ISO 4211-4 Furniture - Tests for Surfaces - Part 4: Evaluation of Resistance to Impact

The International Organization for Standardization (ISO) standard "ISO 4211-4 Furniture - Tests for surfaces - Part 4: Evaluation of resistance to impact" describes a test method for evaluating the resistance of surfaces of finished furniture to impact. Tests are usually performed on panels of sufficient size to meet the requirements of the test and on panels made of the same material and finished in the same way as the finished furniture. This test method is suitable for use as a means of comparing different finishing systems or as a quality control test to ensure that a specified level of performance is achieved or maintained.

When performing the test, in principle, a cylindrical steel weight is dropped from specified heights via a vertically mounted guide onto a steel ball of specified diameter and hardness positioned on the test panel. The degree of damage to the test area is assessed by reference to a descriptive numerical rating code.

The main devices and materials used in these tests include:

• Horizontal base providing solid support for the test panel: When the test area forms a mold of a piece of furniture, the entire product must stand on a solid base.
• Vertically mounted guide tube with an inner diameter of 40 mm plus/minus 5 mm: A 14 plus/minus 05 mm thick disc with a center hole for the ball with a diameter of 10 plus 0,5 mm is attached to the lower end of the guide tube.
• Cylindrical steel weight with a mass of 500 plus/minus 5 g and a diameter approximately 1 mm smaller than the inner diameter of the guide tube: This weight should be made of a softer alloy than the ball so that it will not cause any indentation on the ball. Provision should be made for raising and lowering the weight.
• Steel ball with a diameter of 14 mm and a hardness of 60 to 66 HRC on the Rockwell scale (for example, a rolling bearing ball).
• Magnifier with at least X7 magnification: this apart is equipped with a graticule scale that allows measurements to be taken with an accuracy of at least 0,1 mm.

The test panel should be substantially flat and preferably not less than 120 mm x 140 mm. This panel should be prepared by the same procedure as that adopted in the manufacture of the commercial product. It should be allowed to mature at a temperature of at least 28 degrees with access to free air for at least 15 days. Conditioning should begin at least 7 days prior to testing and should be carried out at a temperature of 23 degrees plus/minus 2 degrees and a relative humidity of 50 percent plus/minus 5 percent.

During testing, no point of impact shall be less than 20 mm from any edge of the test panel. The centres of the points of impact shall not be less than 20 mm apart. If the grid pattern method is to be used, six lines at least 20 mm apart shall be marked on the surface to be tested. If the surface material is anisotropic, the lines shall be perpendicular to the grain or equivalent. Five points of impact shall be marked at least 20 mm apart along each line.

The test panel shall be placed in a fixed position on the horizontal base with all points of impact within the footprint of the base. When testing horizontal surfaces of finished furniture or furniture parts, they shall be aged and conditioned as described above and the unit under test shall be supported on a solid surface. In finished furniture, the impact shall be on the hardest part of the furniture. Tests shall be conducted at an ambient temperature of 23 degrees plus/minus 2 degrees and 50 percent plus/minus 5 percent relative humidity.

Among the numerous tests, measurements, analyses and evaluation studies that our organization has carried out for businesses in various sectors, it also provides testing services defined in the “ISO 4211-4 Furniture - Tests for surfaces - Part 4: Evaluation of impact resistance” standard with its trained and expert staff and advanced technological equipment.