The following table details the characteristics envisaged in the respective standards:

Transcription

1 CHARACTERISTICS AND REQUIREMENTS OF TERRAZZO TILES FOR INTERNAL AND EXTERNAL FLOORS The following table details the characteristics envisaged in the respective standards: Terrazzo tile characteristics Dimensional quality Length and width Thickness Straightness of fair face edge Flatness of the fair face Surface characteristics and visual appearance Bending strength/breaking load Abrasion resistance Slip resistance Water absorption Reaction to fire[ 1 ] Thermal conductivity Climate resistance Water absorption Resistance to frost/thaw cycles External fire performance For internal use [EN ] - - For external use [EN ] NOTE: Standards EN and EN include test methods for evaluating these characteristics or explicitly refer to other standards. Tests are carried out on terrazzo tiles at least 28 days ol d. [ 1 ] Terrazzo tiles need not be tested and are automatically classified as Al fl Dimensional quality Minimum thickness is only considered for double-layer terrazzo tile, two classes being envisaged, depending on whether mechanical polishing processes are applied after the tiles have been installed. The classes and their related codes are the same, independently of the intended location: Class I (Th I): Class II (Th II): Terrazzo facing layer thickness of 4 mm or more Terrazzo facing layer thickness of 8 mm or more, if the product is going to be polished after it has been installed [*] [*] In terrazzo tiles with relief, a minimum thickness of 2 mm is required of the facing layer at the bottom of the groove or bas-relief 1

2 Characteristic Side length or width Thickness (thickness < 40 mm) Thickness (thickness 40 mm) Straightness of edges [ 1 ] Flatness [ 2 ] DIMENSIONAL TOLERANCES Internal or external use ± 0.3% ± 2 mm ± 3 mm ± 0.3 % ± 0.3 % [ 1 ] Measured as maximum difference between the edge and a standard straightedge and expressed as a % in regard to the length of that edge. [ 2 ] Measurement of the maximum deviation at any point in regard to the diagonal of the tile. This is not considered in textured tiles. Surface quality Defined as the absence of projections, depressions, exfoliations, and cracks in the fair face, based on visual inspection at a distance of 2 m, with natural light and dry environment. Smaller holes may be permanently filled, without it being necessary to define these. In addition, it is stated that when colorations are applied, they shall be contained in the terrazzo facing layer or throughout the tile. Slight variations in colour consistency between different lots of tiles, assignable to shade variations in cements and aggregates, changes in the manufacturing process, and/or environmental conditions, are allowed. The manufacturer shall define what is considered a lot. Moisture variations can lead to small differences in colour, which is why maximum protection is always recommended during storage before installation. Bending strength/breaking load There are different classes for these parameters, with their corresponding marking, depending on whether the terrazzo tiles are intended for interiors or exteriors. TERRAZZO TILES FOR INTERNAL USE Bending strength (MPa) The average strength of the four test pieces shall be 5 MPa or greater No individual test value shall be below 4 MPa Breaking load (kn) Class Marking Requirement 1 (*) BL I No requirements 2 BL II Tile surface area 1100 cm 2 No individual value < 2.5 kn 3 BL III Tile surface area > 1100 cm 2 No individual value < 3 kn (*) For the use of this class it is required that the installation substrate or base shall be rigid, and that the tiles shall be installed on a mortar bed. 2

3 TERRAZZO TILES FOR EXTERNAL USE Bending strength (MPa) Class Marking Average strength Individual strength 1 ST TT UT Breaking load (kn) 30 (*) 3T T T T T T T (*) For class 30, it is recommended to install the terrazzo tile on a rigid continuous deck. Abrasion resistance Just as with natural stone, resistance to impairment of appearance by abrasion, here called abrasive wear, is evaluated by measuring the groove made by a disc on the fair face (deep abrasion). In this case, the test method is included in European standard EN An alternative method [Böhm test method] is also put forward, which measures volume loss of the test piece caused by the action of a rotating disc that exerts a constant force of 294 N on the tile surface while it rotates, with artificial corundum being fed between the test piece and the disc. The volume loss is measured after 16 cycles of 22 revolutions per cycle. 3

4 1-Test piece holder 2-Counterweight 3-Test piece 4-Test track 5-Load 6-Rotating disc Böhm test method for the measurement of abrasion resistance In terrazzo tiles for use in interiors, it is assumed that the abrasive wear requirement is met if: No test piece provides a groove exceeding 25 mm, by the deep abrasion method No test piece provides a volume loss per unit surface area exceeding 30 cm 3 /50 cm 2 with the Böhm test Terrazzo tiles for use in exteriors feature four classes with their corresponding marking codes, as shown in the following table. ABRASION RESISTANCE OF TERRAZZO TILES INTENDED FOR EXTERIORS Class Marking Deep abrasion test groove length in mm 1 F Characteristic not measured Böhm test volume loss per unit surface area cm 3 /cm 2 2 G 26 26/50 3 H 23 20/50 4 I 20 18/50 Slip resistance The standard states that unpolished, dry terrazzo tile exiting the factory has satisfactory non-slip performance. As a result, this consideration should be taken into account in customarily dry internal locations. However, now that the Technical Building Code (CTE) has been approved in Spain, the slip resistance shall be characterised of all tiles intended for floors for private communal use and in publicly trafficked architecture, in dry and wet surface conditions, based on the demands of the document on safety against risk of pedestrian slip-falls [SU 1 of the CTE], as already mentioned for both ceramic tiles and natural stone tiles. 4

