Pressure testing methods for pipelines and installations for the supply of gas ISSN Price group 5. Telephone: 02 28 Telefax: 02 28 90 E-Mail: info dvgw. Preface to the 1st edition The DVGW Set of Rules on gas contains a number of Technical Rules regarding the construction of gas lines and installations in the field of gas supply in which reference is made to specific pressure testing methods. This Code of Practice presents a systematic compilation of pressure testing processes for pipelines and installations in the field of gas supply. In the DVGW Technical Rules on the construction and operation of gas supply pipelines and installations, provisions have been set out for the different pressure testing methods and their application by referring to this Code of Practice.
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ISSN Price group 5. Box 14 03 62 D Bonn. Telephone: 02 28 E-Mail: info dvgw. Internet: www. Preface to the 1st edition. The DVGW Set of Rules on gas contains a number of Technical Rules regarding the construction of gas lines and installations in the field of gas supply in which reference is made to specific pressure testing methods.
This Code of Practice presents a systematic compilation of pressure testing processes for pipelines and installations in the field of gas supply. In the DVGW Technical Rules on the construction and operation of gas supply pipelines and installations, provisions have been set out for the different pressure testing methods and their application by referring to this Code of Practice. Eschborn, October Preface to the 2nd edition.
In addition to the new pressure measurement method with precision pressure gauge which helps to simplify and improve measurement processes with air, other amendments and supplementary information has been provided in order to adapt this revised edition of the Code of Practice to the state-of-the-art in the field of pressure testing methods.
Eschborn, July Purpose of pressure test. Classification of pressure test methods. Test media. Hydrostatic tests. Pneumatic tests. Pressure tests with operating gas. Methods - Overview. Pressure test - process sequence. Measuring equipment. Description of pressure test methods. Visual test - Method A. Visual test with water single pressurization — Method A 1. Visual test with water dual pressurization — Method A 2. Visual test with air — Method A 3.
Visual test with operating gas — Method A 4. Pressure measuring methods — B. Hydrostatic pressure testing single pressurization — Method B 1. Hydrostatic pressure testing pressure applied twice — Method B 2. Pressure testing with air — Method B 3. Simplified pressure measuring — Method B 3.
Pressure measuring with precision measuring equipment e. Differential pressure measuring with air — Method C. Differential pressure measurement with test bottle — Method C 3.
Differential pressure measurement with pressurizer — Method C 3. Pressure measurement volumetric test dual pressurization — Method D 2. Regulations and Technical Rules. Diagrams 1 and 2. This Technical Rule applies to the pressure testing of pipelines or installations for public gas supply, such as pipelines for the transmission or distribution of gas, compressor stations, pressure regulating and metering stations.
However, it does not apply to the pressure testing of pipelines. This Technical Rule may be applied to pressure tests performed on other pipelines and installations which do not serve public gas supply, provided that the specific characteristics of the gases and any other applicable provisions are taken into account.
When applying the pressure test methods described in Section 3 , the rules set out in the relevant DVGW Codes of Practice must be observed cf. Section 4. The pressure test method to be applied depends on the materials used, the types of joints between individual pipeline or installation components and on the intended scope of application.
All pressure parameters or pressure values stated in this Technical Rule are overpressures above ambient atmospheric pressures. The pressure tests described herein may either be applied on their own or they may be combined. Pressure test methods are classified depending on whether. Testing media. Irrespective of Section 2. The different test methods always must be carried out with specific test media because of reasons related to the measuring equipment to be used.
A distinction is made regarding hydrostatic testing between single or dual pressurization whereby special attention should be paid to the following:.
Special measures must be taken for lower temperatures. Sufficient time must be allowed for the temperature of the water filled into the pipeline and its surroundings to even out. Already when applying the test pressure the ratio between the amount of water that has been filled in and the subsequent increase in pressure may point to insufficient venting or the presence of major leaks. For the checking of air freeness confer to pressure testing methods B 1 or B 2.
