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Title: A Comparison of Floor Tolerance Measuring Approaches F-Numbers, 10-Foot (305 cm) Straightedge, and Waviness Index

Author(s): Eldon Tipping and Rick Smith

Publication: Symposium Paper

Volume: 338


Appears on pages(s): 29-35

Keywords: flat, gap, level, tolerance

DOI: 10.14359/51724724

Date: 3/1/2020

Two characteristics are of primary interest to those using floor surfaces – the surface bumpiness (flatness) and the levelness. Prior to publication of the 2006 cycle of the ACI 117 document, the ACI 117 committee completed an exhaustive study of the floor surface characteristics evaluated by the F-Number System, The 10-Foot (3 m) Straightedge approach, and the Waviness Index System. The purpose of the study was to evaluate each of the methods and to develop tables that establish a small degree of uniformity among the various tolerance approaches. The F-Number System and Waviness Index use data taken at regular intervals along lines located in random locations on the test surface. The 10-Foot (3 m) Straightedge approach uses a straightedge placed in any location on the floor surface. The largest gap between support points is then measured. Each of the methods utilizes different criteria to evaluate data, so it is important for the specifier to understand the specific surface characteristics controlled by each of the methods. The ACI 117 committee evaluated a set of 600 floor surface profiles. Each of the profiles was 100 feet in length. Six groups of F-number pairings were developed as follows: FF 20/FL 15; FF 25/FL 20; FF 35/FL 25; FF 45/FL 35; FF 60/FL 40; FF 100/FL 60; each of the groups contained 100 profiles. Both the Flatness F-number and Levelness F-number for each of the profiles in each group were within 5% of the respective target values. For each of the 600 profiles, the gap-below-the-straightedge and waviness index statistics were calculated. Results from the study are presented.