Composition of Cold Room Materials: A Complete Guide

As we know, for a cold room to effectively preserve freshness or maintain a frozen state, the indoor temperature must be kept stable at the required room temperature for the products. Therefore, the materials used in constructing a cold room are crucial to its performance and functionality. These materials significantly impact the insulation quality, structural stability, and sealing properties of the cold room. This article will provide a detailed overview of the materials used in cold room construction, hoping to offer useful assistance in understanding their importance.

Cold Room

 

Wall Panels

Wall panels are a critical component of a cold room, requiring both excellent insulation properties and structural stability.

Wall panels

PIR Sandwich Panels

PIR sandwich panels are high-quality insulation materials known for their superior thermal insulation and fire resistance. They consist of two layers of metal surface panels with a core of PIR (polyisocyanurate) foam, forming a sandwich-like structure. The outer metal layers provide protection and support, while the PIR foam core serves as the insulating component.

Materials for Metal Surface Panels

The outer metal surface panels of PIR sandwich panels are primarily made from materials such as PPGI, PPGL, stainless steel, and embossed aluminum.

PPGI

PPGI, or pre-painted galvanized steel, undergoes a process of galvanization and color coating. This not only provides the mechanical strength and formability of steel but also offers a wide range of color choices and good corrosion resistance. However, the surface of PPGI sheet is prone to scratches, which can occur during the loading and unloading process in cold rooms, affecting the aesthetic appearance.

PPGL

Similar to PPGI, PPGL is also a type of pre-painted steel, but it uses an aluminum-zinc alloy coating. PPGL offers better corrosion resistance, maintaining protective properties even when the surface coating is worn. If high corrosion resistance is a priority, PPGL is an excellent choice.

Stainless Steel

Stainless steel is known for its high hardness and resistance to scratches, offering excellent wear and corrosion resistance. Its surface is smooth and without pores, making it less likely to harbor bacteria and offering good antibacterial properties. However, compared to PPGI and PPGL, stainless steel has a higher manufacturing cost and better heat conductivity, which might affect the insulation performance of the cold room and increase energy consumption.

Embossed Aluminum

Embossed Aluminum

Embossed aluminum offers excellent corrosion resistance and high-temperature tolerance. Aluminum is lighter than steel, providing higher strength and rigidity, which helps maintain the stability of the cold room structure while reducing its overall weight. However, aluminum is more expensive than steel and has better heat conductivity, which could impact the insulation within the cold room and lead to higher energy consumption.

Features

Excellent Insulation Performance

PIR sandwich panels have a low thermal conductivity, which means they have poor heat conduction capabilities and can effectively insulate. Therefore, PIR sandwich panels offer excellent insulation performance, making them highly suitable for use in cold rooms.

Excellent Fire Resistance

PIR foam is highly fire-resistant, typically achieving a B2 rating. During production, adjustments in the chemical composition, concentration, and other formulation techniques of the PIR foam material can enhance its fire resistance, with flame retardant levels reaching B1.

Light Weight and High Strength

PIR sandwich panels are lightweight yet structurally strong, ensuring the stability of the cold room structure while also reducing the overall weight of the cold room.

Low Water Absorption

When materials absorb water, it increases their thermal conductivity and can also lead to deformation. Thus, it’s advisable to use materials with low or no water absorption when constructing walls. PIR foam has a very low water absorption rate, about 0.9%, making it particularly well-suited for cold rooms.

Higher Cost

Compared to other materials like PU sandwich panels, EPS sandwich panels, and rock wool panels, PIR sandwich panels are more expensive, which can increase the construction costs of cold rooms.

PU Sandwich Panels

PU sandwich panels are also high-quality insulation materials, known for their excellent thermal insulation and fire resistance properties. These panels consist of two layers of metal surface panels with a core of PU (Polyurethane) foam, creating a sandwich-like structure. The outer metal layers provide protection and support, while the PU foam core serves to insulate.

Materials for Metal Surface Panels

Materials for Metal Surface Panels

Similar to the previously mentioned PIR sandwich panels, the outer metal surface panels of PU sandwich panels primarily include options such as PPGI, PPGL, stainless steel, and embossed aluminum. Each material has its unique characteristics, allowing for the selection of the appropriate type based on specific needs.

