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Think of a cold room as a giant thermos: if the walls are compromised, the lid doesn't matter. Cold room panels form those walls. Get them right, and your compressors run efficiently; get them wrong, and your monthly energy bills will soar. It starts with thermal conductivity. Polyurethane (PU) and Polyisocyanurate (PIR) foams offer ratings around 0.018 to 0.024 W/m·K, vastly outperforming EPS and mineral wool. Simply put, a 100mm PU panel provides the same insulation as 200mm of EPS. Thinner walls mean more usable interior space, translating directly to operational savings. However, raw insulation isn’t enough. True energy efficiency comes from stopping air leaks. Traditional construction leaves gaps where cold air easily escapes, which can account for 15 to 20 percent of total energy loss. High-quality panels use precision tongue-and-groove edges sealed with a continuous bead of flexible sealant, turning the entire wall into a single, airtight envelope. Moisture control is another critical factor. Extreme temperature differentials pull water vapor into walls, and wet insulation inevitably fails. While EPS absorbs water over time, PU and PIR feature closed-cell structures that block moisture. At Propanel, we use PIR with a closed-cell rate above 97% to ensure decades of peak thermal performance. Panel thickness must also perfectly match your operating temperature. A +5°C chiller requires 75mm to 100mm of PU, while a -18°C freezer needs at least 150mm of PIR. Drop below -30°C, and you are looking at 200mm or more. The right thickness prevents overworked compressors and wasted capital. In fact, correctly spec'd panels can save 30,000 to 50,000 RMB annually on a 1,000-square-meter facility. Finally, don't ignore the steel skins. Z150 or Z275 galvanized coatings with polyester or PVDF finishes resist rust and harsh washdowns. A rusty panel creates thermal bridges, allowing heat to bypass the foam and potentially causing a 20% drop in overall insulating value.

Think of Polyurethane (PU) and Polyisocyanurate (PIR) panels as two brothers in the construction world. On the surface, they look identical, they originate from the same chemical family, and they both excel at their main job: keeping cold rooms cold. However, there is a crucial family trait that sets them apart: under extreme heat, PU melts, while PIR chars and holds its ground. Let's begin with what they have in common. Both are closed-cell rigid foams boasting a thermal conductivity of around 0.018 to 0.024 W/m·K—making them roughly 40% more thermally efficient than standard EPS. Both effectively resist moisture and can easily handle freezing temperatures down to -40°C. If you are operating a standard chiller at +2°C, you won't notice a difference in daily performance. If insulation efficiency were the only deciding factor, PU would easily win based on its lower price tag. The real divide between the two comes down to fire performance. PU is a thermoplastic foam. Under sustained heat, it softens, melts, and releases dense smoke. Standard PU panels generally achieve a B2 fire rating; while this passes basic local codes in many regions, it falls short of stricter European and Middle Eastern safety standards. PIR, on the other hand, is a thermosetting polymer. When exposed to a flame, a chemical reaction forces it to form a dense, rigid char layer. This layer actively shields the unburnt foam underneath and drastically slows the spread of the fire. Genuine PIR achieves a strict B1 rating with an oxygen index reliably above 35%. In laboratory testing, PIR's peak heat release rate is approximately 50% lower than PU's, and its char yield jumps from a mere 3% to over 22%. This isn't just marketing—it's measured, proven structural performance. There are a few other differences worth noting. PIR can handle continuous ambient temperatures up to 120°C, whereas standard PU begins to structurally degrade above 100°C. PIR also delivers higher compressive strength. With a density of around 45–55 kg/m³ compared to PU's 35–45 kg/m³, PIR is significantly more dimensionally stable in massive facilities that experience drastic temperature swings.

