【国外标准】 Standard Practice for Guided Side Bend Evaluation of Polyethylene Pipe Butt Fusion Joint

5.1 This standard practice is a procedure to evaluate the ductility of side bend test specimens that are a transverse section of the pipe wall and butt fusion. Side bend test specimens are prepared from bend test coupons from sample polyethylene pipe butt fusion joints that are made using polyethylene pipe having a wall thickness of approximately 1 in. (25 mm) and greater. A three-point bend is applied to the side bend test specimen by pressing the side bend test specimen into a gap between two rotatable supports with a loading nose. The bending load is applied such that the bending strain is transverse to the plane of the fusion joint.5.2 Equipment for cutting bend test coupons, preparing side bend test specimens and conducting this practice is available for laboratory and for field use.5.3 Benchmark criteria for evaluating field testing results are developed by testing a statistically valid number of sample butt fusions in a controlled environment, preferably using equipment for field use. Guided side bend test results from field tests are then evaluated by comparison to benchmark test results from the controlled environment.1.1 This practice provides information on apparatus, specimen preparation and procedure for conducting a guided three point side bend evaluation of a transverse specimen cut from a coupon removed from a butt fusion joint in polyethylene pipe having a wall thickness of approximately 1 in. (25 mm) and thicker. See Fig. 1. This practice provides a means to assess ductility of a butt fusion joint by applying a lateral (side) bending strain across a specimen taken from the full butt fusion cross-section, from outside diameter to inside diameter.NOTE 1: For wall thicknesses less than 1 in. the user is referred to Practice F2620, Appendix X4.1 for bend back testing.FIG. 1 Guided Side Bend Conceptual Schematic1.2 No test values are provided by this practice. The result is a non-numerical report. Criteria for test result evaluation are provided in standards or codes that specify the use of this practice by comparison to benchmark laboratory results as described in 5.3 or by comparison to example results presented in Appendix X1 to this practice.1.3 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.NOTE 2: Laboratory methods that are commonly used for testing polyethylene butt fusion joints include Test Method D638, Test Method D790 and Test Method F2634.NOTE 3: This practice has been developed for use on butt fusion joints in polyethylene pipe with a wall thickness of 1.00 in. or greater. The practice may be used on butt fusion joints in polyethylene pipe with thinner wall thicknesses. However, the applicability of the practice should be determined by the user of the practice.1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.