Practical suggestions by Mr. Rogers Field, M. Inst. C.E., as to water supply, drainage, and sewage disposal for lunatic asylums / issued by the Commissioners in Lunacy.

  • Field, Rogers.
Date:
1892
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Licence: Public Domain Mark

Credit: Practical suggestions by Mr. Rogers Field, M. Inst. C.E., as to water supply, drainage, and sewage disposal for lunatic asylums / issued by the Commissioners in Lunacy. Source: Wellcome Collection.

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    for boilers and laundry purposes. If this is not done the rain¬ water drains must discharge into ditches or water-courses. (22.) The following are some of the main points to be borne Main points in mind in designing a good system of sewerage. to be borne in (<x.) That the sewage must be rapidly removed from the pm(1 in deslgu buildings, and the drains be “ self cleansing,” so that of°sewerage. there is no stagnation or collection of deposit in them. (b.) That the drains should never pass under buildings where it can possibly be avoided, and when such passage is unavoidable, special precautions must be taken. (c.) That the drains should be watertight, so as to void pollution of the soil. (d.) That the drains should be readily accessible for being examined, tested, and cleaned. (■e.) That effective means should be taken to prevent the escape of any air from the drains into the buildings, or the accumulation of foul air in the drains. (23.) Drains should be laid out in straight lines and with Laying out true gradients from point to point, with manholes or inspection drams- shafts at every change of direction or gradient. These manholes and shafts should as a rule have movable iron covers at ground level (not buried beneath the ground). (24.) Drains should not be made larger than necessary, as the Size, larger the drain in proportion to the quantity of sewage passing through it, the less the power of the sewage to carry solid matters along, and vice versa. Where the rain-water is for the most part diverted from the sewage drains, and the falls are fairly good, a 9-inch drain will be sufficient for the outfall from the largest asylum, and a 6-inch drain sufficient for that from a small asylum. If much rain-water is admitted to the sewage drains, special calculations must be made to determine their size. In the case of the branch drains from closet blocks, the governing consideration is not the amount of sewage passing down them, but the foreign substances passed into them by the patients, and it is generally advisable to make such branch drains 6 -inch, though 5-inch if that size could be obtained would often answer. Both 5-inch and 7-inch pipes, though not generally made in stoneware, are very useful sizes. (25.) The falls of the drains should, wherever possible, be ^in¬ sufficient to render them self cleansing with the small amount of sewage that ordinarily passes down them. It has been found by experience that the following gradients will effect this : 4-inch pipes 1 in 30 ; 6-inch pipes 1 in 40 ; 9-inch pipes 1 in 60; and the falls should therefore approximate to these gradients as closely as circumstances will allow/though much flatter gradients will be satisfactory if systematic flushing is adopted. Where fall has to be economised drains near the buildings should have a greater fall than those at a distance. (26.) If the available fall is not sufficient to give the gradients Flushing* above mentioned, provision should be made for systematic daily E 74557. a 5