‘VNA-ready’ floors: Future-proofing distribution centres

Technical Insight

March 20, 2017
by Maurice Dalton

The demand for faster delivery times, fuelled mainly by the inexorable growth of e-commerce is putting new strains on the supply chain and the buildings from which they operate. Understanding these new challenges, Prologis has developed innovative solutions to future-proof its distribution centres and one of its first priorities is the warehouse floor.

Working with Winvic Construction and flooring specialists, Stanford, Prologis has developed a new approach to concrete warehouse floors that will allow customers to evolve their distribution operations at minimum cost. The solution, which is known as ‘VNA-Ready’ concrete flooring has already been installed at DC1 and DC7 Prologis Park Ryton and is set to become a new industry standard.

VNA storage systems

The Challenge

With the growing pressure to shorten delivery times across the logistics industry, occupiers are seeking to increase the pallet positions in their existing warehouses by introducing taller, narrow aisle and very narrow aisle (VNA) storage systems. VNA systems typically operate with wire or rail guided forklift trucks that need very tight tolerances of floor flatness.

Conventionally, warehouse floors are constructed to the FM2 ‘free movement’ flatness classification as defined in The Concrete Society Technical Report 34 fourth edition. As its name implies, forklift trucks can move in any direction on FM2 floors, which are typically constructed using laser screed processes in standard square panels from 30m x 30m to 50m x 50m, with steel reinforcement along the joints.

The FM2 floor is ideal for block stacking and wide aisle racking, but VNA systems demand floors that comply with the more stringent ‘defined movement’ or DM specification. Formerly, if the occupier did not know when a VNA system would be needed and they had two options:​

  • Specify DM flooring at the construction stage in anticipation of possible VNA infrastructure. This involves longer construction time together with increased construction and maintenance costs

  • Convert an FM2 to a DM floor, a variation that is expensive to implement, to maintain and to remediate, because the occupier is required to re-instate the original flooring at the end of it lease

The Solution

Realising that most customers will need VNA systems at some stage during their occupancy, Prologis, Winvic and Stanford have developed the ‘VNA-Ready’ floor that increases the flexibility of the warehouse and minimises the customer’s occupational costs. Their approach is as follows:

  • Change the traditional square slab to a rectangle with dimensions of around 120m x 16m. These new dimensions mean that it is easier to lay and level the concrete, ensuring the refined overall flatness tolerance required by VNA forklift trucks
  • ​The new floor slabs fit exactly between the building columns, typically built at 16m centres. This means that there are no floor joints – which can damage a VNA truck’s tyres - along any of the main aisles

​So, for customers, the ‘VNA-Ready’ floors bring peace of mind. The floors are suitable for general block stacking and wide aisle racking, but they will also adapt to narrow aisle or very narrow aisle systems quickly with little or no additional work and expense.