Maximizing storage capacity is one of the most important considerations when operating a warehouse in Japan. However, simply installing more racks does not necessarily create an efficient warehouse.

If aisles are too narrow, picking and forklift operations become difficult. If they are unnecessarily wide, valuable storage space is lost.

The key is to find the right balance between storage efficiency, shipping capacity, aisle width, and material-handling equipment.

This article explains how to select steel racks and pallet racks, how to determine appropriate aisle widths, and how forklift traffic should be considered when designing an efficient warehouse layout.

Why Rack Selection and Aisle Width Are Critical to Warehouse Efficiency

Warehouse space must serve two different purposes: storing goods and moving goods.

Increasing the number of racks can improve storage capacity, but reducing aisle space too aggressively may create operational problems such as:

• Slower picking operations
• Difficulty maneuvering forklifts
• Congestion during inbound and outbound operations
• Increased interaction between forklifts and workers
• Reduced access to stored goods

For this reason, warehouse layouts should not be designed based on storage capacity alone.

The goal is to maximize the amount of usable storage while maintaining enough space for workers, carts, forklifts, and other equipment to operate safely and efficiently.

How to Balance Storage Efficiency and Shipping Capacity

Two objectives should be considered together when planning a warehouse layout.

Maximize Storage Capacity

Rack dimensions and layouts should make effective use of the available floor area and ceiling height.

The appropriate configuration depends on factors such as:

• Product dimensions
• Cargo weight
• Number of SKUs
• Pallet size
• Storage quantity
• Picking frequency
• Warehouse ceiling height

Using vertical space effectively can increase storage capacity without expanding the warehouse floor area.

Maintain Efficient Inbound, Picking, and Shipping Operations

Storage density should not come at the expense of daily operations.

Aisles must provide sufficient space for the equipment actually used in the warehouse, including picking carts, hand pallet trucks, forklifts, and other material-handling equipment.

Frequently handled products should also be positioned with picking and shipping routes in mind.

A warehouse that stores more products but takes significantly longer to pick and ship them is not necessarily an efficient warehouse.

Reference Aisle Widths for Steel Racks

The required aisle width varies depending on the rack configuration, picking method, equipment, and operating conditions.

The following figures can be used as general planning references rather than universal design standards.

Light to Medium-Duty Racks

A reference aisle width of approximately 900–1,000 mm may be considered for manual picking operations.

This provides workers with space to move and retrieve products while maintaining relatively high storage density.

Medium-Duty Racks

For medium-duty rack layouts, approximately 1,200 mm may be considered depending on the picking method and equipment being used.

Operations Without Order Picking Vehicles

Where goods are picked manually and no picking vehicle or similar equipment enters the aisle, approximately 800 mm may be possible under suitable conditions.

However, the final aisle width should always be determined according to actual worker movement, cargo dimensions, evacuation requirements, and operational conditions.

Reference Aisle Widths for Pallet Racks

Pallet rack aisle width is strongly influenced by the type and specifications of the forklift used.

Counterbalance Forklifts: Approximately 3,700 mm

Counterbalance forklifts generally require a larger turning area.

For this reason, an aisle width of approximately 3,700 mm may be used as an initial planning reference.

Reach Forklifts: Approximately 2,800 mm

Reach forklifts are designed to operate in narrower spaces and are therefore commonly used in high-density pallet storage environments.

An aisle width of approximately 2,800 mm may be considered as a reference depending on the forklift and pallet specifications.

These dimensions should not be treated as fixed requirements. The required operating aisle should be confirmed based on the specific forklift model, turning radius, load dimensions, pallet overhang, rack configuration, and manufacturer recommendations.

Counterbalance vs. Reach Forklifts: How Forklift Type Affects Rack Layout

Choosing the right forklift is closely connected to choosing the right rack layout.

Counterbalance Forklifts

Counterbalance forklifts are widely used for loading, unloading, and transporting palletized goods.

Their advantages include versatility and suitability for various material-handling operations. However, because they require more space to turn and position loads, wider rack aisles are generally necessary.

