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Ductile Iron Manhole cover & frame with Hinges Locking Dervice
Features General Manhole covers and frames shall comply with the specifications in European Standard, EN 124:1994 and the specification m clause 2.7 of this volume. Where the specification in this volume contradict the specification given in EN 124, the specifications in this volume shall take precedence. Load Class For public sewers, manhole covers / frames shall be capable of bearing wheel loads of up to 400kN and as such shall meet the test load requirements for class D 400 manhole tops in EN 124. For other sewers, manhole covers frames shall be: · class D400 where placed m road carriageways, hard shoulders, parking areas and anywhere vehicle access is possible · class C250 for all other location where vehicle access is not possible Material The material for manhole covers and frames shall be either: · Spheroidal or nodular graphite iron (otherwise known as ductile iron) complying with the requirements specified in BS 2789 for grade 500/7 · flake graphite iron (otherwise known as grey iron) complying with the requirements specified in BS 1452 for grade 350 Dimension, Marking and Surface Finish The dimensions, marking and surface finish of manhole covers and frames shall accord with the requirements given in Figure A. 1 and Figure A.4 Tolerance on dimensions shown in Figure A 1 and A2 shall be ± 1 mm. The casting of marking shall be clearly legible. Seating When a random cover is placed iii a random frame, the adjacent top surfaces of the cover and frame shall have flushness of level to within ± 1 mm. Casting All cast units shall be cleanly cast arid shall be free from air holes, sand holes, clod shuts and chill. They shall be neatly dressed and carefully fettled All castings shall be free from voids, whether due to shrinkage, gas inclusions or other causes. Protective Coating All surfaces of manhole covers and frames shall be supplied coated with either a: Water-tightness Where a watertight cover is specified, it shall satisfy the test requirements in Appendix E of AS 3996. Lifting Lugs Covers shall be provided with lifting lugs. The dimensions of lugs shall comply with figure A3 or other design approved by the DGSS and shall be located as shown on figure Al and A2. Lifting lugs shall not permit water to pass Trough the cover. Locking A locking arrangement approved by the DGSS shall be fitted to lock ductile iron covers to the frames and to prevent rocking due to traffic. Bolts and nuts for locking devises shall be hexagon headed, complying with BS 3692 and shall be of stainless steel in accordance with ISO 3506 or BS 6105. Hinge AU manhole covers shall be hinged. The hinge shall be designed such that, when iii the open position, they shall be secured by a positive mechanical retainer to prevent accidental closure of the covers. The opening angle of hinged covers shall be at least 100° to the horizontal. If hinge bolt is used for coupling separate sections of covers and frames, it shall be of stainless steel in accordance with ISO 3506 or BS 6015. Product Certification Manhole covers and frames shall be certified as complying with the requirements of the specifications m clause 2.7 of this volume. Certification shall be undertaken by SIRIM or other third party certification body accredited in accordance with MS EN 45011 and approved by the DGSS. Certified manhole covers and frames shall have met the requirements given in clause10 of EN124. However, the final inspection and tests and the frequency of tests / inspection shall not be as shown in Table A3 of EN 124. Instead, the specification as shown in Table 1.1 below must be followed. All final inspection and test documents shall be retained for at least 5 years. Table 1.1 Final Inspection and testing
The specification of Ductile Iron for manhole cover & frame is complying with BS 2789 in Grade 500/7. The material are made up of the minimum tensile strength 50 kp/mm2. The minimum yield strength 35 kp/mm2 and minimum Elongation 7%(Ductility). To check the specificate for above mentioned is carry out by the test piece (fig. 1), (testing by the Universal Testing Machines to meet the standard requirement.
Remarks: · The parallel portion of this test piece shall be machine-finished. However that of mallceable casting shall, as a rule, not be finished. · If the test piece of the dimensions as specified in (fig. 1) can not be obtained, the diameter of parallel portion and the gauge length may be determined in accordance with the formula L=4 where A is the cross-sectional area of parallel portion. The typical chemical composition related to Grade 500/7 is:
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