1、PFI Standard ES-20 |Denotes Revision (Revised December 2013) WALL THICKNESS MEASUREMENT BY ULTRASONIC EXAMINATION Prepared by Pipe Fabrication Institute Engineering Committee All PFI Standards are advisory only. There is no agreement to adhere to any PFI Standard and their use by anyone is entirely
2、voluntary. Copyright by PIPE FABRICATION INSTITUTE Dedicated to Technical Advancements and Standardization in the Pipe Fabrication Industry Since 1913 USA 511 Avenue of Americas, # 601 New York, NY 10011 CANADA 655, 32ndAvenue, # 201 Lachine, QC H8T 3G6 WEB SITE www.pfi-institute.org PFI Standard ES
3、-20 |Denotes Revision (Revised December 2013) WALL THICKNESS MEASUREMENT BY ULTRASONIC EXAMINATION METRIC CONVERSIONS The conversion of quantities between systems of units involves a determination of the number of significant digits to be retained. All conversions depend upon the intended precision
4、of the original quantity and are rounded to the appropriate accuracy. Pipe sizes together with applicable wall thickness are not shown with metric equivalents. The SI (metric) values where included with the customary U.S. values in this Standard are the rounded equivalents of the U.S. values and are
5、 for reference only. Metric units were derived utilizing the following conversion factor: Conversion Factor inches to millimeter 25.4 1. Scope 1.1 This Standard establishes the requirements for measuring the wall thickness of plate, pipe, fittings and pipe bends by ultrasonic means. 1.2 The resonanc
6、e or pulse echo method may be employed to verify the wall thickness measurements. The data presented in this Standard pertains to the pulse echo method. 2. General 2.1 Wall Thickness measurements may be taken at the discretion of the fabricator for information or when required by the Customers Speci
7、fication or Purchase Order. 2.2 The person taking the measurement readings shall read the operating instructions of the equipment and receive sufficient training to operate the equipment and obtain a correct reading. The training shall include the information necessary for the person taking the thic
8、kness measurements to determine if an erroneous reading is being obtained (i.e., double reading from thin wall material, poor contact, C bore, lamination, etc.). 2.3 Measurements shall be taken in the Fabricators shop prior to shipment. 3. Surface 3.1 The finished contact surfaces (i.e., weld or bas
9、e material) shall be free from weld spatter, dirt, loose scale, foreign material, and any roughness that would interfere with the contact of the transducer or impair the transmission of the ultrasonic vibrations. Unless otherwise specified in the Customers Specification or Purchase Order, only the a
10、rea in contact with the transducer need to be cleaned to this extent. 4. Equipment 4.1 Pulse-Echo Method 4.1.1 An electronic system capable of producing, receiving and displaying high frequency electrical impulses at various frequencies and energy levels. Some systems use a cathode ray tube (CRT) pr
11、esentation, a digital display, or dial indicator readout. 4.2 Transducers 4.2.1 Transducers shall be capable of transmitting and receiving ultrasonic sound waves in the part to be measured. On pipe or fittings of small diameters, curved transducers or shoes may be used. PFI Standard ES-20 |Denotes R
12、evision (Revised December 2013) 5. Couplant 5.1 A liquid couplant such as water, oil, glycerin etc. capable of conducting ultrasonic sound waves from the transducer to the part shall be used. Couplant shall not be detrimental to the material being measured 5.2 Couplants may be removed from the part
13、at the discretion of the fabricator. 6. Calibration 6.1 The instrument shall be calibrated in accordance with the Manufacturers recommended practice on a test specimen of similar surface condition, similar metallurgical structure and the same or equivalent P-Number. P-Numbers 1, 3, 4 and 5A material
14、s are considered equivalent. The thickness of the test specimen should be accurately measured with a micrometer and recorded. The part to be measured may be considered as the test specimen. 7. Measuring Procedure 7.1 Pulse-Echo Method 7.1.1 Clean surface in accordance with Paragraph 3. 7.1.2 Calibra
15、te instrument in accordance with Paragraph 6. 7.1.3 Apply couplant to surface to be measured in accordance with Paragraph 5. 7.1.4 Place transducer firmly on part and read the thickness of the part on the CRT screen, direct digital or dial indicator readout. 7.1.5 The rotation of the probe shall be
16、perpendicular to the axis of the pipe. 7.2 For pipe bends, thickness measurement shall be taken at points approximately 15 degrees part with 3 readings minimum along the length, on the extrados and intrados of bend, beginning at either tangent location. For pipe and fittings, the fabricator may sele
17、ct the location for the measurement to be taken. All readings shall show compliance with the specified minimum wall thickness. 8. Records 8.1 A record of the examination shall be made on the fabricators Standard Report Form as approved by the client. Changes to the Report Form shall be a matter of p
18、rior agreement between the Fabricator and his client. The following are examples of data that may be recorded on the Report Form: a. Date of Measurement b. Location c. Customer d. Acceptance Criteria e. Material Specification f. Product Form g. Surface Preparation h. Method or Procedure i. Type and
19、Model of Equipment j. Distance Between Points k. Results of Thickness Readings l. Name of operator that performed test CURRENT INDEX OF 2014-2015 PFI STANDARDS A complete list of PFI members and available membership CHARTER MEMBERS CONTRACTOR MEMBERS ASSOCIATE MEMBERS AFFILIATE MEMBERS HONORARY MEMB
20、ERS Associate and Affiliate member contributors Walter Sperko Sperko Engineering Services, Inc. Greensboro, NC Thomas Warrelmann Victaulic Company of America Easton, PA Sheryl Michalak Welding Outlets, Inc. Houston, TX PFI Standards and Technical Bulletins are published to serve proven needs of the
21、pipe fabricating industry at the design level and in actual shop operations. Hence, such needs are continually considered and reviewed by the Engineering Committee of the Pipe Fabrication Institute to provide recommended procedures, which have been demonstrated by collective experiences to fulfill requirements in a manner for Code compliance. However, as the PFI Standards are for minimum requirements the designer or fabricator always has the option of specifying supplementary conditions in the form of requirements beyond the scope of the PFI publications.
