ASTM C485-83(1999)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: C 485 – 83 (Reapproved 1999)
Standard Test Method for
Measuring Warpage of Ceramic Tile
This standard is issued under the fixed designation C 485; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope C 242 Terminology of Ceramic Whitewares and Related
Products
1.1 This test method covers procedures for measuring di-
agonal and edge warpages of the following categories of
3. Terminology
ceramic tile:
3.1 Definitions:
1.1.1 Square Tile 2 by 2 in. (51 by 51 mm) or larger, that
3.1.1 tile—see Definitions C 242.
are nominally flat, of uniform overall thickness, and have a
3.1.2 warpage—curvature of a flat tile measured as devia-
smooth face of one of the types: unglazed, bright glazed, matte
tion of the tile surface from a true plane along the edges or the
glazed, or finely crystalline glazed.
diagonals. The deviation is measured at the mid-length of an
1.1.2 Oblong Tile, no facial dimension smaller than 2 in. (51
edge or diagonal, expressed as a percentage of the length of the
mm), that are flat, of uniform overall thickness, and have a
edge or diagonal, and called convex or concave with respect to
smooth face of one of the types: unglazed, bright glazed, matte
the face of the tile.
glazed, or finely crystalline glazed.
1.1.3 Square and Oblong Tile, no facial dimension smaller
4. Summary of Test Method
than 2 in. (51 mm), that are flat, but have an irregular face such
4.1 This test method consists of measuring the deviation
as embossed, sloped, bumpy, wavy, coarsely crystalline, or
from a straight line at the midpoint between reference points on
wire-cut textured.
2 2 the face or back of a tile. Measurements are made along the
1.1.4 Nonrectilinear Tile, larger than 4 in. (26 cm ), that
edges of a tile or along the diagonals, or both. The deviation is
are flat and of uniform body thickness with smooth or irregular
expressed as convex or concave warpage in relation to the tile
face, such as hexagonal, diamond, Spanish type, and so forth.
face, and its magnitude is calculated as a percentage of the
1.1.5 Trim Tile meeting one of the descriptions in 1.1.1-
length of the edge or diagonal.
1.1.4 except that only a part of the tile surface is flat. (Surface
trim tile should be treated as flat tile whenever possible.)
5. Significance and Use
1.1.6 Square or Oblong Tile with facial area less than 4
2 2 5.1 This test method provides a means for determining
in. (26 cm ) and at least two straight sides equal to or greater
whether or not a lot of ceramic tile meets the warpage
than 1.0 in. (25 mm) long. (Modular 1- by 1-in. tile are not in
requirements that may appear in specifications to assure
the scope of this test method.)
satisfactory tile installations. In accordance with this test
1.2 This test method is not applicable to tile having em-
method, warpage is calculated as a percentage of the length of
bossed surfaces that are not flat, or that have a combination of
the edge or diagonal being tested. It is realized that the
variable body thickness and an irregular face.
percentage values based on the overall edge length, or on the
1.3 The values stated in the inch-pound units are to be
overall diagonal length of a tile will be slightly lower than
regarded as the standard. The SI (metric) units given in
those based on the distance between reference points. How-
parentheses are for information only.
ever, the ratio of the overall lengths to the distance between
1.4 This standard does not purport to address all of the
reference points will be practically constant for any particular
safety concerns, if any, associated with its use. It is the
size of tile and, therefore, the percentage values will be
responsibility of the user of this standard to establish appro-
comparable and equally indicative of warpage.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
6. Apparatus
6.1 General Apparatus—The size and arrangement of the
2. Referenced Documents
apparatus for measuring the warpages vary, depending on the
2.1 ASTM Standards:
size and shape of the tile to be measured. In general, the
apparatus consists of two stationary pins (reference pins)
This method is under the jurisdiction of ASTM Committee C-21 on Ceramic
spaced apart ⁄4 in. (19 mm) less than the length of the edge or
Whitewares and Related Productsand is the direct responsibility of Subcommittee
C21.06on Ceramic Tile.
