ASTM C485-83(2003)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: C 485 – 83 (Reapproved 2003)
Standard Test Method for
Measuring Warpage of Ceramic Tile
This standard is issued under the fixed designation C485; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 This test method covers procedures for measuring di- 2.1 ASTM Standards:
agonal and edge warpages of the following categories of C242 Terminology of Ceramic Whitewares and Related
ceramic tile: Products
1.1.1 Square Tile,2by2in.(51by51mm)orlarger,thatare
3. Terminology
nominallyflat,ofuniformoverallthickness,andhaveasmooth
3.1 Definitions:
face of one of the types: unglazed, bright glazed, matte glazed,
or finely crystalline glazed. 3.1.1 tile—see Definitions C242.
3.1.2 warpage—curvature of a flat tile measured as devia-
1.1.2 Oblong Tile,nofacialdimensionsmallerthan2in.(51
mm), that are flat, of uniform overall thickness, and have a tion of the tile surface from a true plane along the edges or the
diagonals. The deviation is measured at the mid-length of an
smoothfaceofoneofthetypes:unglazed,brightglazed, matte
glazed, or finely crystalline glazed. edgeordiagonal,expressedasapercentageofthelengthofthe
edge or diagonal, and called convex or concave with respect to
1.1.3 Square and Oblong Tile, no facial dimension smaller
than2in.(51mm),thatareflat,buthaveanirregularfacesuch the face of the tile.
as embossed, sloped, bumpy, wavy, coarsely crystalline, or
4. Summary of Test Method
wire-cut textured.
2 2
4.1 This test method consists of measuring the deviation
1.1.4 Nonrectilinear Tile, larger than 4 in. (26 cm ), that
fromastraightlineatthemidpointbetweenreferencepointson
areflatandofuniformbodythicknesswithsmoothorirregular
the face or back of a tile. Measurements are made along the
face, such as hexagonal, diamond, Spanish type, and so forth.
edges of a tile or along the diagonals, or both.The deviation is
1.1.5 Trim Tile meeting one of the descriptions in 1.1.1-
expressed as convex or concave warpage in relation to the tile
1.1.4 except that only a part of the tile surface is flat. (Surface
face, and its magnitude is calculated as a percentage of the
trim tile should be treated as flat tile whenever possible.)
length of the edge or diagonal.
1.1.6 Square or Oblong Tile with facial area less than 4
2 2
in. (26 cm ) and at least two straight sides equal to or greater
5. Significance and Use
than 1.0 in. (25 mm) long. (Modular 1- by 1-in. tile are not in
5.1 This test method provides a means for determining
the scope of this test method.)
whether or not a lot of ceramic tile meets the warpage
1.2 This test method is not applicable to tile having em-
requirements that may appear in specifications to assure
bossed surfaces that are not flat, or that have a combination of
satisfactory tile installations. In accordance with this test
variable body thickness and an irregular face.
method, warpage is calculated as a percentage of the length of
1.3 The values stated in the inch-pound units are to be
the edge or diagonal being tested. It is realized that the
regarded as the standard. The SI (metric) units given in
percentage values based on the overall edge length, or on the
parentheses are for information only.
overall diagonal length of a tile will be slightly lower than
1.4 This standard does not purport to address all of the
those based on the distance between reference points. How-
safety concerns, if any, associated with its use. It is the
ever, the ratio of the overall lengths to the distance between
responsibility of the user of this standard to establish appro-
reference points will be practically constant for any particular
priate safety and health practices and determine the applica-
size of tile and, therefore, the percentage values will be
bility of regulatory limitations prior to use.
comparable and equally indicative of warpage.
This method is under the jurisdiction of ASTM Committee C21 on Ceramic
Whitewares and Related Products and is the direct responsibility of Subcommittee For referenced ASTM standards, visit the ASTM website, www.astm.org, or
C21.06 on Ceramic Tile. contactASTM Customer Service at service@astm.org. ForAnnual Book ofASTM
Current edition approved Oct. 1, 2003. Published October 2003. Originally Standards volume information, refer to the standard’s Document Summary page on
approved in 1961. Last previous edition approved in 1999 as C485–83 (1999). the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 485 – 83 (2003)
indicator are mounted firmly on the same rigid metal bar. The
pins may have a hemispherical tip, as described in 6.2.2, or
they may be conical to a point.Amore versatile apparatus for
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.
6.2 Apparatus for Square Tile:
6.2.1 Metal Plate—Aflatmetalplate,6by6in.(152by152
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.Thecentersoftheholesforthereferencepinsarelocated
foreachnominalsizeoftilenearthreeofitscorners, ⁄8in.(9.5
mm) in from each side, when the tile is centered on the plate,
FIG. 1 Apparatus for Square Tile, Set Up for Measurement of 4 ⁄4-
by 4 ⁄4-in. (108- by 108-mm) Tile
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,thecentersoftwoholesarelocatedforeachnominalsize
1 1
of tile ⁄2 in. (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
hole is located on an adjacent side, ⁄2 in. from one of the
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.