1. The Surface Material: Your First Line of Defense In food processing, demand stainless steel skins—never standard painted steel. Most modern facilities utilize 304 stainless steel for general production areas. Its smooth, non-porous finish easily withstands daily high-pressure washdowns. However, for high-risk zones or cleanrooms deploying aggressive sanitizers like vaporized hydrogen peroxide (VHP), upgrading to marine-grade 316L stainless steel is mandatory. While the initial investment is higher, 316L decisively resists the harsh chemical pitting and corrosion that would eat through standard 304 steel within a few years. The surface must remain flawlessly smooth, completely devoid of cracks or crevices where bacteria can hide. 2. The Insulation Core: Thermal Efficiency Meets Fire Safety For the vast majority of food plant cold rooms, Polyisocyanurate (PIR) foam is the undisputed smart choice. Premium PIR boasts an exceptionally low thermal conductivity of 0.018–0.020 W/m·K alongside a strict B1 fire rating. This delivers vastly superior insulation and significantly slower flame spread compared to standard PU foam. Whether you are storing frozen meat, deep-sea seafood, or ice cream at -18°C or below, PIR locks in temperature stability, preventing your heavy-duty compressors from burning out through non-stop operation. For specific fire-sensitive zones where local codes demand 100% non-combustible materials, high-density rock wool (Class A1) is the ultimate solution. Because rock wool insulates slightly less efficiently than PIR, panel thickness must be increased to achieve the target R-value. 3. Panel Thickness: Matching Specs to Operating Temperatures Panel thickness must be strictly calculated based on your target operational temperature: Chillers (+2°C to +5°C): 100mm thickness required. Standard Freezers (-18°C): 120mm to 150mm thickness required. Deep Blast Freezers (≤ -25°C): 150mm to 200mm thickness required. Under-specifying thickness guarantees a perpetual nightmare of surface condensation, ice buildup, and bleeding energy bills. Over-specifying simply wastes capital on unnecessary material. 4. Joint Integrity: Sealing Out Bacteria and Cold Loss Never overlook the panel joints. Cold air and microscopic bacteria will ruthlessly exploit any gap. Premium food-grade panels rely on deep, precision-milled tongue-and-groove edges. During installation, every single joint must receive a continuous, unbroken bead of specialized flexible sealant engineered to remain permanently pliable at sub-zero temperatures. The panel edges themselves must be fully protected during shipping and erection, as hidden dents and scratches inevitably transform into creeping rust spots and un-cleanable bacterial traps.

Constructing ISO-standard clean rooms for the food, pharmaceutical, electronics, and laboratory sectors requires careful attention to panel selection, construction details, and supporting systems; these factors directly determine the facility's effectiveness in dust prevention, bacterial inhibition, and temperature control. I. Selecting the Right Specialized Panels Based on ISO Class Standard sandwich panels are unsuitable for clean rooms.Specialized clean room sandwich panels—featuring smooth, non-shedding, and disinfectant-resistant surfaces—must be used. The core material should be selected based on specific requirements: rock wool offers superior fire resistance, making it ideal for facilities with strict fire safety standards (such as pharmaceutical plants); PIR panels provide low volatility and excellent thermal insulation, suiting temperature-controlled clean spaces; and PU panels offer a cost-effective solution for standard purification workshops. These panels feature smooth, dense surfaces that withstand repeated wiping with disinfectants and do not shed dust or particles, thereby preventing secondary contamination at the source. II. Specialized Accessories to Eliminate Sanitary "Dead Zones" Clean room construction utilizes interlocking panel systems that ensure tight joints and minimal gaps; seams are fully sealed with sealant to prevent the accumulation of dirt and contaminants. Rounded corner accessories are used throughout, eliminating cleaning blind spots at wall-to-floor and wall-to-ceiling junctions. Additionally, specialized airtight doors and sealed observation windows are installed to maintain the overall integrity of the sealed environment. III. Standardized Dry Construction to Minimize Contamination Clean room sandwich panels are prefabricated in the factory and assembled on-site using dry-assembly methods—eliminating the need for plastering or painting—which reduces dust pollution during construction. Sealant application at panel joints must be full and continuous, free of air bubbles or gaps, and all wall penetrations for utilities must be thoroughly sealed to prevent air leakage and dust ingress. IV. Integrating Purification Systems to Complete the Clean room Loop While sandwich panels create the airtight, dust-free enclosure, achieving ISO clean room standards requires the integration of purification HVAC systems, high-efficiency particulate air (HEPA) filters, pressure differential control systems, and air return systems. Stable control of indoor dust and microbial levels is achieved by combining continuous air filtration and the maintenance of stable indoor positive/negative pressure differentials—which block out contaminated external air—with the use of airtight wall panels. V. Standardized Acceptance and Convenient Maintenance Upon completion of construction, rigorous testing for airtightness, dust particle counts, and air leakage is required; the facility may only be put into operation once it meets the relevant standards. Routine maintenance is straightforward, requiring only periodic checks to ensure sealants have not cracked or detached. The panels allow for individual removal and installation, meaning localized damage can be repaired without extensive demolition or refurbishment; this significantly reduces losses associated with workshop downtime. Furthermore, the panels can be flexibly reused during future layout modifications, offering exceptional cost-effectiveness. Conclusion Constructing an ISO-compliant clean room requires selecting the right specialized cleanr oom sandwich panels, ensuring proper sealing and edge treatment, and integrating a comprehensive purification system. Meticulous attention to every construction detail is essential to consistently meet ISO clean room standards and satisfy the dust-free and sterile production requirements of various industries.

