests on electric and optical fiber cables under fire conditions - Part Test for vertical flame spread of vertically mounted bunched wires or cables.
System 6 UTP LSOH Cable (IEC 60332-3C) - International