Optical Fiber Cable Scaffolding for Flaming Droplet Suppression
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Solution Overview
Problem
Existing optical fiber cables struggle to minimize flaming droplet production during burn tests, which is a critical factor in achieving the new burn performance ratings required by regulations such as the Construction Products Regulation (CPR) in Europe.
Innovation Solution
The optical communication cable design incorporates a scaffolding structure within the central bore of the cable, which is made of a material with a higher melting point than the cable jacket. This structure supports the jacket during a burn, preventing it from sloughing off and forming flaming droplets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional optical fiber cable design without scaffolding is used, then the cable structure is simple and easy to manufacture, but flaming droplets are produced during burn tests resulting in poor burn ratings
Solution Approach 1:
A scaffolding structure made of flame-retardant material is introduced as an intermediary component within the cable assembly. This scaffolding acts as a mediator between the optical fibers and the jacket, providing structural support during burn conditions and preventing the jacket from sloughing off to form flaming droplets, while not interfering with normal cable operation
Solution Approach 2:
The cable assembly becomes a composite structure combining multiple materials with different properties: the scaffolding uses flame-retardant material with higher melting point than the jacket, while the jacket uses standard polymer material. This composite approach allows the scaffolding to maintain structural integrity during burning while the jacket performs its normal function
2Quantity of substance
If the cable jacket is made thinner to reduce material usage, then manufacturing cost decreases, but the jacket becomes more susceptible to sloughing off during burn forming flaming droplets
Solution Approach 1:
The scaffolding structure serves as a supporting intermediary that compensates for the reduced thickness of the jacket. By providing internal structural support, the scaffolding allows the jacket to be thinner while still preventing sloughing off during burn conditions, as the scaffolding maintains the jacket's position and integrity
3Object-affected harmful factors
If flame-retardant additives are increased in the jacket material, then burn resistance improves, but manufacturing complexity and cost increase
Solution Approach 1:
The flame retardation function is segmented from the jacket material itself and assigned to a separate scaffolding structure. This allows the jacket to be manufactured using standard materials and processes without complex flame-retardant additives, while the scaffolding provides the necessary fire resistance through its flame-retardant material composition
Solution Approach 2:
The scaffolding acts as an intermediary that provides flame retardation functionality without requiring modification of the jacket material formulation or manufacturing process, thereby maintaining manufacturing simplicity while achieving improved burn resistance
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 introduction of the scaffolding structure significantly improves the cable's performance in flaming droplet tests, allowing it to achieve the best d0 rating under CPR regulations, indicating no flaming droplets.
Implementation Method 1
The optical communication cable includes a scaffolding structure within a central bore of the cable, the scaffolding structure made of a material having a higher melting point than a cable jacket
Data Source
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AI summary
An optical communication cable includes a jacket having an interior surface that defines a cable jacket internal cross-sectional area and a plurality of optical fibers, wherein less than 60% of the cable jacket internal cross-sectional area is occupied by the cross-sectional area of the plurality of optical fibers. A scaffolding structure is provided adjacent to and supporting the jacket such that when the jacket is subjected to a burn and melts, the melted jacket material bonds to the scaffolding structure rather than sloughing off.