Technical Reports

Tank Car Thermal Analysis, Volume II: Technical Documentation Report for Analysis Program

  • 01
  • Nov
  • 1998
AUTHOR: Milton R. Johnson
SUBJECT: Hazardous Materials
KEYWORDS: railroad tank car; tank car failure; hazardous material release; fire effects
ABSTRACT: The computer program AFFTAC is described. The program can be used to analyze the behavior of railroad tank cars when subjected to fire. It is designed to perform the analyses which are required to determine if a tank car meets the requirements of the Code of Federal Regulations, Title 49, Part 179, Section 179.18. The conditions associated with two types of fires are built into the program, the pool fire environment, where the car is fully engulfed in flame, and the torch fire environment, where only a small area of the tank is subjected to a high intensity flame. Other fire conditions can also be analyzed. A wide variety of tank car types can also be considered including cars equipped with a safety relief valve or a safety vent closed with a frangible disc. The program is described in two volumes. This volume describes the assumptions and procedures used in the analysis. Four main conditions must be considered, an upright car orientation where vapor is vented, an overturned car condition where liquid is vented, a shell full condition where the tank contains only product in the liquid phase, and the condition where the tank contains only product in the vapor phase. The source codes of the main program and the subroutines are presented in a series of appendices.