The 12 Principles of High Performance Warehousing #5. Optimise layout for minimum travel path

Optimise your warehouse layout for travel path and processing flow inbound and outbound

Part 5 of a series on the 12 Principles of High Performance Warehousing.  The eBook can be downloaded for free by joining the High Performance Warehouse Network on the Logistics Help website.  Note each new blog post also adds new content with a rewrite of each section so the eBook continually evolves.  If you have an old version it might be worth updating it to get the latest version.

The principles of process design dictate that the design of systems and infrastructure must support the business process.  So in order to get the layout correct you must first design the process that you want it to support - with full knowledge of what is possible and what is affordable.  This is the approach we take to all our warehouse designs – first the process then the layout and systems to support it appropriate to the size and growth path of the business.

An optimised layout is a combination of the right racking for your products in the right place with the right products slotted in the right locations but you can only make these decisions once you have developed the right process for your business

Many people make the mistake of starting with the current system and the existing infrastructure and then designing a process around that.  Unfortunately when you do it this way, you are accepting your current limitations without question and missing the opportunity to unleash greater overall productivity in your business.  What often starts as a need for some new racking, or an observation that you are running out of space in your warehouse can be an opportunity for a major reform and productivity gain if you open your eyes to what is possible.

Do not make the mistake of thinking “I have no budget so I will stick with what I have”.  Far better to develop the ideal process and then work out how to fit it to your budget, than compromise the process design by taking your current infrastructure and systems limitations as an unchangeable given.
If your current warehouse layout is poor then you have locked in poor productivity into your operations.  What’s worse is that this lower productivity is invisible to you because it is not in your front of mind when considering how to improve your operation.

Businesses change over time, a once perfectly suitable layout and racking arrangement can become a drain on productivity.  Perhaps the layout was never planned in the first place but racking was simply put wherever it fitted at the time the installer showed up.

The basic principles of efficient warehouse layout are as follows:

1. There are two ways of arranging racking & shelving (transverse or longitudinal to the main axis of your warehouse).  Unless the floor area allocated to the racking is square, one way will yield more storage locations than the other.  This is easily determined by laying out the racking both ways on building plan. This can be easily done with CAD software or a manual drawing.  If there is a choice then the longitudinal arrangement will be the more efficient and flexible arrangement due to the greater number of travel aisles leading to the despatch dock.
2. Where racking types are mixed (say block stack, pallet racking and shelving) then assess the average pick frequency for each storage block and layout with the most frequently accessed storage nearest the front of the warehouse.  Physical building constraints may still override the optimum positions.  The aim is to get the best position possible.
3. Staging areas must be large enough to stage the expected inbound and outbound delivery requirements and preferably next to separate receiving and shipping doors.  If operational timing permits, (i.e. receive in the morning and despatch in the afternoon) then the staging space can be shared between receiving and shipping.
4. Build travel shortcut aisles into long runs of racking or shelving so pickers can cut across aisles to reduce travel path.
1. Pallet racking should be continuous with beams removed in one rack bay to a sufficient height to let your forklifts travel underneath the higher levels.
5. Maximise the use of the building volume with high level pallet racking, multi-level shelving modules and mezzanine levels.
1. Generally you can stack stock to up to 45cm below the level of your sprinkler heads but check with your fire system provider for the clearance required for your particular installation.
6. Eliminate air – your stock does not need to breathe!
1. When I walk into a warehouse, one of the first things I look for is storage density as indicated by the amount of free space (air) around products in the storage racking.  Lots of air means lots of wasted space which means higher storage cost per unit, longer travel path for put-away and picking and lower productivity.
2. Once you realise that an investment in the most appropriate racking and storage systems for your products is an offset of both rent and operating expense you will not quibble over the cost anymore.  Good racking and storage systems make you money, last indefinitely and are never superseded.  Is any other investment this good? Buy good quality second hand if your budget is tight.  Do not buy cheap damaged racking or inferior quality imports that fit together poorly and that you will not be able to buy more of if you need to add beams or extend your racking in future.  This is a false economy and you will regret the decision.  Old but quality racking is fine.  Old racking was built with a lot more steel in it than modern racking and provided it is not damaged, will last forever.
7. Build optimised workstations for receiving, packing and despatching orders near the inbound and outbound docks.
1. Too much focus just on the pick process and neglecting the whole of the warehouse operations will see you missing out on valuable productivity gains.  Slow receiving will starve the picking operations and make them less efficient.  However your stock comes in or goes out, you need space and efficient process to get it into or out of the warehouse.
2. This means a well laid out operations bench which is kept clear of junk and has everything you need to hand such as labels, packing materials, paperwork, computer workstation (if required) & printers.
8. Allow sufficient staging space for inbound and outbound order staging and processing.
1. Around the workstations and at each dock you need clearance for staging of product in and out.  Nothing kills productivity and throughput rates faster than the double handling caused by inadequate staging space.  I have seen warehouses with insufficient staging areas fill up their racking aisles with outbound or inbound stock.  When they had to pick or put-away to these aisles they had to double, triple, quadruple handle this stock just to keep functioning.
9. Keep fast moving product in the fastest to access areas.  The corollary also applies, put slow moving items in the slowest to access storage areas.
1. If you have a bad building with pillars and walls in all the wrong places then this idea is what will bring back the productivity into your operations.  Many businesses simply do not apply this principle to their warehouses or do not apply it rigorously enough to get the full benefit.
10. Use fixed pick locations near to the despatch dock with a periodic replenishment cycle.  This keeps fast moving products close together to reduce travel path.
1. This requirement must be balanced by the need to allow sufficient access to the pick face so that all of the orders for fast moving product may be picked.  Too close together and you can create congestion as too many pickers need to access the same product at the same time.
11. Store the balance of fast moving stock in randomly located bulk storage racks.
1. As per point 1: in bulk storage racks, keep the faster moving products in the fastest to access locations, which, in pallet racking, will be low and nearest to the despatch dock.  These subsets of bulk storage racking are also referred to as zones.  Zoning at this level requires a warehouse management system to control the put-away process.
2. Points 9-11 are related to the idea that is commonly called product slotting.  They are important to layout because they will impact what type of racking you put in your fast zone.  We will talk more about slotting in principle 7 below.
12. These principles of good warehouse layout must be applied as part of the overall operational process design. This includes the warehouse management system, data collection technology (mobile terminals with barcode scanners, voice directed task technology), racking systems and materials handling equipment.

If you need help to work out the right layout for your warehouse you can contact us here