Notes
Ceramic tiles are derived from mixtures of clay,
sand and other natural materials that are shaped
into slabs and fired at high temperatures, up to
1250° C. Their composition is the same as that of
all ceramic material, from tableware and sanitary
ware to roofing tiles. Like all ceramic material,
ceramic tiles are durable, hygienic,
non-combustible, fire-resistant, and easy to
maintain. Tiles are also rigid and feature
relatively low resistance to shock. These features
are intrinsic to the nature of ceramic materials.
As floor and wall covering, ceramic tile serves a
dual function: an aesthetic function as a
design component and a technical function as
a finishing building material. As a building
material, ceramic tile must be able to withstand a
range of environmental stresses. Features defined by
international norms govern the technical function of
ceramic floor and wall tiles.
|
|
1 - Classification and application
According to current international norms (ISO13006),
ceramic tiles are classified into 9 groups based on
two features: the level of water absorption and the
shaping method (see Table 1). This simple
classification is warranted given the extremely wide
range of products with different trade names and
countries of origin. The chosen features are also
significant factors in defining the performance
specifications of the different products.
As will be
discussed later, there are norms and acceptance requirements
for standardized characteristics within each
group.
|
|
|
|
In
the new ISO norms (ISO 13006), the group BI is
divided in two subgroups: BIa (W.A. < 0,05%) and
BIb (< W.A. < 3 %). In addition to the ISO
norms, other well-established classification systems
(technical and artistic) are still used in trade.
Table 2 shows the technical-commercial
classification used in Italy.
Most ceramic tiles are shaped by dry-pressing (B
groups). About 95 % of tiles produced in Italy are
dry-pressed. Their usage can be roughly outlined as
follows:
- Unglazed
tiles (clinker, cotto, red stoneware and porcelain
stoneware) are used mainly for floors. Clinker and porcelain
stoneware have also been successfully used on walls,
particularly in exterior applications.
- Majolica
and white body-earthenware are typical materials for tiling
indoor walls.
- Single-fired tiles (red and white body) are generally
used for floors. However, in recent years, "monoporosa", a
porous single-fired material, has been developed for wall
applications.
- Cottoforte
is used for tiling indoor floors and walls.
- Vitrified,
dry-pressed tiles (BI) and extruded tiles, mostly unglazed
(clinker and cotto), are used mostly in exterior
installations.
|
| This
outline demonstrates the range and variety of
product types that can be included in the
classification of ceramic tile for floors and walls.
The range of technical and aesthetic features and of
the performances by the different types is vast as
well. The performance range in particular has
expanded in recent years, thanks to the development
of glazed and unglazed products with superior
resistance to a variety of environmental stresses.
Once relegated to kitchens and baths, ceramic tile
is now a viable alternative for any public and
industrial application. The versatility of ceramic
tile is further enhanced by the almost endless range
of colors, textures, and decorative motifs, and by
the range of sizes from less than 10 x 10 cm to more
than 60 x 60 cm. |
|
|
|
|
