The F-number system is a method for determining which floor characteristics?

• A. Floor flatness and levelness
• B. Concrete compressive strength
• C. Air content
• D. Curing temperature

Answer: (A)

The F-number system measures floor surface quality, focusing on how flat and level the concrete floor is. It uses two values: one for flatness (how well the surface lies in a single plane over short stretches) and one for levelness (how parallel the surface is to a perfectly horizontal plane over those stretches). These numbers come from profiling the floor with a device that records the surface profile as you move across the area, then translating that data into FF (flatness) and FL (levelness) values. A lower number means tighter tolerances and a smoother, more even surface, while a higher number allows more deviation. This system is specifically about the surface characteristics that affect finishing and coatings, not about concrete strength, air content, or curing temperature, which are governed by other tests and procedures.