EN 427-1994 pdf download.Resilient floor coverings Determination of the side length, squareness and straightness of tiles.
This EN 427 specifies methods for determining side lengths of floor tiles measuring at least 150 mm, the squareness of rectangular tiles and the straightness of edges.
NOTE For composition cork floor tiles. use the apparatus and procedure described in Iso 9366.
2 Principle
The surface dimensions of a tile of minimum side length 150 mm are measured by a contact. method at three positions in each direction. To assess the squareness, each corner of a right-angled tile is fitted into the dihedral angle of a precision square and the maximum gap between the arm of the square and the ends between the arm and the edge is measured at any point along the edge to assess the straightness.
3 Apparatus
3.1 Length
3.1.1 A sliding caliper gauge or equivalent device. e.g. a table with comparators and stop unit, of accuracy 0,05 mm.
3.1.2 A flat surface with dimensions larger than those of the tiles, e.g. a plate of thickness greater than or equal to 10 mm.
3.1.3 A rigid plate, squared and finished, with dimensions 5 mm to 10 mm less than those of the tiles. The mass per unit area of the plate shall be approximately 20 kg/rn2, e.g. steel of thickness 2,5 mm, duralumin of thickness 7 mm.
3.2 Squareness and straight ness
3.2.1 A precision square, with arms longer than the side length of the tiles. The linearity error for the arms shall be less than or equal to 0,01 mm and the angular error shall be less than 0,02 mm at 300 mm.
3.2.2 A flat surface as described in 3.1.2.
3.2.3 A rigid plate as described in 3.1.3.
3.2.4 A set of thickness gauges ranging from 0,20 mm to 0,55 mm in steps of 0,05 mm.
4 Sampling
Take five tiles from the sample as test pieces. Where a pack of tiles comprises the sample, ensure that, the first and last tiles are not used as test pieces.
5 Conditioning
Condition the tiles at a temperature of (23 ± 2) °C and relative humidity (50 ± 5) % for a minimum of 24 h.
Maintain these conditions when carrying out the test.
6.1 Length
Place the tile on the flat surface with the squared plate on top. Take three measurements of the distance between the opposite sides in each direction, two of these measurements approximately 10 mm from the perpendicular edges and the third equidistant from the first two.
6.2 Squareness and straightness Place one edge of the tile against an arm of the square and slide up to touch the other arm. Then place the rigid plate on top without moving the tile. Determine the thickest gauge which can be easily inserted between the second arm of the square and the tile at the end of the edge to assess the deviation from the squareness (see Figure 1 and Figure 2). Determine the thickest gauge which can be easily inserted at any point between the second arm of the edge of the tile to assess the straightness of the edge (see Figure 3).
7.2 Squareness and straightness
Express the maximum deviation for each side of each tile in millimetres, to the nearest 0,05 mm for:
a) the end of the edge for squareness; b) any point along the edge for straightness.
Report the greater size of deviation of a) or b) for each side.
8 Test report
The test report shall contain the following information:
a) a reference to this standard, i.e. EN 427; b) a complete identification of the product tested, including type, source, colour and manufacturer’s reference number:
c) previous history of the sample;
d) the mean length for each direction per tile:
e) the maximum deviation for each edge of the tile, and whether the deviation refers to squareness or straightness;
f) any deviation from this standard which may have affected the results.EN 427-1994 pdf download.