Installation issues: a set of standards for high-quality installation
Date:June 22, 2016
by Stefano Carrà (Mapei Corporate Research & Development Laboratory)
The quality levels of ceramic tile adhesives are described effectively and succinctly in the classification categories contained in European standard EN 12004. The first edition of this standard dates back to 2001 and was written by a group of technicians working for CEN, the European Committee for Standardization.
These classes are divided into two categories, fundamental and optional. The fundamental classes for cementitious products are C1 and C2: whether a product belongs to the first class (normal) or the second class (improved) depends on the level of adhesion of the product.
Similarly, adhesives in dispersion may be either class D1 or D2, while for reactive adhesives there is only one class, R. The optional classes covered in the standard only apply to cementitious adhesives, and they are F for fast-setting adhesives, E for adhesives with extended open time, T for adhesives with no vertical slip, S1 for deformable adhesives and S2 for highly deformable adhesives.
The aim of the fundamental classes is to define the characteristics listed in the CE mark for the product, which is obligatory for any product marketed within the European Union. Class C1 thus defines the minimum requirements of a cementitious adhesive for ceramic tiles in Europe. The CE mark (Fig. 1) must be displayed on the bag used to package the product and states the minimum requirements of the fundamental class to which it belongs. The overall classification, including the optional classes, is indicated by a separate mark (Fig. 2). Almost fifteen years after its introduction, EN 12004 is still an exceptional communication and marketing tool.
It offers a number of advantages to users and to people responsible for writing technical specifications for the installation of ceramic tiles, the most important of which are the following:
• The possibility of making an accurate comparison between adhesives from different suppliers;
• Its ability to summarise a significant portion of a product’s areas of use, making the detailed description contained in the product’s Technical Data Sheet almost superfluous.
Below are a number of examples to demonstrate the second point:
➢ To install porcelain tiles with low water absorption it is preferable to use a product with higher bonding strength, in other words a product belonging to class C2;
➢ The installation of large or heavy ceramic tiles on walls requires an adhesive with no vertical slip and consequently belonging to class T;
➢ To install ceramic tiles on external surfaces during the summer in hot climates or locations subject to strong winds, an adhesive with extended open time is recommended, which means class E;
➢ To install large ceramic tiles on façades, the recommended adhesive has an overall classification of C2TE S1, or even S2;
➢ During the winter, when installing ceramic tiles on building sites with insufficient heating, a rapid-setting adhesive is recommended, i.e. from class F.
The same class is required in rooms where the floor needs to be put quickly into service after installation for pedestrian use.
It should be stressed, however, that adhesives also have other characteristics that may be just as important but are not described in the standards, particularly those concerning workability, rheological properties and colour.
Another fact that is worth mentioning is that the standard specifies ranges of values or minimum requirements for the various classes, and that there may be products that offer better performance levels than those specified whose use may be more appropriate under certain circumstances.
It is always extremely important that the classification of a product is demonstrated by clear, transparent documentation that is readily accessible to clients.
EN 12004 itself establishes to a certain degree what actions a company needs to take to support the classification declaration of a product.
It is important, above all, that the declaration is backed up by a certificate issued by one of the notified European bodies on the basis of a test report that includes the data recorded during the tests carried out to determine the product’s classification.
These certificates must be obtained before marketing the product itself. Furthermore, the classification must be maintained over the years by complying with an FPC (Factory Production Control) system that involves periodic inspections and tests on the raw materials and production processes.
New regulations for construction products
On 1 July 2013, the new regulations for construction products introduced a mandatory Declaration of Performance (DoP). For each product carrying the CE mark, adhesives included, the manufacturer must issue a DoP indicating its performance characteristics based on the relevant standard. The aim of the DoP is to enable clients and users to compare the various products available on the market on the basis of a series of easily identifiable, measurable elements so that they can then identify which product is the most suitable for their specific requirements.
The DoP for adhesives, an example of which is shown in Fig. 3, carries the name of the body that issued the test report and the product certificate.
If the company decides to optimise a certain product by modifying its formulation in some way, a new certification must be requested from the certification bodies.
The regulations require a DoP to be available to all clients, but many companies have decided to make life easier by publishing them and making them accessible for download from their website. Indeed, it is entirely in the company’s interests to provide documented evidence of its DoPs and to make all the certificates that back them up readily available. This is something that doesn’t always happen in the building industry, where a simple search soon reveals that the information available is of poor quality, confusing or inconsistent.
For a company that considers quality as one of its cornerstones, it is important to fully and transparently exploit this value, which is only possible if all the information required is provided to demonstrate the truth behind the declarations of performance. Only by doing this will it be possible to keep customers fully informed about the characteristics and properties of the adhesive they are using, making it truly safe to use the material they are installing within the specific area of use and on every single building site.