1、March 2016 English price group 19No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 23.040.01!%Le 16 Circumferential w
2、elds on pipes and pipe fittings 20 % Branches, fillet welds; including socket welds. 20 % Table 8 Inspection standards Examination Standard(s) Visual inspection EN ISO 17637 Ultrasonic examination EN ISO 16810 and EN ISO 17640 Radiographic examination EN ISO 17636-1 Magnetic particle testing EN ISO
3、17638 Penetrant testing EN ISO 3452-1 8.4 Testing personnel Non-destructive examination shall be carried out by persons who are competent and appropriately qualified for the duties they are to perform. Non-destructive examination personnel shall be qualified to at least level 2 of EN ISO 9712:2012.
4、DIN EN 16125:2016-03 EN 16125:2015 (E) 25 All companies providing such personnel should be certificated according to an appropriate standard e.g. EN ISO/IEC 17020 1. 8.5 Acceptance criteria Acceptance criteria shall be in accordance with EN ISO 5817. 8.6 Repairing welds Before proceeding with the re
5、pair of a weld, consideration shall be given to whether the repair can reasonably be expected to improve the quality of the weld. If not, the weld shall be rejected. Rejected parts of welds shall be cut out and the pipe shall be re-welded before being re-examined. Parts of welds containing unaccepta
6、ble defects shall be removed by grinding or cutting down to sound metal before proceeding with repair. Slag and oxide deposits shall be removed. Repairs shall be carried out in accordance with an approved procedure. No further repairs are permitted on repaired parts of a weld. All weld repairs shall
7、 be examined and be subjected to 100 % non-destructive examination as per 8.3. 8.7 Brazed copper joints Non-destructive examination of brazed joints shall be in accordance with EN 12799. 9 Inspection and documentation 9.1 General Before testing and commissioning, the installation and associated docu
8、mentation shall be inspected to ensure that it meets the design specification and will be safe to operate within the design parameters. The technical file and operating manual shall be available to those involved in the inspection. The following points shall be considered during the inspection: the
9、complete installation shall be checked to confirm it is correctly assembled using the specified materials/components and that there is no mechanical damage; control and safety devices (e.g. regulators, hydrostatic relief valves) shall be checked to confirm location, orientation and correct set press
10、ures. Any equipment that meets the operating pressure requirements but is not suitable for the proof test pressure shall be replaced with a spool piece or shall be blanked off; non-return valves are installed in the correct orientation; welded joints have been tested and/or inspected as required by
11、the relevant design and welding standards, see Clause 8; fittings, flanges, gaskets and bolts shall be examined to ensure that they are of the correct specification and that they are correctly assembled and aligned; threaded connections shall be examined to ensure that they are correctly assembled,
12、sealant is appropriately used and that there are no excessive exposed threads (i.e. the threads are correctly engaged and not mismatched); compression joints shall be examined to ensure that there is no undue distortion of the tube and that the nuts have not been over tightened; DIN EN 16125:2016-03
13、 EN 16125:2015 (E) 26 capillary joints shall be visually examined to confirm that the spelter or solder has run correctly between the tube and fitting; joints on non-metallic pipework shall be examined to ensure that they are correctly made and that there is appropriate above-ground pipe protection;
14、 there shall be no undue strain on any joint, pipe or support; pipe supports shall be checked to confirm the support distances are not exceeded; verification of corrosion protecting measures; specific requirements for the inspection of composite pipe required by the manufacturer, see E.3.2; and the
15、pipework is safe for subsequent purging and commissioning. The results of the inspection shall be recorded in writing. 9.2 Inspection and testing of corrosion protection 9.2.1 Coatings on underground pipework Carbon steel pipe joints, bends and fittings that require the application of a coating on s
16、ite, and any visible coating damage that has been repaired, shall be checked for defects e.g. with a spark tester (holiday detection). If any air is found trapped under the coating, the defective coating shall be removed, and re-applied. 9.2.2 Above-ground pipework protection Any protection shall be
17、 checked for defects and any damage shall be repaired. 9.2.3 Recording of test results The result of the inspection of each component shall be recorded in the technical file and shall be clearly traceable in the examination and radiographic reports. 10 Testing 10.1 General The completed tests for ea
18、ch section and a leak test on the full installation shall be recorded. 10.2 Test media The test water shall be tested to establish its initial quality and to ensure that the water is of the required quality for both flushing and hydraulic test use. Depending on the water source, filtering of the wat
