| Popis: |
In the article the authors offer their suggestions for improving the reliability of the standardization requirements for water supply facilities in Vietnam, as an analog of building regulations of Russia 31.13330.2012. In Russia and other advanced countries the reliability of the designed water supply systems is usual to assess quantitatively. Guidelines on the reliability assessment of water supply systems and facilities have been offered by many researchers, but these proposals are not officially approved. Some methods for assessing the reliability of water supply facilities are informally used in practice when describing their quality. These evaluation methods are simple and useful. However, the given estimations defy common sense and regulatory requirements used by all the organizations, ministries and departments, for example, of Russia, in the process of allowances for restoration and repair of water supply facilities. Inadequacy of the water supply facilities assessment is shown on the example of assessing the reliability of pipeline system. If we take MTBF of specific length of the pipeline as reliability index for a pipeline system, for example, 5 km, a pipeline of the similar gauge, material and working conditions with the length of 5 m, according to the estimation on the basis of non-official approach, must have a value of MTBF 1000 times greater than with the length of 5 km. This conclusion runs counter to common sense, for the reason that all the pipes in the area of 5 km are identical, have the same load and rate of wear (corrosion, fouling, deformation, etc.). It was theoretically and practically proved that products of the same type in the same operating conditions (excluding determined impact of a person), work as an entity, which MTBF is equal to the average lifetime. It is proposed to take the average service life as a reliability indicator of a pipeline. Durability, but not failsafety of the pipe guarantees pipeline functioning. It is proved that not a specific pipeline length should be taken for an element of a pipeline system, but the repair area, which is in two sides limited by isolation valve and is completely disconnected for the time of recovery or any other need. |
