FM1. This category will rarely be used and only for a free movement area where very strict flatness and levelness tolerances are thought to be essential. The limits specified for FM1 are extremely onerous and difficult to achieve in practice and probably restrict the method of floor construction to the long strip technique. This category, and its limits, are unchanged from TR34. The basic limits of this category are unchanged from TR34 but some small allowance is made for a degree of discrepancy beyond these limits.
FM2. This category provides a high degree of flatness and will be appropriate for many free movement areas in warehouses. Wide aisle warehousing, transfer aisles for very narrow aisle (VNA) and automated-guided-vehicle (AGV) areas are typical uses for this specification class. FM2 should be selected for wide aisle warehousing where the stacking height or potential stacking height is greater than 8 m.
FM3. This category will be used in wide aisle warehouses where reach trucks are used and where the stacking height or potential stacking is less than 8 m. This classification will also be used for manufacturing facilities where special flatness facilities are required. End user equipment suppliers may require a higher classification.