Forklifts are indispensable machinery used daily in warehouses to lift and move heavy loads over short distances. However, the hasty way in which they are operated is the main cause of rack damage in warehouses. As most industry experts will attest, rack systems as well as building structure components, are subject to collisions with forklifts, which can lead to disastrous consequences. To prevent accidents and to protect the racks, it is important to understand how forklifts damage them.
Here are Five Frequent Ways Forklifts Damage Racks:
1. Maneuvering Out of Position (Backing Into Racks Across the Aisle)
|Figure 1. Removing a pallet from a slot.||Figure 2. Deformed column base.|
When retrieving a pallet, the driver must both focus on clearing the pallet from its slot and prevent from backing into anything across the aisle. Typically, a rooky driver will be very careful and take much time in doing so. As the driver gains experience and confidence, speed may increase without necessarily creating damage. But if the lift is too close to the rack across the aisle, instead of lightly bumping it at slow speed, the lift damages the rack. The energy transferred to the column is proportional to the speed of the lift squared. You could say that speed kills racks!
Encumbered aisles or very narrow aisles increase the risk for this type of impact. It is important to use the correct forklift type according to the aisle dimensions. For more information, read this article on the connection between forklift types and aisle widths.
Adequate column protection is recommended to prevent these types of damages. Other remedies include impact and proximity sensors, adequate and frequent training for the drivers, extra training for “new drivers” during peak season, and widening of narrow aisles. A solid overhaul of the warehouse culture towards safety may be necessary.
2. Entering or Exiting an Aisle (Rear-end Swing While Moving Forward)
|Figure 3. Turning corners.||Figure 4. Deformed end of aisle brace.|
On forklifts, the back wheels are the ones providing direction. Think of it as driving your car facing backwards. Because they operate normally in rather tight aisles, the back wheels rotate for the lift to pivot around a surprisingly short radius. When driving forward without a pallet, if a turn is initiated a bit too early near the end of an aisle, the back end may swing drastically and come in contact with the racks (Figure 3 and Figure 4). Again, speed doesn’t help as the driver will not have time to react.
This type of impact can also happen because of encumbered aisles, or misevaluation of the forklift dimensions and the radius that the rear-end will take during the turn.
As a precaution, using an effective end of aisle protection is highly recommended, but like for the previous point, training is essential. Some operators equip the lifts with side-mounted safety lights that help pedestrian and drivers keep their distances.
3. Forks, Mast and Outriggers
|Figure 5. Deformed bottom level beam.||Figure 6. Deformed and twisted column base.|
Forklift components like forks, lifting mast and outriggers are repeat offenders when it comes to rack damages. When forklift operators load or unload racks, these components often accidentally impact the beams (Figure 5), the columns (Figure 6), and the anchors. Upper level racking components can be more subject to fork collisions because of loss of 3D perception by operators when placing pallets at higher elevations. Double-deep racks will often see the first few beam levels badly damaged by the mast as the operators wrongfully use them as a depth gauge to position pallets with the reach forks. Forklift outriggers often come into contact with column anchors in seismic zones or directly with the base of the columns, as shown in Figure 6.
Providing cameras at fork level may prevent beam damages at higher elevations. Using very strong column base guards and outrigger stoppers can prevent damages to anchors, columns, and bottom beams (Figure 5).
4. Repeated Friction Between Pallets and Racks
|Figure 7. Deformed diagonal brace.||Figure 8. Deformed back column.|
The repeated friction between pallets and horizontal or diagonal braces when putting and removing pallets in slots is another common way that racks get damaged (Figure 7). It has to do with the angle of approach of the pallet which in turn is related to aisle width and clearance to make the turn before the pallet is positioned or after it is retrieved. It could also be that the pallets are too deep or too wide to fit the slots. Remember that pallets must be 3” clear off rack columns and 6” clear with other pallets.
Damage commonly occurs when the load is raised for removal while the pallet is slightly in contact with a brace. This type of damage will often manifest itself as a single brace lip that is bent.
Another type of damage is crushing the back column upon entering the slot (Figure 8). Like for damaged braces, this type of damage is harder to see during inspections.
Solutions to prevent these damages include making sure pallet dimensions and aisle width are adequate, as well as using upright side protection barriers or side panels.
5. Unclipping and Overloading Beams
|Figure 9. Deflected beam.||Figure 10. Partially detached beam connector.|
Although beam connector safety pins are mandatory by code, detached or partially detached beam connectors are often found during inspections (Figure 10). The rack design code calls for a 1000 lb of uplift resistance per safety pin. Knowing how strong some forklifts are, it is still possible to break these safety devices while lifting a pallet full of rigid products.
Overloading beams may cause their permanent deformation which will result in them having to be replaced. Dropping loads violently may also generate local deformation of the top surface of the beam but also may crack beam welds and damage the connection holes in the column. All these points affect the performance of the rack and may even cause a violent collapse.
The correct safety solutions to these problems are to better train drivers and regularly inspect the racks.
Preventative Measures and Safety Tips
Racks are highly efficient structures that require components to be free from damage to fully bear the loads placed on them. They are typically not designed to resist impact and although some damages could be minor, accumulated damages over time can result in catastrophic consequences such as the complete collapse of a racking system. Therefore, maintaining healthy racks is essential to their performance and taking the following preventive actions is a great way to stop the endless cycle of replacing damaged parts:
- Train forklift operators thoroughly and regularly;
- Inspect racks regularly;
- Keep aisles clutter-free;
- Match pallet size, rack size and aisle width;
- Protect braces at pallet level with upright side panels;
- Use base guards and/or column guards to protect column base and anchors;
- Use outrigger stoppers to protect bottom beams;
- Use fork-level cameras to protect top beams;
- Use end of aisle protection and side-mounted safety lights on the forklifts;
- Use rear-view-mirrors and proximity sensors to prevent backing incidents;
- Check how the warehouse culture affects rack damage.
Lastly, find a reliable and experienced rack safety partner who can guide you in finding the most suitable and efficient rack safety solutions to not only prevent or repair damage to your racking systems, but to also help you improve the overall safety of your warehouse.
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