The following must be observed when carrying out pneumatic tests:. If a test pressure is applied which is sufficiently higher than 6 bar and if the entire pipeline or system or parts of it have not been tested priorly with the same or a higher test pressure, special safety precautions must be taken such as destructive tests on all girth welds, tighter construction or. This test is carried out with operating gas with the testing pressure corresponding to the working pressure of the feeding line or system.
If, when carrying out pressure testing with operating gas, higher pressure nitrogen is added, for example, the test pressure in the pipeline or system may rise to a level which is above that of the working pressure of the feeding line or system. Furthermore, Section 2. If the pressure tests are classified by the method of testing. A visual method. B pressure measurement. C differential pressure measurement. The time plan of a pressure test can be broken down into different segments.
As an example, Fig. Process sequence. All measuring equipment used for testing must be in perfect working order. For the setting and measuring of test pressures, master pressure gauges of at least class 0. Other necessary measuring devices and their respective requirements are dealt with in the Sections on test methods B 1 , B 2 , B 3 , and C 3.
Operating gas. Test method. Visual method. Pressure measuring method. Differential pressure measuring method. Table 1 : Pressure testing methods - overview. The purpose of visual testing of a pipeline or system is to visually assess its tightness, and, if the testing pressure significantly exceeds maximum allowable operating pressure, also its strength when exposed to the testing pressure. For all visual test methods, the pipeline or system to be tested must be exposed; in particular pipe joints, fittings, valves, pressure vessels, etc.
The test pressure, however, must at least be 1. After filling and venting cf. Section 2. During this time, the pipeline or component assemblies of the system must be inspected for tightness in particular at the joints and where parts have been installed flanges, sockets, valves etc.
After having reduced the pressure to the lowest possible level holding time 30 minutes , which at the high point must still be at least 2 bar, and after having increased the test pressure a second time, the pressure is held again for at least 90 minutes. The test pressure must be based on the Technical Rules of the DVGW which are applicable to the pipeline or system to be tested. Where these rules stipulate minimum values, the exact test pressure must be defined before beginning with the test.
The pipeline joints to be tested must be free from grease or coatings. It is recommended to repeat the test with foaming agent after having lowered the test pressure to approximately 2 bar. The test pressure corresponds to the operating pressure and must not exceed 1. During the increasing of pressure and after an appropriate holding time, all pipeline joints, valves, flanges and similar items must be tested for tightness with a foaming agent.
Any joints to be tested must be free from grease and coatings. When applying pressure measuring methods, the strength and tightness of a pipeline is evaluated on the basis of the pressure survey obtained during pressure testing by precision measurements. That is why these methods are in particular suitable for buried pipelines which do not provide the accessibility needed for visual tests. The pressure test proper only begins when the temperatures of the test medium and adjoining soil or atmosphere have balanced out.
The test pressure must be at least 1. The exact test pressure must be determined before beginning with the test. If the tests are carried out in seasons during which frost might occur, any exposed sections of the pipeline must be protected against freezing. In order to confine temperature fluctuations to a minimum, the pipe trench must be filled out as best as possible.
ISSN Price group 5. Box 14 03 62 D Bonn. Telephone: 02 28 E-Mail: info dvgw. Internet: www. Preface to the 1st edition.
81302285 Pressure Testing Methods Dvgw g 469
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DVGW G 469:2010-06
Embed Size px x x x x Preface to the first issueThe DVGW code of practice on gas contains a number of technical regulations for the installation of gas supply piping and facilities, referring to certain pressure testing methods. In this particular code of practice, the pressure testing methods applied for gas supply piping and facilities are systematically compiled and described. The DVGW's technical regulations for the installation and operation of gas supply piping and facilities specify provisions for the pressure testing methods to be applied with reference to this code of practice. Preface to the second issueNow that the newly developed and practice-tested pressure measurement method using air by means of precision pressure gauges, e. In addition to the new pressure measurement method by means of precision pressure gauges, resulting in simplification and improvement of the measurement method using air, further amendments and additions for adjustment in line with the state of the art for pressure testing methods have been included in the new issue of this code of practice.
Compact air compressor of the KLK1030 for pressure and leak testing