Wolfman development milestone 2021

99 10 Manhole Tops and Drainage Gratings Manhole Tops and Drainage Gratings Type Purpose, areas of use Test load kN Group B125 Sidewalks, parking lots or parking surfaces, areas for pedestrians 125 2 C250 Close to curbstones, no further than 0.50 m into the road, mainly rectangular drainage gratings installed on catch basins in proximity to the curbstone. 250 3 D400 Roads, pedestrian malls, hard road shoulders and parking areas 400 4 Purpose of the cover Clear opening of the cover Cover that may be used for the passage of a person 600 mm or more Cover for a manhole deeper than 1.25 m Cover not used for the passage of a person Any diameter as needed, such as 400, 500, 600 mm. Street group1 group1 group2 group2 group3 group4 group3 General sheet 1. Standard for manhole tops The official Standard for manhole tops in Israel is IS 489 (2003). This Standard is almost identical, except for a few minor differences, to European Standard EN-124. 2. Choosing a cover The main types and most useful ones are B125, C250, D400 3. Choosing the cover diameter The diameter of the cover means the diameter of the clear opening through the frame of the cover. One should differentiate between manhole tops through which a person is permitted to pass in order to enter an inspection chamber and manhole tops a person will not pass. The cover of a manhole 1.25 m or deeper is considered a cover through which a person is supposed to pass. The requirements for choosing the cover diameter are derived from section 7.3 of IS 489 and the Directives for Sanitation Facilities. Manhole tops from group 1, type A50 for areas used only by pedestrians and cyclists are mostly not useable. 4. Setting the cover/grating within the frame Manhole tops installed in roads have to withstand various traffic loads. The Standard requires that the planning of the cover be such that ensures proper functioning under the relevant traffic conditions. This can be obtained by means of one of the following arrangements or a insertion of them: 1. Locking device (see later reference). 2. Sufficient mass per area unit (as required by the Standard). 3. Special design (the reference is to depth of the insertion, structure of the seat, linings to dampen noise, processing of the contact surface and such like). 5. Depth of the insertion of the cover with the frame (depth of the seat) Regarding type D400 manhole tops for roads, the Standard requires a insertion depth of at least 50 mm (in manhole tops without locks). The Wolfman Company supplies its D400 type manhole tops with a insertion depth of 60 mm (greater than the Standard requirement). This ensures good stability of the cover and prevents the possibility of the cover coming out of the frame under conditions of fast-moving and heavy traffic. 6. Processing the contact surfaces The D400 type manhole tops supplied by the Wolfman Company have machined contact surfaces. This improves the stability of the cover and prevents the cover from“rocking” in the frame 7. Lining to dampen noise In the D400 type manhole tops for roads supplied by the Wolfman Company, are installed special linings to dampen noise between the cover and the frame. The linings are manufactured from special materials that are installed in the frame and prevent direct vertical contact between the metal of the cover and the metal of the frame, thereby reducing the noise under fast-moving vehicular traffic. 8. Lockable manhole tops The Wolfman Company’s D400 type “Click-Lock”manhole tops have a hinge and spring lock. In our opinion locking devices using bolts are invalid and are not recommended for use. Advantages of the Wolfman manhole tops 1. In the D400 manhole tops for roads – the contact surfaces between the cover and the frame are machined . 2. All frames are supplied cast with a reinforced concrete frame, which improves the installation and makes it easier. 3. All the D400 type manhole tops are made of spheroidal cast iron that is unbreakable. 4. All the D400 manhole tops for roads have special linings to dampen noise. 5. All kinds of covers and gratings of the same type and same diameter are interchangeable in frames for instance a cover and grating are interchangeable.