They are suitable when:

• Wide operating areas are available
• Pallets frequently move between indoor and outdoor areas
• Loading and unloading operations are a major part of the workflow

Reach Forklifts

Reach forklifts can handle pallets in narrower aisles, making them suitable for warehouses where storage density is a priority.

They are particularly useful when:

• Floor space is limited
• High-density pallet storage is required
• High rack levels are used
• Indoor pallet handling is the primary operation

Selecting the forklift and rack system together can help prevent a situation where racks are installed first and the required material-handling equipment cannot operate efficiently afterward.

How to Design Efficient Forklift Traffic Routes

Aisle width alone does not determine warehouse efficiency. The overall forklift traffic pattern must also be considered.

Keep Main Routes as Straight as Possible

Simple, direct routes reduce unnecessary turning and travel distance.

This can shorten transportation time between storage, picking, staging, and shipping areas.

Reduce Forklift and Pedestrian Intersections

Areas where forklifts, workers, and carts frequently cross require particular attention.

Where possible, pedestrian routes and forklift routes should be separated or clearly defined to reduce interaction between them.

Maintain Required Evacuation and Access Routes

Storage equipment should never be planned solely around maximizing rack capacity.

Emergency evacuation routes, entrances, fire-safety equipment, columns, doors, and other building conditions must also be incorporated into the layout.

Case Study 1: Medium-Duty Rack Layout Designed for Storage and Picking Efficiency

Challenge

The customer wanted to increase storage capacity while maintaining efficient picking and inbound/outbound operations.

Simply increasing the number of racks would have reduced aisle space and made daily work more difficult.

Solution

We reviewed the picking frequency and equipment used in the warehouse and designed the rack layout with approximately 950 mm aisles.

The layout was planned to provide sufficient access while making effective use of the available floor area.

Result

The warehouse achieved higher storage density while maintaining smooth access to stored goods.

This demonstrated that storage efficiency can be improved without unnecessarily sacrificing operational efficiency.

Case Study 2: Pallet Rack Layout Designed for Reach Forklift Operations

Challenge

The customer required high-density pallet storage while maintaining efficient forklift handling and shipping operations.

Solution

Based on the use of reach forklifts, the pallet rack layout was designed with approximately 2,800 mm operating aisles.

The rack positions and forklift routes were planned together rather than treating them as separate elements.

Result

The resulting layout balanced pallet storage capacity with efficient forklift access, creating a warehouse environment suitable for both storage and daily material handling.

What to Check Before Deciding Rack Aisle Width

There is no single aisle width that is appropriate for every warehouse.

Before finalizing a rack layout, the following conditions should be checked:

• Rack type and dimensions
• Product and pallet dimensions
• Maximum cargo weight
• Forklift manufacturer and model
• Forklift turning and stacking requirements
• Picking carts and other equipment
• Worker traffic
• Inbound and outbound volume
• Columns and other building obstacles
• Emergency and evacuation routes
• Future changes in inventory or operations

Particularly for pallet racks, designing the aisle based only on a general reference value can result in insufficient operating clearance.

The layout should therefore be verified using the actual forklift, pallet, load, and rack specifications.

Conclusion: Optimize Rack Layouts Based on Storage, Aisle Width, and Forklift Operations

An efficient warehouse layout is not simply the layout that fits the greatest number of racks.

The best design balances storage capacity, picking efficiency, shipping capacity, forklift maneuverability, and safety.

When planning steel racks or pallet racks, consider:

• The type and dimensions of stored goods
• Required storage capacity
• Appropriate aisle widths
• Forklift type and specifications
• Picking and shipping routes
• Worker and forklift traffic
• Future operational changes

By evaluating these factors together, it is possible to make better use of limited warehouse space while maintaining smooth daily operations.

Logical provides support for rack selection, warehouse layout planning, forklift traffic design, and rack installation based on actual site conditions.

If you are looking to increase warehouse storage capacity without compromising operational efficiency, contact us to discuss the most suitable rack layout for your facility.