RISK ASSESSMENT OF INDOOR REFUELING AND SERVICING OF CNG-FUELED MASS TRANSIT BUSES. PHASE 2. FINAL REPORT. VOLUME 2. FAULT TREE MODELS, DECEMBER 1988-NOVEMBER 1990

A probabilistic risk assessment (PRA) was conducted to estimate the risk of accidental ignition (and consequent fire/explosion) from indoor refueling and servicing of compressed natural gas-fueled mass transit buses. Five scenarios were considered. Risks associated with each scenario for the refueling equipment, bus system, refueling/servicing facility, and refueling process were evaluated using event and fault tree analyses. The study considered the initiating events to be gas leakage and the presence of ignition sources, resulting in the top event (ignition). Using component reliability data, the probability of incident was estimated. A publicly available database of safety-related information on natural gas vehicles was developed to support the PRA. The results using U.S. data suggest a probability of incident per refueling between 3.27E-9 and 6.87E-9. The variation depends on certain characteristics of the refueling/servicing station (e.g., outdoor refueling and indoor servicing, combined diesel and CNG refueling, isolated CNG refueling, etc.), the refueling mode, and other factors.

• Supplemental Notes:
  • See also Volume 1, PB91-161364. Also available in set of 2 reports PC E99/MF E99, PB91-161356.
• Corporate Authors:

  Science Applications International Corporation

  1710 Goodridge Drive
  McLean, VA  United States  22102
• Authors:
  • Friedman, D M
  • Farkondehpay, D
• Publication Date: 1990-8

Media Info

• Pagination: 183 p.
• Serial:
  • Volume: 2

Subject/Index Terms

• TRT Terms: Bus transit; Bus transportation; Compressed natural gas; Diesel fuels; Ignition; Leakage; Probability; Refueling; Risk assessment; Safety; Service stations
• Uncontrolled Terms: Probabilistic analysis
• Old TRIS Terms: Bus services; Fueling
• Subject Areas: Data and Information Technology; Highways; Motor Carriers; Public Transportation; Safety and Human Factors; Vehicles and Equipment; I96: Vehicle Operating Costs;

Filing Info

• Accession Number: 00615945
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: GRI-90/0191.2
• Files: TRIS
• Created Date: Sep 30 1991 12:00AM