Flame Arrester Mesh for Ventilated Curtain Wall Fire Safety

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Solution Overview

Problem

Rear-ventilated curtain walls with continuous air spaces pose a risk of rapid fire spread across floors due to their chimney-like effect, and existing fire protection measures often compromise air circulation and ventilation, increasing structural complexity.

Innovation Solution

A floor-spanning air space with a horizontally extending flame arrester featuring a net-like or lattice-like surface structure with openings of maximum clear width ≤0.75 mm, ensuring air circulation while preventing flame spread by completely filling the air space and using an intumescent sealing element to enhance fire protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a continuous air space is provided for ventilation, then air circulation and moisture removal are improved, but fire spread risk increases due to chimney effect

Engineering Contradiction:
Improveventilation performanceVSAvoidfire spread risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The continuous air space is segmented by installing a flame barrier at floor level that divides the ventilation cavity into separate sections. This segmentation prevents uncontrolled fire spread while maintaining ventilation functionality through carefully designed openings in the flame barrier.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The flame barrier is designed with non-uniform opening distribution - dense mesh structure in critical areas to prevent flame passage, while incorporating sufficient total opening area to maintain ventilation. The local quality of the barrier varies to balance fire protection and air circulation requirements.

Inventive Principle:
Principle #3Local quality

2Reliability

If a flame barrier is installed to prevent fire spread, then fire protection is improved, but air circulation and ventilation are compromised

Engineering Contradiction:
Improvefire protectionVSAvoidair circulation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The flame barrier utilizes a porous mesh structure with numerous small openings that are sufficient to block flame propagation but large enough to allow air passage. The porous nature enables the barrier to fulfill both fire protection and ventilation functions simultaneously.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The opening dimensions of the flame barrier are precisely controlled within specific ranges (opening size between 0.2-1.0mm) to achieve the optimal balance between fire resistance and ventilation performance. By adjusting the opening parameters, both contradictory requirements are satisfied.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the free cross-section of air space is interrupted by fire barrier, then fire spread is prevented, but structural complexity increases requiring additional openings

Engineering Contradiction:
Improvefire barrier effectivenessVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The flame barrier is integrated directly into the existing substructure components (vertical battens, horizontal connectors) rather than being a separate additional element. This merging approach prevents fire spread without significantly increasing structural complexity, as the flame barrier functionality is combined with the ventilation framework.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The substructure components serve multiple functions: they provide structural support for cladding elements, create the ventilation air space, and simultaneously act as the flame barrier when equipped with the mesh structure. This multi-functionality reduces overall structural complexity while achieving fire protection.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 prevents fire spread across floors by allowing air circulation without compromising ventilation, maintaining temperature below 600°C and preventing heat and combustion gases from rising, thus protecting areas above the flame arrester.

Implementation Method 1

A horizontally extending flame arrester (6), in particular a roll or tube made from a net- or grid-like surface structure (7), with openings (8) having a maximum clear width w ≤ 0.75 mm

Methodology Applied
Scientific EffectFlame arrestion:

Implementation Method 2

using an intumescent sealing element to enhance fire protection

Methodology Applied
Scientific EffectIntumescent expansion: Intumescent Materials

Data Source

PatentEP3486390B1Construction of an exterior wall and flame arrester for a construction of an exterior wall
Publication Date: 2020.08.26 STO SE & CO KGAA
  • EP3486390B1 patent drawingFigure 1
  • EP3486390B1 patent drawingFigure 2~4
  • EP3486390B1 patent drawingFigure 5~6

AI summary

The invention relates to an exterior wall construction (1) with an air space (2) extending across multiple stories for ventilating cladding elements (3), which are attached to a load-bearing wall (5) by means of a substructure (4) bridging the air space (2). According to the invention, a horizontally extending flame arrestor (6) is arranged in the air space (2), extending over the entire cross-section (a) of the air space (2). This flame arrestor comprises at least one mesh- or grid-like surface structure (7) with openings (8) having a maximum clear width (w) ≤ 2.0 mm, preferably ≤ 1.0 mm, and more preferably ≤ 0.75 mm, wherein the clear width (w) is not less than 0.01 mm, preferably not less than 0.025 mm, so that the necessary air circulation in the air space (2) for ventilation is ensured. The invention further relates to a flame arrestor (6) for an exterior wall construction (1) according to the invention.