Design procedure prevents PE pipe rupture
- Southwest Research Inst., San Antonio, TX (United States)
A rupture prevention design procedure for plastic gas distribution pipe is nearing completion at Southwest Research Institute (SWRI). Given the pipe size, polyethylene (PE) resin, and minimum operating temperature, the maximum safe operating pressure can be determined for which rapid crack propagation (RCP) cannot occur. A computer program, called PFRAC, has been developed for this purpose and uses Charpy energy as the measurement of fracture toughness of PE. Present efforts, however, involve replacing Charpy energy with a dynamic toughness measurement obtained from the Small Scale Steady State (S4) test that is required in ISO 4437. The program is being financed by the Gas Research Institute, Chicago. RCP events in PE pipe have been rare primarily because operating pressures are low and pipe diameters are small in most gas distribution systems. However, controlled RCP experiments in the US and other countries clearly demonstrate that as the gas industry moves toward higher line pressures and larger diameters, the likelihood of an RCP event increases. Recognizing this, ISO includes a requirement for RCP in its ISO 4437 standard for pipe greater than 10 inches in diameter or operating pressures greater than 58 psig. The S4 test may be used on all pipe diameters. A full scale test or the S4 test can be used on pipe greater than 10 inches diameter.
- OSTI ID:
- 175971
- Journal Information:
- Pipeline and Gas Journal, Vol. 222, Issue 12; Other Information: PBD: Dec 1995
- Country of Publication:
- United States
- Language:
- English
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