Pallet Racking

Wooden pallets were originally designed in 1925 to facilitate the movement and stacking of goods with a forklift.  Initially pallets had wide bottom bearers to spread the load and prevent damage to the product beneath. With the invention of Dexion type pallet racking in the 1950’s, wooden pallet designs were adapted for placement on rack load beams. Racking allowed pallets to be stacked higher, increasing warehouse storage capacities.  While pallet sizing, design, loading capacities and now construction materials vary around the world, the standard pallet in South Africa remains the 1000 by 1200mm 4-way entry pallet epitomized by CHEP, a global provider of supply chain solutions. The CHEP Code 1 is detailed below. There are also 1200 by 1200mm 4-way entry pallets designed mainly for 240-liter drums and other 2-way pallets of varying sizes to accommodate mainly packaging materials. In Europe the standard is the 800 mm by 1200 mm 2-way entry pallet while the American ones are measured in feet and inches. The 1000 x 1200 mm CHEP Code 1 pallet is a general-purpose platform that can be safely used for most applications in the distribution and transportation of goods and products. It is made up of 100% recyclable materials and upon return to a CHEP service center, every pallet is inspected, and any damaged elements replaced to ensure that only top-quality pallets are available for use. In Australia, where palletization was first commercialized as the Commonwealth Handling Equipment Pool (CHEP) after WW2, the standard pallet is a 1165 mms by 1165 mms 2-way pallet with cut outs on the solid sides to allow secure storage on rack loading beams. These pallets were sized to fit 20 per Australian RACE container. They also come in two types, 19mm boards to carry 1000kgs and 25mm boards to carry 2000kgs. Pallet design is dictated mainly by container/truck size, weight of product and the need for racked storage in the supply chain. Case dimensions are designed to suit the pallet and not generally the other way around. Global containerized supply chains have increased pallet demand but also added challenges. As the cost of returning wooden pallets to their country of origin is uneconomic, disposable pallets are currently preferred for exports. Disposable pallets are designed to be as light and cheap as possible. If made of wood, they are fumigated to prevent the inadvertent migration of pests. They can also be made of lightweight plastic or cardboard.  Specifically, the corner support blocks on disposable pallets can be reduced from 150mms square, as per the CHEP example above, to as little as 50mms.  Stringer, top and bottom beams are reduced in thickness and width.  When stored in selective pallet racking the pallet blocks do not always sit directly over the load beams. With drive in and shuttle racking pallet deflection can be problematic.  Racked storage can still work well for disposables when the gross pallet weights remain under 1000kgs.  However, high cubed (2450mms) deciduous fruit pallets can exceed 1300kgs gross and citrus, especially lemons can approach 1500kgs.  These weights significantly exceed those officially stipulated for even the heavy duty CHEP Code 1 pallet. In addition to pallets becoming lighter and product heavier, rising costs have encouraged fruit pack houses to find savings in containerized transport costs. These include slightly decreasing pallet dimensions to increase the pallet numbers that can be stowed per 12-meter container. Green block pallets, 950mms by 1125mms, increase pallet numbers per container from 20 to 22. Black block pallets, at 1000mms by 1160 mms, have a packing configuration of 21.  Most fruit pallets are rack supported on the long side either in static/ mobile racking where the rack beams are 1100mms outside to outside or drive in where the rails are designed for a 1200mm wide pallet.  Decreasing the pallet length to either 1160 or 1125mms makes the pallets difficult to place, decreases the safety margin on pallet overhang and increases the strain on the already overloaded design. Barpro initially noticed this with increased breakages on the base level where the support beams are 1020mms apart as opposed to the racking where the spacing is 1100mms. Smaller support blocks together with thinner weaker slats meant that the full weight could be taken on the slat resulting in some bottom slat failures. With deceasing pallet sizes pallet overlap on the higher rack beams for green block pallets is notionally 12.5mms.  Placement in drive in racking especially at higher levels is similarly affected. Put away and retrieval challenges can be magnified if Flexi or Bendi trucks are used in narrow aisle applications. Solutions to these challenges in mobile or fixed racking include the following: At about R180 installed PSBs are a cost-effective solution to support 1000 by 1200mm disposable pallets.  Painted yellow against orange load beams, PSBs provide a put away reference at higher beam levels so drivers can center the pallet over the PSB. However, pallet placement should have the central block on the PSB for maximum support. This increases the bearing width of the base beams and solves the challenge on the base level, but not in the racking superstructure above. Closed decking normally 19mm thick at around R300 per pallet position can solve both weight and sizing problems. However, wooden decks take up vertical space, cut down on ventilation and can be seen as a fire hazard.   These come in two varieties, either additional or full support. The latter allows pallets to be placed safely between load beams solving both size and weight challenges at about R600 per pallet position. Additional support grids still require the pallet to be placed on the load beams and cost about R 400 each.    The 75mm beam Increases the bearing area at higher pallet levels. 75mm deep beams are more expensive than the 50mm variety. Developed by Manny Dos Anjos CEO of Precool Cold Storage in Hammarsdale. These galvanized bars have solved the problems on the static and mobile racking at Precool Cold Storage and fully support fruit pallets of most sizes, enhancing safety while preventing sag and eliminating breakages at a cost of

Rack load notices are fixed to warehouse racking and contain all the critical information required to use the racking safely. Amongst other things the rack load notice should show the following. Rack supplier contact details. This allows staff to quickly contact the rack supplier for spares or inspections.    Maximum rack bay load.  A bay being defined as the space between two frames. The weight of the bottom pallet level is excluded if pallets are located on the warehouse floor.   Maximum uniformly distributed load per pair of beams. This will normally be 2 or 3 pallets of say 1000 kgs gross weight.  It doesn’t mean one pallet of 2000/3000 kgs gross.   Height from floor or ground beam to top of first beam and subsequent spacing between beam levels. The first beam level is critical factor in rack design and determines the maximum bay load. If the first beam level is moved upwards the bay load will decrease.    Preferably pallet dimensions and gross weight. Important in that oversized pallets can damage the rack frames. Overweight pallets can also be quickly identified.   Date supplied and some sort of project reference. This allows regular inspections to be organized. Ideally there should be a load sign on every run of racking. This is because different rack designs are frequently found in the same warehouse. The racks may look the same but have significantly different design loads.     Barpro Storage supplies rack safety and PRRS (Person Responsible for Racking Safety) training. But without the correct load notices it is not possible to check the racks properly as the bay and beam loads and levels are unknown. If there are no load notices in a warehouse, then the original rack supplier can be contacted and new rack load signs or the relevant information requested. If the original supplier is unknown, then an engineer with rack experience should inspect the racking and calculate the load sign information from first principles.  When requesting new load signs from the rack supplier make sure that the design pallet weight dimensions match what is currently stored on the racking and that the beam levels have not changed.    On a practical note, I have frequently found rack load notices to be incorrect as they can be attached as part of a “tick box” exercise and their accuracy not confirmed. On several occasions, the original rack load signs are on the racking, but the first beam level has been removed to accommodate higher pallets.  Beam levels must not be changed without the original supplier’s consent or sign off from an engineer. Once the beam levels have been changed, the existing load signs must be replaced with new ones. If you need additional information or have queries about rack load signs, please do not hesitate to contact us on either: CPT – 021 552 9190 JHB – 011 392 1702 DBN – 066 232 7363