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Figure 4.1
House connection to buried chamber |
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reduce the likelihood of the cover being damaged by traffic. It is significant that residents in both Faisalabad and Karachi have been observed to bury conventional chamber covers in order to protect them from traffic. |
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4.2.4
Dimensions of Access Manholes and Chambers |
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The function of manholes and chambers is to allow access to the sewer in order to inspect it and clear any blockages which may occur in it. A manhole, as its name suggests, has to be entered in order to carry out these operations, while a chamber can be accessed from ground level and requires rather smaller plan dimensions. |
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The internal dimensions adopted for access chambers in Yusufabad were 500 × 500 mm. These dimensions are adequate when the sewer is very shallow but it is doubtful whether it would be possible to rod the sewer from such chambers when the depth to invert exceeds about 800 mm. Bearing this in mind, Table 4.4 gives standards based on those adopted for the manholes and chambers used in North-east Lahore (the dimensions given in bold type are those actually used while those in normal type are roughly equivalent alternatives). |
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A comparison may be made with the standards recommended in Sewers for Adoption (WSA, 1995) and with the recommenda- |
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