Naval shipboard fire risk criteria - berthing compartment fire study and fire performance guidelines

Abstract

Judicious application of shipboard materials and choice of compartment furnishings can significantly reduce the threat of serious fire on board ship. Unfortunately, the fire performance of materials is currently difficult to ascertain from laboratory fire tests on the materials. Full size and quarter-scale compartment fires in conjunction with an analytical treatment were performed to obtain an improved understanding of the relationships between the laboratory fire test assessment and the observed behavior of materials in actual fires. The compartment fire experiments indicated that the temperature of the hot air layer below the ceiling is a suitable quantitative measure of the level of fire buildup in a compartment. When this temperature exceeds 700°C there is sufficient radiation from the hot air layer and the heated upper surfaces to cause ignition of all combustible materials in the compartment. For a3x3x2.1m (10x10x7 ft) space lined with asbestos millboard having a 0.69 x 1.9 m (27 x 75 in) open doorway, a heat production rate of about 72 kW/m(6.3 Btu/s/ft^) of deck area is enough to attain this condition. Fires in some bunk configurations alone could exceed this critical rate of heat generation. Ventilation and its points of application were found to be very important considerations. Observations of the fire scenarios in the compartment tests along with an empirical and analytical analysis of fire growth in compartment spaces have resulted in an improved application of the fire test ratings. Consequently more rational design rules for fire safe material usage have been developed taking into account the ignitability , flame spread, rate of heat release, potential heat and smoke generation potential of materials. The study also indicated the practicality of using quarter-scale fire tests for studying fire performance in full size compartments. 1.

Tests on insulative barriers as a method of protecting neoprene core mattresses

“…This model was based on the scaling rules developed in the Navy berthing compartment study [2]. The enclosure was intended to provide the radiation feedback from the walls and the ceiling that might occur in an actual compartment fire.…”

“…In addition the protected mattress would be 2-1/4 to 3 times as heavy as the unprotected mattress . 2 The unprotected mattress weighs about 6.4 kg (14 lb) and the insulated mattresses have been calculated to weigh from 14.2 to 20.9 kg (31 to 46 lb).…”

“…However, in berthing compartment tests also performed for NAVSEC by NBS it was observed that the neoprene mattress still contributed to the fire when piloted by severe flame Impingement or high local thermal exposure [2]. Methods were sought for eliminating or reducing the mattress involvement and NBS was asked by NAVSEC to test the use of noncombustible insulative barrier systems completely surrounding the mattress core as a possible solution.…”

Fire buildup in shipboard compartments - characterization of some vulnerable spaces and the status of prediction analysis

“…In this report, interior finish is taken to mean the materials serving as the exposed surfaces of bulkheads, overheads, decks, and which may be in the form of panels, sheets, tiles, insulation, carpet, coatings, etc. The present Navy fire performance requirements given in MIL STD 1623 B for interior finish and furnishings has contributed significantly in the selection of fire safe materials [1] • Research on shipboard compartment fires [ 2 ] has helped reinforce the flame spread requirements in this standard and has provided the rationale and guidelines for restricting the ignitability , flame spread, rate of heat release, potential heat and smoke generation of interior finish materials.…”

“…The ignition source, the quantity and arrangement of combustible items, the space configuration, the degree of ventilation, and the thermal properties of the materials in the compartment all affect its fire behavior. The performances of some materials have been evaluated in test fires in a shipboard compartment arrangement where the ventilation and interior finish were varied [2]. More fire situations must be studied to help generalize the fire behavior characteristics of materials.…”