Two important factors have to be taken into account in choosing the correct surface regularity standard. Firstly, the higher the standard specified, the greater the cost of the floor. Secondly, if a surface regularity standard is set unnecessarily high it may prevent the use of the large pour area floor construction technique, which is invaluable where large area floors need to be constructed quickly. The technique can also avoid the need for formed joints commonly used in strip construction which sometimes give trouble.
There are occasions when a free movement area specification has to be applied to a floor where defined movement traffic in very narrow aisles will be used but where, at the time of floor construction, aisle locations are not precisely known. In this situation a building owner in conjunction with his designer will have to choose a category from FM1, FM2 or FM3 in relation to the potential height of the racking or stacking that might be used. The higher the FM standard achieved, the less adjustment of floor flatness and levelness will be needed on wheel tracks in aisles when their exact location is known, but the more costly the floor will be to construct. Also, if racking or stacking orientation is not known and the tightest FM1 standard is specified, this may exclude the use of large area pour methods which can eliminate the formed joints needed between strips in strip construction. It is essential to note that racking aisles which are located transverse to strips can give a troublesome situation because truck wheels are more likely to damage the numerous formed joints which have to be crossed. The decision on the choice of FM specification standard must take all of these factors into account.