Double-Leaf Door Pressure-Equalizing Channel for Fire Safety

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Solution Overview

Problem

In fire situations, the pressure difference between the interior of a building and the space between the inner and outer doors of a double-leaf door structure creates a significant force that prevents the inner door from opening inward, potentially trapping individuals behind the door due to the excess pressure caused by the fire.

Innovation Solution

Equipping the inner door with a pressure-equalizing channel that allows free airflow between the interior of the building and the other side of the door, reducing the holding force to a range of 1-100 N, enabling the door to be opened even under high pressure conditions by equalizing pressures on both sides.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the inner door is equipped with a pressure-equalizing channel, then the door can be opened during fire situations by equalizing pressures, but the door structure becomes more complex and thermal insulation performance may deteriorate

Engineering Contradiction:
Improvedoor operability in fire situationVSAvoiddoor structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a pressure-equalizing channel with perforations or porous structure that allows air flow through the door leaf. This porous approach enables pressure equalization between the fire-exposed side and the protected side while maintaining the door's structural integrity and thermal insulation properties. The porous material or perforated pattern allows controlled airflow without creating large openings that would compromise security or insulation.

Inventive Principle:
Principle #31Porous materials

2Reliability

If the pressure-equalizing channel is always open, then pressure equalization is effective, but thermal insulation and sound insulation performance deteriorate

Engineering Contradiction:
Improvepressure equalization effectivenessVSAvoidthermal and sound insulation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent incorporates a valve mechanism that dynamically controls the opening and closing of the pressure-equalizing channel. During normal conditions, the valve remains closed to maintain thermal and sound insulation. When pressure difference exceeds a threshold (indicating fire situation), the valve automatically opens to equalize pressure. This dynamic control allows the system to adapt to different operational states, providing both insulation and pressure equalization as needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The valve acts as an intermediary element between the two sides of the door, controlling the flow of air and pressure equalization. It mediates between the conflicting requirements of maintaining insulation (closed state) and enabling pressure equalization (open state). The valve body, seal elements, and control mechanism work together to provide controlled access between the pressurized and pressurized-free zones.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the intermediate space volume is increased to 100-600 litres, then pressure equalization capacity is improved, but the door structure size and complexity increase

Engineering Contradiction:
Improvepressure equalization capacityVSAvoidintermediate space volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent divides the pressure equalization function into multiple smaller channels or pathways distributed through the door structure, rather than relying on a single large intermediate space. The door leaf is segmented with multiple pressure-equalizing channels or perforations that collectively provide sufficient pressure equalization capacity. This segmentation allows achieving the required pressure equalization effect while keeping the door thickness and overall structure compact.

Inventive Principle:
Principle #1Segmentation

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 pressure-equalizing channel significantly reduces the force required to open the inner door, allowing it to be opened during a fire, thereby preventing individuals from being trapped by the smoke, even when the pressure difference is substantial.

Implementation Method 1

a pressure difference caused by the fire is generated between the space between the inner door and outer door of the double-leaf door structure and the interior of the building, which creates a force that pushes the inner door outward

Methodology Applied
Scientific EffectPressure equalization: Pressure Gradient

Implementation Method 2

the inner door is equipped with a pressure-equalizing channel through the inner door, i.e. through the thickness of the leaf, in order to equalize the pressures on the different sides of the inner and outer doors

Methodology Applied
Scientific EffectFree flow of gas: Convection

Data Source

PatentEP3536887A1Method in a fire situation in connection with a double-leaf door, and a double-leaf door structure
Publication Date: 2019.09.11 ASIVO OY
  • EP3536887A1 patent drawingFigure 1a~1b
  • EP3536887A1 patent drawingFigure 2
  • EP3536887A1 patent drawingFigure 3

AI summary

Door structure and method for eliminating excess pressure caused by a fire and the concomitant force that holds an inner door shut in connection with a double-leaf door structure (100) in a fire situation. In the method according to the invention, excess pressure is equalized between the room interior (H1) and the intermediate space (V) between the inner door (T1) and the outer door by equipping the inner door (T1) with a pressure-equalizing channel (O1), by means of which the air space in the room interior (H1) and the air space in the intermediate space (V) are joined, whereupon the opening of the inner door (T1) is facilitated and the force holding the door shut resulting from the pressure difference is significantly reduced.