Pallet Racking layouts
In any Pallet Racking layouts there are four components:
1. The space occupied by the goods and the equipment on which they may be stored, with the necessary clearances.
2. The aisles between the goods, for direct access to the goods.
3. The gangways at the right angles to the aisles.
4. Any other areas, devoted to such things as marshalling of goods, loading and unloading of lorries, fire escape routes, clearances round heating systems etc.
Normally, the goods are stored within the perimeter of the pallet. If not, the comments about pallets will apply to the area occupied by the goods.
Aisle Widths
The width of the aisle is the clearance between the pallet, goods or rack, whichever clearance is the smallest:
Width of the aisle is determined by the type of forklift truck to be used. This is usually given by the manufacturer assuming a 1200mm x 1000mm pallet is being used. But check, sometimes they assume a 1000mm x 1000mm pallet.
If the pallet is being used by the customer is larger, a bigger aisle is required.
ALWAYS INCREASE THE MANUFACTURERS RECOMMENDED AISLE BY AT LEAST 200MM.
Why?
Warehouse Pallet Racking layouts invariably involve a compromise between the use of the available space and the speed of the materials handling. Working to the manufacturers minimum aisles is like parking in a very tight parking space. It can be done, but it takes time and it can cause considerable wear on the vehicle and driver. It is reasonable to expect between 20 and 30 pallet movements in an hour. The throughput will be halved with restrictive aisles.
When calculating minimum aisle widths, fork truck manufacturers assume that pallets will be located as far back as possible on the fork
Fig.1 – Correct Pallet Position
Fig.2 – Incorrect Pallet Position
Fig.1
Fig.2
and that pallets have been placed on racks accurately.
Fig.3 – Correct Pallet Position
Fig.4 – Incorrect Pallet Position
Fig.3
Fig. 4
Quick method of assessing layout.
For calculating the number of runs of pallet locations that can be positioned into the width of the room, a module consisting of one aisle + two pallets + the clearance between the back of the pallet can be used. e.g.
Gangways
Gangways are used to gain access to aisles. The absolute minimum width of one gangway should be 1800mm. This permits only one forklift truck to use it at a time. Although this is more than sufficient for one truck to drive down, the space is needed for turning in and out of aisles. If more than one fork lift is being used then the gangway should be 3000mm.
Gangways are basically dead space. They should be kept to a minimum. Consequently the best utilisation of space is usually achieved when the racks run the same directions as the longest dimension of the space. This rule holds true in 90% of cases. The number of gangways is frequently determined by the requirements of the fire officer and Fire escape routes.
E.g Optimum layout may be:
This would be rejected because there are aisles with access from one end only, causing dead ends or blind alleys. Thus there should normally be gangways at the end of the aisles.
It is possible, of course, to convert a gangway into an aisle like this.
The number of gangways required – (which then determine the length of the racks) is determined by a number of factors such as the amount of access required, number of forklifts in use, positioning of marshalling area. However, it is desirable that the racks should not exceed 30 metres length. Longer than this the forklift truck drivers effectiveness decreases, causing things such as difficulty locating pallet positions and greater distance penalties for choosing wrong aisles etc.
The beam length is determined by number of pallets per beam x left – to – right dimension of pallet, plus at least 75mm clearance between each pallet, and 75mm clearance between pallet and frame. So taking into account 2 x UK spec pallets at 1200m x 1000mm sitting side by side.
2 x 1200 = 2400 + 3 x 75mm
= 2400 + 225 = 2625mm
75mm minimum clearance as this allows for 100mm clearance when your beam level exceeds 6000mm
Our standard is 2700mm
When calculating a run length it is important to also allow for the width of the uprights.
If you have any other Pallet Racking Layout queries, please do not hesitate to get in touch. Or take a look at our Technical hub for more topics.