In modern building heating, ventilation, and air conditioning (HVAC) systems, duct systems directly affect air delivery efficiency, energy consumption, and indoor environmental quality. Fiberglass ducts, as composite duct products integrating insulation, sound absorption, and ventilation, are widely used in commercial buildings, industrial plants, hospitals, data centers, and other locations due to their lightweight, fire resistance, and energy-saving characteristics. This article will systematically analyze the service life of fiberglass ducts from the perspectives of material performance, environmental factors, construction quality, and maintenance management.

I. Structural Characteristics and Durability Basis of Fiberglass Ducts

Fiberglass ducts are typically made of high-density fiberglass sheets as the base material, pressed into shape, and covered with a moisture-proof and fire-resistant surface material. Their internal porous fiber structure combines insulation and sound absorption functions. Compared to traditional galvanized iron ducts with an external insulation layer, fiberglass ducts have an integrated structure, reducing the risk of cold bridging and condensation.

From a material properties perspective, fiberglass is an inorganic material with good aging resistance. It is not easily decomposed or corroded under normal temperature and humidity conditions, which is the basis for its long-term service life.

II. The Influence of Temperature and Humidity on Service Life

Fiberglass ducts are generally suitable for operating environments ranging from -30℃ to 120℃, meeting the temperature requirements of most air conditioning supply and return air systems. Under stable operating conditions, its thermal conductivity remains relatively stable.

Humidity is one of the important factors affecting service life. If the system design or construction is improper, condensation may occur, and moisture may penetrate into the material, leading to a decrease in structural strength. Therefore, in high-humidity areas, sealing and moisture-proof design should be strengthened. As long as the moisture-proof system is complete, the performance degradation of fiberglass ducts is relatively small during long-term use.

III. Mechanical Factors and Structural Stability

During operation, the duct is affected by wind pressure, vibration, and stress from the hanging supports. Fiberglass ducts are lightweight and have low load requirements on supports, but if the installation spacing is unreasonable or the fixing is not secure, deformation or joint cracking may occur.

Reasonable support design and standardized hoisting construction can effectively avoid structural fatigue problems during long-term operation. Under the premise of complying with design specifications, the structural stability of fiberglass ducts can generally be maintained for a long period.

IV. Fire Resistance and Safety Stability

Fiberglass ducts are classified as Class A non-combustible materials with excellent fire resistance. They will not support combustion or release large amounts of harmful gases in a fire environment, contributing to improved overall building safety. The material's fire resistance stability does not significantly decrease over time, which is one of the important reasons for its suitability for long-term use.

V. Impact of Cleaning and Maintenance on Lifespan

The air quality inside the duct directly affects the material's condition. Severe dust accumulation over a long period may affect the system's ventilation efficiency. Therefore, it is recommended to regularly inspect and clean the duct system to ensure a stable internal environment.

In addition, the sealing of joints should be checked regularly, and damaged areas should be repaired promptly to prevent the expansion of localized air leaks or condensation.

VI. Actual Service Life Reference

Under normal design and construction conditions, the service life of fiberglass ducts can typically reach 15 to 25 years. With mild environmental conditions and proper maintenance management, some projects can achieve even longer operating periods.

In high-humidity, high-corrosion, or high-vibration environments, it is recommended to strengthen external protection or select reinforced products based on actual working conditions to extend service life.

VII. Comprehensive Evaluation Conclusion

Considering the material properties, structural performance, and practical application experience, fiberglass ducts possess good long-term service capabilities. Their integrated insulation structure, good fire resistance, and low energy consumption advantages make them occupy an important position in modern building energy-saving systems.

For engineering projects that prioritize energy efficiency, construction efficiency, and system stability, fiberglass ducts are a mature and reliable solution. Through scientific selection, standardized construction, and regular maintenance, their service life can be effectively extended, achieving continuous improvement in energy conservation and economic benefits.