EN 1128-1995 pdf download.Cement-bonded particleboards – Determination of hard body impact resistance.
This EN 1128 specifies a method of determining the hard body impact resistance of cement-bonded particleboards with a nominal thickness equal to or greater than 9 mm.
2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN 326-I, Wood-based panels — Sampling, cutting and inspection — Part 1: Sampling and culling of test pieces and expression of test results.
3 Principle
The resistance to hard body impact is determined by the free dropping, from progressively increased heights, of a hard body with a defined mass onto a rigidly clamped test piece until the test piece is penetrated or cracked.
4 Apparatus
The apparatus shall comprise a frame which at its base will have means of clamping the test piece in a horizontal position, so that there is no possibility of vibration. This can be achieved using a collar which is clamped to the frame. When the test piece is clamped the free distance between its underside and the bottom of the frame shall be at least 50 mm. The free space between the supports shall be (290 ± 5) mm. The upper part of the frame is provided with guides enabling the falling body fixed on a soft non-alloy steel rod to fall freely and vertically Onto the centre of the test piece.
The falling body shall have a hemispherical extremity with a radius of(25 ± 0,5) mm and a mass (ni) of(4,5 ± 0,05) kg, including the associated Parts.
The frame or guide(s) should be marked at intervals of 25 mm to enable the height from which the body is dropped to be measured.
An example of the type of apparatus is given in Figure 1, Figure 2 and Figure 3. In Figure 1, the guides are fitted with hail hearings to ensure free fall.
5 Test pieces
5.1 Sampling and cutting
Sampling and cutting of test pieces shall be carried out in accordance with EN 326-1, with values of rn (test pieces per panel) = 4 and n (panels) = 5, i.e. 20 test pieces.
5.2 Dimensions of test pieces
The test pieces shall be square with a side dimension of (310 ± 5) mm. Where a jointed test piece is to be tested, it shall be assembled so that the point of impact will be on the grooved haft of the test piece and 30 mm from the joint line showing on the upper surface of the test piece as shown in Figure 4. Where the joint is glued, it should be allowed to cure before conditioning and testing.
5.3 Conditioning
The test pieces shall be conditioned to constant mass in an atmosphere with a relative humidity of (65 ± 5) % and a temperature of (20 ± 2) °C.
NOTE Constant mass is considered to be reached when the results of two successive weighing operations. carried out at an interval of 24 h. do not differ by more than 0.1 % of the mass of the test piece.
6 Procedure
Position the test apparatus on a level, solid, rigid floor, e.g. concrete. Clamp the test piece to the supporting frame so that it overlaps all four sides equally by not less than 7 mm (see Figure 2).
Raise the falling body 25 mm above the surface of the test piece and allow it to drop freely. The falling body or its guide rod, should be caught after impact so that the falling body shall not bounce and strike the test piece a second time.
Repeat this step, but increase the drop-height by 25 mm each time until the falling body either Penetrates the test piece leaving a clearly visible hole, or leaves a series of cracks (see notes 1 and 2). Record this height.
NOTE I Penetration has occurred if. on removal of the test piece from the frame, light can been seen through it at any point around the hemispherical indentation produced by the falling body.
NOTE 2 Exceptionally, cracks can appear. radiating from the point of impact. before the test piece is penetrated. In this case, the drop-height that first produces such cracks i taken as the final measurement.EN 1128-1995 pdf download.