- VDMA is the Association of German Machine and Plant Construction (Verband Deutscher Maschinen- und Anlagenbau e.V.) which publishes industry standards, including those used to describe floor levelness and flatness for:
- Guided Very Narrow Aisle (VNA) Industrial Trucks and other Industrial Trucks travelling with elevated loads (see EN 1726- 2/ prEN ISO/DIS 3691-3)
- Operator positions inside very narrow aisles, or near racking in wide aisles.
The VDMA guidelines within ‘Floors for use with VNA Trucks’ has been written for 3 properties of surface regularity:
- Transverse properties describe the differences in elevation between the centres of the front load wheels of a forklift truck, in millimetres. This method of measurement is the same in all defined movement traffic specifications.
The diagram shows the transverse elevational control.
- Longitudinal – In accordance with DIN 15185
The longitudinal property of DIN 15185 is based around a straight edge of variable lengths, derived from the DIN 18202 specification.
DIN 15185 provides two methods of checking a floor. A gap under a straight edge, or the departure at the mid-point from a mean line between two points a given distance apart.
- Longitudinal micro small wavelength – ‘Fx’ number.
A Longitudinal micro small wavelength measurement or ‘Fx’ number is calculated using an ‘Fx’ meter to measure, within a fraction of a millimetre, slope change between two elevations readings, 50mm apart.
The ‘Fx’ meter has 9 steel wheels on three axles, with each wheel measuring 40mm diameter, and the edge being tapered to a width of 0.5mm.
To date, unlike other defined movement specifications, the VDMA guidelines have had very little validation.