Steel stillages are considered safe if moved and stacked correctly, designed for the load they need to support, along with the dynamic stacking load when stillages are stacked more than 2 units high and fully loaded with stock. If you don’t manage the loads applied to the manufacturer’s requirements, you can risk a stack of stillages falling over and damaging people or property.
What is a Steel Stillage?
Steel stillages are a material handling storage system designed to organise, store, and secure materials, either free sitting or on pallets. They are typically built in stacked horizontal rows and accessed by forklifts. Comprised of steel upright frames and horizontal beams, they maximise warehouse floor space, improves efficiency, and allow for safe retrieval of materials.
Steel stillages are ideal for long, awkward products that don’t stack easily into standard pallet racking or fixed steel pallet cages. These items can be polypipe, steel or concrete pipes, carpet rolls, reinforcing steel, machined parts, sub-assemblies, and the list goes on.
Steel stillages and pallet cages are often seen in high production environments like car manufacturing assembly lines, allowing the product to be placed beside the operator or robot for maximum efficiency.
Common Steel Stillage Safety Issues
Some of the most common stillage accidents include:
Forklift Impacts
Stillages are typically lifted and moved in factory or warehouse environments by a forklift, and collisions with stillages or pallet cages can damage uprights and reduce the structural integrity of the steel frame. This can severely impact load capacity and even cause structural failure.
Improper Installation
Steel stillages and pallet cages must have a way of being positively stacked, either by using welded pallet feet or, alternatively, using stacking cups and channel receivers. These act as a positive lock between each individual stillage or pallet cage.
We also recommend that any bolted connections in flat packed stillages be inspected every 3-6 months to ensure bolts remain firmly tightened.
Incorrect Load Calculations
All stillages and pallet cages should be designed to accept a recommended safe working load. This should apply to the individual unit as well as the stack. For example, a standard 1.2m square stillage that is 1.2m in height may hold 500kgs of load, but when stacked 5 units high, this bottom stillage is effectively supporting the weight of 5 x 500kgs + the TARE weight of the steel stillages stacked above. This load design should be verified by an engineer under Australian Standard AS3990.
If calculated incorrectly, the stillage load capacity may not be able to support the weight of stacked materials.
Racking Overload
Do not overload or surpass the Safe Working Load (SWL) that is marked by the manufacturer. Ideally there is an SWL weight capacity noted on each stillage as well as a maximum stack load height.
Placing more weight, can lead to damages which then becomes a high-risk issue for safe storage of product.
Lack of Maintenance
Failing to regularly examine stillages and pallet cage systems to identify issues like bent pallet feet, bent stacking caps, or damaged or rusty steel work, can lead to weakened and dangerous stacking of products.
Falling Objects
Multiple stillages that are improperly stacked, or materials that are not secured correctly, can cause materials to fall, risking injury to workers and damage to inventory.
How to ensure your steel stillages are safe
To ensure your steel stillages are safe, it’s important to consider:
Load Capacity and Safety
Steel stillage load capacity is determined by an Engineer and the design is to Australian Standards AS3990 and AS1170. Some aspects of stillage designs also fall under the Australian Standard for Steel Storage Racking -AS4084-2023. This Australian standard governs the design, testing, and maintenance of steel storage racking.
Key load capacity factors include:
Frame Capacity
Stillages can be rated to just about hold any load from 100kgs up to 10,000kgs and the design is paramount for safety and efficiency of use. Standard every day stillages and pallet cages tend to hold loads between 500kgs – 1000kgs and have a capacity of stacking up to 5 units high in most warehouse environments.
You could also require a stillage to hold a heavy piece of mining equipment that may not stack but allow forklift operation around a yard or warehouse for efficient movement of product.
Load Distribution
The TARE weights need to be calculated into the overall load design as part of the total load applied to the individual unit as well as the stacked load.
This also aids the forklift operator to better understand the total moving load for safety purposes, and to not exceed the manufacturer’s ratings of load capacity.
Impact Load
When designing stillages or pallet cages there needs to be an understanding that the impact load adds 25% of one stillage’s weight, to take into consideration the extra stress of forklift impact.
Floor Anchors
All pallet feet and base supports must be designed to accommodate the stacked load capacity.
Side Load
Side loading on steel stillages and pallet cages must be considered in the design. This can involve an engineer looking at seismic loads on posts and supports to ensure this stacked load is safe from impact or movement. This type of testing ensures the racking can withstand accidental impacts from forklifts and the lateral pressure of storing long materials.
Additional Load Capacity Considerations
The Importance of Pallet Feet Testing
The pallet feet used on steel stillages and racking systems need to undergo rigorous testing to ensure their structural integrity and safety under heavy loads. Key testing methods that conform to AS 4084-2023 include weld inspections, load-bearing capacity assessments, tilt and stability testing, and materials durability checks.
Structural Design Actions
The Australian Standard AS/NZS 1170 defines how structures must resist load like wind, earthquakes, snow, and permanent dead loads, and this applies to steel storage racking. The standard ensures structures can withstand environmental and usage forces, including:
- Seismic Loading
Steel racking seismic load testing involves assessing the structural integrity and stability of storage systems under simulated earthquake conditions. This is primarily done through shake table tests, pull-back tests, and component-level cyclic tests. These tests ensure racking can withstand significant horizontal ground acceleration, minimise inventory loss, and prevent racking collapse.
- Wind Loading
If racking is stored outdoors or exposed to environmental forces, wind load testing should also be conducted. Testing ensures that racking systems can withstand lateral (side to side) pressures that could lead to buckling or collapsing.
Forklift Safety
It is critical that forklift operators are trained and adhere to strict safety protocols when handling uneven, high density and heavy loads. Forklift operators must also ensure that the load does not exceed the forklift’s operating capacity (WLL), the tynes are fully inserted and, ideally, stacking is limited to two high for loaded stillages.
Annual Inspection Requirements
Annual inspections by a qualified, independent third-party inspector should be conducted once a year, and check all aspects of the final design from bent or damaged pallet feet or stacking cups to broken welds, damage to surfaces or bent base plates.
Use quality Australian-made racking built to Australian Standards
Always use steel stillages that are designed to Australian Standards and meet the relevant code of practice. This will give your WH&S team some level of optimism that the design is fit for use. Ideally, the steel stillages are Australian made, welded to AS1554, and provide an engineer load certificate.
The SWL of the steel stillage or pallet cage should be shown visually on each unit for the operator to understand the load limitations.
Are you looking for Quality Australian Made Steel Stillages?
Bremco Metal Products manufactures quality, Australian made materials handling equipment including pallet racking and steel stillages. Our steel stillages are fully welded, built tough to Australian Standards, and engineer load certified. Contact the friendly Bremco team for expert advice and a fast quote.