Hiroto Taguchi, Hideto Kurokawa, Kaori Numata
Papers # 2016 Berlin
This study pursued a quantitative evaluation of “the resistance to third party attacks”, whether pipes are destroyed or not, of two polyethylene pipes (PE80 and PE100) and two polyamide12 (PA) pipes. Two types of tests that simulate the impact from actual digging machine (attack simulation test) and four types of the typical impact test using test pieces were conducted to compare the results. The impact resistance from both of the two attack simulation tests of PA pipes was higher than that of PE pipes. The order of the puncture impact strength was similar to the order of the impact resistance from the attack simulation tests. From these results, it is considered that the fracture mode of third party attacks especially by a digging machine is similar to the fracture mode of the puncture test.
Polyethylene pipes have been widely used for gas distribution and transportation network up to 1.0 MPa as an alternative for steel pipes to reduce installation and maintenance costs. In many cases of Japan, polyethylene pipes (PE80) are used at very low pressures around 2.3 kPa because of the concern for damage from third party attacks by, for example, digging machines during excavation work. Damage from third party attacks is an important key issue for using plastic pipes at higher pressures. However, the quantitative evaluation method of the resistance to third party attacks has not been established. Especially, few studies for whether pipes are destroyed by third party attacks and gas leaks have been reported. In this study, for the purpose of quantitative evaluation of the resistance to third party attacks, two types of tests that simulate the impact from actual digging machine were conducted to two polyethylene pipes (PE80 and PE100) and two polyamide12 (PA) pipes made by different manufacturers and three types of impact tests, which are the puncture test, the Charpy impact test and the tensile-impact test, using test pieces were conducted to compare the results. Here it is found that the resistance of PA pipes to the attack by digging machines is higher than that of PE pipes and the fracture mode of the attack by digging machines is considered to be similar to the fracture mode of the puncture test.
