LIQUEFIED GAS CARRIERS--STATISTICAL ANALYSIS OF AMBIENT DESIGN TEMPERATURES FOR THE UNITED STATES

In the Inter-Governmental Maritime Consultative Organization (IMCO) Code, Chapter 4, there is provision for evaluating the cargo containment system insulation and the hull steel assuming that the cargo tank and secondary barrier, if installed, are at the temperature of the cargo and the ambient outside air and sea water design temperatures are: General Worldwide, Still Air: +5 deg C (+41 deg F); Sea Water: 0 deg C (+32 deg F). There are also provisions for an Administration to specify higher or lower ambient design temperatures, or unstricted service to the United States these temperatures are: Lower 48 States, Air (at 5 knots): -18 deg C) (0 deg F); Sea Water: 0 deg C (+32 deg F); Alaska, Air (at 5 knots): -29 deg C (-20 deg F); Sea Water: -2 deg C (+28 deg F). These lower ambient design temperatures are discussed in various Coast Guard regulations, documents and papers on the subjects. In specifying the lower ambient design temperatures for unrestricted service to the United States, it is recognized that there are existing liquefied gas ships designed to the general worldwide ambient design temperatures. During the many discussions on this subject, the Coast Guard has consistently stated that: (a) U.S. flag vessels carrying liquefied gas in bulk and foreign flag vessels carrying liquefied gas in bulk on the navigable waters of the United States must be designed for the ambient design temperatures which provide for unrestricted service. (b) A further study of the ambient air temperatures for numerous U.S. ports would be made to consider the possibility of restricted service to the United States. A further study of the ambient design temperature for air has been made for certain U.S. ports. The results show that it is possible to provide for restricted service to the United States for certain liquefied gas ships that have: a. Cargo containment system requiring a secondary barrier, and b. Cargo containment system insulation and contiguous hull structure designed to the general worldwide ambient temperatures. Liquefied gas ships having a cargo containment system of independent tanks type C, must meet the standards of a recognized classification society.

Media Info

  • Features: References;
  • Pagination: p. 115-130

Subject/Index Terms

Filing Info

  • Accession Number: 00173739
  • Record Type: Publication
  • Source Agency: Gastech 76 Proceedings
  • Files: TRIS
  • Created Date: May 3 1978 12:00AM