Floors and walls have large surface areas and must therefore need wiping cloths and techniques designed for thorough sterilisation.
For cleaning floors, linear strokes are suggested, wiping from the cleanest to the dirtiest areas. To achieve linear wiping strokes, flat surface mops using pre-wetted mop covers (or booties) are convenient. These mop covers are changed when they become visibly dirty or after a prescribed surface area has been cleaned.
For the mopping from clean to dirty technique, the dirtiest area of the cleanroom is the entry door adjacent to the gowning area, as it gets the most traffic. The cleanest area is either a very lightly trafficked zone, or the area furthest from the door. The entry door area should be cleaned at least daily.
Walls are generally cleaned less frequently than floors because they do not encounter contact the same levels of contamination transfer. Flat surface mops work well here also. The cleanest area of the walls is at floor level. Two wiping pattern options are available, vertical wiping and horizontal wiping.
Vertical wiping is most convenient and ergonomically satisfying, since gravity assists the downward wiping motion. Horizontal wiping also works well, having the advantage that mop covers may need to be changed less frequently as the top two thirds of the wall surface is likely very clean and new mop covers should not be required for cleaning those areas. Soiled mop covers should also not be required for cleaning those areas and should be changed immediately.