In building HVAC, water supply and drainage, and industrial pipeline insulation projects, rubber and plastic insulation systems are widely used for both thermal and cold insulation applications. Compared to the performance of a single material, the system's airtightness directly determines whether the rubber and plastic insulation layer can maintain stable performance over a long period, especially playing a crucial role in preventing condensation and moisture. This article analyzes the airtightness requirements of rubber and plastic insulation systems from an engineering application perspective.

First, the core objective of airtightness is to block water vapor penetration. Rubber and plastic materials achieve good moisture-proof performance through their high closed-cell ratio; however, if the system joints, interfaces, or nodes are not properly treated, water vapor can still enter the insulation layer through these gaps, leading to localized condensation and performance degradation. Therefore, the airtight design of rubber and plastic insulation systems should be based on the fundamental principle of forming a continuous and complete water vapor barrier.

Second, joint treatment is a key aspect of airtightness control. During the splicing process of rubber and plastic sheets or pipe shells, uneven cutting or inadequate bonding can easily create tiny gaps, which become channels for water vapor penetration. During construction, ensure a tight seal at joints, using specialized adhesives for full adhesion to avoid spot bonding or incomplete adhesion, ensuring a continuous overall system seal.

Third, sealing requirements for interfaces and irregularly shaped areas are more stringent. At points where valves, flanges, and supports penetrate, the rubber-plastic insulation layer is often interrupted. Insufficient sealing can easily lead to cold bridging and condensation. Specialized treatment should be implemented for these areas during the design and construction phases, using segmented wrapping, enhanced sealing, or additional local protective layers to reduce the risk of seal failure.

Fourth, the compatibility of sealing materials is crucial. Adhesives and sealing accessories used in rubber-plastic systems should possess similar flexibility and temperature resistance to the rubber-plastic materials themselves. Under alternating hot and cold conditions or long-term operation, hardening, cracking, or loss of adhesion in the sealing material will directly compromise the system's seal. Therefore, specialized accessories compatible with the system should be prioritized during project selection.

Fifth, the construction environment and process control directly impact the sealing effect. Construction under conditions of low temperature, high humidity, or unclean substrate can easily lead to a decrease in adhesive bonding effectiveness, affecting the sealing quality. A standardized construction process should include substrate cleaning, even application of adhesive, thorough pressing, and necessary curing time control to ensure the reliability of the sealing layer.

Finally, the system's sealing performance also needs to be guaranteed through subsequent inspection and maintenance. During long-term operation, rubber-plastic insulation systems may experience localized damage due to external forces or environmental changes. Regularly inspecting joints and critical nodes, and promptly repairing damaged areas, helps extend the system's service life and maintain stable insulation and anti-condensation performance.

Overall, the sealing performance of a rubber-plastic insulation system is the result of the combined effects of material properties, design details, and construction quality. Only through scientific sealing design, standardized construction management, and reasonable maintenance measures can the technical advantages of rubber-plastic materials in building and industrial insulation systems be fully utilized, providing long-term, reliable operational assurance for projects.