Current edition approved Jan. 28, 1983. Published March 1983. Originally
published as C 485 – 61 T. Last previous edition C 485 – 83 (1993). Annual Book of ASTM Standards, Vol 15.02.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
C 485
6.2 Apparatus for Square Tile:
6.2.1 Metal Plate—A flat metal plate, 6 by 6 in. (152 by 152
1 7
mm) square and ⁄4 in. (6.4 mm) thick, with a ⁄16-in. (11-mm)
wide slot starting at the midpoint of one side and running at
right angles to that side for a distance of 2 ⁄8 in. (67 mm)
toward the center of the plate. The plate also has a ⁄16-in.
diameter hole in the exact center of the plate. One side of the
1 1
plate has two ⁄8-in. (3.2-mm) thick, ⁄2-in. (13-mm) wide, and
1-in. (25-mm) high projections, located not more than ⁄2 in.
from the corners, and a similar projection located on an
adjacent side and not more than ⁄2 in. from one of the corners
of the first side. These projections serve as permanent registry
stops for 6- by 6-in. tile during measurement.
6.2.1.1 In addition, the plate has a series of tapped holes for
insertion of removable reference pins and removable registry
stops. The centers of the holes for the reference pins are located
for each nominal size of tile near three of its corners, ⁄8 in. (9.5
mm) in from each side, when the tile is centered on the plate,
except that for 2- by 2-in. (51- by 51-mm) tile the distance in
from the edges is ⁄4 in. (6.4 mm). To receive the three registry
stops, the centers of two holes are located for each nominal size
1 1
of tile ⁄2in. (13 mm) from the corners of one side and ⁄8 in.
(3.2 mm) from the edge of the tile, while the center of a third
1 hole is located on an adjacent side, ⁄2 in. from one of the
FIG. 1 Apparatus for Square Tile, Set Up for Measurement of 4 ⁄4-
1 1
by 4 ⁄4-in. (108- by 108-mm) Tile
corners of the first side and ⁄8 in. from the edge of the tile.
6.2.2 Reference Pins—Three movable reference pins ⁄8 in.
(16 mm) high and ⁄4 in. (6.4 mm) in diameter, with the free end
ground to a hemispherical tip and the other end threaded for a
distance of ⁄4 in. The reference pins are inserted in the metal
plate to support the tile during measurement.
6.2.3 Registry Stops—Three ⁄4-in. (6.4-mm) diameter and
1 ⁄4-in. (32-mm) high, movable, flat top registry stops with a
1 1
⁄16-in. (1.6-mm) wide and ⁄8-in. (3.2-mm) deep slot on one
end for the insertion of a screwdriver and threaded on the other
end for a distance of ⁄4 in. The registry stops are inserted in the
metal plate to fix the horizontal position of the tile during
measurement.
6.2.4 Dial Indicators—Two adjustable dial indicators, read-
ing in 0.001-in. (0.025-mm) increments and accurate to
60.001 in. One is inserted from the bottom through the ⁄16-in.
(11-mm) hole in the center of the plate, permanently fastened
to the underside of the metal plate, and used for measuring
diagonal warpage. The other is inserted into the slot in the plate
and fastened in any one of four positions which represent
midpoints between reference pins on one side of each of the
different nominal sizes of tile. This dial indicator is used for
determining edge warpage.
6.2.5 True Reference Plates—Four ⁄8-in. (9.5-mm) thick
FIG. 2 Apparatus as Shown in Fig. 1, Showing Arrangement of
plates of true plane surface, made of steel or polished glass, one
Stem Extender
each of the same dimensions as the four nominal sizes of tile
diagonal being tested, and a dial indicator tip midway between
which can be measured on this apparatus.
the stationary pins and in line with them. The pins and the dial
6.3 Apparatus for Oblong Tile:
indicator are mounted firmly on the same rigid metal bar. The
1 1
6.3.1 Metal Plate—A flat rectangular metal plate 8 ⁄2 by 4 ⁄4
pins may have a hemispherical tip, as described in 6.2.2, or
in. (216 by 108 mm) and ⁄4 in. (6.4 mm) thick, having two
they may be conical to a point. A more versatile apparatus for
⁄16-in. (11-mm) wide slots. One slot should start at the
standard sizes of tile consists of a metal plate having three
movable reference pins, three movable registry stops, and the
necessary number of dial indicators. See Fig. 1 and Fig. 2.
Three drawings showing construction details are available from ASTM
Headquarters. Order ADJC0485.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
C 485
midpoint of one 4 ⁄4-in. side and run at right angles to that side side. Insert the proper reference plate and adjust the two dial
for a distance of 2 ⁄4 in. (70 mm) towards the center of the indicators to zero reading when the reference plate rests on the
plate. The other slot should start at the midpoint of one 8 ⁄2-in. reference pins and is in contact with the three registry stops.
side and run at right angles to that side for a distance of 1 ⁄4 in.