19、er to remove contaminants, such as debris, shall be undertaken. The environmental impact of any chemical treatment or addition of anti-freeze shall be assessed and confirmed to be acceptable. The impact of chemical treatment on the bulk modulus of test water (e.g. volume change affecting pressure),
20、particularly use of anti-freeze, should also be established. If test water is transferred from one test section to another, the quality of the water shall be checked and additional chemicals shall be added, as required, to bring it back up to specification. Pneumatic testing shall be performed with
21、dry and oil free air or inert gas. DIN EN 16125:2016-03 EN 16125:2015 (E) 27 10.3 Strength testing 10.3.1 General A hydraulic test shall be applied as a strength test. Where a hydraulic test is not always practical, a pneumatic test should be used, provided that appropriate safety precautions have b
22、een taken. NOTE A strength test is not always necessary where pipework contains components that have already been tested and certified by the manufacturer as being strength tested to at least 1,43 times the maximum allowable pressure. 10.3.2 Test Procedure The procedure shall consider the following:
23、 type of test; pressurising medium to be used; maximum safe working pressure of the installation being tested. This may vary in different parts of the system; extent of the installation to be tested; test pressure(s); rate of pressure rise and release; duration of test(s). For leak tests the period
24、of temperature stabilization shall be established; NOTE Temperature changes can be induced by air compressors (increasing temperature) or by compressed gas cylinders (reducing temperature by expansion). test equipment and point(s) to apply the pressure; how to retest any connections that may need to
25、 be undone to allow the pressure to be applied; means of positive isolation, and where necessary, protection of appliances or parts of the installation not being included in the tests; identification of items, which may isolate sections, e.g. non-return/back check valves, pressure regulators etc., a
26、nd invalidate the test; any additional securing of pipework for the duration of the test; precautions including the provision of warning signs and, if necessary, barriers to keep unauthorised persons from the test area; precautions shall be taken when carrying out pneumatic testing due to the potent
27、ial energy stored in the system, which could be released in the event of a catastrophic failure of the equipment. A safety exclusion zone of at least 5 m from any part of the system under test is therefore required. The test pressure and monitoring of the test pressure should be done from a point ou
28、tside of this exclusion zone. DIN EN 16125:2016-03 EN 16125:2015 (E) 28 10.3.3 Test pressure and duration The test pressure shall be at least 1,43 times the maximum allowable pressure. The test duration shall be such as to reliably expose any defects in the construction that might lead to a failure
29、of the pressurized pipework. The test pressure shall be initially raised to 1 bar to check for gross leakage and then the pressure shall be raised at a rate not exceeding 5 bar per minute. The release of the test medium shall be at the same rate. The minimum temperature stabilization and test period
30、 for hydraulic testing of pipework shall be 30 min. On completion of hydraulic testing, the water shall be immediately drained. NOTE LPG is not a potential contaminant of water. When LPG equipment is subjected to a hydraulic test or other pressure tests, the water shall be disposed of in an environm
31、entally friendly manner. 10.3.4 Acceptance criteria The test pressure shall be read at the beginning and at the end of the test. Loss of test pressure during the test shall not exceed 5 % of the test pressure. The joints shall be inspected for leaks at the beginning, during and at the end of the tes
32、t period. No additional pressure shall be introduced during the test period. There shall be no leak on any part of the pipework system during the test period. For pneumatic tests inspection shall not take place until the pressure in the pipe has been stable for at least 5 min. 10.3.5 Repairs and ret
33、est If leaks are identified, the system shall be de-pressurized before any repairs are undertaken. Pipework shall be retested after repairs are completed. 10.4 Leak testing 10.4.1 General All installations shall be leak tested before being commissioned. All pipework shall be leak tested initially wi
34、th air or inert gas, using either a pressure decay method or leak detector fluid to EN 14291. After a satisfactory air or inert gas leak test, the pipework shall be purged and LPG vapour introduced. The leak test shall then be repeated. 10.4.2 Gauge Selection The pressure gauge for leak testing shal
35、l comply with EN 837. The gauge pressure range, resolution and accuracy shall be suitable to detect pressure loss resulting from leakage in the leak testing period. 10.4.3 Test pressure and duration The test pressure of the pipework shall be above the nominal operating pressure and a minimum of 5 bar. DIN EN 16125:2016-03
