Forbo ESD Tile Main Page Other types of ESD Floor Tiles
Forbo Colorex ESD Tile, ESD Flooring Tile Installation A static control floor covering, such as Forbo AS and EL ESD Flooring Tile provides a conductive pathway from the person to ground, thus allowing electrostatic charges to flow safely from the body. The person typically wears static control shoes or foot grounding devices in combination with the flooring. Static control flooring also controls electrostatic charges on rolling equipment such as carts, chairs, test equipment and transport means of subassemblies or completed product. The rolling equipment must have conductive casters and electrical continuity between the cart frame, shelves and casters. Preparation of installation Check that the following environmental and subfloor conditions are met: The installation of Colorex should not begin until the work of all other trades has been completed, especially overhead trades. Areas should be cleaned, fully enclosed, weathertight with the permanent HVAC system set at a minimum of 68o F (20o C) for a minimum of 72 hours prior to, during and after installation. The flooring material should be conditioned in the same manner. Areas to receive flooring shall be adequately lighted to allow for proper inspection of the substrate, installation and seaming of the flooring and for final inspection. Wood floors should be double construction with a minimum thickness of 1 inch. The floor must be rigid, free from movement and have at least 18" of well ventilated air space below. Floor coverings cannot be installed over wooden subfloors built on sleepers over, on, or below grade concrete floors. Floors shall be smooth, flat, level, permanently dry, clean and free of all foreign material such as dust, paint, grease, oils, solvents, curing and hardening compounds, sealers, asphalt and old adhesive residue. Concrete shall have a minimum compressive strength of 3500 psi. Patch and repair minor cracks and other imperfections with Portland-base patching compounds. Do not install floor coverings over gypsum-based leveling or patching compounds. Floor covering should not be installed over expansion joints. Expansion joint covers compatible with the floor covering should be used. It is essential that moisture tests be taken on all concrete floors regardless of the age or grade level. The test should be a calcium chloride test. One test should be conducted for every 1000 sq. ft. of flooring (minimum of 3). The test should be conducted around the perimeter of the room, at columns and where moisture may be evident. The moisture emission from the concrete shall not exceed 5.0 lbs per 1000 sq.ft. in 24 hours. A diagram of the area showing the location and results of each test should be submitted to the Architect, General Contractor or End User. If the test results exceed the limitations, the installation must not proceed until the problem has been corrected. Planning the installationBasically the installation of floor tile begins from the middle of a room. In very large rooms, it is necessary to divide the room into smaller areas. Again, always start the installation from the middle of the smaller area.
Figure 1--Installation layout Copper strip / grid NOTE: Due to the increased conductivity of the adhesive the following grounding method is now obsolete. For information on how to ground TODAY'S ESD conductive floors and adhesive please visit our tech document and observe the basic grounding method. For areas smaller than 40 m2 (500 sqft) we recommend
gluing 1 Lm (3 feet) of copper strip to the subfloor, the loose end to be
connected to a grounding point by an electrician.
Testing the copper strip grid The resistance of the copper strip system can be easily measured and checked with a resistance measuring instrument. It is also possible to use very simple devices like buzzers.
Providing ground connection points This is the responsibility of the building owner, electrical subcontractor, or architect rather than the flooring installer. The ground connection Most commonly, the copper strip/grid will be connected to the normal electrical grounding network of the building. In highly ESD-sensitive areas, like the assembling or the manufacturing of electronic components etc., the procedure usually involves a separate, "equipotential" grounding system, provided by the end user. In all cases the grounding must comply with local electrical and building codes and regulations.
Figure 4:Example of connecting COLOREX to ground Applying the Conductive primer If required prime the floor with Forbo conductive primer before spreading adhesive. The primer is a black, watery solution with a resistance of < 10E5 Ohms. It is applied with a roller until the surface has a fully black, uniform colour. The primer dries in about 3 hours (it depends on the air humidity and on the temperature) and is then ready for the application of the adhesive. COLOREX EL and AS tile are installed using only Forbo Conductive Adhesive. This watery acrylic contains conductive fibbers and has a resistance of less than 10E5 Ohms. It must be applied with the trowel blade provided with the adhesive to assure proper adhesion and resistance and to prevent an accumulation of conductive fibbers when spreading the adhesive. Trowel--1/16" x 1/16" x 1/16" square notch. Spread Rate-approx. 150 sq.ft./gal. When the primer is dry, proceed with the laying of COLOREX EL or AS For a good installation, we recommend measuring the room and the subfloor temperatures and allowing the tiles to come to room temperature. It is recommended that the room temperature be maintained at 68° F for at least 72 hours prior to, during, and after installation.