The sandwich panel factory building is a refined enclosure system, and 80% of the problems are caused by irregular installation. Common problems during the installation process are as follows: 1. Improper tightening of screws, causing chronic water leakage Self-tapping screws and EPDM waterproof washers are key waterproof nodes. If the screws are tightened too loosely, the gasket cannot fully fit the board surface, and tiny gaps will appear, allowing rainwater and moisture to slowly penetrate into the board core; if the screws are tightened too tight, the board surface will be crushed and the core material will be squeezed and damaged, causing the gasket to be permanently deformed and lose its waterproof performance. Many projects begin to seep water and have uneven board surfaces after half a year of use. This is basically caused by improper screw torque control. 2. The seams between the panels are not properly sealed and there is no complete vapor barrier. Some construction teams only rely on tongue-and-groove splicing of boards, omitting sealants and waterproofing auxiliary materials. The seemingly tight seams are actually full of tiny gaps. Especially in cold storage, slaughterhouses, and water-washed clean areas, moisture will continue to penetrate into the core of the board, causing the insulation layer to fail to absorb water, causing the board to become moldy and breed bacteria. In severe cases, it cannot pass the HACCP health acceptance. Insufficient overlap length of roof panels and glue faults are the number one causes of roof leakage. 3. Neglecting cold bridge treatment, serious condensation in cold storage This is the most fatal mistake in cold storage projects. In many construction sites, the panels are installed directly against the steel purlins and steel columns without adding heat insulation pads. Metal conducts heat very quickly, forming a large number of cold bridges. The temperature difference between inside and outside is conducted rapidly, causing frequent condensation and dripping on walls and ceilings. Not only does it increase the power consumption of the cold storage, but long-term water accumulation can also cause the steel plates to rust and the core materials to become damp and aged, significantly reducing the overall thermal insulation performance. 4. The installation direction of the roof panel is reversed and drainage fails. Roof panels must be laid strictly in the water direction from the eaves to the ridge. Reverse installation will directly block the flow of rainwater, causing rainwater to pour back and accumulated water to flow into the seams of the boards. If the ribbed roof panels are installed upside down, the panels will not be able to drain naturally. Long-term water accumulation will accelerate the aging and corrosion of the paint surface and shorten the service life of the panels. Confusing the installation sequence will also lead to uneven joints and reduced sealing. 5. Random cutting on site will destroy the edge sealing structure of the board. Random cutting of panels at door and window openings and corners will destroy the original factory sealing and edge sealing, causing the core material to be directly exposed. Once the incisions of rock wool and PIR boards are not subjected to secondary sealing treatment, they are easily susceptible to moisture absorption, delamination, and degumming, resulting in local insulation failure and a decrease in fire protection level, seriously affecting the overall project quality.   Sandwich Panel Project, Standardized screw fastening, sealing technology, cold bridge partitions, downstream installation, and incision protection can truly ensure that factories, cold storage, and clean workshops will not leak, condensate, or mold for a long time, making the project stable and durable.

