PVC Strips for Refrigerated Container

PVC Strips for Refrigerated Container

Strip curtains, plastic strips, PVC strips for shipping container size 20 or 20 HC.

With our strip curtains, you can significantly reduce heat loss. Strip curtains are high-quality and flexible PVC strip curtains. The individual strips are hung so that they slightly overlap.

We supply strip curtains already made and cut in a strip or rail directly according to the type of shipping container size 20 or 20 HC. After delivery, the PVC strips only need to be screwed into the container entrance.

PVC strips are a suitable solution to prevent drafts and heat dissipation from cooling and freezing containers. They also reduce the noise level of operations and the risk of dirt and dust entering from the outside.

They can also be used to separate individual spaces or sections – especially in the food industry in cooling and freezing containers.

Strip curtains are made of clear softened PVC, so they allow quick and easy passage of people and passage of equipment, such as forklifts. All this without preventing the passage of light.

Delivery includes:

• 12 pcs of PVC strips, width on average approx. 19-23 cm depending on the manufacturer
• top strip / rail

Transport is not included in the price.

1. Definition: What are PVC strips for a refrigerated shipping container?

PVC strips for a refrigerated shipping container are flexible strip curtains made of special polyvinyl chloride (PVC) compounds, designed for use in refrigerated and freezer containers (reefer containers). These strips, often referred to as strip curtains, strip doors, or strip barriers, are installed as an internal barrier – usually hanging in overlapping rows at the entrance to the container.

The main purpose of these curtains is to create a secondary, semi-permeable barrier that significantly reduces the escape of cold air when the container doors are opened. They allow maintaining a stable internal climate, protect sensitive cargo from thermal shock, minimize condensation and frost formation, and limit the ingress of dust, insects and other impurities. Such control is essential in industries where hygiene, preservation of quality and energy efficiency are important – especially in the food, pharmaceutical, flower logistics and chemical storage industries.

From a legislative point of view, PVC strip curtains are recognized as effective, safe for food contact and meet major international standards such as GMP (Good Manufacturing Practice), HACCP and relevant regional standards (e.g. FSSAI in India, ISO 22000 worldwide, FDA in the USA).

2. Context and significance in reefer containers

2.1. What is a refrigerated shipping container (reefer)?

Refrigerated shipping container, commonly referred to as reefer container, is a highly insulated, mobile refrigeration unit equipped with an integrated refrigeration system. These containers are designed for multimodal transport (by sea, rail, road) as well as for stationary storage, capable of maintaining internal temperatures from normal values down to -60 °C depending on the type of equipment (e.g. Carrier, Thermo King, Daikin, Star Cool, Mitsubishi and Super Freezer).

Standard dimensions are 20 or 40 feet, with high cube (HC) variants for larger volume. The insulation usually consists of high-density polyurethane foam panels, complemented by robust door seals and reinforced corners. The cooling unit is powered externally (from a ship, truck or generator) and allows precise temperature and humidity control.

Reefer containers are indispensable in the international chain for the transport and storage of goods that are perishable or temperature sensitive, including:

• Meat, dairy products, fish, frozen vegetables, ice cream
• Vaccines, pharmaceuticals and biological materials
• Cut flowers and plants
• Special chemicals and cosmetics

2.2. Why are PVC strips used in these containers?

Opening the doors of a reefer container, even for a short time, causes a rapid exchange of cold internal air with warm and humid outside air. This leads to several negative impacts:

• Heat loss: Rapid warming inside, which can cause spoilage or temperature fluctuations in sensitive goods.
• Increased load on the cooling system: The cooling unit has to expend more energy to maintain the set temperature, which increases consumption and wear and tear on the equipment.
• Condensation and frost: Ingressing humid air condenses and freezes on surfaces and goods, which can damage the cargo and block airflow.
• Ingress of impurities: Open doors allow the entry of dust, insects, rodents and microorganisms – which is a critical risk in the food, pharmaceutical and clean logistics industries.

PVC strips (strip curtains) are a cost-effective, easy-to-install solution to these problems. Overlapping strips:

• Significantly reduce cold air leakage by creating a flexible but effective air barrier.
• Allow easy passage of people and equipment without the need to open solid doors.
• Serve as protection against contaminants, pests and dust.
• Support compliance with strict hygiene and safety standards (FSSAI, ISO 22000, FDA CFR 21, European Regulation EC 1935/2004).

3. Construction and material properties

3.1. What are they made of?

Material: The strips are made of advanced blends of softened, flexible polyvinyl chloride (PVC), often referred to as “polar grade” or “freezer grade” PVC. This material retains its flexibility and strength even at low temperatures (typically -25 °C to -40 °C, even lower for super freezers).

Main properties:

• Transparency: Most strips are clear or lightly tinted, ensuring good visibility and safety.
• Low toxicity: Quality strips are cadmium-free, silicone-free and meet REACH standards for chemical safety.
• UV stabilization: The addition of UV stabilizers prevents yellowing and degradation, especially in containers exposed to the sun.
• Resistance to chemicals and abrasion: PVC is non-porous and resistant to most detergents, disinfectants and wear.

Physical parameters:

• Strip width: Usually 19–23 cm (for pedestrians and light equipment); wider strips (up to 30–40 cm) for heavier traffic or windy locations.
• Thickness: Standard 2–3 mm; thicker (up to 4 mm) for more demanding conditions.
• Length: Adapted to the height of the container opening (usually 2.2–2.6 m for 20′, up to 2.7–2.9 m for 40′ HC).
• Overlap: Strips are installed with 30–50% overlap to minimize gaps and improve thermal insulation.

