In the optical fiber industry, we may have all seen the words “pressurized” or “riser”, because these are the two most common jacket types in the United States. But there are other options that are not well known and talked about, such as Low Smoke Zero Halogen (LSZH) and Polyethylene (Pe).
When you look at the structure of any fiber optic cable, you will notice that the outer sheath is the first line of defense against chemicals, water, burning, and other potential damage that may endanger the viability of the fiber optic cable. The cable sheath comes in a variety of colors, with industry-standard color codes, such as OM3 Aqua or single-mode Yellow, but in some cases, color sheaths can be customized.
You will see some specific things on the sheath, such as a foot mark that shows the length of the cable, and a printed string that shows the type of fiber, the cable manufacturer, and the type of cable structure. Most cable sheath materials are made of polyvinyl chloride or polyvinyl chloride, and the additives to polyvinyl chloride ultimately determine its sheath level. The ratings of the static pressure chamber and riser are given by the National Electrical Code (NEC).
As well as setting up the standards for what cables qualify as static or riser cables, they are also responsible for ensuring they adhere to those standards. This standard basically states that if a fire starts in a structure, how many of these compounds will cause the fire, and create a source of “fuel” to transport the fire from the place along the path of the cable, and a large amount of toxic gas will be generated when the cable is burned.
Most of the optical cables that meet these fire protection standards have been tested by UL (Underwriters Laboratories), that is, the cable jacket has the UL mark, and has passed the NEC standard cable jacket type certification. These UL lists are independently tested and qualified to ensure that safety measures are followed. They (UL) have no financial interest in the items they test, and consumers can rest assured that this UL list means that safety standards have been maintained.
These lists are given and can be deleted at any time if the quality of the product cannot continue to meet UL standards. The real question many technicians ask in the field is where to use which type of sheath. Below we will enter some of the cable sheath ratings and the classifications they can be used in buildings or structures.
1. Plenum cable
The static pressure box has the highest fire rating, which means that it can be installed in all the static pressure box spaces of the building, such as air ducts and ventilation systems, basically any part of the building that is related to heating or cooling airflow. As an alternative, the static pressure chamber can be practically applied to any space in the building.
In the event of a fire, pressurized cables are less dangerous and produce less smoke. If the work requires static pressure cables, then static pressure cables must be installed. There is no other option for this type of cable installation. For the reasons mentioned above, booster cables are usually slightly more expensive than most other cable sheaths.
2. Riser Cable
Riser cables are only used for riser spaces in buildings, such as building shafts, for vertical operation. It should be a backbone cable. The fire rating for riser-rated cables is not as stringent as a pressure box. You can use riser cables in riser spaces, but you cannot use riser cables in riser spaces. For example, in the case of a ventilation shaft, you cannot install a rising cable because this is an air space, but you can be on the building floor between the elevator shafts. Generally, riser cables are cheaper than static pressure boxes because the standards are less stringent.
3. Low Smoke Zero Halogen (LSZH) Cable
Low-smoke halogen-free cable jacket or LSZH is a separate classification from a riser or inflatable cable, because it does not contain the same compound or thermoplastic that produces smoke and other harmful chemicals, which may be harmful to humans and animals, and maybe nearby cables If it should burn.
To consider low-smoke halogen-free cables, the PVC sheath must be made of flame-retardant materials, does not discharge halogen, and also produces little or no smoke when it burns. Low-smoke cables are different from pressurized cables in that they have two different fire ratings.
Although the use of low niacin in every space of the building seems to be beneficial, this type of cable is not suitable for every individual application. Since this sheath material is much more expensive than other compounds, it does not make sense to install this type of cable in areas where low-hazard or low-smoke materials are not required. It is recommended to use low-smoke and halogen-free in places with poor ventilation, where people tend to gather, or in confined spaces. lzh jackets are currently mainly used in Europe, but this type of cable is gaining traction in the US market.
4. PE cable
PE (polyethylene) sheath is mainly used for outdoor-rated cable sheath; this is not a cable that can be installed inside a building. PE cable’s superior weather resistance and water resistance make it the best choice for severe weather conditions and installation, but its rigidity makes it difficult to use in environments that require cable flexibility or movement. This cable sheath also has excellent UV protection properties because its black color absorbs sunlight, which is a typical feature of outdoor-rated cables.
Although there are more cable ratings and classifications than shown above, these are the most common types that your technician will encounter more than once at work. For installation technicians, it is good knowledge to be familiar with the rating of cable jackets. Understand and be able to define what constitutes a static pressure cable static pressure box or riser cable riser, which will benefit future work technology.