5 For the sake of safety, it is advisable to test this characteristic in all unpolished terrazzo tiles, since they may be intended for interiors with risk (floors that are often wet, floors that can be accessed from outside, etc.) If the tiles display reliefs or a rough surface texture, it may be assumed that they are slip resistant, though this statement cannot be generalised, since terrazzo tiles with certain polished (or even unpolished) high reliefs exhibit poor wet anti-slip performance (for example, in pavements and outdoor urban paving). The test values and demands according to the above SU 1 document of the Spanish CTE are given below. 1 Sample holder 2 Sample 3 Adjustable mass 4 Water inlet 5 Adjustable abrasive hopper and dispensers 6 Polishing wheel 7 Rubber ring Flat-bed polishing machine 1 Scale C (126 mm slip length) 2 Scale F (76 mm slip length) 3 Pointer 4 Pendulum arm 5 Rubber slider 6 Levelling screw 7 Test piece 8 Bubble level indicator 9 Vertical adjustment screw Pendulum friction tester FLOOR CLASSIFICATION ACCORDING TO SU 1 Slip resistance R d Floor classes R d 15 Class 0 15 < R d 35 Class 1 35 < R d 45 Class 2 R d > 45 Class 3 5

6 Dry internal areas FLOOR CLASS AS A FUNCTION OF SLIP RISK Area Floor class - surfaces with a slope of less than 6% Class 1 - surfaces with a slope of 6% or higher and stairs Class 2 Wet internal areas, such as bathrooms, kitchens, indoor swimming pools, etc. (1) - surfaces with a slope of less than 6% Class 2 - surfaces with a slope of 6% or higher and stairs Class 3 Internal areas in which, in addition to water, there may be agents that reduce slip resistance (grease, lubricants, etc.), such as industrial kitchens, slaughter houses, garages, areas of industrial use, etc. Class 3 External areas. Swimming pools (2) Class 3 (1) (2) These include floor areas around building entrances from outside, except when direct accesses to dwellings or to areas of restricted use, as well as covered terraces, are involved. In areas intended for barefoot users and swimming pool floors, in areas not deeper than 1.50 m. In addition to the characterisation of the slip risk of terrazzo tiles that have been subjected to mechanical polishing and subsequent lapping treatment, terrazzo tiles should also be characterised that are intended for public flooring under a wide spectrum of risks, including the presence of grease and other substances that encourage slipping. In short, it is very important to determine the USRV (unpolished skid resistance value) of a terrazzo tile, and it is to be appreciated when the manufacturer supplies that value for a polished surface. Water absorption In terrazzo tiles it is sought to combine water absorption of the rear (generally of the tile mass), which allows installation with mortar according to the different variants of the traditional technique, with limited fair surface suction that will not encourage dirt to lodge. As a result, standard EN establishes two test results to measure absorption: Per unit surface area, by capillarity at atmospheric pressure, expressed in g/cm 2, and measured after 24 h immersion Total water absorption of the terrazzo tile, expressed as a % in relation to the dry mass of the test tile For tiles intended for interiors, maximum values of water absorption through the fair face are set of 0.4 g/cm 2 (for no individual tested piece) and of 8% for total absorption. In terrazzo tiles intended for exteriors, standard EN establishes certain classes, linking total water absorption (in %) to the climate resistance parameter, which correlates that absorption with the results of the frost/thaw cycle test, using dissolved de-icer salts and evaluating the results by the mass loss of the test pieces, expressed in 6

7 kg/m 2, after 28 cycles from +20 to -20ºC. The climate resistance classes are presented in the following table. Class CLASSES BY CLIMATE RESISTANCE (TERRAZZO TILES FOR EXTERNAL USE) Marking Water absorption (% by weight) Mass loss after frost/thaw test cycles (in kg/m 2 ) 1 A Not evaluated Not evaluated 2 B #6 (as an average) Not evaluated 3 D Not evaluated 1.0 as an average No individual value > 1.5 Reaction to fire Just as with ceramic tiles and natural stone tiles, terrazzo tiles need not be tested in order to be automatically classified as Al fl [Commission Decision 96/603/CE], unless they contain 1% by weight or more of the tile in organic matter. This consideration extends to in-factory surface treatments that involve the application of organic products (sealants, primers, etc.). Fire resistance is a key characteristic that shall be included in the CE marking. External fire performance This parameter is included in standard EN for terrazzo tiles intended for exteriors, as deck elements, the same consideration being applied as for the reaction to fire (automatic classification as Al fl ). Thermal conductivity Parameter to be considered when terrazzo tiles are intended for a construction element that is required to provide thermal efficiency. In that case, the manufacturer shall state the thermal properties using the data given in Table L.2 of standard EN