3.2. Special properties

• Freezer grade (polar grade): Specially developed for flexibility at -25 °C to -40 °C; ordinary PVC becomes brittle below -15 °C.
• Hygienic surface: Smooth, non-porous, easy to clean – essential for contact with food and pharmaceuticals.
• Flammability class and toxicity: Quality strips meet class A or B (EN ISO 11925-2, ASTM E84) and produce a minimum of smoke and toxic fumes when burned.
• Color design: In addition to clear, also colored strips (blue for meat operations, yellow against insects, red for hazardous zones).

4. Functions and benefits

4.1. Thermal insulation

Main benefit: PVC strip curtains form a flexible, tight barrier that significantly reduces the escape of cold air and the ingress of warm air when the doors are opened. This is key to maintaining prescribed temperatures for sensitive cargo.

Results:

• Stable internal temperature: Reduces temperature fluctuations.
• Reduced risk of spoilage: Protects food and pharmaceuticals from temperature shocks.
• Less frost formation: Less humid air means less frost on goods and evaporators.
• Energy saving: Significantly reduces compressor operation and electricity consumption (see section 7).

4.2. Protection against contamination

• Barrier against dust, insects and pests: Physical curtain prevents the entry of flies, insects, birds and dust – essential in the food and pharmaceutical industries (FSSAI, ISO 22000).
• Noise reduction: PVC dampens noise from outside well.
• Zoning: Colored strips allow the separation of clean and unclean zones, raw material and finished areas or allergen sections.

4.3. Operational flexibility

• Unlimited passage: People, trolleys and forklifts can pass through without having to handle the doors.
• Partial opening: Only the part of the curtain that is currently being used is opened – limiting the overall air exchange.
• Partitions: Allows internal division of the container into multiple temperature or operational sections.

4.4. Safety and visibility

• Transparency: Transparent strips allow you to see approaching people or equipment, which reduces the risk of collisions.
• Soft impact: Flexible material prevents injury or damage to goods in case of accidental contact.
• Touchless operation: No need to touch handles – higher hygiene in high-risk operations.

5. Installation and compatibility

5.1. How are PVC strips installed in shipping containers?

Assembly procedure:

• Fittings: The strips are hung on stainless steel or galvanized strips, fixed inside the container frame (soffit) or above the door opening (face fixing).
• Overlap: The strips overlap 30–50 %, double overlap is recommended for higher frequency of operation or drafts.
• Precise dimensions: Suppliers offer pre-cut sets for standard containers (20′, 40′, HC) or custom manufacturing.
• Tools: You can handle the assembly with common tools (drill, screws/bolts, meter).

Recommendations (FSSAI/ISO/HACCP):

• Use only stainless steel fittings to prevent rust and meet hygiene requirements.
• Ensure smooth and burr-free edges for safety and easy cleaning.
• For frequent washing, choose systems with removable strips or quick-release hooks.

5.2. Compatibility

• Universal use: Suitable for reefer/freezer containers (Carrier, Thermo King, Daikin, Star Cool, Mitsubishi), but also for regular containers, freezer boxes and doors in the food industry.
• Easy retrofitting: Can be retrofitted or manufactured into the container.
• Compatibility with accessories: Can be combined with other elements such as insulated panels, rubber door seals, floor partitions.

6. Uses and application examples

6.1. Main sectors

• Food production and processing: Meat, poultry, fish, dairy products, baked goods, frozen foods, ready meals.
• Pharmacy: Vaccines, biologics, temperature-sensitive drugs, samples for clinical trials.
• Floristry and horticulture: Cut flowers, live plants, seeds.
• Chemicals and cosmetics: Sensitive chemicals, paints, adhesives, cosmetics.

6.2. Operational scenarios

• Frequent entrances: Distribution centers, catering, mobile cold stores and backrooms of shops with frequent door openings.
• Mobile refrigeration: Containers deployed at festivals, humanitarian events, construction sites or mines.
• Zoning: Separation of different temperature or hygiene zones in one container, separation of allergen areas.

7. Energy efficiency and savings

7.1. How do PVC strips save energy?

Measurable benefits:

• Reduced compressor load: By limiting temperature fluctuations, the compressor runs less often and for shorter periods.
• Lower electricity consumption: Expert studies show that properly installed PVC curtains reduce energy losses with open doors by 40–60 %.
• Longer equipment life: Less frequent switching means less wear and longer maintenance intervals.

Example calculation:

• Assumptions: The container is opened 10 times a day for 5 minutes. Without strips, the loss is X kWh, with strips 40–60 % less.
• Annual savings: For a typical 20′ reefer, this can amount to hundreds of euros/dollars in annual electricity savings – a return on investment in a matter of months.

7.2. Other savings

• Less defrosting: Less ingress of moisture means less frost, which means less need for defrosting.
• Less maintenance: Cleaner air inside reduces evaporator fouling, mold and corrosion.
• Longer shelf life of goods: Stable temperatures extend the shelf life of food and reduce losses.

8. Hygiene, cleaning and maintenance

8.1. Hygienic properties

• Suitable for food contact: Production according to FDA, EU or regional standards (e.g. EC 1935/2004, FDA CFR 21).
• Non-absorbent: The smooth PVC surface does not absorb moisture, grease or proteins, limiting microbial growth.
• Easy cleaning: Can be cleaned with common food grade cleaners and disinfectants; the smooth surface prevents dirt from sticking.