BS EN 892:2012 pdf free.Mountaineering equipment -Dynamic mountaineeringropes – Safety requirementsand test methods.
BS EN 892 The falling mass shall be made of metal, and its fall shall be guided by two vertical rigid guidance rails. Apartfrom items of negligible mass, the system of falling mass and guidance rails shall have a common plane ofsymmetry midway between the guidance rails. The surface of the orifice plate shall be at right angles to thisplane of symmetry, and the centre line of the orifice shall lie within ±2 mm of the plane of symmetry. Thefalling mass and guidance system shall be positioned such that the horizontal distance between the centre-line of the orifice plate and the centre-point of the means for rope attachment to the falling mass is(80±10) mm throughout the drop (see Figure 9).
The dimensions of the falling mass, and of the guidance rails are not defined, but there are constraints onsome dimensions, on the design, and on the shape of the falling mass, as follows:
The falling mass shall be designed to fall freely with minimum contact with the guidance rails until the test sample comes under tension, when some contact with the guidance rails will occur. To keep the frictionlow between the falling mass and the guidance rails, the falling mass may be fitted with roller or ballbearings or plane bearings with low friction surfaces. In all cases there shall be free play between thefalling mass and the guidance rails amounting to a maximum of 8 mm both in the plane of the guidancerails and at right angles to this. The minimum vertical distance between points on the falling mass whichcan come into contact with the guidance rails shall be defined as a distance B.
Means shall be provided for measuring the time at which the falling mass passes two timing points, referred torespectively as the upper and lower timing points. The position of the upper timing point shall correspond withthe position of the falling mass when it has fallen (3 000 ± 2) mm from its initial pre-release position. Theposition of the lower timing point shall be (1 000 ± 2) mm vertically below the upper timing point. The timingmeans are not described in greater detail, but the accuracy shall be such that the time interval betweenpassing the upper timing point and passing the lower timing point can be obtained to within ± 0,25 ms.
The mounting of the orifice plate shall be sufficiently rigid that the following requirement is satisfied. Pass arope through the orifice in the orifice plate, wind it three times around the bollard, and fix it at the clamp. Applya static load of (16 ± 0,5) kN to the free end of the rope, downwards within 2° of vertical. The movement of anypart of the orifice plate from its initial unloaded position shall not exceed 1 mm in each of the X- Y- and Z-directions.BS EN 892 pdf download.