Push Back Rack – LIFO Rack System Optimizing Cold Storage Space

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Push Back Rack is a high-density pallet storage system operating on the LIFO (Last In – First Out) principle, allowing 2-5 pallets to be stacked on the same support beam with an automatic inclined cart mechanism. In Vietnamese frozen food cold storage facilities, Push Back Rack increases pallet capacity by 60-80% compared to Selective Rack, while reducing forklift aisles by up to 50%.

What is Push Back Rack? Structure and operating principle

Push Back Rack is a heavy-duty racking system using carts placed on inclined rails. When the first pallet is placed, the cart slides backward; the second pallet pushes the first pallet further back. When retrieving goods, the outermost pallet is removed first, and the pallets behind automatically slide forward by gravity.

The main structure of Push Back Rack includes: Q345 steel upright frame, load-bearing beam, cart system with steel or plastic wheels, and guide rails inclined at 3-5°. Each storage level holds up to 5 pallets in depth, with a load capacity of 500-3,000kg/beam. Việt POS Rack manufactures Push Back Rack with Omega columns 100×75, 2.0-3.0mm thick, beams 120×50, 2.0-3.0mm thick, with safe deflection ≤ L/200.

How does the LIFO principle in Push Back Rack work?

LIFO (Last In – First Out) in Push Back Rack operates based on gravity: the last pallet placed in will be at the outermost position and is retrieved first. The sliding carts automatically move the pallets behind forward when the front pallet is removed.

Specifically: the forklift places the first pallet onto cart No. 1, and the pallet pushes the cart backward into the rack. When placing the second pallet, the forklift’s pushing force moves cart No. 1 further back, making room for cart No. 2. This process repeats until 5 pallets are loaded. When retrieving goods, the forklift pulls out the outermost pallet; cart No. 1 slides out, and the carts behind sequentially bring pallets forward. The entire operation takes 15-25 seconds per pallet.

Comparing Push Back Rack with Selective and Drive-In Racking

Push Back Rack sits between Selective (product variety, low density) and Drive-In (very high density, FIFO/LIFO). Compared to Selective, Push Back increases density by 60-80% but is only suitable for LIFO. Compared to Drive-In, Push Back offers 30-40% faster retrieval times because the forklift does not need to enter the lane.

Criteria	Selective Racking	Push Back Rack	Drive-In Racking
Principle	FIFO/LIFO	LIFO	FIFO/LIFO
Storage density	100% (baseline)	160-180%	200-250%
Number of aisles	Many (1 aisle per row)	Reduced by 50%	Reduced by 70%
Retrieval time	15-20 seconds/pallet	20-30 seconds/pallet	40-60 seconds/pallet
Cold storage suitability	Yes (few pallets)	Yes (moderate)	Best
Cost per m²	Lowest	Average	Highest

Push Back Rack applications in frozen food cold storage

Frozen food cold storage (meat, fish, seafood, frozen vegetables) typically requires LIFO because goods are received last and shipped first to ensure proper turnover. Push Back Rack maximizes warehouse height (8-12m) and reduces the number of aisles, saving expensive cold storage floor space.

In Vietnam, seafood export cold storage facilities in Can Tho and Dong Thap often use Push Back Rack for block frozen products (pangasius, shrimp). Each 1,200×1,000mm block pallet weighs 800-1,200kg. With 4-deep Push Back, one 2.4m x 4.8m lane holds 8 pallets instead of 4 pallets with Selective. Temperatures of -18°C to -25°C require hot-dip galvanized racking (80μm) for corrosion resistance. Viet POS Rack provides galvanized Push Back Rack for cold storage, meeting AS4084 standards, with a 24-month warranty.

Advantages and limitations of Push Back Rack

Push Back Rack has advantages: increases density by 60-80%, reduces the number of aisles, faster retrieval time than Drive-In, low maintenance (no motor). Limitations: only suitable for LIFO, not for fast-expiring goods, higher cost than Selective, requires a forklift with suitable lifting height.

Detailed advantages:

• Increases storage capacity by 2-3 times compared to Selective on the same floor area.
• Reduces forklift aisles by 40-50%, saving cold storage space.
• No electrical power required (gravity-operated).
• Simple maintenance: only periodic inspection of slide wheels and guide rails is needed.
• Suitable for homogeneous goods of the same type (same pallet size).

Limitations:

• Only applies to LIFO – not for FIFO goods (fresh food, pharmaceuticals).
• Cannot store multiple product types in the same lane.
• Investment cost is 20-30% higher than Selective.
• Requires a forklift with a minimum lifting height corresponding to the number of levels.

Push Back Rack production process at Viet POS Rack

Viet POS Rack manufactures Push Back Rack through a closed 7-step process at its 10,000m² factory in Tan Duc Industrial Park, Long An, ensuring quality meets AS4084 and EN 15512 standards.

1. Order receipt + 3D AutoCAD design: Survey the cold storage, measure pallet dimensions, load capacity, warehouse height, and layout. Quote within 48 hours, free design.
2. Q345 steel cutting with CNC laser: Tolerance of ±0.1mm, creating uprights and beams according to drawings.
3. Roll forming – punching – stamping profiles: 200-400 ton hydraulic machines create Omega uprights, box beams, and precise punched holes.
4. Frame welding with MIG/MAG robots: Penetration weld inspection according to AS4084 joint design.
5. Surface treatment: Degreasing → acid → phosphating → washing → drying → electrostatic powder coating 60-80μm (orange-blue) or hot-dip galvanizing 80μm (for cold storage).
6. QC: Load test with safety factor ≥1.5, squareness check, paint inspection, sampling 5-10% per batch.
7. Packaging + delivery + onsite installation: Pallet wrap + corner protectors, technical team installs at warehouse, 24-month warranty.

Notes on designing and installing Push Back Rack for cold storage

When designing Push Back Rack for cold storage, pay attention to: choosing temperature-resistant materials (galvanized), calculating thermal expansion, ensuring safe clearance between lanes, and installing anti-collapse systems (column protectors).

• Material: Cold storage at -25°C requires hot-dip galvanized steel (80μm) instead of powder coating, as low temperatures make paint brittle and prone to peeling.
• Clearance: Between Push Back lanes, a minimum of 100mm is required for cold air circulation, preventing moisture buildup that causes rust.
• Safety: Install column protectors (2.5mm steel boxes) at column bases, attach load tags clearly stating the maximum load per lane.
• Forklift: Choose a forklift with lifting height ≥ top level height + 300mm, and fork length ≥ pallet depth.
• Maintenance: Inspect slide carts every 6 months, lubricate guide rails with temperature-resistant grease.

Frequently asked questions about Push Back Rack

Contact Viet POS Rack for a free consultation and quote on Push Back Rack for your cold storage. Hotline: 0796 700 777 – Email: info@vietposrack.vn – Free 3D warehouse layout design.