Intumescent Coated Electrical Box Fire Sealing
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Solution Overview
Problem
In post-and-beam construction walls with double gypsum plasterboard cladding, openings for electrical installations compromise fire resistance, allowing flames to spread between rooms, particularly with 'back to back' installations of light switches.
Innovation Solution
An installation box with a layer of electrically insulating plastic and a partial coating of intumescent material on its outer surface, combined with a flexible material covering the openings for cables and conduits, ensures sealed closure during fires by the intumescent material's expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If openings are made in the planking for electrical installations, then electrical installations can be installed, but fire resistance is compromised and flames can spread between rooms
Solution Approach 1:
The installation box is pre-filled with intumescent material before installation. When exposed to fire, this pre-positioned material automatically expands to seal the opening, preventing flame spread. This preliminary preparation ensures fire protection activates automatically without requiring additional components or assembly steps.
Solution Approach 2:
The installation box serves as an intermediary element between the planking opening and the interior space. It provides a fire-resistant barrier while allowing electrical installations to pass through, mediating between the need for electrical access and fire protection requirements.
2Object-affected harmful factors
If intumescent material is used to seal openings, then fire protection is improved, but the structure of the installation box is destroyed by expansion forces
Solution Approach 1:
The installation box is designed with locally optimized properties: the walls are sufficiently thick and structurally reinforced to contain the expansion forces of the intumescent material, while the opening area allows for fire sealing. Different parts of the box have different functional requirements - structural integrity in the walls, fire sealing at the opening.
Solution Approach 2:
The expansion forces of the intumescent material, which could potentially damage the box structure, are converted into a beneficial sealing action. The material expands to press against and seal the opening, transforming the potentially harmful expansion force into a protective fire-sealing mechanism.
3Ease of operation
If light switches are installed back to back in neighboring rooms, then standardized positioning is achieved, but fire can spread directly through the opening
Solution Approach 1:
The installation box is pre-filled with intumescent material that will automatically expand to seal the opening when exposed to fire. This preliminary preparation ensures that even in back-to-back installations where openings are directly opposite each other, the fire sealing action occurs automatically without requiring additional protective measures.
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
Prevents flame and smoke gas escape, enhancing fire protection while maintaining standard dimensions and internal space, with the flexible material sealing until it liquefies and the intumescent material takes over, delaying smoke gas spread and allowing safe evacuation.
Implementation Method 1
The well-known intumescent material consists of expandable graphite. This expandable graphite has the property of expanding when heated. This expansion takes place with such forces that the structure of a conventional cavity wall box is destroyed.
Implementation Method 2
This expandable graphite has the property of expanding when heated. This expansion takes place with such forces that the structure of a conventional cavity wall box is destroyed.
Implementation Method 3
The flexible material has a lower temperature resistance than the intumescent material. The temperature resistance of the intumescent material relates to the temperature at which the intumescent effect of the material begins. Below this temperature, the flexible material seals the opening in the planking. When this temperature is reached or exceeded, the flexible material dissolves in such a way that this material becomes liquid and loses its shape.
Data Source
AI summary
The present invention relates to an electrical installation box comprising an inner layer of an electrically insulating plastic and a coating of an intumescent material, which is applied at least in certain areas to the outer surface of the inner layer. According to the present invention, the installation box has openings for the insertion of cables and/or conduits. A soft elastic material is also applied to the outer surface of the inner layer, covering at least these openings. Insofar as the areas of the outer surface of the inner layer where the intumescent material is applied are further provided with a coating of the soft elastic material, the soft elastic material is applied such that the intumescent material is positioned between the inner layer and the soft elastic material.Alternatively, the intumescent material can also be applied to the area of the outer surface where the soft elastic layer is not present. Furthermore, the intumescent material can alternatively be applied to the inside of the junction box.