DIYAN is also denoted by D.
Although it is repeated with the low-halogen D, it has been accepted and is not misunderstood in the model combination.
The international standard for low smoke is light transmittance ≥60%.
It must be pointed out that China's PVC based so-called low halogen and low smoke materials made of wire and cable, its low smoke does not meet the above requirements, should not use the low smoke model.
Unless otherwise stated in the product standard, such as an indicator for reduced light transmittance, and stating that the indicator is below the requirements of international or national standards, in order to avoid user misunderstanding.
For DIDU, we can't use D anymore, we can use U.
The IEC standard is still under consideration.
At present, the British Naval Engineering standard NES713 is more commonly used, which is indicated by toxicity index (TI), such as the requirement that the toxicity index of insulation material is less than
The toxicity index of the sheath is less than 5.
Some domestic manufacturers can provide halogen-free, low smoke, non-toxic cable, said here that the non-toxic is not appropriate, should be low toxicity.
Toxic CO will be produced when halogen-free and low-smoke materials are burned. If P, N and S are contained in the materials, more toxic gas will be generated.
When a certain type of electric wire or cable has a variety of combustion characteristics, according to international practice, a certain type and the designation shall be in the following order (items that are not included should be omitted);
No (low) halogen, low smoke, low toxicity, flame retardant and fire resistance, for example:
(1) Flame retardant (A) class POLYvinyl chloride insulated polyvinyl chloride sheathed power cable, model: ZA-VV
(2) Low halogen flame retardant (Class B)PVC insulated PVC sheathed power cable, model: DZB-VV
(3) Low halogen, low smoke, flame retardant (Class C)PVC insulated, PVC sheathed power cable, model: DDZC-VV
(4) Halogen-free, low smoke and flame retardant (Class A), crosslinked polyethylene insulated steel strip pin-mounted polyolefin sheathed power cable, model: WDZA-YJY23 (Polyolefin sheathed sheath number 3)
(5) Halogen-free, low smoke and flame retardant (Class B) crosslinked polyethylene insulated polyolefin sheathed power cable, model no. :
(6) Halogen-free, low-smoke and fire-resistant (Class A) Crosslinked polyethylene insulated polyolefin sheathed power cable, model no. :
Fire-resistant (Class B) PVC insulated PVC sheathed power cable, model: NB-VV
Must pay attention to the problem
The method of determining the corresponding model and appellation according to the burning characteristic of wire and cable is put forward above.
Some of the current problems and how to deal with them are explained as follows:
(1) Do not put a high hat on flame retardant wire and cable to achieve flame retardant requirements, there are a variety of ways.
, for example, USES the inorganic flame retardants as the base of cement filling (so-called "oxygen insulation layer", "" fire insulation layer, etc.) or with inorganic flame retardants as the base city of paint coating of the flame retardant belt (the so-called" high flame retardant belt ", "isolate HuoDai oxygen", etc.) bag, in dealing with cross-linked polyethylene insulation composed of flammable materials such as flame retardant cable problem plays A very important role, even can achieve the level of the flame retardant class A.
But don't give it "high flame retardant," "super high flame retardant," "super high flame retardant," don't use the GZR model.
This is because, according to the same combustion test methods and indicators, are IEC332-3 or GB12666.5, so no matter what means and methods to achieve flame retardant, its model and title should be the same.
The current highest level of flame retardancy is ZA.