Clean rooms in sectors such as traditional food processing, pharmaceuticals, electronics manufacturing, and laboratories often utilize latex paint or tiled wall finishes. These surfaces are characterized by numerous micropores and seams that easily harbor dust and microorganisms, making thorough cleaning difficult; furthermore, they are prone to mold growth in humid environments, struggling to consistently meet high cleanliness standards. Clean room sandwich panels address these pain points through their fundamental design. Featuring dense metal facings on both sides, the panels offer a smooth, non-porous surface that resists the accumulation of dust and grease. They can be directly wiped down with disinfectants and withstand repeated sanitization without fostering bacterial growth. These panels utilize a specialized interlocking tongue-and-groove design, ensuring flush joints that are sealed with sealant. The use of curved corner accessories eliminates right-angled "dead zones" and crevices where dirt might otherwise accumulate. Core materials—such as PIR or rock wool—are resistant to moisture absorption, thereby minimizing the risk of mold growth at the source and preventing the generation of secondary dust pollution caused by crumbling or shedding. Clean room sandwich panels are prefabricated in the factory according to specific dimensions and assembled directly on-site. Unlike plastering or painting, which generate significant construction waste, this method reduces pollution during the construction phase. Maintenance is straightforward; localized damage requires replacing only the affected panel rather than large-scale demolition, thereby minimizing facility downtime. Additionally, the panels can be dismantled and reused during workshop renovations. In summary, clean room sandwich panels mitigate contamination risks at the source rather than relying on intensive cleaning to compensate for material deficiencies, effectively maintaining workshop hygiene and cleanliness standards.

When constructing clean rooms for industries such as food processing, pharmaceuticals, or electronics, many clients face a dilemma regarding wall materials, Should they choose traditional options like latex paint and ceramic tiles, or specialized clean room wall panels? In terms of initial cost alone, traditional materials are cheaper. However, in a clean room environment, their shortcomings become glaringly obvious. Ceramic tiles and plastered walls require complex installation processes—involving leveling, tiling, and grouting—which result in long construction times and high labor costs. Grout lines and microscopic surface pores easily accumulate dust and grime, fostering mold growth over time that is difficult to fully eradicate. Latex-painted walls are prone to peeling and cracking; once damaged, they require extensive scraping and repair, leading to costly production downtime. For facilities requiring dust-free or sterile environments, traditional wall surfaces often struggle to consistently meet cleanliness standards. Clean room wall panels (often made of color-coated steel) are prefabricated factory products available with various core materials—such as rock wool, PIR, or PU. They are assembled directly on-site,being lightweight and easy to handle, they significantly reduce construction time and labor costs. Their surfaces are dense and smooth, allowing dust and oil stains to be wiped clean instantly with a damp cloth. Panel joints are sealed to eliminate dirt-trapping crevices, meeting the rigorous demands for frequent disinfection in clean rooms. These panels are lightweight, reducing the load on the building's structural framework. Furthermore, core materials and thicknesses can be customized to meet specific requirements—such as fire resistance, thermal insulation, and humidity control—for applications ranging from operating rooms and laboratories to temperature-controlled workshops and cold storage facilities. They also facilitate future facility modifications, as the panels can be dismantled and reused with minimal waste. While the upfront procurement cost of clean room wall panels is higher than that of standard paint or tiles, and installation requires skilled craftsmanship—as improper sealing can compromise cleanliness—they offer distinct advantages. In summary，traditional building materials are a cost-effective choice for standard warehouses or factories that do not require clean room standards. For production environments requiring dust-free conditions, antibacterial properties, and frequent cleaning, clean room wall panels entail a higher initial investment; however, their ease of maintenance, long service life, and lower overall cost—combined with the ability to mitigate the risk of product contamination—make them a superior choice.

