Understanding the Fire Rating and Jacket of Fiber Optic Cable

Fiber optic cable is made up of an inner core, an outer jacket, cladding, and strengthening material. The shielding and conductors inside the cable require protection from the jacket since the bare fiber is readily torn. A fiber cable's first line of defense against moisture, mechanical damage, flames, and chemicals is its cable jacket.

Material for Fiber Optic Cable Jackets

Several kinds of materials are used to make fiber cable jackets. When choosing a jacket type for an application, compatibility with the connections and surroundings is crucial. Some of the most popular fiber cable jacket material types for both indoor and outdoor cables are included in the table below:

Jacket Material	Benefit of Jacket Material
PE (Polyethylene)	PE offers good electrical characteristics over a wide temperature range and great moisture and weather resistance. Moreover, it resists abrasion. Thus, PE is the industry standard for fiber optic cable jackets used outdoors.
PVC (Polyvinyl Chloride )	PVC is a material that may be made to work in a number of conditions and applications because it is often inexpensive, flexible, fairly durable, and oil- and flame-resistant. In other words, both indoor and outdoor cables can use it as their jacket material.
PVDF (Polyvinyl Difluoride)	Plenum cables are made of PVDF because it is less smoke-producing and has superior fire-retardant qualities than PE.
LSZH (Low Smoke Zero Halogen)	The LSZH jacket is free of halogenated substances, which when burned, can produce harmful and corrosive matte. A unique cable known as LSZH cable, which is a good option for interior installations, is made from LSZH materials. Yet the cost of the jacket material is the highest.

Color Code for Fiber Optic Cable Jackets

The fiber optic cable color code, as defined by EIA/TIA-598, specifies the jacket color codes for various fiber kinds (SMF or MMF). The jacket color for single-mode fiber is commonly yellow. Whereas the jacket color for multimode cable can be orange (OM1 and OM2 cable), aqua (OM3 cable), or purple (OM4 cable). The typical jacket color for wires used in outdoor plants is black. Please see How to Recognize the Fiber Optic Cable Color Code for more details regarding fiber optic cable color codes.

Fire Rating for Fiber Optic Cable

The NEC typically specifies eight categories of fire resistance for both conductive and non-conductive wires (National Electrical Code). All indoor fiber optic cables need to be correctly installed and designated for their plenums, risers, and general purpose areas of use.

Note:

(1) A building's plenum area is a room utilized for air circulation or an air distribution system (drop ceiling and raised floors).

(2) A floor aperture, shaft, or duct that extends vertically across one or more floors is referred to as a riser area.

(3) All other space on the same floor that is neither a plenum or a riser is referred to as a general purpose area.

Code	Description	Application
OFNP	Optical Fiber Non-conductive Plenum Cable	Plenum, overhead, fiber only
OFCP	Optical Fiber Conductive Plenum Cable	Plenum, overhead, hybrid (fiber/wire)
OFNR	Optical Fiber Nonconductive Rise Cable	Riser, backbone, fiber only
OFCR	Optical Fiber Conductive Rise Cable	Riser, backbone, hybrid
OFNG	Optical Fiber Nonconductive General-Purpose	General purpose, horizontal
OFCG	Optical Fiber Conductive General-Purpose	General purpose
OFN	Optical Fiber Nonconductive	General purpose, horizontal, fiber only
OFC	Optical Fiber Conductive	General purpose, horizontal, hybrid

OFNR versus OFNP

OFNP and OFNR are two varieties of fiber optic cables that are utilized in buildings, as was already explained. OFNP cables offer properties that make them fire-resistant and low-smoke producers. No other cable types can be substituted because this fiber cable has the greatest fire rating. Hence, plenum regions are where these cables are typically put. The fiber resistance and low smoke of OFNR cables, however, are inferior to those of OFNP. OFNR cables can be replaced by OFNP plenum cables. It is important to note that while comparing OFNR with OFNP, the former can be utilized in riser areas, whilst the latter cannot be used in plenum areas. OFNP and OFNR can both be utilized for general purposes.

T&S Plenum/Riser Fiber Optic Cable Solutions in the nutshell, plenum appraised and riser appraised cables are for the most part conveyed inside the buildings. Choosing the correct sort of appraised cables can successfully decrease loss when the cables are burning. In case your cabling application requires materials that are flame-retardant or compliant with strict safety guidelines, it would be ideal if you continuously prefer plenum-rated cables.

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