Multiple- and double-deep storage

Due to its considerable savings in volume, automated storage is increasingly being designed and implemented as a double- or multiple-deep system. One less aisle in the design also means one less stacker crane, which in turns reduces the level of capital expenditure. Recent studies show that even despite the inevitable relocation operations (in the absence of direct access to the bay far from the aisle), double-deep storage can yield higher rates of throughput than single-deep storage.

Implementing multi-deep storage places its own special demands
on the warehouse management and material flow control system, however, such as:

  • Specialised putaway strategies, to minimise the likelihood of goods relocation
  • Reservation of handling units near the aisle for removal, wherever possible
  • Pair formation also needs to be taken into account by the removal strategy
  • Relocation strategies are needed for creating single-material/-delivery shelves in low-activity periods
  • etc.


In the past, one might have had the impression that SAP TRM (SAP Task and Resource Management) was unable to provide this kind of SAP-assisted stacker crane control. As part of successful SAP logistics projects undertaken for several customers, IGZ was able to "crack this nut" as well in 2005/06, implementing a double- and multi-deep storage solution for HBW and AS/RS for small parts in standard SAP LES (SAP Logistics Execution System) and SAP EWM (SAP Extended Warehouse Management)!

The use of single, dual, or multiple load handling gear on stacker cranes is also now being implemented with SAP TRM. Analytical runtime models for multi-deep storage featuring intelligent operating strategies can be implemented in a number of different ways in SAP and are comprehensively simulated by IGZ in SAP-side tests made before commissioning.

IGZ routinely factors in the corresponding adjustments to the SAP control station (SAP TRM Monitor).

Further details of the implementation scenarios for double- and multi-deep storage with SAP LES/TRM/EWM can be requested from

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