Dual-Layer Pipe Insulation for Compact Passive Fire Protection

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Solution Overview

Problem

Conventional fire protection systems for pipes, especially those handling compressed air and hydrocarbon fires, face challenges in maintaining effective fire resistance while minimizing bulkiness and addressing high temperature and heat flux densities encountered in severe fire scenarios like jet fires and hydrocarbon pool fires.

Innovation Solution

A dual-layer insulating and protecting element is used, with an outer layer of inorganic fibers like stone wool providing high heat insulation and an inner layer of high-density materials such as concrete or gypsum offering high heat storage capacity, connected by a heat-resistant adhesive like water glass, to create a passive fire protection system that slows down temperature increase and maintains fire resistance even at critical temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If the thickness of the insulating layer is increased to improve fire resistance, then the fire protection duration is improved, but the bulkiness and diameter of the pipe section increase

Engineering Contradiction:
Improvefire protection durationVSAvoidpipe section diameter
Core Design Contradiction:
Duration of action of stationary objectVSVolume of moving object

Solution Approach 1:

The insulating layer is divided into two distinct layers with different functions: an outer layer (4) with high heat insulating properties and an inner layer (5) with high heat storing properties. This segmentation allows each layer to optimize its specific function, achieving better fire protection duration without proportionally increasing the total thickness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the insulating system have different material properties tailored to their specific needs. The outer layer uses materials with superior insulation properties to face the fire exposure, while the inner layer uses high-capacity materials to protect the pipe. This local optimization enables effective fire protection with reduced overall thickness.

Inventive Principle:
Principle #3Local quality

2Device complexity

If conventional single-layer insulation is used, then the structure is simple, but the fire resistance under extreme heat flux densities is insufficient

Engineering Contradiction:
Improveinsulation structure complexityVSAvoidfire resistance reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system uses a composite insulating structure combining two different materials with complementary properties. The outer layer (4) comprises inorganic fibers providing excellent heat insulation, while the inner layer (5) uses high-density materials with high heat capacity. This composite approach delivers superior fire resistance reliability under extreme conditions while maintaining reasonable structural complexity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The insulating system features a nested dual-layer configuration where the inner layer (5) is positioned inside the outer layer (4). This nesting arrangement allows both layers to work synergistically, with the outer layer providing primary insulation and the inner layer providing heat storage and secondary protection, achieving enhanced reliability without excessive complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

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

This configuration effectively reduces the speed of temperature increase and maintains fire resistance for extended periods, allowing the pipe to withstand extreme heat flux densities and temperatures, while being compact and cost-efficient, with the ability to be easily assembled and maintained.

Implementation Method 1

the outer layer has higher heat insulating properties than the inner layer being in contact with an outer surface of the pipe

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

the inner layer has higher heat storing properties than the outer layer

Methodology Applied
Scientific EffectHeat storage: Thermal Energy Storage

Data Source

PatentEP3767150A1A system comprising a pipe and an insulating and protecting element and insulating and protecting element
Publication Date: 2021.01.20 ROCKWOOL AS
  • EP3767150A1 patent drawingFigure 1
  • EP3767150A1 patent drawingFigure 2
  • EP3767150A1 patent drawingFigure 3

AI summary

System comprising a pipe (2), preferably for compressed air, and an insulating and protecting element (3.1,3.2) surrounding the pipe and providing a passive fire protection against fire, like hydro carbon pool or jet fire, tunnel fire, cellulosic fire, etc., and consisting of at least two layers (4, 5) having different heat insulating and heat storing properties, whereby the outer layer (4) has higher heat insulating properties than the inner layer (5) being in contact with an outer surface of the pipe (2), whereby the inner layer (5) has higher heat storing properties than the outer layer (4), whereby the outer layer comprises inorganic fibers, preferably stone wool fibers and whereby the inner layer (5) has a specific heat capacity Cp of at least 0.85 kJ/(kg.K).