FEM 9.831 is a recognized, albeit non-harmonized, guideline issued by the Federation Europeenne de la Manutention (FEM) for use with storage and retrieval machines (SRMs) in automated high-bay warehouses. It describes in detail the tolerances, deformations, and necessary clearances that must be taken into account during planning, manufacture, assembly, and operation in order to ensure the functional and operational safety of high-bay warehouses.
What does FEM 9.831 regulate?
The standard specifies:
• Definition and scope of tolerances and deformations in warehouse operations.
• Calculation bases for clear clearances between storage and retrieval machines, storage aids (e.g., pallets, mesh boxes), and the rack structure.
• Factors influencing tolerances and deformations: base plate, guide rails, load unit, profile controls, staging areas, equipment tolerances, rack construction.
The guideline applies to high-bay warehouses with rail-guided, rail-supported storage and retrieval machines that mechanically pick up loads and handle pallets or similar load units.
Why is FEM 9.831 important?
In highly automated high-bay warehouses, even the smallest deviations in the system’s components can affect operational safety:
• Insufficient clearance can cause the storage and retrieval machine to become blocked or damaged.
• Excessive clearance means inefficient use of space and thus a loss of storage capacity.
• The standard therefore serves to strike a balance between safety, cost-effectiveness, and maximum space utilization.
Contents and structure of the norm
FEM 9.831 contains about 100 pages and is structured in several sections:
1. Introduction and objectives – describes the purpose and scope of application.
2. Definitions – key terms such as “clearance,” “tolerance,” “deformation,” and “positioning tolerance.”
3. Influencing factors – detailed analysis of how components such as travel and guide rails or base plates influence tolerances.
4. Tolerances and deformations – compilation of permissible dimensional deviations from manufacturing, assembly, and operation.
5. Clearances and run-in dimensions – Determination of the minimum distances to be maintained between the storage and retrieval machine, rack structure, and load units.
6. Calculation examples – Practical, verifiable calculations for validating tolerances.
Current facts and norm references
• The FEM 9.831-1 (Part 1) guideline is currently the main document used to calculate tolerances in pallet warehouses.
• It is used in conjunction with related FEM documents such as FEM 9.832 (small parts warehouses) to cover various warehouse scenarios.
• FEM 9.831 continues to be important in standards collections, but is increasingly being supplemented or replaced by current EN standards such as EN 15620 and EN 15512 on limit deviations and deformations in racking systems.
Criticism and practice
A frequent point of criticism is that the original 1995 version was created without the involvement of shelving and high-bay racking manufacturers, which has led to discussion about its practical relevance.
Nevertheless, it is widely used in practice as a guideline for planning, manufacturing, and measurement technology, e.g., in 3D measurements of systems, adjustments, and acceptance processes.
Conclusion - Relevance for planning and operation
FEM 9.831 is an important document for logistics, warehouse, and plant planners and operators because it:
- Defines tolerances for installation and operation
- Specifies limits for deformation due to weight, wind, or temperature
- Provides a basis for clearance and safety calculations
- Serves as a reference for measurement and adjustment
You can find more information under Storage and retrieval machines.
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