BS ISO 5721-1:2013 pdf free

BS ISO 5721-1:2013 pdf free.Agricultural tractors一Requirements, test procedures and acceptance criteria for the operator’s field of vision
For the purpose of determining the masking effects in the sector of vision to the front, the masking effects due to the frame of the windscreen and to any other obstacle may be considered as a single effect,provided that the distance between the outermost points of this masking effect does not exceed 700 mm.
Outside the sector of vision to the front, masking effects exceeding 700 mm but not exceeding 1 500 mm are, however, permissible if the components causing them cannot be redesigned or relocated: on each side there may be a total of either two such masking effects, one not exceeding 700 mm and the other not exceeding 1 500 mm, or two such masking effects, neither exceeding 1 200 mm.
The tractor shall be placed on a horizontal surface as shown in Figure 2. On a horizontal support level with the reference point, there shall be mounted two point sources of light, e.g. two x 150 W, 12 V,65 mm apart and symmetrically located with respect to the reference point. The support shall be pivotable at its centre point about a vertical axis passing through the reference point. For the purpose of measuring the masking effects, the support shall be so aligned that the line joining the two light sources is perpendicular to the line joining the masking component and the reference point.
The silhouette (deepest shadow) overlaps projected on to the semi-circle of vision to the front by the masking component when the light sources are switched on simultaneously or alternately shall be measured in accordance with 3.4 (Figure 3).
The tractor shall be placed on a horizontal surface as shown in Figure 2. On a horizontal support level with the reference point, there shall be mounted two point sources of light, e.g. two × 150 W, 12 V,65 mm apart and symmetrically located with respect to the reference point. The support shall be pivotable at its centre point about a vertical axis passing through the reference point. For the purpose of measuring the masking effects, the support shall be so aligned that the line joining the two light sources is perpendicular to the line joining the masking component and the reference point.BS ISO 5721-1 pdf download.