Features

Good Insulation Performance

PU sandwich panels also have good insulation properties, although their thermal conductivity is usually a bit higher than that of PIR sandwich panels, making their insulation slightly less effective.

Good Fire Resistance

PU sandwich panels also have good fire resistance, although they are slightly inferior to PIR sandwich panels in this regard. Typically, the fire retardant rating for PU panels is B3, but this can be improved to B2 with the addition of appropriate fire retardants.

Lightweight and High Strength

PU sandwich panels are lightweight yet offer high structural strength, ensuring the stability of the cold room structure while also reducing its overall weight.

Low Water Absorption

Materials that absorb water can increase their thermal conductivity and are prone to deformation. Therefore, it is advisable to use materials with low or no water absorption in wall construction. The water absorption rate of PU foam is slightly higher than that of PIR foam, usually between 2.5% – 3%, but it is still quite suitable for cold rooms.

Moderately Priced

Compared to other materials such as EPS sandwich panels and rock wool panels, PU sandwich panels are relatively expensive. However, due to their slightly inferior performance compared to PIR sandwich panels, the price of PU panels is somewhat lower than that of PIR panels.

EPS Sandwich Panels

EPS Sandwich Panels

EPS sandwich panels are a common type of building insulation material, known for their excellent thermal insulation properties. They consist of two metal surface panels with a core of EPS (Expanded Polystyrene) foam, forming a sandwich-like structure. The outer metal layers provide protection and support, while the EPS foam core serves the purpose of insulation.

Materials for Metal Surface Panels

As previously mentioned, the outer metal surface panels of EPS sandwich panels primarily include materials such as PPGI, PPGL, stainless steel, and embossed aluminum. Each material has its unique characteristics, allowing for the selection of the appropriate type based on specific requirements.

Features

Good Insulation Performance

EPS sandwich panels have a low thermal conductivity, providing effective insulation and excellent thermal resistance.

Light Weight and High Strength

EPS sandwich panels are light in weight yet have high structural strength, which not only ensures the stability of the cold room structure but also reduces the overall weight of the cold room.

Poor Fire Resistance

EPS sandwich panels have poor fire resistance as EPS foam is highly flammable, making them unsuitable for buildings where high fire resistance is required.

High Water Absorption

When used in cold rooms, EPS sandwich panels are prone to absorbing water, which can affect the insulation performance of the cold room. Therefore, proper moisture and waterproofing measures are essential during construction.

Relatively Low Cost

Compared to PIR and PU sandwich panels, EPS sandwich panels are less expensive, making them a cost-effective option for building cold rooms.

Rock Wool Sandwich Panels

Rock Wool Sandwich Panels

Rock wool sandwich panels consist of two metal surface layers and a core made from rock wool, forming a sandwich-like structure. The outer metal layers serve protective and supportive roles, while the rock wool core provides insulation. Rock wool sandwich panels are known for their good insulation properties, excellent fire resistance, and sound absorption capabilities.

Materials for Metal Surface Panels

As previously mentioned, the outer metal surface panels of rock wool sandwich panels primarily include materials such as PPGI, PPGL, stainless steel, and embossed aluminum. Each material has its own unique characteristics, allowing for the selection of the appropriate type based on specific requirements.

Features

Good Insulation Performance

Rock wool sandwich panels have a low thermal conductivity, which allows for effective insulation and heat retention. However, their insulation performance is slightly inferior compared to PIR and PU sandwich panels.

Excellent Fire Resistance

Rock wool has excellent fire resistance properties and is non-combustible, making rock wool sandwich panels highly suitable for buildings with strict fire safety requirements.

Good Sound Absorption

Rock wool features a porous structure that can effectively absorb sound waves, reducing indoor noise and enhancing indoor comfort.

Lower Strength

Rock wool has relatively low strength and can easily fracture. Therefore, care must be taken to avoid heavy pressure or severe impact during the transportation, installation, and dismantling of rock wool sandwich panels.

