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The surface profiles of a ground-supported floor need to be controlled so that departures in the profile 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 requires tighter control on surface regularity than a low-level factory or warehouse. Inappropriate surface regularity of a floor may result in equipment having to operate more slowly, reducing productivity, or requiring increased maintenance.
Surface regularity needs to be limited in two ways. The floor should have an appropriate flatness, in order to limit the bumpiness and general stability in operation of the materials handling equipment, and an appropriate levelness, to ensure that the building as a whole with all its static and mobile equipment can function satisfactorily. Flatness relates to variations over short distances and has been traditionally measured over a distance of 300 mm. Levelness relates to variations over a longer distance, typically 3 m, as well as the building’s overall datum.
Definitions of the floor surface regularity requirements for various applications are given in Technical Report 34, Concrete industrial ground floors along with guidance on appropriate measurement techniques. The TR 34 flatness specifications can only be used for floors that are nominally horizontal. If floors are not horizontal, e.g. laid to falls, a straight-edge method of assessing flatness is appropriate, see BS 8204.
Acknowledgement: The Concrete Society
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