Document ID: chunk:federal_register_of_legislation:F2025L00028:front:0:p26
Version: federal_register_of_legislation:F2025L00028
Segment Type: other
Provision Reference: 
Character Range: 73993–76790

increasing deflection (see paragraph 2.1. below). Front and rear aluminium plates are attached to the aluminium honeycomb blocks.

              2.1. Honeycomb blocks

              2.1.1. Geometrical characteristics

              2.1.1.1. The impactor consists of six joined zones whose forms and positioning are shown in Figures 1 and 2. The zones are defined as 500 ± 5 mm x 250 ± 3 mm in Figures 1 and 2. The 500 mm should be in the W direction and the 250 mm in the L direction of the aluminium honeycomb construction (see Figure 3).

              2.1.1.2. The impactor is divided into 2 rows. The lower row shall be 250 ± 3 mm high, and 500 ± 2mm deep after pre-crush (see paragraph 2.1.2. below), and deeper than the upper row by 60 ± 2 mm.

              2.1.1.3. The blocks must be centred on the six zones defined in Figure 1 and each block (including incomplete cells) should cover completely the area defined for each zone).

              2.1.2. Pre-crush

              2.1.2.1. The pre-crush shall be performed on the surface of the honeycomb to which the front sheets are attached.

              2.1.2.2. Blocks 1, 2 and 3 should be crushed by 10 ± 2 mm on the top surface prior to testing to give a depth of 500 ± 2 mm (Figure 2).

              2.1.2.3. Blocks 4, 5 and 6 should be crushed by 10 ± 2 mm on the top surface prior to testing to give a depth of 440 ± 2 mm.

              2.1.3. Material characteristics

              2.1.3.1. The cell dimensions shall be 19 mm ± 10 per cent for each block (see Figure 4).

              2.1.3.2. The cells must be made of 3003 aluminium for the upper row.

              2.1.3.3. The cells must be made of 5052 aluminium for the lower row.

              2.1.3.4. The aluminium honeycomb blocks should be processed such that the force deflection-curve when statically crushed (according to the procedure defined in paragraph 2.1.4. below) is within the corridors defined for each of the six blocks in Appendix 1 to this annex. Moreover, the processed honeycomb material used in the honeycomb blocks to be used for constructing the barrier, should be cleaned in order to remove any residue that may have been produced during the processing of the raw honeycomb material.

              2.1.3.5. The mass of the blocks in each batch shall not differ by more than 5 per cent of the mean block mass for that batch.

              2.1.4. Static tests

              2.1.4.1. A sample taken from each batch of processed honeycomb core shall be tested according to the static test procedure described in paragraph 5. of this annex.

              2.1.4.2. The force-compression for each block tested shall lie within the force deflection corridors defined in Appendix 1. Static force-deflection corridors are defined for each block of