Many cold storage experience frequent problems after being put into use, such as frost buildup, water leakage, slow cooling, soaring electricity bills, and panel deformation. These are not equipment malfunctions, but rather hidden problems created during the construction phase. Today, we summarize some of the most common mistakes in cold storage construction and provide practical solutions to help you avoid these pitfalls and build a durable, low-consumption standard cold storage facility.   I. Blindly Choosing Low-Priced Materials: Incompatible Panel Thickness and Density with Operating Conditions This is the most common problem. Many people, in an effort to cut costs, choose thin, low-density, inferior insulation panels, or use generic panels regardless of temperature range. Using thin panels in low-temperature cold storage will result in severe cold leakage and thermal bridging, leading to long-term frost buildup and a gradual decline in insulation performance. Furthermore, neglecting flame retardant ratings poses a significant fire safety hazard.   Solution: Select materials precisely according to the storage temperature. For cold storage above freezing, use 50–75mm PU composite panels; for freezing below freezing, use 100–150mm high-density PU composite panels; and for ultra-low temperature quick-freezing, prioritize 150–200mm B1-grade PIR composite panels. Before construction, verify the density, thermal conductivity, and flame retardant rating of the boards to prevent the use of inferior materials.   II. Neglecting Construction Details: Inadequate Sealing and Ground Treatment. Incomplete sealing of board joints, missing seams, and lack of edge reinforcement are major causes of cold air leakage. Furthermore, many small cold storage facilities neglect ground insulation and moisture protection, making them highly susceptible to frost heave, cracking, and arching under low-temperature conditions, directly leading to deformation of the storage structure and door jamming.   Prevention Methods: Ensure thorough sealing of board joints and proper edge reinforcement; low-temperature cold storage floors must be covered with a moisture-proof membrane and a pressure-resistant insulation layer, combined with frost-resistant concrete pouring, and maintain ground flatness to prevent frost damage at its source.   III. Mismatch Between Refrigeration Equipment and Storage Structure. Either pursuing high-power units results in energy waste, or prioritizing low-power units to save money leads to slow cooling, 24-hour full-load operation of units, rapid equipment aging, and high electricity costs. Meanwhile, improper installation of temperature control probes can lead to inaccurate temperature readings and large temperature fluctuations.   Solution: Accurately match the unit model to the cold storage area, storage temperature, and frequency of goods entering and leaving the warehouse, and install temperature control equipment according to regulations to ensure uniform and stable temperature and reduce equipment operating load.   IV. Neglecting Compliance Design and Acceptance Testing Some cold storage facilities are haphazardly laid out, lacking evacuation routes and fire compartments, failing to meet fire safety regulations, resulting in extremely high rectification costs later. Furthermore, many projects are put into use directly after completion, omitting no-load testing and hiding numerous operational hazards.   Solution: Plan the layout in accordance with regulations before construction, reserving safety passages and implementing fire compartments. After completion, conduct a 72-hour no-load temperature measurement and defrosting test to ensure stable temperature and normal equipment operation before putting the facility into use.   Summary: Cold storage construction should prioritize details over low prices. Reasonable material selection, standardized construction, and precise configuration are essential to effectively reduce later maintenance costs, extend the lifespan of the cold storage, and achieve long-term stable and low-cost operation.

Cold storage panel are typically composed of double-layer galvanized steel sheets and a layer of polyurethane (PU or PIR) insulation core material. Their thermal conductivity is only 0.024–0.041 W/m·K, providing excellent insulation performance. Common panel thicknesses include 50mm, 75mm, 100mm, 150mm, and 200mm. Thicker panels offer better insulation, lower refrigeration unit load, and more stable internal temperature.   The thickness of the cold storage panel directly determines the energy consumption, temperature control stability, and overall lifespan of the cold storage facility. Improper thickness selection can easily lead to temperature fluctuations, frost formation on the walls, increased power consumption, and panel deformation and damage. Storage temperature is the sole core factor in selecting panel thickness.   1. Fresh-keeping cold storage (+2℃ ~ +10℃) | 50–75mm is preferred. This temperature range is often used for preserving fruits and vegetables, fresh produce, dairy products, and in temperature-controlled food processing workshops. The temperature difference between the inside and outside is small, and the operating conditions are relatively simple. 50–75mm thick insulated cold storage panel fully meet the requirements, effectively blocking outdoor heat penetration and maintaining a stable internal temperature environment. This thickness offers high cost-effectiveness, balancing construction costs and long-term energy consumption, making it the optimal choice for above-zero cold storage.   