TCNA environmental classifications

Humidity and maximum temperature allowed for tile and stone installation

Both practical and aesthetical, on walls, floors or roofs, tiles have influenced architecture and engineerings as no other material has ever done. Tiles are available in different sizes, thicknesses, and variety such as terracotta, ceramic, porcelain, natural stone and glass. Ancient Egyptians used to decorate their walls with glazed tiles. The Mesopotamians then improved this art and created elaborate wall reliefs. But it was the Romans that first understood that tiles could be useful as much as they were beautiful. They made wide use of tiles on walls, floors and roofs (to make them waterproof) using them in a great variety of buildings, from religious temples to public facilities such as the Roman baths.

The Roman baths – beauty and usefulness at the same time
Many of the Roman uses concerning bathrooms, kitchens, swimming-pools and fountains, and water treatment plants are still in use today in all sectors of industrial, commercial, and residential construction. At the time tiles were already being used outdoors on walls, floors, and roofs; but the Romans were the first ones to use them alongside an elaborate heating system. In public Roman baths air and water could reach 38 °C (100 °F) temperature with a relative humidity of 100% thanks to a furnace placed in a cavity under the floor (ceiling) of the caldarium, which lay on columns of piled up tiles called pilae (Fig. 1 and Fig. 2.). The hot air would go through the hollow bricks and then be eliminated through the chimneys.


Environmental ratings – Quantification of exposure to humidity and temperature
Sir Winston Churchill once affirmed: “The farther back you can look, the farther forward you are likely to see.” These words get their full meaning if we consider the important technological progress made by the Romans in architecture, especially as far as the conceptual idea of tile, stone, and glass is concerned. How to define the notions of ‘dry’, ‘wet’, and ‘hot’? In modern architecture it is essential to carefully consider which environmental conditions tiles and stones will be exposed to. A wrong assessment of the needs may provoke a partial or total insufficiency of the installation with subsequent considerable costs increase due to materials and labour. It could also be responsible for bad reputation if customers are not satisfied, and people might loose confidence in the whole system. A few years ago the tiles and stone industry started to recognize the importance of standards rules such as ISO 13007 to demystify the choice of materials and cement grouts. On a similar note, many companies got aware of the fact that it was necessary to better define the environment tiles and stone are laid down, setting a common reference point as to exposure to humidity and heat. For many years industry operators have used terms such as intermittent humidity, excellent resistance to water, occasional exposure to water, short-term exposure due to squirts, long- or permanent exposure, exposupre to weak, moderate or high heat, and so on. These are the answers a designer or a budget editor could give; or also an installer who’s been asked to set what grade of exposure to heat or to humidity there is (Fig. 3, Fig. 4 and Fig. 5).


Let’s make a couple of examples. On one hand a retired couple sharing the same bathroom; on the other hand public showers in the sports hall of a university. While the retired couple uses the shower every other day, public showers are being used intensely every day of the week and, according to season, at weekends too. It is impossible to use any of the above mentioned expressions to assess the grade of exposure to water of these two situations. When these conditions add up to such factors as heat, high humidity and steam, it becomes even more difficult to assess the situations. Let’s compare a home sauna to a commercial one. In both cases, internal environment can change very quickly. Generally speaking, in a commercial sauna room temperature is relatively dry and fresh (23 °C [73 °F] and 50 % of relative humidity) when not functioning; but as soon as it is switched on the environment quickly fills with very hot water vapour (46 °C [115 °F] and 100 % of relative humidity). In these two types of plants the room is exposed to humidity and heat, but what about the exposure time and cleaning methods? Are they the same? In this type of environment tiles and stone have to endure high levels of temperature and humidity, so that the whole system can adapt itself to deformities, movements and shrinkage due to the alternation of the ON/OFF modality (Fig. 6 and Fig. 7).


TCNA environmental classifications
Res 1 (Residential Dry) – not exposed to moisture or liquid, except when cleaning; for example: the living room)
Res 2 (Residential Limited Water Exposure) – subject to moisture or liquid, but not soaked; for example: bathroom floors
Res 3 (Residential Wet Areas) – subject to moisture or liquid, often soaked; for example: shower walls and floors
Res 4 (Residential High Humidity, Heavy Moisture Exposure) – subject to continuous high humidity plus heat and moisture, with intermittent use; for example: combination steam shower
Res 5 (Residential High Temperature Air/Water > 52 °C [125 °F]) – subject to water and/or vapor of 52 °C (125 °F); for example:furnace areas
Res 6 (Residential Exterior) – subject to exterior conditions; e.g. balconies
Com 1* (Commercial Dry) – not exposed to moisture or liquid, except when cleaning; e.g. interior rooms
Com 2* (Commercial Limited Water Exposure) – subject to moisture or liquid, but not soaked; e.g, bathroom floors
Com 3* (Commercial Wet Area) – subject to moisture or liquid, often soaked; e.g., shower walls and floors, not gang showers
Com 4* (Commercial High Humidity, Heavy Moisiture Exposure) – subject to continuous high humidity plus heat and moisture, with continuous use; e.g., public steam showers, including gang showers
Com 5* (Commercial High-Temperature Air/Water> 52 °C [125 °F]) – subject to water and/or vapour of 52 °C (125 °F); e.g., saunas
Com 6* (Commercial Exterior) – subject to exterior conditions; e.g., commercial façades
* Note: Commercial designations, Com 1-6,
will always have a greater exposure to water, moisture and heat – both in increased levels and duration time. This increased exposure also includes more rigorous cleaning regimens in a commercial or industrial environment that are performed on a continuous basis.

When a commercial steam room is constructed in an exterior application, it is no longer under design control conditions but is also exposed to the elements – rapid or prolonged temperature and humidity fluctuations and cycles of freeze. A tile or stone design is doomed to failure if the degree of exposure (suche as temperate, moderate and severe climate regions within the Americas) is not taken into account when specifying an exterior installation, as with a commercial building façade or plaza entrance. In order to eliminate ambiguous terms such as “intermittent exposure to moisture” and subsequently leave the degree of “moistureand heat exposure” up to interpretation by architects and installers, new environmental classifications were introduced in the 2011 Tile Council of North America (TCNA) Handbook to quantify the degree of water and heat exposure. The designations “Res” (Res 1 – 6) for residential and “Com” (Com 1.6) for commercial include a detailed description of the exposure conditions for each designation. These environmental classifications have been added to each tile and stone installation method in the TCNA Handbook. It is important to note that, when specifying an installation using these classifications, each method may have more than one exposure limitation designation; for example, TCNA RH110A-12 (Interior Floors with Radiant Heat over Concrete) installation methods recommend the following environmental classification designations: Res 1, 2, 3, 5 and Com 1, 2, 3, 5.

Environmental classifications and waterproofing standards
Throughout 2011 and into 2012 with the collaborative efforts of various industry associations – including the Ceramic Tile Distributors Association (CTDA), TCNA, Materials & Methods Standards Association (MMSA), National Tile Contractors Association (NTCA) and Marble Institute of America (MIA) – installers, contractors and manufacturers have worked to develop and make these environmental classifications a reality. It is to everyone’s benefit that the tile and stone industry continues to shape measurable, performance-based classifications standards to help both design professionals and installers alike optimize installation success.

Source: Realtà Mapei Americas 17/2013