Experimental measurement of a shipboard fire environment with simulated radioactive materials packages

Abstract

ABSTRACT:Results from a series of eight test fires ranging in size from 2.2 to 18.8 M W conducted aboard the Coast Guard fire test ship Mayo Lykes at Mobile, Alabama are presented and discussed. Tests aboard the break-bulk type cargo ship consisted of heptane spray fires simulating engine room and galley fires, wood crib fires simulating cargo hold fires, and pool fires staged for comparison to land-based regulatory fire results. Primary instrumentation for the tests consisted of two pipe calorimeters that simulated a typical package shape for radioactive materials packages. The calorimeters were both located adjacent to the fires and on the opposite side of the cargo hold bulkhead nearest the fire. The calorimeters were constructed from 1.5 m length sections of nominal 2 foot diameter schedule 60 steel pipe. Type K thermocouples were attached at 12 locations on the circumference and ends of the calorimeter. Fire heat fluxes to the calorimeter surfaces were estimated with the use of the Sandia SODDIT inverse heat conduction code. Experimental results from all types of tests are discussed, and some comparisons are made between the environments found on the ship and those found in land-based pool fire tests. KEYWORDS: Ship fires, calorimeters, radioactive materials shipments, cargo firesThe safety of land transport of radioactive materials packages has been studied for many years. For example the "modal studies" [l] conducted during the 1980s considered truck and rail shipment of radioactive cargoes. Sea shipments of such cargoes, on the other hand, have not been studied to the same level of detail. In an effort to increase the knowledge of the possible fire exposure that a package might receive during sea transport, a series of eight shipboard fire experiments have been conducted aboard an actual breakbulk cargo ship. The tests were intended to measure a range of possible fire exposures for packages on ships, and give some basis for comparison to fires specified in current safety regulations. This paper presents some key results from the tests. More detail in a report format, including plots of all data collected, is available in Reference Series 6 regulations [5] must also be followed. Together these regulations limit the types of fires that must be considered during sea shipments. For example, the IMDG code specifies that for break-bulk freighters, a watertight bulkhead must separate radioactive cargo from flammable cargo. Thus, the most likely fires on this type of ship are fires with flammable materials in adjacent holds such as engine rooms, galleys and crews quarters, and combustible cargo fires in the same ship hold.The tests were conducted aboard the Mayo Lykes, a World War I1 Victory class cargo ship, maintained by the United States Coast Guard at Mobile, Alabama, specifically for the purpose of fire testing. Two holds, Holds 4 and 5, at the aft end of the ship were selected for the tests. Level 1 of these holds, immediately below the weather deck, was used for all fires and measurements. In all cases t...