2. Low-Temperature Cold Storage (-5℃ ~ 0℃) | 80–100mm is preferred This is primarily used for the low-temperature storage of cooked food, semi-finished meat products, and beverages. This temperature range already possesses low-temperature properties; using thin 50mm panels would result in insufficient insulation, leading to heat penetration, condensation on the panels, and dampness on the inner walls, damaging the storage environment.   80–100mm thick cold storage panel is the standard configuration for this scenario, significantly reducing hot and cold air exchange, eliminating condensation and frost problems, ensuring long-term stable operation of the cold storage, and effectively reducing energy consumption.   3. Conventional Cold Storage (-10℃ ~ -25℃) | 100–150mm is preferred  This temperature range is commonly used in commercial frozen goods, seafood, and meat cold storage warehouses, and is also the most frequently used freezing condition in cold chain engineering.   The industry prioritizes 100–150mm thick insulation panels. The high-density, thickened core material effectively locks in the low temperature, prevents cold air leakage, and reduces the frequency of refrigeration equipment start-ups and shutdowns.   4. Ultra-Low Temperature Quick-Freezing Storage (-30℃ ~ -55℃) | 150–200mm is preferred Quick-freezing workshops, deep-sea food storage, and medical low-temperature storage scenarios experience extreme temperature differences, requiring stringent insulation performance. Ordinary thickness panels are unsuitable.   150–200mm thick high-density cold storage panels are a mandatory standard for these projects. They can withstand extreme temperature shocks, preventing frost penetration, panel deformation, and temperature imbalances, protecting high-value goods. Although the initial investment is slightly higher, it ensures long-term stable operation of the cold storage and is a reliable solution for ultra-low temperature projects.   In conclusion, the appropriate thickness of the cold storage panel depends on the storage temperature of the cold storage facility. Selecting PU/PIR cold storage panel of different thicknesses based on varying temperature requirements can mitigate construction risks, reduce energy waste, and result in a cost-effective, stable, and durable high-quality cold storage unit.  

Cold storage panel installation is a core process in cold storage engineering, and the details of the construction directly determine the insulation effect, energy consumption, and service life of the cold storage. Many cold storage facilities experience problems such as cold leakage, frost formation, deformation, and water leakage later on, and 80% of these are caused by improper installation.   1. Pre-construction preparation. Verify the panel parameters in advance, confirm the panel thickness and flame retardant rating according to the temperature control requirements of the cold storage, and check the panel surface for dents, delamination, and damage. At the same time, clean the construction ground, ensuring it is flat, dry, and free of debris. For low-temperature cold storage, a moisture-proof layer must be laid in advance to prevent the floor from stretching the panels due to freezing. Prepare specialized sealant, angle aluminum, and pressure strips in advance; do not use ordinary household sealing materials.   2. The installation of the base plate and walls requires control over flatness and sealing. First, locate and mark the installation points of the panels accurately, ensuring overall horizontal and vertical alignment. When installing the bottom panels, ensure even gaps are left, and apply a full layer of special low-temperature sealant to all joints to prevent hollow gaps. This is a crucial step in preventing cold bridging and condensation. After the wall panels are assembled, reinforce them with strips and angle brackets immediately, paying special attention to sealing edges and corners to prevent cold air leakage. Continuously check verticality throughout the installation process; deviations must be kept within specifications.   3. Top panel installation is the most error-prone stage. Top panel joints must not have upward-facing gaps. All joints must face inwards, and the sealant must be full, dense, and free of breaks or air bubbles. Reinforcing brackets must be installed at load-bearing locations on the top panels to prevent them from being suspended and deformed or detached under long-term stress. Avoid drilling holes for pipes; ensure all openings are properly sealed to prevent cold air leakage.   4. Pay close attention to finishing details and acceptance procedures. Irregularly shaped areas such as doors, vents, and access panels require meticulous sealing to prevent air leakage from dead corners. After all panels are installed, apply a final coat of sealant, inspect all seams and edges, and repair any omissions or defects. Finally, conduct a no-load cooling test to observe for frost, water seepage, abnormal temperature differences, etc. Once everything is confirmed to be in order, the project is considered complete and ready for handover.   In summary, proper material selection, standardized splicing, and meticulous sealing are essential for cold storage panel installation. This not only improves the insulation stability of the cold storage and reduces future energy consumption but also minimizes rework and rectification, enhancing the project's delivery reputation.

