Low Smoke, halogen-free, and flame retardant cables should be used for data center cabling.

With the development of science and technology, various industries are in full swing Planning and Building data centers. As the infrastructure of data centers, Integrated Wiring has attracted users' attention. In addition to high-bandwidth and high-reliability, the key aspect of integrated cabling in data centers is fire prevention.

The first five to ten minutes of a fire is the best time for refuge. The essential condition for escape is to ensure clear sight and delayed burning. However, at present, most of the worldwide cables contain halogen, because adding halogen can enhance the flame retardant performance of the outer skin. These cables emit smoke and toxic acidic chemicals during combustion, endangering the safety of people and damaging expensive equipment:

◆ The smoke produced by the burning of many dense common cables in the data center makes employees lose their way and obstruct breathing, which is easy to be smothered and difficult to escape from the fire scene, resulting in serious consequences of casualties.

◆ In a fire, halogen-containing cables may produce acidic gases, seriously damaging the nose, mouth, and throat of people. At the same time, due to the ventilation effect of heat dissipation fans in expensive active devices in the data center, acidic substances may seriously corrode the active components in the equipment, resulting in permanent or intermittent equipment faults, hindering the reliable operation of the data center.

Therefore, it is recommended that the data center cables use cables with low smoke, halogen-free external skin to solve the above security problems.

Low Smoke, as its name implies, is a low degree of smoke. cables emit low smoke when burning, ensuring that employees have enough light to find the exit. The IEC 61034 standard promulgated by the International Electrotechnical Commission is applicable to Smoke density Generation. The test consists of a 3 m³-square-meter transparent cube and a photometric system with a light source. Alcohol is used as the combustion source. A blower ensures that the smoke produced by the burning of cables is evenly distributed in the cube. When the alcohol is burned, the recorder writes down the amount of light weakened. Smoke density is measured by Light Transmittance. If the Light Transmittance is reached 60%, the cable material will reach the low smoke standard. The higher the Light Transmittance, the less smoke will be released when the outer skin of the cable is burned.

Halogen-free, that is, halogen-free, cables do not emit acidic gases during combustion, so that personnel safety and active equipment are not corroded. The International Standard IEC60754 is a specification for the corrosive Acidity of combustion gases. This test is used to measure the Acidity of halogen acid gases produced by cable skin materials during combustion. It is determined by the pH value and conductivity of the aqueous solution. According to the test, the burner is pushed to 800 ℃, and a built-in sample of the Z tube is pushed into the furnace, at the same time start to note. The pH value and electrical conductivity are measured every 1 minute 5 minutes before the sample is burned. The next 25 minutes are measured every 5 minutes. Generally, the pH value of Halogen-free cables is greater than 4.3, and the conductivity is less than 10 μs. The smaller the pH value, the higher the acidity of halogen acid gases.

Low smoke halogen-free cables must meet the requirements of low smoke halogen-free cables, but must also reach a good Flame retardant grade. In order to evaluate the performance of the Flame retardant Flame Propagation cable, IEC has developed three international standards: 60332-1, 60332-2, and 60332-3. The IEC60332-1 and the IEC60332-2 are used to evaluate the flame retardant capability of a single cable when it is laid down vertically. IEC60332-3 is used to assess the flame retardant capacity of the bundle cable vertical combustion, in contrast to the bundle cable vertical combustion in the flame retardant capacity requirements much higher. IEC60332-3 testing, bundle 3.5 m long cable samples are fixed on the trapezoid test frame, the number of samples according to different categories of non-metallic materials required. The sample is vertically mounted on the combustion furnace, and the air is introduced into the Combustion Furnace Through the air inlet on the bottom plate. The burner is in contact with the sample with a flame of 750 ℃, and the sample is subject to a forced air blow discharge of 5 m³/minute, with a wind speed of 0.9 meters/second, the cables cannot be burned up within 20 minutes of vertical combustion, and are automatically extinguished within 2.5 meters of flame spreading. IEC60332-3 has class A, Class B, Class C and Class D, further evaluate the advantages and disadvantages of flame retardant performance. IEC60332-3A flame retardant performance is the best, in the vertical combustion of 40 minutes can not burn up.

Therefore, data center users must comply with the standards promulgated by IEC 61034, IEC60754 and IEC60332-3 when selecting non-smoke halogen-free cables, cable manufacturers are required to provide non-Smoke and halogen-free cables that meet the above standards to help users achieve ideal fire-proof and flame-retardant data centers.

Both the non-smoke, halogen-free copper and optical fiber cables provided by the United States are tested by a third-party certification authority to meet the IEC61034, IEC60754 and IEC60332-3A standards, to achieve the ideal flame retardant level, helping users improve the Fire Safety of data centers.

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