LNG elastic felt is mainly used in liquefied natural gas pipelines, cryogenic storage tanks, and cryogenic equipment, with long-term operating temperatures down to approximately -160℃. The cryogenic conditions necessitate careful consideration of the material's performance in terms of shrinkage, elastic recovery, and sealing continuity during construction; otherwise, cracking, delamination, or frost formation may occur after commissioning.

I. Basic Construction Requirements for Cryogenic Conditions

While LNG elastic felt possesses excellent cryogenic flexibility, its performance depends on proper construction conditions. The core objective during construction is to allow sufficient space for cryogenic shrinkage and deformation under normal temperature conditions, while ensuring the insulation layer remains continuous, dense, and stable during cryogenic operation.

Therefore, construction methods cannot be simply equated with those for ordinary rubber and plastic or conventional insulation materials.

II. Construction Environment and Substrate Condition Control

Before construction of the cryogenic system, the environment should be kept dry and clean. The surfaces of pipelines or equipment must be free of moisture, oil, frost, or ice crystals. If the moisture content of the substrate is too high, an ice layer can easily form at the interface after the system cools down, damaging the adhesion and bonding effect.

The anti-corrosion layer of the metal substrate should be fully cured to prevent interface peeling due to anti-corrosion layer failure during low-temperature operation.

III. Key Points for Material Layout and Stress Control

In cryogenic systems, LNG elastic felt must not be installed under stress. During construction, the material should be naturally laid out; stretching, compression, or forced alignment is prohibited.

If the material is artificially stretched at room temperature, it will further shrink under cryogenic conditions, easily leading to tearing or detachment at the joints. The correct approach is to ensure the material is in a "naturally relaxed state" after installation, allowing for deformation due to cryogenic shrinkage.

IV. Cutting Accuracy and Adhesion Continuity

The elastic felt should be cut to accurate dimensions with straight cuts and tight joints. Cutting too small will create tensile stress, while cutting too large will cause wrinkles and gaps, both detrimental to cryogenic operation.

During adhesion, ensure full contact between the material and the substrate, avoiding any gaps, bulges, or air pockets. Air pockets can become cold bridges and sources of frost under cryogenic conditions.

V. Low-Temperature Adaptability Treatment of Joints and Overlaps

Joints are a critical control point in the low-temperature construction of LNG elastic felt.

Joints should adopt a reasonable overlap pattern, with the overlap width meeting design requirements and ensuring continuity and uniformity at the interface.

In multi-layer insulation structures, joints of each layer should be staggered to avoid forming through gaps. During low-temperature operation, such through gaps easily become channels for concentrated cold release.

Joint sealing materials should possess low-temperature flexibility, ensuring they do not crack or detach at -160℃.

VI. Multi-Layer Construction and Interlayer Stability Control

LNG systems often employ multi-layer elastic felt structures. After each layer is constructed, its integrity, fit, and sealing should be checked before proceeding to the next layer.

Dust, moisture, or foreign matter must not be trapped between layers; otherwise, interlayer slippage or localized voids may occur during low-temperature shrinkage, affecting the overall insulation effect.

VII. Low-Temperature Matching of Moisture Protection and Outer Protective Structure

Although LNG elastic felt possesses a certain resistance to cold shrinkage, the overall moisture protection performance of the system depends on the outer protective structure.

The moisture-proof layer should be continuous and intact, with reliable joint seals to prevent moisture from penetrating the insulation layer and freezing during operation.

The outer protective structure must balance mechanical strength and thermal displacement adaptability to avoid additional stress caused by temperature changes, which could damage the insulation layer.

VIII. Low-Temperature Operation Risk Inspection After Construction

Before the system is put into operation, the following should be checked:

Whether the insulation layer is continuous and intact;

Whether there are signs of tension, compression, or obvious stress;

Whether the joints and overlaps are reliably sealed;

Whether the moisture-proof and outer protective system is closed.

If necessary, a focused inspection can be conducted at the initial stage of cooling to promptly identify potential problems.

In summary, the core of low-temperature construction of LNG elastic felt is not simply "applying it," but rather "stress-free, continuous, and shrinkable." Only by strictly controlling stress, joints, and protective details during the construction phase can we ensure that it can maintain stable cold insulation performance under extremely low temperature conditions for a long time.