Cold storage insulation materials are currently mainly divided into three types: PU polyurethane, PIR modified polyurethane, and EPS polystyrene. These three differ significantly in insulation performance, price, and suitable application scenarios. In practical applications, the appropriate material can be selected based on specific needs.   PU polyurethane sandwich panels are the preferred material for general cold storage. With a thermal conductivity of 0.022-0.024 W/m·K, high closed-cell rate, and low water absorption, their thermal insulation and sealing performance is superior to ordinary insulation panels. The panels have high structural strength and are not easily deformed. The flammability rating can reach B1 (with added flame-retardant formulation), and is mostly B2 under normal operating conditions. The long-term applicable temperature range is -35℃ to +10℃, suitable for most commercial cold storage conditions, including fresh-keeping warehouses, low-temperature warehouses, and general frozen warehouses. The panels have tight joints, effectively reducing cold bridging and leakage problems. With outstanding overall cost-effectiveness, it is currently the most widely used cold storage insulation material on the market. The market price is moderate, suitable for conventional cold chain projects with a controllable budget.   PIR modified polyurethane sandwich panel, specifically designed for high-end low-temperature cold storage.  Its thermal conductivity reaches 0.019-0.022 W/m·K, offering slightly better insulation performance than PU panels. It boasts superior flame retardancy, is less prone to producing molten droplets during combustion, and consistently achieves B1 flame retardancy rating. It also exhibits better high-temperature resistance. With a long-term operating temperature range of -55℃ to +15℃, it shows minimal insulation degradation under ultra-low temperature conditions. The panel exhibits stronger anti-aging properties, making it suitable for high-end projects with stringent fire safety standards, such as blast freezers, ultra-low temperature cold storage facilities, and medical cold chain warehouses. While offering excellent insulation and low-temperature stability, its main drawback is its higher cost, exceeding that of ordinary PU panels by 15%-30% per square meter. It is more suitable for critical projects with high safety and temperature control requirements.   EPS polystyrene sandwich panel, an economical alternative for cold storage. EPS insulation panels are lightweight, inexpensive, and easy to install, making them suitable for cold storage facilities with limited budgets and less stringent temperature requirements. Its thermal conductivity is 0.038–0.041 W/m·K, indicating weak thermal insulation capabilities and poor moisture and frost resistance. Long-term use at low temperatures can lead to water absorption, deformation, and decreased insulation performance. It is only suitable for fruit and vegetable preservation and ambient/constant temperature workshops, and is not recommended for low-temperature or frozen storage.   In summary, cold storage insulation materials should be selected according to specific needs. PIR insulation panels are preferred for high-end low-temperature or ultra-low-temperature cold storage, PU insulation panels are suitable for conventional commercial high and low-temperature cold storage, and EPS insulation panels are suitable for ordinary preservation and constant temperature scenarios.  

The service life of sandwich panels is primarily determined by the facing material, facing coating, core material type, operating environment, and subsequent maintenance; lifespan varies significantly depending on the materials used and the application scenario.   The facing material is a key factor determining service life: in standard inland environments, panels featuring an Al-Zn (aluminum-zinc) alloy substrate (AZ100/AZ150) with a PE (polyester) coating typically last 12–15 years, whereas those with a PVDF (fluorocarbon) coating offer superior weather resistance, extending the lifespan to 20–25 years. In highly corrosive environments—such as coastal areas with salt spray or chemical industrial parks—standard Al-Zn panels are prone to rusting; in these cases, 304 stainless steel substrates with PVDF coatings are recommended, offering a service life of over 25 years with proper maintenance.   Performance also varies based on the core material: PIR and rock wool sandwich panels offer structural stability; closed-cell PIR sandwich panels provide excellent moisture and aging resistance, maintaining their shape over long-term use. Conversely, EPS sandwich panels are prone to shrinkage and degradation in high-temperature or humid environments, which can shorten their service life.   Additionally, proper installation and regular maintenance can effectively extend the lifespan of sandwich panels. Avoiding impact, promptly repairing coating damage, and ensuring effective joint sealing help minimize rust and core material damage. With appropriate material selection and maintenance, high-quality sandwich panels can achieve a service life of over 30 years in certain applications.