Floor Levelness Number Conversion

These f numbers make up the face floor profile.

Floor levelness number conversion. The degree of a slab s flatness is expressed by two numbers the ff and the fl. Flatness is how close to geometric planarity a slab approaches. F numbers were first used in 1983 on a commercial project and we continue to use them today in order to achieve floor flatness and levelness. Together these are the f numbers.

F l specified overall value 25 minimum local value 18 c. This standard establishes the method for measuring f numbers by using a statistical analysis of measured points which are 12 300mm apart taken along straight lines in a prescribed pattern within each sample area. F number measurements are standardized under astm e 1155 standard test method for determining f f floor flatness and f l floor levelness numbers and the aci 302 1r 04 guide for concrete. 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.

F numbers provide architects and contractors a method of determining the flatness and levelness of a concrete floor slab. F f and f l tolerances shall be tested in accordance with astm e 1155. What does a specification for a floor flatness of 1 8 inch in 10 feet equal in f numbers. It provides methodology for selecting an appropriate number of random samples from various sizes and configurations of floors to.

Floor levelness profile numbers f numbers. They describe a concrete slab s flatness ff and levelness fl. The profile of. There are actually three f numbers that are used for concrete floors depending on whether the floor will have a random traffic pattern or.

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. The scale is linear so that relative flatness levelness of two different floors will be in proportion to the ratio of their f numbers. F numbers were developed in the 1980s to provide a systematic quantitative way to indicate the flatness and levelness of a concrete floor. Ff flatness and fl levelness.

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. Actual overall f numbers shall be calculated using the inferior superior area method. A sample area must. Astm e1155 standard test method for determining f f floor flatness and f l floor levelness numbers specifies both the data collection procedure and how to convert the raw data into the floor s f f and f l numbers.

Timeliness of floor profile tests reports.