In HVAC systems, ducts not only function as air transport devices, but their fire resistance is also crucial to the overall safety of the building. Fiberglass ducts, integrating insulation, sound absorption, and structural functions, are increasingly popular in engineering applications. This article will systematically explain the fire resistance performance of fiberglass ducts from the perspectives of material properties, fire resistance mechanisms, and engineering performance.

I. Basic Requirements for the Fire Resistance Performance of Ducts in Buildings and HVAC Systems

In building fire protection design, duct systems typically require:

Materials that are not easily combustible

Do not support combustion or spread fire in the event of a fire

Maintain structural stability for a certain period of time

Do not produce significant molten drippings

Therefore, the fire resistance performance of duct materials becomes an important indicator for HVAC system selection.

II. Material Composition and Fire Resistance Basis of Fiberglass Ducts

Fiberglass ducts are typically composed of the following structure:

Fiberglass as the main substrate

An inner inorganic fiber insulation layer

An outer protective layer (aluminum foil or composite material)

Fiberglass itself is an inorganic fiber material, possessing natural advantages in fire resistance. III. The Formation Mechanism of Fire Resistance of Fiberglass Ducts

1. Fire-Resistant Characteristics of Inorganic Fiber Materials

Fiberglass in high-temperature environments:

Does not participate in combustion

Does not release combustion-supporting substances

Maintains fiber morphology at high temperatures

This characteristic is the core basis of the fire resistance of fiberglass ducts.

2. The Inhibiting Effect of Composite Structure on Fire Spread

Fiberglass ducts have a multi-layered structure:

The inner fiber layer can block heat transfer

The composite lining can delay the contact of flames with the core structure

The overall structure does not form a continuous combustible channel

This helps reduce the risk of fire spreading along the duct.

3. Structural Stability Under Fire Conditions

In a fire environment, fiberglass ducts typically exhibit the following characteristics:

No significant melting or dripping occurs.

The structure does not collapse rapidly.

It helps prevent the spread of flames through the duct system.

IV. Practical Significance of Fiberglass Duct Fire Resistance in Engineering

1. Reduced Risk of Fire Spread

Compared to some metal-plus-organic insulation structures, fiberglass ducts:

Aim for more stable overall fire resistance.

Reduce secondary risks caused by insulation layer combustion.

2. Enhanced Overall System Fire Integrity

Fiberglass ducts integrate their own insulation layer:

Avoid introducing flammable factors through later insulation installation.

Facilitates unified fire protection design for the system.

3. Meets Diverse Building Fire Protection Requirements

Fiberglass ducts are commonly used in:

Public buildings

Commercial complexes

Industrial plants

Machine rooms and equipment floors

V. Key Factors Affecting the Fire Resistance of Fiberglass Ducts

1. Raw Materials and Manufacturing Process

Glass fiber purity

Fiber Molding and Curing Process

2. Selection of Outer Covering Materials

Does the covering material possess fire-resistant properties?

Is the covering structure complete and continuous?

3. Installation and System Design

Treatment methods when ducts pass through fire compartments

Coordination with fire dampers and fire seals

VI. Comparison and Understanding of the Fire Resistance Performance of Fiberglass Ducts and Traditional Ducts

From a System Perspective:

Fiberglass Ducts: Inorganic structure, stable fire resistance

Metal Ducts + Organic Insulation: Fire resistance depends on the insulation layer

Composite Ducts: Requires comprehensive evaluation of the overall structure

Fiberglass ducts have a significant advantage in terms of consistent fire resistance.

The fire resistance of fiberglass ducts stems from their inorganic fiber material properties and integrated composite structure design.

Under the premise of standardized selection and correct installation, fiberglass ducts can effectively reduce the risk of fire spread in HVAC systems, providing reliable protection for building fire safety.