(16mm)highand ⁄4in.(6.4mm)indiameter,withthefreeend
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
endfortheinsertionofascrewdriverandthreadedontheother
endforadistanceof ⁄4in.Theregistrystopsareinsertedinthe
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
FIG. 2 Apparatus as Shown in Fig. 1, Showing Arrangement of
Stem Extender diagonalwarpage.Theotherisinsertedintotheslotintheplate
and fastened in any one of four positions which represent
midpoints between reference pins on one side of each of the
6. Apparatus
different nominal sizes of tile. This dial indicator is used for
6.1 General Apparatus—The size and arrangement of the
determining edge warpage.
apparatus for measuring the warpages vary, depending on the
6.2.5 True Reference Plates—Four ⁄8-in. (9.5-mm) thick
size and shape of the tile to be measured. In general, the
platesoftrueplanesurface,madeofsteelorpolishedglass,one
apparatus consists of two stationary pins (reference pins)
spaced apart ⁄4 in. (19 mm) less than the length of the edge or
diagonal being tested, and a dial indicator tip midway between
Three drawings showing construction details are available from ASTM
the stationary pins and in line with them.The pins and the dial Headquarters. Order ADJC0485.
C 485 – 83 (2003)
each of the same dimensions as the four nominal sizes of tile 8.2 Procedure for Square Tile:
which can be measured on this apparatus.
8.2.1 Depending upon the size of tile to be tested, insert the
6.3 Apparatus for Oblong Tile:
three registry stops and the three reference pins into the proper
1 1
6.3.1 Metal Plate—Aflatrectangularmetalplate8 ⁄2by4 ⁄4
tapped holes in the metal plate and fasten them. Move and
in. (216 by 108 mm) and ⁄4 in. (6.4 mm) thick, having two
fasten the adjustable dial indicator in the slot so that its tip will
⁄16-in. (11-mm) wide slots. One slot should start at the
fallatthemidpointbetweenthetworeferencepinsonthesame
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 Insertapieceoftilewithitsfacerestinguponthethree
(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:
usedformeasuringdiagonalwarpage.Onesideoftheplatehas
1 1
8.3.1 Both diagonals of oblong tile cannot be measured for
two ⁄8-in. (3.2-mm) thick, ⁄2-in. (13-mm) wide, and 1-in.
1 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 cornersandasimilarprojectionlocatedonanadjacent side
1 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
1 1 indicators, one in each slot of the plate and located so that the
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
insertionofmovablereferencepinsandmovableregistrystops.
between reference pins of one long dimension. Using the
Thecenteroftheholesforthereferencepinsislocatedforeach
3 properreferenceplatesothatitrestsonthethreereferencepins
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.
centersoftwooftheholestoreceivethethreeregistrystopsare
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
onesideand ⁄8in.(3.2mm)fromtheedgeofthetile,whilethe edges are in contact with the registry stops and read the three
dialindicators.Turnthetile180°andreadtheedgewarpageof
center of the third hole is located on an adjacent side, ⁄2 in.
from one of the corners of the first side and ⁄8 in. from the thesecondshortandsecondlongdimensionofthetile.Inorder
to determine the warpage of the second diagonal, change one
edges of the tile.
6.3.2 Reference Pins—See 6.2.2. of the reference pins and read the warpage of the second
6.3.3 Registry Stops—See 6.2.3. diagonal,afterfirstresettingthedialindicatorstozerowiththe
6.3.4 Dial Indicators—Three adjustable dial indicators, reference plate. (In practice it will be found more expedient to
reading in 0.001-in. (0.025-mm) increments and accurate to read the edge warpage and the warpage of one diagonal of all
60.001in.Oneofthem,usedforthedeterminationofdiagonal the tile in a sample before changing the one reference pin to
warpage,ispermanentlyfastenedontheundersideoftheplate, determine the warpage of the second diagonal.)
withitsstemprojectingthroughthe ⁄16-in.(11-mm)holeinthe
8.4 Procedure for Square or Oblong Tile with an Irregular
center of the plate. The other two, used for measuring edge
Face, as defined in 1.1.3.
warpage, are inserted, one into each of the two slots in the
8.4.1 Tile with an irregular face on which accurate warpage
plate, and fastened in any one of the various positions
measurements can not be made must be measured on the back,
representing midpoints between reference pins on the same
if possible. If the back is also unsuitable, no warpage measure-
side of the various nominal sizes of tile. Because two of the
ments can be made in accordance with this test method.
dialindicatorsareinonelineforviewing,oneofthemmustbe
8.4.2 Asuitable back may be flat, embossed with a pattern,
arranged at a different elevation than the other by using a stem
or ribbed if the following criteria are satisfied:
extender, so that both dials may be read simultaneously (Fig.
1 1
8.4.2.1 For diagonal warpage a flat area at least ⁄4 by ⁄4 in.
2).
(6.4 mm) in or near the center of the back must be in the same
6.3.5 True Reference Plates—See 6.2.5.
nominal plane and in line with similar flat areas near the
7. Test Specimens corners of the back.The points within these flat areas at which
the stationary points and the dial indicator tip of the apparatus
7.1 Select the required number of tile specimens at random
contact the tile back may be chosen with reasonable latitude,
for the lot to be tested.
but the same locations must be used on each tile in the sample.
8.
...