Cable Jackets classification
Cables with a Poly Vinyl Chloride (PVC) jacket are the most commonly used and are often referred to as general purpose cables. These types of cables are intended for installations with no particular fire safety code requirements. Some examples are home or office environments for CPU to monitor connections. In a fire, PVC-coated wires can form HCl fumes; the chlorine serves to scavenge free radicals and is the source of the material's fire retardance. While HCl fumes can also pose a health hazard in their own right, HCl breaks down on surfaces, particularly in areas where the air is cool enough to breathe, and is not available for inhalation.
Plenum (CMP) Rated Jacket
Cables with plenum rated jackets are intended for installations where cables are routed through an air handling conduit (often called a plenum). Plenum cables must self extinguish and not reignite. They also produce less smoke than traditional PVC cables. The smoke and fumes are toxic. This requirement is usually imposed by fire safety codes and is related to the stringent burn test that this type of cable must meet. Complies with NFPA-262 and UL-910.
Low Smoke Zero Halogen (LSZH) Rated Cable
Cables with a LSZH jacket are intended for applications where both low smoke and low corrosive gases are needed. Used in shipboard applications and computer networking rooms where toxic or acidic smoke and fumes can injure people and/or equipment. Examples of Halogens include Fluorine, Chlorine, Bromine, and Iodine. These materials when burned produce acidic smoke that can harm people and computer equipment. Low Smoke means the cable does not produce the heavy black soot and smoke common with PVC cables. These cables will self extinguish but cannot pass UL-910 or UL-1666 for a plenum or riser rating.
Riser (CMR) Rated Cable
Comples with UL-1666. Defined for usage in vertical tray applications such as cable runs between floors through cable risers or in elevator shafts. These spaces cannot be used for environmental air. These cables must self extinguish and must also prevent the flame from traveling up the cable in a vertical burn test.
General Purpose (CM, CMG, CMx) Cable
Will burn and partially self extinguish. Not for use between build floors or in air plenum spaces. Often these cables are used for workstation cables and patch cords. Complies with UL-1581 testing.
Limited Use Cable
This cable has certain restriction on open laying, ex. It’s usage is permitted only in residential buildings, it’s laying is allowed only in tubing made of incombustible material or maximal diameter is limited etc.
FR-PVC (fire retardant polyvinylchloride)
FR-PVC insulation has better fire retardant properties than normal PVC. It has significant advantages in terms of lower acid emissions and smoke generation. The amount of chlorine in the flame-retardant PVC (FRPVC) jacket cable is significantly higher (5%) than the conventional PVC jacket cable. FRPVC has good electrical insulation properties below 100°C.
HFFR (Halogen Free Flame Retardant)
HFFR cables help to prevent cable fires from occurring, and even if fire does break out, there is considerably less accompanying smoke. Therefore, they are especially important in protecting the lives of people and animals.
For HFFR cables too, top priority is mechanical and electrical product properties and the best possible melt processability. This can only be achieved through the optimum adhesion of fillers and polymers and through good cross-linking of the polyethylenes.
The advantages of HFFR compounds: increased loading levels, high flame retardation, significantly reduced water uptake into the polymer, much improved electrical properties, increased throughput during cable production, improved mechanical properties.
PE is a semi-crystalline thermoplastic material and one of the most commonly used plastics. It is generally ductile, flexible and has low strength. There are two basic families: LDPE (low density polyethylene), and HDPE (high density polyethylene).
HDPE (high density polyethylene)
HDPE is the high density version of PE plastic. It is harder, stronger and a little heavier than LDPE, but less ductile. The use of UV-stabilizators (carbon black) improves its weather resistance but turns it black. HDPE is also more opaque and it can withstand rather higher temperatures (120°C for short periods, 110°C continuously). HDPE has many advantages: chemical-and corrosion-resistant, light-weight, low moisture absorption, non-staining, thermoforming performance, non-toxic, high tensile strength.