Floor Flatness 30

F numbers were developed in the 1980s to provide a systematic quantitative way to indicate the flatness and levelness of a concrete floor.

Floor flatness 30.

Concrete contractor pours the concrete and finishes it to the specified floor flatness requirement as stated in aci 117 specification for tolerances for concrete construction and materials the f f must be measured within 72 hours of the concrete pour. Concrete slab flatness slab flatness the degree of a slab s flatness is expressed by two numbers the ff and the fl together these are the f numbers they are the face floor profile numbers developed by allen face from 1978 to 1987. Concrete strengths rebar average rebar weights welded wire mesh pan slabs slab flatness and f numbers. When bidding a new construction project reading the 03 30 00 cast in.

The tool provides an accuracy of 1 8 inch at 30 feet and laser line visibility of 30 feet. They describe a concrete slab s flatness ff and. For example an ff 30 fl 24 floor is exactly twice as flat and twice as level as an ff 15 fl 12 floor 03 guidelines for f number substrate concrete floor finish tolerances under resilient floors. With modern finishing equipment achieving overall floor.

Since it was introduced in the 1970s f numbers have proven to be useful in measuring and improving concrete floor flatness and levelness. The scale is linear so that relative flatness levelness of two different floors will be in proportion to the ratio of their f numbers. The gsl 2 provides high accuracy for detecting uneven spots by checking the floor surface in a radius of up to 65 feet in a matter of minutes. The more bumps there are the lower the ff number will be and the more difficult it will be for a polished concrete floor to have a uniform appearance.

Although there are no direct equivalents between f numbers and straightedge tolerances aci 302 construction of concrete floors and slabs gives the following table of approximate values. They are calculated using the standards set forth in astm e1155 which is the standard test method for determining f f floor flatness and f l floor levelness numbers the american concrete institute indicates acceptable ranges for flatness and levelness in aci 302 1 guide. Floor flatness levelnessone of the things that distinguishes a high tolerance floor is its f number requirement. The working range of the laser is up to 65 feet when being operated with the remote control.

The higher the f number the flatter or more level the floor. F numbers provide architects and contractors a method of determining the flatness and levelness of a concrete floor slab.