High Water Absorption

Rock wool sandwich panels can absorb moisture, which may impact the insulation effectiveness in cold rooms. Proper moisture and waterproofing measures must be implemented during construction.

Relatively Low Cost

Compared to PIR and PU sandwich panels, rock wool sandwich panels are less expensive, making them a cost-effective option for constructing cold rooms.

 

Roof Panels

Roof Panels

Roof panels are one of the main components of a cold room and also need to have good insulation performance and stable structure. Typically, the materials used for roof panels are the same as those used for wall panels, primarily including PIR sandwich panels, PU sandwich panels, EPS sandwich panels, and rock wool sandwich panels. 

As mentioned earlier, different materials have different characteristics, and the appropriate roofing material should be chosen based on specific needs. For cold rooms that require high insulation and fire resistance, PIR and PU sandwich panels are usually selected. If fire resistance is not a high priority and cost savings are desired, EPS sandwich panels might be chosen. If insulation is not the primary concern but high fire resistance is needed for cost savings, rock wool sandwich panels can be a suitable choice.

 

Floor Panels

The floor panels used in cold rooms typically need to be slip-resistant, wear-resistant, and corrosion-resistant, while also considering the load-bearing capacity of the floor. Here are some commonly used floor materials.

Floor Panels

Epoxy Floor

Epoxy floor is made from a mixture of epoxy resin and a hardening agent. The floor undergoes various pre-treatment processes such as leveling, sanding, repairing, and cleaning before an even layer of epoxy coating is applied. To enhance slip resistance, anti-slip particles can be evenly sprinkled over the surface of the epoxy layer.

Epoxy floors are known for their excellent wear resistance, corrosion resistance, and dust resistance, making them easy to clean and less likely to harbor bacteria. Additionally, epoxy coatings are available in a wide range of colors, which can be customized according to specific needs. However, the construction cost of epoxy flooring is relatively high and it requires professional equipment and construction techniques, making its use in cold rooms less common.

PVC Floor

PVC floor is primarily made from PVC material and is composed of a surface coating, decorative layer, middle layer, and backing layer. PVC floors offer excellent waterproof and slip-resistant properties, and are easy to install and clean. For anti-static requirements, conductive materials can be incorporated into the PVC floor to create anti-static PVC floors. However, PVC floor is less wear-resistant and can be prone to wear and deformation. Regular cleaning is necessary to prevent issues like water accumulation, and care should be taken to avoid scratches from sharp objects.

Insulated Layer Floor

Insulated Layer Floor

 

Insulated layer floor involves installing a layer of insulation material, such as PIR or PU sandwich panels, over an existing floor. To enhance slip resistance, one side of the PIR or PU sandwich panel typically has a non-slip aluminum surface, while the other side is color steel sheet. This floor provides excellent slip resistance and enhances the thermal insulation of the cold room, preventing ground freezing. However, insulated layer floors have relatively lower load-bearing capacity and cannot support the operation of heavy equipment like forklifts inside the cold room, making them more suitable for small cold rooms.

Concrete Floor

After treating the existing floor base with waterproofing, moisture protection, and insulation measures, concrete is poured over it. Typically, PE plastic film and XPS panels are used for waterproofing, moisture protection, and insulation of the floor. PE plastic film is cost-effective and easy to install, providing a barrier against moisture penetration. XPS panels offer excellent insulation, fire resistance, and moisture resistance. They do not absorb water and do not expand or deform even in damp conditions for extended periods.

Concrete floors not only provide excellent insulation but are also highly wear-resistant and impact-resistant, capable of supporting the operation of transportation equipment like forklifts within the cold room. Therefore, concrete floors are more suitable for medium and large cold rooms.

 

Doors

To ensure the thermal efficiency of a cold room, the doors must have excellent insulation and sealing properties. Here are some common types of cold room doors.

Doors

Hinged Doors

Hinged doors are the most commonly used type of cold room door. They are usually made from steel sheets and polyurethane or other insulating materials to effectively block cold air when the door is closed. Additionally, they often feature special sealing strips to prevent cold air leakage and are equipped with robust hinge systems to ensure stability and durability.