Figure 9--Combination The tile should be laid immediately after application of the adhesive. Do not allow the wet glue to dry. Should the adhesive coverage on the back side of the tile be under 70% there could be an increase in resistance. Because of the wet adhesive, the tiles laid first in the middle of the room may start slipping away as additional tiles are laid. If this occurs, apply adhesive to both the subfloor and the middle tile with a toothless spatula and allow to air dry. This will allow the tiles in the middle to adhere to the floor and further installation on the wet adhesive does not present any other problem. During installation, the installer should be careful not to apply any pressure on the adhesive with his knees. Knee protectors should be worn. Also, dirt on the primer, like grains of sand, reduces adhesive properties. In areas using heavy vehicles, inadequate adhesion can present critical future problems.
COLOREX does not have a visible direction of manufacture, however, during manufacturing, the surface is subject to a finishing that might lead to an unequal light reflection. The back of the tiles are clearly marked with a arrrow all arrows must face the same direction. COLOREX must be rolled while the adhesive surface is still wet. Gently lift up single tiles to check the moistness on the back side. The adhesive requires a drying time of at least 24 hours until the floor can be used or welded. The time for the adhesive to fully cure depends
There is little concern regarding installing COLOREX EL or AS in a bed of adhesive, which is too wet. However, there is a big risk that the adhesive will cure too quickly resulting in inadequate adhesive coverage on the back side of the tile. Usually, COLOREX does not need to be welded. If the tile is properly installed and rolled according to directions, it is possible to damp-clean the unwelded COLOREX. However, in case of hospital theatres or industrial applications with hygienic requirements we recommend welding. This will avoid dust contamination in the seams or damage to the adhesive by disinfectants. Before being welded the tiles have to be grooved to 2/3 of their depth with a grooving tool such as the Forbo-groover and an air-dryer. It is important that the excess welding rod be trimmed shortly after the welding. Use a special crescent knife made for this purpose and trim while the welding rod is still warm and soft. After the welding rod is completely cold, a final trim can be made using with the crescent knife. If necessary, remove excess adhesive from the surface of the tile. Usually this can easily be done by means of a damp cloth or an abrasive hand pad. In any case, avoid the use of any cleanser or solvent if adhesive is still wet. As soon as any excess adhesive is removed, an additional cleaning may be performed as required by the customer. All maintenance should use a minimum amount of water. COLOREX was designed in a manner that maintenance and cleaning do not require any protective floor finish or polymer. Be aware that floor finishes may cause an increase in resistance from 10 to 30 times. That is the reason why a floor installed to have a resistance of 10E6 Ohm may actually have resistance readings of 10E8 Ohm. There is no single universally accepted method to measure the resistance of the floor after installation. The two most common methods in the U.S. are ANSI/ESD 7.1 and ASTM F150, the most common one in Europe is the DIN 51953. The user needs to specify which standard will be used to measure the resistance of the floor. These standards define the test voltage, electrodes, methods, and points of measurement to be used. In large installations it is common to measure the intersection points on an imaginary grid. It is not important that such points are located with precise tolerances. Variation in resistance readings at various points is normal. The resistance values should be recorded and averages and medians calculated. The test data should cover points with high resistance, low resistance, means, and medians. Measuring single tiles before installation In certain cases, we suggest spot-checking single tiles before the installation. Be sure the surface of the tile is clean. Place a tile of COLOREX on a wet cloth. The wet cloth simulates the conductive adhesive used to install the tile. Simulate a ground connection by connecting the edge of the wet cloth to the measuring instrument. Perform the rest of the measurement as described below. The values obtained with this technique do not correspond to the laboratory measurements the way they are normally conducted with standard measurement techniques.
Figure 11--Measuring resistance on uninstalled tile according to DIN-51953 Before starting, be sure the measuring instrument is calibrated and prepared according to the manufacturer's instructions. Electrodes It is important that the electrode (in accordance with standards) has good electrical contact with the floor. Some specifications (ASTM F150, for example) recommend covering the bottom of the electrode with aluminium foil. This is not totally satisfactory since the imperfections of the primer or the roughness of the floor surface cannot be compensated for in this way. It is more advisable to use conductive rubber such as required by ANSI/ESD 7.1. Cleaning before measuring Dust or dirt can be a strong insulating material. Therefore, the points to be measured have to be thoroughly cleaned. If necessary, use an abrasive. Any floor finishes also have to be completely removed. Measuring surface (point to point) resistance The expression "surface resistance" is actually a little confusing. The use of 2 identical electrodes in accordance to the specifications does not measure the surface resistance but only the resistance between two points on the surface. For this measurement, the two electrodes are placed on the surface of the material the specified distance apart. The specified voltage is applied and the resistance recorded.
Figure 12--Measuring resistance point-to-point on the surface of the flooring Measuring surface to ground resistance The second type of resistance measurement is that taken from the surface of the material to ground or a groundable point. One electrode is placed on the surface of the material. A second connection is made to the point at which the floor has been connected to ground. If the specific connection is not accessible, use any accessible ground point. If the installation of COLOREX has been carried out satisfactorily, the resistance should correspond to that specified for the product. Possible discrepancies normally occur from incorrect measurement technique and from improper installation.
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