Pallet Rack Systems
Last updated: August 23, 2026
System Types and Cost Comparison
| System Type | Storage Density | Selectivity | Best For |
|---|---|---|---|
| Selective | Low–Medium | Every pallet | Diverse SKUs, fast access |
| Double-Deep | Medium | Every other pallet | Moderate SKU count |
| Drive-In | High | LIFO | Bulk storage, few SKUs |
| Drive-Through | High | FIFO | Bulk storage with rotation |
| Push-Back | High | LIFO (multiple deep) | Medium throughput |
| Pallet Flow | Very High | FIFO | Perishables, strict FIFO |
| Cantilever | Medium | Every position | Long materials |
For detailed cost comparisons, see the Pallet Racking guide.
Selective Pallet Rack Systems
Selective racking provides direct access to every pallet position, making it the most common warehouse storage configuration. Available in roll-formed (lighter duty, lower cost) and structural (heavy duty, higher capacity) designs.
Key Characteristics
- Selectivity: Every pallet directly accessible
- Configuration: Uprights with adjustable beam levels at regular vertical intervals
- Aisle width: Varies by forklift type (counterbalance, reach truck, VNA)
- Best for: High SKU count, diverse products, frequent picking
Roll-Formed vs Structural
Roll-formed: Cold-formed steel profiles with teardrop or keyhole connections. Lower cost, suitable for most standard applications. Easier to reconfigure.
Structural: Hot-rolled I-beam construction with bolted connections. Higher load capacity, better for seismic zones, heavier products, or rack-supported buildings. More expensive and rigid configuration.
Double-Deep Pallet Rack Systems
Double-deep systems store two pallets deep per side of the aisle, reducing aisle count and increasing storage density versus selective. Requires double-reach forklifts with telescoping forks.
Key Characteristics
- Selectivity: Every other pallet — must access front pallet to reach rear pallet
- Density gain: Higher pallets per square foot versus selective
- Equipment: Double-reach forklift required
- Best for: Moderate SKU count, space-constrained facilities
Operational Considerations
Pair identical SKUs in front-back positions. Front pallet picked first exposes rear pallet. Works well for products with predictable depletion rates where both pallets picked within similar timeframes.
Drive-In and Drive-Through Systems
Drive-in systems use continuous rails allowing forklifts to drive into the rack structure. Pallets rest on rails rather than beams. Drive-in (single entry, LIFO) versus drive-through (entry both ends, FIFO).
Key Characteristics
- Storage depth: Multiple pallets deep per lane
- Density gain: Higher versus selective (eliminates aisles)
- Access pattern: LIFO (drive-in) or FIFO (drive-through)
- Best for: Low SKU count, high volume per SKU, cold storage
Design Requirements
- Rail strength: Must support full pallet weight with continuous sliding contact
- Entry guides: Protect uprights from forklift impact at lane entrance
- Top ties: Connect upright frames across lanes for lateral stability
- Forklift clearances: Maintain safe clearance between mast and uprights
Push-Back Rack Systems
Push-back systems use nested carts on inclined rails to store multiple pallets deep per lane. Loading a pallet pushes existing pallets back; unloading allows gravity return to pick face.
Key Characteristics
- Storage depth: Multiple-deep configurations available
- Access pattern: LIFO (last in, first out)
- Density gain: Higher versus selective
- Best for: Moderate SKU count, multiple pallets per product
Cart Mechanisms
Nested carts ride on inclined rails with each pallet positioned on a separate cart. Speed controllers prevent carts from accelerating too quickly on return. Regular maintenance required for wheels and rails.
Pallet Flow (Gravity Flow) Systems
Pallet flow uses roller conveyors on a slight decline. Pallets loaded at high end automatically flow by gravity to picking face at low end, ensuring first-in, first-out rotation.
Key Characteristics
- Storage depth: Multiple pallets deep per lane
- Access pattern: FIFO (first in, first out)
- Density: Very high cube utilization
- Best for: Perishables, pharmaceuticals, food products with expiration dates
Design Features
- Roller tracks: Full-width or skate-wheel configurations
- Decline: Gentle slope depending on pallet weight and roller type
- Speed controllers: Brake mechanisms prevent pallet damage at pick face
- Separators: Keep adjacent lanes independent for proper flow control
Maintenance Requirements
Rollers require regular inspection and lubrication. Speed controllers need periodic adjustment. Damaged pallets can jam lanes — immediate clearing essential to maintain throughput. Budget for annual maintenance contract.
Cantilever Rack Systems
Cantilever racks use arms extending from a central column, ideal for long or bulky materials that won't fit on standard pallet beams (lumber, pipe, steel bar stock, sheet goods).
Key Characteristics
- Configuration: Arms extend from upright column
- Adjustability: Arms reposition vertically for different material heights
- Capacity: Arms rated individually; consult manufacturer specifications
- Best for: Lumber yards, steel service centers, pipe and tubing distributors
Single-Sided vs Double-Sided
Single-sided: Arms on one side only, typically against wall. Lower cost, suits narrow spaces.
Double-sided: Arms on both sides of central column. Higher capacity utilization, requires wider aisles, more common in open warehouses.
System Selection Criteria
By SKU Count and Volume
- High SKU count, low volume per SKU: Selective
- High SKU count, moderate volume: Double-deep
- Moderate SKU count, multiple pallets per product: Push-back
- Low SKU count, bulk quantities per product: Drive-in or drive-through
- Low SKU count, perishables, FIFO required: Pallet flow or drive-through
By Space and Budget Constraints
- Maximum selectivity, budget-focused: Selective roll-formed
- Heavy loads or seismic zone: Selective structural
- Space-constrained, moderate budget: Double-deep or drive-in
- Space-constrained, higher budget, LIFO acceptable: Push-back
- Maximum density, FIFO critical: Pallet flow (highest cost)
Combination Strategies
Many warehouses use multiple rack systems in different zones based on product characteristics:
- Fast-movers in selective: High-velocity SKUs in easy-access selective racks near shipping
- Slow-movers in drive-in: Reserve or seasonal inventory in high-density storage
- Perishables in flow racks: Dated products in FIFO lanes
- Overstock in push-back: Excess inventory of medium-velocity SKUs
Installation and Permitting
All systems require proper installation following manufacturer specifications and published structural standards:
- Concrete requirements: Slab thickness requirements depend on load and seismic zone; consult structural engineer
- Anchoring: Floor anchors per manufacturer specifications; high-seismic zones require additional anchorage
- Plumb and level: Uprights must be plumb within manufacturer tolerances
- Load placards: Permanent signage showing capacity per bay required at end of each row
- Engineered drawings: Stamped drawings by licensed PE may be required for permits
Frequently Asked Questions
What are the main types of pallet rack systems?
Main pallet rack systems include: selective (direct access to every pallet), double-deep (access to every other pallet), drive-in (LIFO/FIFO), push-back (multiple-deep LIFO), pallet flow (FIFO), and cantilever (for long materials). System selection depends on SKU count, inventory volume per SKU, and required selectivity. Consult the pallet racking guide for detailed cost comparisons.
How do I choose between different pallet rack systems?
Choose based on SKU velocity and storage density needs. High SKU count with diverse products: selective. Low SKU count with bulk quantities: drive-in. Moderate SKU count with multiple pallets per product: push-back. Perishables requiring FIFO: pallet flow or drive-through. Long materials: cantilever.