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
Issue:
Appears on pages(s):
29-35
Keywords:
flat, gap, level, tolerance
DOI:
10.14359/51724724
Date:
3/1/2020
Abstract:
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.