8.2.2 Insert a piece of tile with its face resting upon the three
(45 mm) towards the center of the plate. These slots are used
reference pins and its edges in contact with the three registry
for inserting the two dial indicators necessary to measure the
stops. Read the two dial indicators, turn the tile 90° clockwise,
edge warpage of one long and one short dimension of the tile
and repeat the procedure until all four sides and the two
simultaneously. There is also a ⁄16-in. hole in the exact center
diagonals have been measured.
of the plate for insertion of the third dial indicator, which is
8.3 Procedure for Oblong Tile:
used for measuring diagonal warpage. One side of the plate has
8.3.1 Both diagonals of oblong tile cannot be measured for
1 1
two ⁄8-in. (3.2-mm) thick, ⁄2-in. (13-mm) wide, and 1-in.
warpage without changing one of the reference pins. Depend-
(25-mm) high projections, located not more than ⁄2 in. from
ing upon the size of tile to be tested, insert the three registry
the corners and a similar projection located on an adjacent side
stops and the three reference pins into the proper tapped holes
and not more than ⁄2 in. from one of the corners of the first
in the metal plate and fasten them. Insert the two movable dial
side. These projections serve as permanent registry stops for
indicators, one in each slot of the plate and located so that the
1 1
8 ⁄2 by 4 ⁄4-in. tile during measurement.
stem of one is at the midpoint between reference pins of one
6.3.1.1 In addition, the plate has a series of tapped holes for
short dimension and the stem of the other at the midpoint
insertion of movable reference pins and movable registry stops.
between reference pins of one long dimension. Using the
The center of the holes for the reference pins is located for each
proper reference plate so that it rests on the three reference pins
nominal size of tile near its four corners, ⁄8 in. (9.5 mm) in
and its sides are in contact with the registry stops, adjust the
from each side, when the tile is centered on the plate. The
three dial indicators to zero reading.
centers of two of the holes to receive the three registry stops are
8.3.2 Place a tile face down on the reference pins so that its
located for each size of tile ⁄2 in. (13 mm) from the corners of
edges are in contact with the registry stops and read the three
one side and ⁄8in. (3.2 mm) from the edge of the tile, while the
dial indicators. Turn the tile 180° and read the edge warpage of
center of the third hole is located on an adjacent side, ⁄2in.
the second short and second long dimension of the tile. In order
from one of the corners of the first side and ⁄8 in. from the
to determine the warpage of the second diagonal, change one
edges of the tile.
of the reference pins and read the warpage of the second
6.3.2 Reference Pins—See 6.2.2.
diagonal, after first resetting the dial indicators to zero with the
6.3.3 Registry Stops—See 6.2.3.
reference plate. (In practice it will be found more expedient to
6.3.4 Dial Indicators—Three adjustable dial indicators,
read the edge warpage and the warpage of one diagonal of all
reading in 0.001-in. (0.025-mm) increments and accurate to
the tile in a sample before changing the one reference pin to
60.001 in. One of them, used for the determination of diagonal
determine the warpage of the second diagonal.)
warpage, is permanently fastened on the underside of the plate,
8.4 Procedure for Square or Oblong Tile with an Irregular
with its stem projecting through the ⁄16-in. (11-mm) hole in the
Face, as defined in 1.1.3.
center of the plate. The other two, used for measuring edge
8.4.1 Tile with an irregular face on which accurate warpage
warpage, are inserted, one into each of the two slots in the
measurements can not be made must be measured on the back,
plate, and fastened in any one of the various positions
if possible. If the back is also unsuitable, no warpage measure-
representing midpoints between reference pins on the same
ments can be made in accordance with this test method.
side of the various nominal sizes of tile. Because two of the
8.4.2 A suitable back may be flat, embossed with a pattern,
dial indicators are in one line for viewing, one of them must be
or ribbed if the following criteria are satisfied:
arranged at a different elevation than the other by using a stem
1 1
8.4.2.1 For diagonal warpage a flat area at least ⁄4 by ⁄4 in.
extender, so that both dials may be read simultaneously (Fig.
(6.4 mm) in or near the center of the back must be in the same
2).
nominal plane and in line with similar flat areas near the
6.3.5 True Reference Plates—See 6.2.5.
corners of the back. The points within these flat areas at which
7. Test Specimens the stationary points and the dial indicator tip of the apparatus
contact the tile back may be chosen with reasonable latitude,
7.1 Select the required number of tile specimens at rand
...