Special Investigation Report: Brittle-Like Cracking in Plastic Pipe for Gas Service

Despite the general acceptance of plastic piping as a safe and economical alternative to piping made of steel or other materials, the National Transportation Safety Board notes that a number of pipeline accidents it has investigated have involved plastic piping that cracked in a brittle-like manner. This special investigation report concludes that the procedure used in the United States to rate the strength of plastic pipe may have overrated the strength and resistance to brittle-like cracking of much of the plastic pipe manufactured and used for gas service from the 1960s through the early 1980s. As a result, much of this piping may be susceptible to premature brittle-like failures when subjected to stress intensification, and these failures represent a potential public safety hazard. The safety issues discussed in this report are the vulnerability of plastic piping to premature failures due to brittle-like cracking; the adequacy of available guidance relating to the installation and protection of plastic piping connections to steel mains; and performance monitoring of plastic pipeline systems as a way of detecting unacceptable performance in piping systems. As a result of this special investigation, the National Transportation Safety Board issued recommendations to the Research and Special Programs Administration, the Gas Research Institute, the Plastics Pipe Institute, the Gas Piping Technology Committee, the American Society for Testing and Materials, the American Gas Association, MidAmerican Energy Corporation, Continental Industries, Inc., Dresser Industries, Inc., Inner-Tite Corporation, and Mueller Company.

• Record URL:
  http://www.ntsb.gov/safety/safety-studies/Documents/SIR9801.pdf
• 
• Corporate Authors:

  National Transportation Safety Board

  490 L'Enfant Plaza, SW
  Washington, DC  United States  20594
• Publication Date: 1998

Language

• English

Media Info

• Media Type: Web
• Features: Appendices; Figures; Tables;
• Pagination: 55p

Subject/Index Terms

• TRT Terms: Brittleness; Cracking; Gas pipelines; Installation; Monitoring; Performance; Pipeline safety; Plastic pipe; Recommendations; Steel pipe; Structural connection
• Subject Areas: Maintenance and Preservation; Pipelines; Research; Safety and Human Factors;

Filing Info

• Accession Number: 01010914
• Record Type: Publication
• Report/Paper Numbers: NTSB/SIR-98/01
• Files: TRIS
• Created Date: Nov 30 2005 2:56PM