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?.
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It is not anticipated that such a test would ever be conducted as a failure could result in significant personal danger and environmental damage could result. 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.
If the instrument verification shows it does not comply, it may not be used. The effect of dissolution of air remaining in the test section is described in, and may be estimated in accordance with Paragraph A4. The name of the pipeline, the test section number, its length, chainages where applicable, pipe diameter, thickness and material specification and grade. Records of verification tests shall be maintained.
The test liquid may contain corrosion inhibitors or other appropriate additives. These characterisations tend to show distinct differences in calculated values when changing between ranges. Standardized spreadsheet routines could be supplied to testers undertaking such work, requiring insertion of density and pipe details to derive the variables. Where the test liquid will be subject to temperatures near freezing, precautions shall be taken to protect the equipment and the test section.
A significant improvement in accuracy results from their use.
The duration of strength tests is defined to verify the strength of the test section by sa time for any near critical defects to grow to failure. A test section may show diurnal pressure cycles more or less in phase with the diurnal temperature cycle.
Figures G1, G2, G3, G4 and G5 relate the theoretical volume of water loss which can be determined from the lost pressure multiplied by the slope to the equivalent circular smooth hole diameter to achieve the same leak rate in 288.55 of different thickness and subject to different test pressures.
Consider the restrained test section, the details of which xs given in Paragraph C. The values in Columns 6 aa 7 are plotted against each other and a line which is the best visual fit is drawn through the origin Figure F2. If in the example of test section No. The basic procedure is essentially the same for both—the pipeline is closed off section by section, pumped full of testing fluid to a certain pressure called the end-point, and the fluid is held at that pressure for a specified time.
As these procedures commonly take place over a short time interval, particularly in the case of depressurization, and backfill materials and the surrounding soil are generally of poor conductors of heat, temperature changes in the test section are to be expected. Such pipe wall temperature-measuring devices for leak test evaluation are used to determine temperature changes on pipe walls where in ground temperatures may show diurnal changes of approximately 0.
Tests that are assessed as not likely to result in yielding of pipe may be 28885.5 to a predetermined pressure end point. Procedures for pressurizing the test section. The presence of an identified leak does not invalidate a strength test.
AS Pipelines-Gas and liquid petroleum – Field pressure testing_图文_百度文库
The leak sensitivity will be improved by a hold period of 2 or 3 days, and the Standard recognizes this as an acceptable basis for testing sections with xs volume larger than 25 ML. This appears to be a test section of approximately 25 mL capacity. The 8285.5 is independent of section length and constraint conditions, however its effects will be experienced the most in large volume test sections, that is long or large diameter pipelines with corresponding low allowable unaccountable pressure changes as in the example of test section No.
Records of the initial and all subsequent pressure tests shall be retained for the life of the pipeline. It will be noted that cold expansion has introduced a linear portion and a relatively high half-slope end-point. The water in the test section at the commencement of the leak test will have experienced a resultant temperature change of 0.
Where the permanent record of test data is in electronic format, it is recommended that it be stored on a non-volatile medium, e. The pipeline industry has, however, traditionally carried out leak tests at a higher pressure for a number of reasons, including the following: In some Australian pipelines, field test pressures in fact influence target operating pressure, just as field test pressures determine allowable actual operating pressures of corroded or upgraded lines under the United States Department of Transportation regulations.
Before commissioning or recommissioning of a pipeline, field pressure tests are specified in AS The pressures given in Item b above are intended to ensure that the leak test is carried out above, but close to, MAOP so that assessment of uncertainty relates closely to the pipeline service.
G4 4 Equation G4 1 and Equations G4 2G4 3 and G4 4 can be rewritten in multiples and submultiples of S1 units which are commonly used in the pipeline industry.
SCOPE OF ACCREDITATION
Procedures for cleaning and filling the test section. Unlike the hold pressure for the pressurecontrolled test, the hold pressure for the yield test is not known in advance of the test but is determined during the test from the actual behaviour of the test section in situ. Where there is a seasonal change in temperature, very sensitive pressure and temperature readings are essential to account for this effect.
Leaks are easier to repair at the hydrostatic testing stage than during operation. The full record of the hydrostatic testing of the pipeline shall be retained by the operating authority for the life of the pipeline. The effect of this aspect of the Standard will again be to encourage the setting of the mill test pressures at a level more appropriate to the field test pressure rather than the traditional test pressures used for pipe to API 5L.
Bourdon tube pressure gauges are particularly susceptible to damage from shock loading in transport and in use, and from impurities in the liquid such as sealing tape. This is achieved by monitoring the pressure over an extended period, usually 24 h.
Where a gas leak is found by a leak detection survey required by Figure 5.
Subject to their length, road, rail and river crossings are generally pre-tested to their appropriate maximum test pressure before being included in a test section that may have different wall thickness or steel properties. It is important that readers assure themselves they are using a current Standard, which should include any amendments which may have been published since the Standard was purchased. Notwithstanding all such 285.5, diurnal temperature variations may produce significant pressure a.
An example draft calculation for jet A1 liquid for p?
Where sections of pipe are tested prior to field testing i. Provision is made for the graph to be plotted at about the size of a small drawing board and it is specified that readable units be provided on each axis up to SMYS.
The relationship is more complex where a large number of pipes of different properties receive different pressures according to their position in a test section that has a range of elevations.
The non-proportional total volumetric strain is calculated as the ratio of the nonproportional offset volume to the section volume. For semi-conductor probes as commonly used, a sensitivity of 0. If the pressure is below kPa, air in the test section may mask the ability to detect leaks.
Where adequate information is not available, it is recommended that 0.