Double deep racking for manufacturing plants offers the core benefit of maximizing floor space, reducing aisle space, and lowering the cost per pallet for long-term storage. However, this solution also requires trade-offs: slower retrieval speeds, the need for specialized forklifts, and near-perfect installation precision. Read on to learn more about this type of racking.
1. Why use double-deep racking for a manufacturing plant?
Optimize warehouse space
While selective racking is popular, it has a major drawback: each row of racks requires a separate aisle for forklifts, meaning the aisles can take up a lot of warehouse space without creating additional storage value.
Double Deep racking overcomes this limitation by stacking two pallets lengthwise on the same row and having two opposite rows share a single aisle, thereby significantly reducing the number of aisles required and increasing storage capacity by approximately 40-50% without expanding warehouse space.
Cost per Pallet Position
Investing in Double Deep racking is a one-time cost with a typical lifespan of 15-20 years.
A typical analysis shows that Double Deep’s cost per pallet position is 20-35% lower than expanding the floor space, while keeping goods within the factory and reducing internal transportation costs and increasing production response speed.
Adaptability to large scale
It is no coincidence that Double Deep racking is considered the optimal solution for internal logistics systems by large-scale factories in many industries:
- Store large batches of the same item in two locations (outside and inside).
- Reduce forklift travel time with high storage density.
- Easily integrated with AGV (Automated Guided Vehicle) systems in Industry 4.0 factories.
2. Structure of double-deep racking for manufacturing plants
Double Deep racking is essentially an upgraded variant of conventional pallet racking, but redesigned to accommodate the storage of two pallet levels vertically. The constituent parts include:
- Omega support legs: Reinforced with thicker legs to withstand the heavy load from two deeply stacked pallets.
- Support bars: These are the components that support and directly contact the pallets. The support bars are placed in the middle of the rack, attaching to the beams at both ends.
- Beam: Use double beams or reinforced Z-shaped/Z+ beams to ensure they do not sag under heavy loads on the inner side.
- Bracing: Connects the support frames in the same row, increasing vertical rigidity.
- Anti-collision bar: Connects two rows of shelves joined back-to-back, preventing vibration and shaking when a forklift is operating.
- Impact guard: Mounted at the base of the first support post in the row – the area most likely to be hit by a forklift.
3. Specifications of double deep shelving
Load capacity per floor: 1,000 – 5,000 kg/floor
Maximum shelf height: 10 – 12m
Storage depth: 2 pallets deep
Compatible pallet sizes: 800 × 1,200mm or 1,000 × 1,200mm
Spacing between shelves: hole spacing 50mm or 75mm
Walkway width: 2,700 – 3,500mm
Material: Cold-rolled steel with electrostatic powder coating
Surface finish: powder coating with a thickness of 60 microns or more.
4. Considerations when installing Double Deep racking in a factory.
Forklift requirements
To access the deepest positions, it is necessary to use a forklift with Double Reach forks – a type of forklift with a mechanism that allows the forks to extend a little further, enough to insert into the second pallet without the forklift having to move further into the rack.
The cost of a double-reach forklift is typically 20-40% higher than that of a standard forklift. Businesses need to factor this into their total investment budget from the project planning stage to avoid unforeseen expenses.
Goods retrieval speed
No warehousing solution is absolutely perfect. Double Deep optimizes storage density, but at the cost of slower loading and unloading speeds compared to Selective racking.
Therefore, Double Deep is best suited for:
- The product has few SKU variations but a large quantity of each type.
- The goods are shipped at a moderate frequency, not requiring frequent pickups throughout the day.
- Goods are stored in batches and shipped out in batches (batch in – batch out).
Warehouse floor system
Double-deep racking systems create extremely high point pressure on the factory floor through the support legs. Each support leg can bear a load of 3-5 tons, with a contact area of only 10×10 cm. If the floor is not flat enough and the compressive strength is poor, the consequences are:
- Local subsidence → shelf tilts → unsafe.
- Incorrect vertical alignment → forklift cannot extend its forks correctly.
Solution: Measure the flatness of the floor (DIN 18202 standard), pour an additional layer of reinforced concrete 150-200 mm thick, grade ≥ 300, if necessary .
Construction accuracy
With single-shelf racking, a tolerance of ±10mm between rows is acceptable. With double-deep racking, the alignment requirement for rows on the same axis is up to ±3mm.
Because double-reach forklifts have long and narrow forks, even a 5mm misalignment of the shelving unit can cause the forks to scrape against the support during operation, leading to accidents. Therefore, you should only choose contractors with 3D laser measuring equipment and at least 10 years of experience installing double-deep systems.
5. Images of Double Deep racking projects for manufacturing plants implemented by One Tech Rack.
Investing strategically right from the design stage will lay the foundation for a double-deep racking system in your manufacturing plant to become a real competitive advantage for your plant’s internal logistics operations. Contact One Tech Rack today for detailed advice and a free quote.
