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.
Dipstick floor flatness.
Some of the industry misconceptions for floor flatness and levelness are the following.
F numbers provide architects and contractors a method of determining the flatness and levelness of a concrete floor slab.
The astm that directs how the ff and fl values are to be collected and calculated is astm e1155 standard test method for determining ff floor flatness and fl floor levelness numbers ref.
Dipstick was selected for the construction of the world s tallest building and to measure the flattest and most level superflat slab ever constructed.
The instrument is used in 66 countries on six continents to measure the flatness and levelness of concrete floor slabs and pavements.
Dipstick readings are guaranteed to be accurate to 0 0125 mm less than 0 0005 that s 5 10.