Planning a new distribution facility takes time. Schemes evolve as operating criteria and budgetary or planning constraints change. Having worked on many start-up projects Mezzanine International is always aware that initial schemes may develop and is therefore both accustomed and willing to assist in this process.

When the international healthcare company Roche Diagnostics was considering a new South of England distribution centre, on an existing site, it discussed a variety of possibilities with its logistsics consultants Alan Wilson Associates. Originally Roche Diagnostics intended constructing a 14 metre high building alongside an existing 6 metre former retail shed that was being used for overflow storage. This combination would have doubled the useable building volume and outline planning permission was accordingly obtained.

The client considered two layouts. The first used the existing low rise building for all throughput support activities - including those requiring a temperature controlled environment - with the proposed new structure being used for narrow aisle storage. Consideration was also given to use the low rise building for bulk storage, enabling rented out 3rd party storage to be dispensed with, and to use the new high rise building, with multiple mezzanine levels designed by Mezzanine International, for all throughput activities.

Subsequently a corporate strategy review substantially reduced the bulk storage requirement. This meant that the stock/order fulfilment solution could be made entirely within the original shell and the eventual layout could be established utilising only the low rise building and incorporating a mezzanine floor. According to AWA's Alan Wilson the key challenges were:

i) Although on a piled site, no reliable drawings existed showing the precise pile locations. This necessitated the use of ground penetrating radar to establish where mezzanine stanchions could be positioned.
ii) Part of the stock needed to be stored in chilled conditions. Under current legislation the chiller roof would have to be supported to avoid collapse were the chiller walls to distort in the event of a fire. The old building roof structure could not be used to support the chiller roof and so the mezzanine would have to be designed to incorporate a suitable chiller roof support structure that would be independent of the building.

Mezzanine International Ltd was chosen to design and install the main ambient temperature order picking mezzanine, the 23.4 metre long chiller roof support structure and a rack supported mezzanine within the chiller.

The design allowed for orders to be picked into tote boxes from shelving and flow racks on the main 3.5m high 32m x 23m mezzanine and then to be moved on conveyors designed and installed by Knapp Logistics & Automation and, via a Knapp tote lift, to and from the ground level. A maintenance platform to allow access to the tote lift was to be built out from the main mezzanine level and a conveyor run to the ground level needed to be supported from the side of the mezzanine to maximise the useable space on the mezzanine. This was achieved by extending a number of the mezzanine beam lines beyond the mezzanine's perimeter.

The main mezzanine columns adjacent to the chiller were extended to a height of 6.75 metres and portal frames were constructed, spanning the 12 metre wide chiller, to support its roof structure. Within the chiller itself a rack supported mezzanine structure, complete with access staircase, was constructed to allow optimum use of the available storage height.

A 15m x 8.5m extension to the main mezzanine was designed to be built over the goods inward area and partitioned from the ground to the mezzanine level. Both the partitioning and the mezzanine structure were designed to incorporate a full height quick-action loading bay door. The object was almost to create an ‘air lock' environment so that during loading/unloading, when the external roller shutter doors are open, the inner quick action door remains shut and more or less hermetically seals the warehouse area.

Suitable access to and from the mezzanine level was achieved by way of a standard ‘Part K' staircase and also by positioning an ‘ambulant access' staircase, in accordance with Part M of Building Regulations, in a confined area alongside the chiller. A bridge from the mezzanine also allowed access/egress directly through a new fire exit into an existing two storey office area.

Once all parties were committed to the final design, a build programme agreed with AWA and the client ensured that the construction of the mezzanine areas was integrated expediently with the conveyor and shelving suppliers and other site trades to provide Roche Diagnostics with a satisfactory and timely project conclusion. Roche Diagnostics' Logistics Manager commented "The Alan Wilson Associates/Mezzanine solution for a difficult site proved that the location could be viable and in practice the distribution centre certainly meets all our requirements".