Wire and Cable Fire-Resistant Test and Flame Retardant Test

Wire and Cable Fire-Resistant Test and Flame Retardant Test

Flame Retardant Test

In order to evaluate the flame retardant performance of the cable, the International Electrotechnical Commission has formulated three standards, IEC60332-1, IEC60332-2 and IEC60332-3. IEC60332-1 and IEC60332-2 are used to evaluate the flame retardant ability of a single cable when it is laid at an angle and vertically (the corresponding domestic standards GB12666.3 and GB12666.4). IEC60332-3 (domestic equivalent to GB12666.5-90) is used to assess the flame retardancy of bundled cables when they burn vertically, compared to the requirements for flame retardancy when bundled cables are burned vertically.

IEC 60332-1 / BS 4066-1 (single wire or cable vertical burning test)

This is the flame retardant standard for a single cable. The test stipulates that a 60 cm long sample is vertically fixed in a metal box opened on the front wall, and a propane burner with a flame length of 175 mm contacts the cable at a 45-degree angle from the position of 450 mm from the upper fixed end of the sample. If the burning damage of the sample is no more than 50mm from the lower part of the fixed end, the test passes.

IEC 60332-3 / BS 4066-3 (Vertical burning test of bundled wires or cables)

This is the flame retardant standard for bundled cables. The test stipulates that the bundle of 3.5m long cable samples is fixed on the trapezoidal test frame with iron wire, and the number of samples is determined according to the non-metallic materials required by different classifications. The sample is hung vertically on the back wall of the furnace, and air is introduced into the furnace through the air inlet on the bottom plate. The propane flat burner is in contact with the sample at a flame of 750 ° C. The sample must not be ignited within 20 minutes of vertical combustion when the sample is forced to blow (air flow discharge 5m3 / min, wind speed 0.9m / sec). Self-extinguishing within 2.5 meters. IEC60332 has Class A, Class B, Class C and Class D to evaluate the flame retardant performance.

IEC fire resistance test

Refractory cable refers to the ability to maintain normal operation for a certain period of time when the flame is burning, that is, to maintain the integrity of the circuit (Circuit Integrity). In order to evaluate the fire resistance performance of cables, the International Electrotechnical Commission and the British Electrotechnical Commission have developed two standards, IEC60331 and BS6387, respectively. In contrast, BS6387 has much higher fire resistance requirements than IEC60331.

IEC60331 flame retardant level

In IEC60331-1999, the fire supply temperature is required to be 750 ℃ / 3h level, which means that 300 volt voltage level is applied at 750 ℃ to burn for 3 hours without breakdown.

BS6387 flame retardant grade

BS6387 is required to pass the horizontal combustion test, water spray test and mechanical shock vibration test. The horizontal combustion experiment is 650 ℃ / 3h for Class A, 750 ℃ / 3h for Class B, 950 ℃ / 3h for Class C and 950 ℃ / 3min for Class S. Class A means burning at 300 volts at 650 ℃ for 3 hours without breakdown; Class B means burning at 300 volts at 750 ℃ for 3 hours without breakdown; Class C means applying 300 volts at 950 ℃ No breakdown after burning for 3 hours; Class S means that it will burn for 3 minutes at 300 volts at 950 ° C without breakdown. The water spray combustion test is divided into W grade, which means that it is burned for 15 minutes after applying 300 volt voltage and then immersed in water for 15 minutes without breakdown. The shock vibration test is divided into X-class 650 ℃ / 15min, Y-class 750 ℃ / 15min and Z-class 950 ℃ / 15min, X-class means that 300 volt voltage is applied at 650 ℃ while burning while mechanical shock and vibration every 30 seconds for 15 minutes. Breakdown; Y level means 300 volts applied at 750 ℃ while burning and mechanical shock every 30 seconds for 15 minutes without breakdown; Z level means 950 ℃ applied 300 volts while burning and mechanical shock every 30 seconds No breakdown for 15 minutes at a time. The highest level model required by BS6387 is CWZ.