Fire Resistant Optical Cable Intumescent Layer Design

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Solution Overview

Problem

Existing optical communication cables lack effective multi-stage fire resistance, as they are prone to heat propagation and oxygen penetration, which can lead to combustion and damage to the optical fibers.

Innovation Solution

The cable incorporates multiple fire-resistant materials, including intumescent materials that expand to block airflow and form a ceramic coating upon heat exposure, combined with non-intumescent materials like aluminum hydroxide, to slow heat transfer and increase combustion time, providing a multi-stage fire-resistant property.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional cable materials are used, then the cable structure is simple and easy to manufacture, but the cable is prone to heat propagation and combustion

Engineering Contradiction:
Improvefire resistanceVSAvoidcable structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The cable employs a composite structure combining intumescent materials (expandable polymer foam) and non-intumescent fire-resistant materials (aluminum hydroxide, magnesium hydroxide) within the cable layers. This multi-material approach provides both heat insulation and oxygen barrier properties, achieving superior fire resistance while maintaining structural integrity

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The fire-resistant materials are nested within the cable structure, with intumescent material forming an inner layer adjacent to the optical fibers and non-intumescent materials forming outer layers. This nested arrangement allows the cable to maintain a relatively compact overall structure while incorporating multiple protective functions

Inventive Principle:
Principle #7Nested doll (Nesting)

2Duration of action of stationary object

If fire-resistant materials are added to the cable, then the combustion time increases, but the cable structure becomes more complex

Engineering Contradiction:
Improvecombustion timeVSAvoidcable structure
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

Different fire-resistant materials are applied at different locations within the cable structure based on their specific functions. Intumescent material is placed where expansion is needed to seal gaps, while non-intumescent fire-resistant materials are placed where heat insulation and oxygen barrier properties are prioritized. This localized material distribution optimizes fire resistance without uniformly increasing structural complexity

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If intumescent material is used to block airflow, then oxygen penetration is reduced, but the cable structure becomes more complex

Engineering Contradiction:
Improveoxygen penetrationVSAvoidcable structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The intumescent material undergoes a phase transition when exposed to heat, transforming from a compact solid state to an expanded foam state. This phase change allows the material to rapidly increase in volume and block airflow paths, sealing gaps and preventing oxygen penetration without requiring additional structural elements in normal conditions

Inventive Principle:
Principle #36Phase transitions

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution effectively limits heat penetration and oxygen access, significantly increasing the combustion time of the cable components and protecting the optical fibers from fire damage, thereby enhancing the overall fire resistance of the optical communication cable.

Implementation Method 1

one or more fire retardant materials (e.g., intumescent materials) are positioned adjacent the inner passage of the cable and are configured to expand upon exposure to heat in a manner that blocks or limits air flow through the central passage of the cable body

Methodology Applied
Scientific EffectIntumescent expansion: Intumescent Materials

Implementation Method 2

various components of the cable maybe coated with a layer of fire resistant materials that forms a ceramic coating upon exposure to heat providing a heat insulating layer that slows heat propagation

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 3

a layer of fire resistant materials that forms a ceramic coating upon exposure to heat providing a heat insulating layer that slows heat propagation and slows oxygen reaching the coated component, and thereby increases the combustion time of the coated component

Methodology Applied
Scientific EffectCeramic coating formation: Deposition (physical)

Data Source

PatentEP3069180B1Fire resistant optical communication cable
Publication Date: 2020.05.06 CORNING OPTICAL COMMUNICATIONS LLC
  • EP3069180B1 patent drawingFigure 1~2
  • EP3069180B1 patent drawingFigure 3~4
  • EP3069180B1 patent drawingFigure 5

AI summary

A fire resistant optical communication cable is provided. The fire-resistant optical communication cable includes an extruded cable body including an inner surface defining a passage in the cable body and an outer surface. The fire-resistant optical communication cable includes a plurality of elongate optical transmission elements located within the passage of the cable body. The fire-resistant optical communication cable includes a layer of intumescent particles embedded in the material of the cable body forming an intumescent layer within the cable body. The cable may include one or more elements having flame resistant coatings that, upon exposure to heat, form a ceramic layer increasing the combustion time of the coated element.