DIN EN 13798 pdf free download

DIN EN 13798 pdf free download. Specification for a reference raingauge pit.
2 Design and construction of the reference raingauge pit Figures 1 – 3 show the design of the pit, including the required dimensions of the pit and the grating, and the method of installation of the raingauge. The specified dimensions are not critical, but shall be used whenever possible. Variations are acceptable within the indicated tolerances. The pit shall preferably be sited on level ground to avoid possible surface runoff into it during prolonged heavy rain. However, in mountainous areas, this may not be possible or desirable and adequate drainage shall be provided in such cases. The sides of the pit shall be formed of brick, concrete, corrugated iron, plastic, preserved wood or other suitable material. They shall be supported to prevent collapse. Supports shall be provided around the edges, or at the corners of the pit, on which to rest the grating. The grating shall either be strong enough to walk on, or be made in two sections to allow half to be lifted, to give access to the raingauge. The base of the pit shall allow water to drain away and, for this purpose, an overlay of gravel or other suitable material may be used. Plastic sheeting laid over bare soil shall not be used if it does not permit water to drain quickly away. Weed growth shall be prevented either by weeding or by periodic application of weed killer. The pit shall be at least 300 mm deep. 3 Design and construction of the grating The grating shall be constructed from material sufficiently strong to maintain its shape without distortion. The strips of the grating shall be not more than 5 mm thick, to prevent splashing from their top surfaces. NOTE 1 Thickness will depend partly, however, on the material used, such that in the case of galvanised steel, 2 mm will probably be found sufficient. NOTE2 The grating should preferably be of galvanised sheet steel, but can be of plastic or wood or other suitable material. 4 Installation of raingauges The orifice of the raingauge shall be level with the top of the grating. In the case of large raingauges, the square space in the centre of the grating shall be approximately 250 mm larger than the diameter of the raingauge collector, so as to prevent in-splash from the grating. NOTE Tall raingauges, such as the mechanical recording type, can need access to the chart via the side of the gauge some distance from the top of the gauge. For such gauges, which are sometimes up to a metre or so in height, a deeper pit can be made to accommodate the full height of the gauge. Larger gauges can present problems, although it can be possible to provide a central.recess to give extra depth (see Figure 3).DIN EN 13798  pdf download.