Surface Regularity

Summary

Surface Regularity - Generic term to describe the departure of a floor profile from a theoretical perfect plane.

Technical Information

Surface profiles of floors must be controlled so that departures from a theoretically perfectly flat plane are limited to an extent appropriate to the planned use of the floor. For example, high lift Materials Handling Equipment (MHE) requires tighter control on surface regularity than for a low-level factory or warehouse.

Inadequate surface regularity increases the risk of collision between the trucks and racking, causes driver fatigue and forces MHE to be operated at lower speeds.

The floor should have an appropriate flatness in order to provide a suitable surface for the operation of MHE, and an appropriate levelness to ensure that the building as a whole, with all its static equipment and mhe, can function satisfactorily.

The difference between flatness and levelness is illustrated below:

It can be seen that flatness is generally related to variations over shorter distances whereas levelness is generally related to longer distances. These distances are not easily definable, but traditionally flatness has been controlled over a distance of 600mm and levelness over a distance of 3m. Where mhe is operated in defined-movement areas, floor surfaces are measured over distances relative to the dimensions of the mhe.

The methods of assessing surface regularity described below assume the floor is to be horizontal and not laid to falls.

Departure from datum – The deviation in height of the surface of all new floor construction should be within +/- 15mm of the mean floor level.

Free and defined-movement – In warehouses, mhe is used in two distinct areas of traffic movement:

In free movement (FM) areas, mhe can travel randomly in any direction. Free-movement areas typically occur in warehouses with wide aisle racking installations, factories, retail outlets, low-level storage, marshalling zones and food distribution.
In defined-movement (DM) area, vehicles use fixed paths. Defined-movement areas are usually associated with high level storage racking with Very Narrow Aisles (VNA) in warehouses.

Distribution and warehouse facilities often combine areas of free-movement for low-level activities such as unloading and packing alongside areas of defined-movement for high level storage.

Different surface regularity specifications are required for each floor use so that appropriate performance of the floor can be achieved. The different specifications are reflected in the survey techniques used and the limits on measurements (proprieties) that are prescribed.

Where racking layouts have not been determined at the time of construction, the developer is advised to build to as high a standard as possible: a free movement surface regularity category FM2 is suggested. This will limit the amount of grinding required in aisles to meet defined-movement tolerances if VNA is subsequently installed.