Hinged doors are easy to install and are suitable for small to medium-sized cold rooms. Depending on the requirements of the cold room, you can choose between half-buried hinged doors or All-buried hinged doors, and single or double hinged doors. The size can also be customized according to your specifications.

All-buried Hinged Doors

All-buried hinged doors are embedded entirely into the wall, flush with the wall surface, creating a neat and aesthetically pleasing appearance. The overall structure is stable, but installation and maintenance can be relatively complex.

Half-buried Hinged Doors

Half-buried hinged doors do not align flush with the wall, making them easier to install and maintain. However, the structural strength of these doors is generally lower compared to all-buried hinged doors.

Sliding Doors

Sliding Doors

Sliding doors are another commonly used type of cold room door, typically made from steel sheets and polyurethane or other insulating materials. The door panels are mounted on a track either on the wall or within the door frame, allowing them to move horizontally along the track. This design enables the doors to open and close without requiring additional space, making them suitable for environments where space is limited or needs to be conserved. Sliding doors come in both manual and electric types. Depending on the requirements of the cold room, you can choose between single or double doors.

Manual Sliding Doors

Manual sliding doors offer several advantages including space efficiency, good sealing, simple operation, cost-effectiveness, and relatively easy installation and maintenance. They are suitable for small to medium-sized cold rooms.

Electric Sliding Doors

Electric sliding doors provide efficiency and convenience, with simple operation, time-saving and labor-saving benefits, and high reliability. However, their installation and maintenance are relatively complex, making them suitable for medium to large cold rooms.

Industrial Sliding Doors

Industrial sliding doors are primarily composed of door panels, tracks, transmission mechanisms, and seals. They are widely used in large cold rooms and are suitable for wide cold room entrances. The door panels are typically made from steel sheets and polyurethane or other insulating materials. Similar to sliding doors, the panels of industrial sliding doors are mounted on tracks either on the wall or within the door frame, allowing them to slide vertically. This design allows the doors to open and close without requiring extra space, making them suitable for environments where space is limited or needs to be conserved. There are two types of industrial sliding doors: manual and electric.

Fast-rolling Doors

Fast-rolling doors consist of a curtain, tracks, transmission mechanisms, and seals. They are extensively used in environments that require frequent opening and closing, such as food processing plants, logistics centers, room centers, and supermarkets. The frame of a fast-rolling door is usually made of stainless steel or aluminum alloy, and the curtain is often made from high-strength polyester fiber wear-resistant fabric. This material offers excellent flexibility and durability, capable of withstanding frequent usage. Fast rolling doors feature a vertical rolling mechanism that saves space and allows for quick opening and closing, enhancing operational efficiency.

 

Sealing Materials

Sealing materials are primarily used to seal doors, windows, wall panels, and other joints. To prevent the loss of cold air inside cold rooms and ensure the stability of the internal temperature, sealing materials are essential in the installation of cold rooms. Below are some common types of sealing materials.

Sealing Materials

Sealant

Commonly used sealants include silicone and polyurethane foam sealants, which are effective at filling irregular surfaces and small gaps. They also offer good temperature resistance and corrosion resistance, making them suitable for sealing connections in cold room walls, ceilings, and floors.

Rubber Seals

Commonly used rubber seal materials include nitrile rubber (NBR) and chloroprene rubber (CR), both of which offer excellent temperature resistance and corrosion resistance and are not prone to cracking from freezing. Rubber seals are also known for their flexibility and elasticity, making them easy to cut and install. They can be shaped to fit various sizes and shapes of doors and windows, effectively filling the gaps between door frames and walls to ensure a good seal for cold room doors.

PVC Seals

PVC seals possess good temperature resistance, corrosion resistance, and elasticity. They are easy to cut and install, capable of fitting various shapes and sizes of doors and windows. PVC seals effectively fill the gaps between door frames and walls, ensuring good sealing performance for cold room doors.

Conclusion

The materials used in constructing a cold room significantly influence its insulation capabilities, structural stability, and sealing performance. Different materials offer various features and advantages within a cold room. Therefore, when selecting materials, it is crucial to consider the specific needs of the cold room and evaluate the characteristics of each material to ensure that the chosen materials meet the practical requirements of the cold room.

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