System 06 · Full selectivity, half the aisle
VNA racking: keep every pallet accessible, give back the aisle.
Very narrow aisle racking is selective racking served by a turret truck that does not turn to face the rack — it slews its forks instead. Aisles shrink from around 3.5 m to 1.6–2.0 m while every pallet stays directly accessible, and heights of 12 m and above become practical. It is the answer when land is expensive and the SKU count is too high for any density system.
In brief
VNA racking is selective racking served by a turret truck that slews its forks instead of turning. Aisles shrink to 1.6–2.0 m and heights above 12 m become practical, while every pallet stays directly accessible.
- Full selectivity with 40–50% less aisle space — the answer when land is expensive and SKU counts are high.
- A superflat floor is a hard requirement above roughly 9 m of lift; assess the slab before anything else.
- The turret truck and floor works usually cost more than the racking itself, so run the arithmetic against leasing space.
- Uprights are set to tighter plumb tolerances because the truck works within centimetres of the structure at height.
01 — The system, honestly
VNA is a building decision, not a racking decision
The racking is the least demanding part of a VNA project. The truck, the floor and the guidance system are what make or break it.
A man-up or man-down turret truck travels the aisle and slews or shuttles the forks to either side without rotating the chassis. It is a substantial capital item, often more expensive than the racking it serves.
Aisles are guided by floor rails or by wire embedded in the slab. Rail guidance is simpler and common in Indonesia; wire guidance costs more but leaves the floor clear.
Floor flatness is a hard requirement, not a preference. At 12 m of lift, a small slab deviation becomes a large deflection at the fork tips. Existing slabs often need grinding or replacement — survey this before committing.
Uprights are set and shimmed to tighter plumb tolerances than conventional racking, because the truck works within centimetres of the structure at height.
02 — Qualifying criteria
When VNA is the right investment
High SKU count, low depth per SKU
Where a density system would leave lanes half full, VNA gives density through aisle reduction while keeping every pallet accessible.
Expensive or constrained land
Urban and near-port locations where extending the building is impossible and rent per square metre is high.
Tall clear height already available
If your building has 12 m or more of clear height and you are using 6 m of it, VNA converts unused air into pallet positions.
Old or uneven slab
Remediation cost can exceed the racking cost. Assess the floor before anything else.
Low throughput operations
Turret trucks are expensive to own and to crew. Light throughput rarely justifies the capital.
Frequent layout changes
Guidance and floor works make a VNA aisle a semi-permanent commitment; plan for the long term.
03 — Space arithmetic
What the aisle reduction is worth
| Configuration | Working aisle | Practical height | Selectivity | Floor used for storage |
|---|---|---|---|---|
| Counterbalance selective | 3.2–3.9 m | Up to about 6 m | 100% | 30–40% |
| Reach truck selective | 2.6–3.0 m | Up to about 11 m | 100% | 35–45% |
| VNA | 1.6–2.0 m | 12 m and above | 100% | 45–55% |
| Double deep | 2.6–3.0 m | Up to about 11 m | About 50% | 45–55% |
VNA and double deep reach similar floor utilisation by opposite routes: VNA keeps full selectivity and pays for it in equipment and floor works; double deep keeps standard equipment and pays in selectivity.
04 — Project requirements
What a VNA enquiry needs to include
- Slab thickness, concrete grade and an existing floor flatness survey if you have one.
- Clear height to the underside of structure, and sprinkler head positions.
- Intended truck model, or a note that truck selection is still open so we can design to a range.
- Guidance preference: floor rail or wire, and whether the slab can be cut.
- Pallet weights, dimensions and the SKU count you need simultaneously accessible.
- Whether the building will remain operational during installation — VNA aisles are usually built aisle by aisle.
Questions buyers ask
Frequently asked questions
How narrow can a VNA aisle be?
Typically 1.6–2.0 m in service, set by the truck’s turret envelope plus a working clearance on each side. The truck manufacturer’s aisle requirement is the governing figure and we design the racking to it.
Do I really need a superflat floor?
For lift heights above roughly 9 m, yes. Slab deviation is amplified by mast height, so a floor that is fine for a counterbalance forklift can make a turret truck unusable at 12 m. This is assessed before design, not discovered during commissioning.
Can I convert existing selective racking to VNA?
Sometimes the uprights can be reused if they were designed for the required height and load, but the runs must be re-spaced, re-plumbed to tighter tolerance and often extended upward. The floor and guidance work is usually the larger part of the project.
What happens if the turret truck breaks down mid-aisle?
Recovery planning is part of the design: aisle end clearances, access for a recovery truck and, in some layouts, a policy of not filling the last positions. We discuss this at layout stage because it affects the design.
Is VNA suitable for cold storage?
It can be, and the space saving is valuable where refrigerated volume is expensive. However, guidance systems, truck batteries and operator comfort all behave differently at low temperature, so the truck specification needs particular attention.
How long does a VNA installation take?
Longer than conventional racking, because of the plumb tolerances, guidance installation and any floor works. We build aisle by aisle where the building must keep operating, and give a phased programme with the quotation.
Talk to engineering, not a call centre
Before you rent a second warehouse, check what VNA does to this one.
We model your current layout against a VNA layout in the same building and show both pallet position counts, plus the floor flatness and truck requirements that come with it.