Australian New Zealand Standard AS / NZS Pipelines – Gas and Liquid Petroleum – Field Pressure Testing – Western Australia. AS – , Field Pressure Testing, Revision committed formed, Expected AS – , Safety Management Studies, With. AS/NZS Accessed by CITIC PACIFIC MINING PTY LTD on 03 Dec AS/NZS Australian/New Zealand Standard?.
|Country:||Turks & Caicos Islands|
|Published (Last):||26 November 2015|
|PDF File Size:||7.6 Mb|
|ePub File Size:||20.72 Mb|
|Price:||Free* [*Free Regsitration Required]|
L Calculated pressure loss due to observed leak Normal pipeline filling practices should reduce the air content to acceptable levels but, if the filling practice is not normal or something goes wrong, and the air content is unacceptable, it will be apparent during pressurizing for the strength test.
Testing for 2 or 3 days may allow separation of temperature effects and leakage. Take readings of the values of the pressure and added volume at pressure increments not greater than the following: Tests for which the maximum pressure has the potential to result in yielding of any pipe under test are required to be conducted in a manner that monitors the amount of straining during the test.
Records of verification tests shall be maintained.
Note the extended linear portion and elevation of the half-slope end-point compared with Figure D2 and Figure D3. Where the pipe temperature at one or more points on the test section is changing in the opposite direction to the average, extra care has to be used in assessing the results.
A minimum value of 1. Fully restrained conditions normally only occur in long buried pipelines restrained by soil friction, or in pipe between two or more anchors that are much stiffer than the pipe and only when the pipe is free of substantial changes in direction.
SCOPE OF ACCREDITATION
The highest degree of certainty approaching absolute certainty is 22885.5 when the factor is at least 1. A more accurate prediction is possible if the more complex Fanno line approach?
The von Mises hypothesis relates the effects of three principal stresses acting at right angles ws product yielding. For the measurement of temperature, the uncertainty of measurement is the sum of the sensitivity, repeatability and stability of the instrument coupled with the characteristics of the readout or recording device.
If the air determination is made on an ascending pressure cycle, the table is prepared accordingly.
The testing liquid is normally water, but provision is made for the use of certain hydrocarbon liquids that do not vaporize rapidly. The pressure in any part of the test section shall not exceed the maximum test pressure specified in the test program.
Strength tests may be carried out by raising qs pressure to az predetermined level and holding for a ad time. The Standard recognizes that a number of different types of test section require a leak test and provides that the method of leak detection be appropriate to the section under test.
Graphs of pressure and temperature against time need only a time scale of 1 h for the smallest graph unit. The volumetric flow rate at pipeline conditions is given by the following equation: The time taken for stabilization to occur depends on the temperature of the test liquid at the time of filling, specific heat capacity of the test liquid, pipe diameter, burial depth, undisturbed ground temperature and the thermal conductivity of the backfill and ground, which can be affected by ground water.
2885.5 altered values shall be justified and approved. Where the difference between the changes during the leak test period is less than the allowable unaccountable pressure change converted to temperature, this location is considered to be thermally stable. The combined effect of residual stresses and Bauschinger effect on a flattened test piece may lead to an underestimation or overestimation of the true hoop yield stress properties.
Accordingly, the emphasis of the Standard is on the sensitivity and accuracy of the equipment and techniques for testing. The instrument measures precisely both pressure and pressure change. The strength required of a pipeline is determined by the methods described in the pipeline application Standards and is stated 288.55 the form of the maximum allowable operating pressure MAOP multiplied by a factor.
AS Pipelines-Gas and liquid petroleum – Field pressure testing_图文_百度文库
The size of test section for which it is feasible to identify a pressure change amid pressure changes caused by ambient conditions represents the practical upper limit. Before commissioning or recommissioning of a pipeline, field pressure tests are specified in AS This Appendix describes two methods of residual air determination as follows: The volume of air that can dissolve is approximately 20 ppm at the relevant conditions. These values apply only to tests whose validity is determined in accordance with Clauses 5.
Where a half slope end-point has been chosen, stop pressurization when the water volume required to cause a pressure increase becomes twice the amount required to cause an identical pressure increase during the obviously linear portion of the pressure-added volume graph.
The Committee has always believed that it is important to set standards for measuring equipment and techniques, but in recent years the need to set objective criteria for the acceptability of large volume leak tests has been recognized.