Picking From the Top Levels: What Height Does to a Warehouse Layout
There is a question that decides more about a warehouse layout than pallet counts, aisle widths or beam capacities, and it is almost never asked out loud at the quotation stage:
Which levels will a person reach into with their hands, and which levels will only ever be touched by a machine?
Get that answered before the beam heights are set and everything downstream follows sensibly. Leave it unanswered and the building answers it for you, at about the second month of operation, when somebody needs one carton off level three and the only tool to hand is a ladder.
The two jobs a rack level can do
A pallet position is doing one of two jobs, and they have almost nothing in common.
A pick face is reached into by a person. Cartons come off it, boxes are opened on it, someone stands in front of it several times a day. Pick faces belong at floor level and at the first beam level — the range a person can work in without climbing anything.
A reserve position is handled only as a complete unit load, by a truck. Nobody's hands go into it. It can be as high as the building, the truck and the fire protection allow, and that is exactly what upper levels are for.
Almost every avoidable problem in this area comes from a position quietly changing job — a reserve position that becomes a pick face because that is where the fast-moving SKU ended up. We wrote about designing the pick face deliberately in carton flow and piece picking from selective racking.
Where the risk actually enters
Under Singapore's Workplace Safety and Health framework, work at height is not something a business decides to allow informally. Work at height requires a risk assessment and a fall prevention plan, and the duty sits with the occupier of the workplace — not with the person who happened to climb.
The practical version, in a warehouse, is that there are only three ways a person gets above floor level near racking, and two of them are usually improvised.
1. A ladder or step platform. Three problems, in increasing order of seriousness. It closes the aisle to trucks while it is there, so it costs throughput. It is often leaned against the racking, and an upright frame is designed to carry vertical load through the frame, not a sideways push part-way up. And it puts a person on a ladder holding a carton, which is the classic fall.
2. On the forks. Tines are designed to carry pallets. If people genuinely have to be raised, that requires equipment designed and certified for lifting persons, with the procedure and training that goes with it — not a pallet, not a cage borrowed from another site, not "just for a minute".
3. An order picker. A man-up truck is the piece of equipment actually built for the job: the operator is raised on a platform with a harness anchorage, and the truck is designed around that duty. It is the right answer where high-level picking is genuinely part of the operation — and it is a decision that reaches back into the rack design, because man-up trucks bring guide rails, floor flatness requirements and aisle geometry with them. That is the same territory as VNA floor preparation and what happens when the fleet changes under an existing rack design.
How this shapes the layout
Beam heights follow the trucks and the loads, not a ruler. Evenly spaced levels look tidy on a drawing and waste height in reality. The spacing that matters is pallet height plus clearance, and the top usable level is set by the real lift height of the truck you actually own — not the one in the brochure, and not the one you might buy. The rest of that arithmetic is in clear height and how many levels you actually get.
Fast movers go low. A pallet at the top level takes longer to retrieve, is harder to place accurately and is where most travel damage happens. Sorting by velocity rather than by product family puts the frequently-touched stock in the range that needs no height at all — which is the same decision that keeps people off ladders.
The top level is not free. Sprinkler clearance sets a hard ceiling above the highest stored load, and it is a condition of approval rather than a guideline. That is covered in sprinkler clearance and racking approval.
Load notices have to be readable from the floor. The rated capacity per level and per bay is what tells an operator what may be placed up there, and a notice nobody can read is a notice nobody follows — see load notices and SWL signage.
Five things that tell you it is already happening
If you want to know whether people are working at height in your warehouse without anyone having decided that they would, walk the aisles and look for these.
- A ladder or step stool stored in an aisle. Nobody keeps one there for no reason.
- Scuff marks or footprints on beams. People climb the racking. It is quick, it is quiet, and it is the single most common unreported behaviour in a warehouse.
- Opened cartons on upper levels. A reserve position with a broken case in it is a pick face that nobody declared.
- Loose items resting on top of a pallet load. Somebody put them there from height, or took something from height and left the rest.
- Mesh decking or panels missing on upper levels only. Often removed to reach through. It also removes the thing that stops a dropped item falling into the aisle — the decking decision itself is covered in steel panel, wire mesh and chipboard decking.
What to do if the answer is yes
The cheapest fix is almost always a layout one, not an equipment one.
Move the SKUs being picked by hand down to the two lowest levels and let the upper levels revert to full-pallet reserve. In most warehouses a small proportion of SKUs accounts for most of the picking, so the reshuffle is smaller than it sounds and it removes the reason anyone was climbing. Where that is not possible because the range is genuinely too wide for the ground and first level, the options are a mezzanine or platform to create more accessible pick frontage, a carton flow or shelving section for the small items, or an order picker with the rack design to support it.
What is not an option is leaving it as an unwritten habit. The aisles are also where trucks are moving, and a person on foot at height with a carton, in an aisle sized for a reach truck, is two risks compounding — which is why aisle width and traffic are part of the same conversation, set out in forklift turning radius and aisle width.
The short version
- Decide which levels are pick faces and which are machine-only reserve, before the beam heights are set.
- Work at height in a workplace needs a risk assessment and a fall prevention plan; the duty sits with the occupier, not the person who climbed.
- Ladders in aisles cost throughput, load uprights sideways, and put someone on a ladder holding a carton. Forks are for pallets, not people.
- An order picker is the right tool where high-level picking is real — and it changes the rack design, so it is not a late decision.
- Set beam heights from the actual lift height of the trucks you own, keep fast movers low, and respect the sprinkler clearance at the top.
- Footprints on beams and opened cartons upstairs mean it is already happening.
- The cheapest fix is usually reorganising the slots, not buying a machine.
Not sure whether your layout is quietly asking people to climb? WhatsApp us on 9107 2601 — tell us how many levels high the racking is, what is being picked and which trucks you own, and we will tell you whether the fix is a reslot, more pick frontage or a change to the rack design. See also our racking systems page.