According to the standard GBT 19666, flame-retardant cables are ZR and divided into four levels: A/B/C/D

ZA: Flame retardant category A, supply time and temperature: 40 minutes/815 degrees, sample capacity: V/M 7 liters/meter, qualified judgment: coking height less than or equal to 2.5 meters, self extinguishing time less than or equal to 60 minutes.
ZB: Flame retardant category B, supply time and temperature: 40 minutes/815 degrees, sample capacity: V/M 3.5 liters/meter, qualification judgment: coking height less than or equal to 2.5 meters, self extinguishing time less than or equal to 60 minutes.
ZC: Flame retardant category C, fire supply time and temperature 20 minutes/815 degrees, sample capacity: V/M 1.5 liters/meter, qualified judgment: coking height less than or equal to 2.5 meters, self extinguishing time less than or equal to 60 minutes.
ZD: Flame retardant category D, fire supply time and temperature 20 minutes/815 degrees, sample capacity: V/M 0.5 liters/meter, qualified judgment: coking height less than or equal to 2.5 meters, self extinguishing time less than or equal to 60 minutes.



note
Class A flame retardant Z is strict, Class B flame retardant also has high requirements, suitable for occasions with strict flame retardant requirements, Class C is general flame retardant, suitable for most occasions with flame retardant requirements; The commonly used flame-retardant cables in general civil buildings are Class C; ZR generally refers to C-grade flame retardant.



Low smoke halogen-free flame retardant

According to the standard GBT 19666, low smoke halogen-free flame retardant is WDZ, and flame retardant is still divided into four levels: A/B/C/D, namely WDZA/WDZB/WDZC/WDZD (as shown in the above figure).
According to the standard IEC60332, the low smoke halogen-free flame retardant is LSOH, and its smoke density is based on IEC 61034; Halogen testing according to IEC 60754-2; Its flame retardant rating can be divided into LSOH IEC60332-1 and LSOH IEC60332-3C according to standards.

IEC 60332-1 (Vertical Burning Test for Single Cable)
The testing environment of IEC 60332-1 standard is to test an independent vertically placed cable. Place a burner at a 45 degree angle to the cable and extinguish it after burning for one minute. This standard stipulates that cables that have been burned must be able to self extinguish under these testing conditions. And the burnt cable part cannot exceed 50mm from the cable fixing point at the upper end of Z.

IEC 60332-3C (Vertical Burning Test for Bundled Cables)
The testing environment of IEC60332-3C standard is for testing bundled cables. The entire test was conducted in a four meter high cabinet, which required the use of 1.5 liters of flammable material per meter for testing, with a burning time of 20 minutes. This standard specifies that under these testing conditions, the maximum allowable distance for flame extension is Z