• Pressed floor tiles in compliance with ANSI A137.1 may be vitreous, semivitreous, or nonvitreous.

• Mosaic tiles in compliance with ANSI A137.1 may be impervious, vitreous, semivitreous, or nonvitreous.

Tiles may vary in color, texture, or appearance according to the manufacturer’s design for that particular tile series or product line. The following designations classify the range of such variation.

V0 tiles are very uniform in appearance and smooth in texture. When measured by a colorimetric spectrophotometer, they have an overall color difference (delta E) of less than 3 Judds.

V1 tiles have a generally uniform appearance with minimal production run differences among pieces. Some color differences can be observed.

V2 tiles are similarly colored with variations in texture and/or pattern, which are clearly distinguishable.

V3 tiles are moderately variant, and although the colors and/or textures present on a single piece are indicative of the colors and/or textures on another, the amount of colors and/or textures on each piece may vary significantly. It is recommended that the range be viewed before selection and that a mock layout be made.

V4 tiles are substantially variant with random color and/or texture differences from tile to tile, where one tile may have totally different colors and/or textures from another. Because a final installation with V4 tiles will be unique, it is recommended that the range be viewed before selection and that a mock layout be made.

Although checking the range of color and texture for V3 and V4 tiles is specifically recommended, all of the categories above have some range and should be checked and generally installed from several boxes in random fashion to avoid aesthetic issues.

ANSI A137.1 specifies two test methods for determining abrasion resistance, one for unglazed tiles and the other for glazed tiles.

Unglazed tiles are tested for deep abrasion resistance by test method ASTM C1243, in which tiles are quantitatively evaluated for material loss after being subjected to an abrasive disk. For an unglazed tile, the total material loss from abrasion must be below a specified maximum. The maximum value depends on whether the tile was pressed or extruded and its water absorption category: impervious, vitreous, semivitreous, or nonvitreous.

Glazed tiles are tested for visible abrasion resistance by test method ASTM C1027 in which the tiles are qualitatively evaluated and categorized based on visually noticeable changes in gloss or color following increasing cycles of abrasion. Although many products are tested per this methodology, it should be noted that the following limitations are referenced in ASTM C1027:

Although a complete explanation of these qualifiers requires an in-depth understanding of the method, it is sufficient to note that with the evolution of more sophisticated glazes, and the increased durability of such, it has been observed that the test method does not appropriately characterize the real world performance of some glazed tiles, especially glazed porcelain. Where information is desired regarding the wear characteristics of such tiles, it is recommended that the manufacturer be contacted directly.

Tiles in compliance with ANSI A137.1 shall meet the specified criteria for facial dimensions, thickness, warpage, and wedging. Facial dimension criteria specify the maximum allowable variation in size and deviation from the manufacturerspecified nominal size. Thickness criteria specify the acceptable range of thickness variation. Warpage criteria establish allowable deviation from planarity of a tile’s surface, and wedging criteria define the allowable extent tiles can be out-ofsquare.

Tiles may be rectified (mechanically finished along their edges to achieve more precise facial dimensions), calibrated(sorted to meet a specified caliber range), or “natural” (packaged directly after manufacturing with no rectification or sorting). Depending on the type of tile, dimensional criteria may be given for one, two, or all three categories as detailed in

See Grout Joint Size and Pattern Considerations for related information.

Tiles in compliance with ANSI A137.1 shall have an average breaking strength equal to or greater than 250 lbf. for pressed floor, porcelain, quarry, and mosaic tiles, and 125 lbf. for glazed wall tiles.

When tested per ASTM C482, they shall exhibit a bond strength of at least 50 psi and demonstrate no evidence of crazing when tested per ASTM C424 and no evidence of thermal shock when tested per ASTM C484.

When tiles will be used in an environment subject to freeze/thaw cycling, testing per ASTM C1026 can be required to evaluate their potential performance under such conditions.

When static coefficient of friction (SCOF) data are required for a specific project, testing shall conform to ASTM C1028. However, because area of use and maintenance by the owner of installed tile directly affect coefficient of friction, the SCOF of the manufactured product shall be as agreed upon by manufacturer and purchaser. Water, especially standing water, oil, grease, etc., create slippery conditions. Floor applications with exposure to these elements require extra maintenance and caution in product selection.

While stain and chemical resistance are not required, ceramic tiles generally perform very well in these categories. Testing for stain resistance is performed per ASTM C1378 and testing for chemical resistance is performed per ASTM C650. Depending on the number of stains or chemicals that affect the surface, the tiles are classified from A (no effect) to E, where 4 or more stains or chemicals affected the tile.

Mounted tile is assembled into units or sheets by suitable material to facilitate handling and installation. Mounted tile assemblies shall have sufficient exposure to bonding surfaces of the tile body to allow for 80% coverage of the bond mortar in dry areas and 95% in wet areas. Tile manufacturers must specify whether their assemblies are suitable for installation in swimming pools, on exteriors, and in other wet areas. Paper back-mounted mosaics are not recommended in wet areas.

Back-mounted and edge-mounted tile assemblies may have perforated paper, fiber mesh, resin, polyurethane, or other bonding material on the back or edges of each tile, which becomes an integral part of the tile installation. Clear film-faced tile is assembled with clear plastic adhesive film on the face, which is removed after final set has occurred. Paper-faced tile has paper applied to the face of the tile with water-soluble adhesives, which should be removed during the installation process by wetting and removing the paper, followed by adjusting the tile prior to its final set.

Specialty tiles are designed to meet special physical requirements or to have special appearance characteristics. They are not required to meet all requirements of ANSI A137.1. Consult the manufacturer’s specifications. They are sometimes manufactured to create an architectural effect toward the casual. These tiles vary in size, one tile from the other. Variations in plane may be expected. Larger tiles will usually require greater variations in joint width. For each specialty tile being chosen, review installation guidelines supplied by manufacturer/distributor of specialty tiles and/or adhesive manufacturer. Specialty tiles include, but are not limited to, tiles made from nonceramic materials.