In liquefied natural gas (LNG) storage and transportation and related supporting projects, the reliability of the insulation system directly affects operational safety and energy efficiency. Among these, the system's sealing design is a crucial aspect ensuring the long-term stable operation of LNG elastic felt. Due to the extremely low temperature of LNG, any sealing defects can lead to heat loss, frost formation, and even structural risks. This article analyzes the sealing design requirements of LNG elastic felt systems from an engineering application perspective.

First, the sealing design should prioritize preventing moisture intrusion. LNG systems often operate in high-humidity environments. Once external moisture enters the insulation layer, it will rapidly condense and frost under low-temperature conditions, increasing heat loss and potentially damaging the elastic felt structure. Therefore, the system design should ensure a continuous and complete moisture-proof seal on the outer side of the insulation layer, avoiding discontinuous or weak areas.

Second, seams and overlaps are key areas for sealing design. LNG elastic felt typically employs a multi-layered structure. Improperly treated seams between materials and layers can easily become channels for moisture penetration. The design should clearly define the overlap width and direction, and, considering the characteristics of the low-temperature environment, select sealing materials that maintain flexibility and adhesion under cryogenic conditions to ensure that the joints do not crack or detach during long-term operation.

Third, the sealing material must have good low-temperature adaptability. Adhesives or sealing tapes that perform well at room temperature may become brittle or lose adhesion in ultra-low temperature environments. The sealing design of LNG elastic felt systems should focus on the sealing material's ability to maintain elasticity at low temperatures, its aging resistance, and its compatibility with the elastic felt substrate to avoid system failure due to material incompatibility.

Fourth, the effects of structural displacement and thermal expansion and contraction should be fully considered. LNG pipelines and equipment experience significant temperature changes and structural displacements during start-up, shutdown, and operation; the sealing system needs to have a certain degree of deformation adaptability. Rigid connections should be avoided in the design, and appropriate deformation space should be reserved in critical areas to ensure the sealing layer maintains continuity with structural changes.

Fifth, the sealing integrity of the outer protective layer is equally important. The outer protective layer not only provides mechanical protection but is also an important component of the sealing system. The interfaces, penetration points, and termination areas should be specifically designed to ensure effective connection with the moisture-proof layer and avoid the risk of multiple overlapping gaps.

Finally, the sealing design should also consider construction feasibility and quality control. Overly complex sealing structures are difficult to maintain consistency during actual construction, increasing the risk of failure. The design phase should be optimized in conjunction with construction techniques, and a systematic inspection should be conducted after construction to ensure the continuity and integrity of the sealing layer.

Overall, the sealing design of an LNG elastic felt system is a systematic project that requires a balance between material performance, structural adaptability, and construction controllability. Only through scientific and rigorous sealing design can the risk of moisture intrusion be effectively reduced, ensuring the long-term safe and stable operation of the LNG insulation system. This is also a key technical direction that building and industrial insulation material companies should focus on when serving LNG projects.