Optical fire cables

UE 910 Standardfor Safety, Test Methodfor Fire and Smoke Characteristics of Electrical and Optical Fiber Cables used in Air Handling Spaces, Underwriters Laboratories, Inc. Northbrook, lU., 1985. 

Tests for Fire Resistance of Roof Covering Materials, 1983. (similar to ASTM E 108) Tests for Flame Propagation and Smoke Density Values for Electrical and Optical Fiber Cables in Spaces Transporting Environmental Air, 1991. 

Chapter 7 is the chapter dealing with Special Conditions and it addresses most of the cables with highly improved fire performance. Thus, Articles 725 (Class 1, Class 2, and Class 3 Remote-Control, Signaling, and Power-Limited Circuits), 760 (Fire Alarm Systems), and 770 (Optical Fiber Cables and Raceways) all use the same two schemes for fire performance of cables, as shown in Figures 21.4 and 21.5. The figures show that the best is NFPA 262,65 a cable fire test for flame spread and smoke, conducted in a modified Steiner tunnel (86 kW or 294,000 BTU/h), for which the requirements in the NEC are that the maximum peak optical density should not exceed 0.5, the maximum average optical density should not exceed 0.15, and the maximum allowable flame travel distance should not exceed 1.52m (5 ft). The next test, in the order of decreasing severity is UL 1666,64 known... 

ASTM D 6113 Standard Test Method for Using a Cone Calorimeter to Determine Fire-Test-Response Characteristics of Insulating Materials Contained in Electrical or Optical Fiber Cables ASTM D 6194 Standard Test Method for Glow Wire Ignition of Materials ASTM D 6413 Standard Test Method for Flame Resistance of Textiles (Vertical Test)... 

UL 1685 Standard Vertical-Tray Fire-Propagation and Smoke-Release Test for Electrical and Optical-Fiber Cables... 

IEC 60332-1 Tests on electric and optical fibre cables under fire conditions Test for vertical flame propagation for a single insulated wire or cable, IEC, Geneva, Switzerland, 2004. 

The increasing use of fiber optics for electronic communications poses critical communications risks. The fire resistant requirements of fiber optical cables are currently similar to the requirements of fire resistant ratings applied to electrical cables within the specifications of the NEC. 

UL 1975 Standard for Fire Tests for Foamed Plastics Used for Decorative Purposes UL 2024 Standard for Optical-Fiber and Communications Cable Raceway UL 2043 Standard for Safety Fire Test for Heat and Visible Smoke Release for Discrete Products and Their Accessories Installed in Air-Handling Spaces... 

The proposed end applications of Kevlar (Yang, 1989) and related fibers include ballistic and fire protective apparel, hard armors, reinforced tires and rubber goods, various forms of composites, filament wound pressure vessels, marine ropes, optical cables and industrial gloves. Almost all of them utilize the high tensile properties and high heat-resistance. 

The smoke test generates an optical density/time curve. Results are expressed in terms of Ds, For cellular foams, the Fire Research Organisation specifies a maximum (Ds 1.5) of 100 and a (Ds 4.0) of 175. With the exception of wire and cable, the D, 4.0 value for all other materials may not exceed 200. 

The National Electrical Code (NEC ) is a document issued every three years by the National Fire Protection Association . The document specifies the requirements for the safety of premises wire and cable installations, and also sets requirements to minimize the risk and spread of fire in commercial buildings and individual dwellings. Section 770 of the NEC defines the requirements for fiber optic cables. Although the NEC is advisory in nature, its content is generally adopted by local building authorities as Code. 

In order to increase availability redundant subsystems may be deployed. The redundant controllers may work in l-out-of-Z principle (or dual cross wired) comprise two subsystems of identical design. They could be kept electrically isolated from one another, and are synchronized over fiber-optic cables. In the event of a fault, there should be a bumpless transfer from the active subsystem to the backup subsystem. Though it is possible to keep two subsystems but in the same rack, or spatially it is better to keep them apart so that in case of fire both systems may not be lost. 

Fiber optics are commonly used for electronic communication appHcations and pose critical communication risks that may affect all aspects of how a facility is maintained and operated. The fire resistance requirements are similar to the requirements for fire ratings as apphed to electrical cabling within the specifications of the National Electrical Code (NEC). 

Pedersen et al. (2006) describe the cascading effects of a freight train derailment in a tunnel, carrying hazardous chemicals. It caused a fire that led to a water main to break above the tunnel causing localized flooding. The fire also destroyed the fiber optic cables in the tuimel that resulted in major disruptions to phone and cell phone service, email service, and data services to major corporations. Disruption to rail services and the consequent delays in deliveries of coal and limestone were significant. 

---