Evaluation of Intumescent Coatings for Shipboard Fire Protection

Abstract

In response to several claims from Manufacturers that intumescent coatings could be used in place of fire insulation and provide equal protection to shipboard structures during a fire, U.S. Navy conducted an extensive investigation of several fire protective coatings for use aboard ship. These fire protective coatings included water and solvent based coatings, insulative coatings, and foams. The objective of this program was to identify passive fire protection (PFP) coatings for shipboard interior applications capable of meeting U.S. Navy (USN) fire resistance requirements (DRAFT MIL-PRF-XX 381) of 30 min rating with backside average temperature rise less than 139 C using UL-1709 fire curve (post flashover fire). This evaluation consisted of small scale fire, adhesion, and impact tests; intermediate scale room corner fire tests, and full scale fire tests conducted aboard ex-USS SHADWELL. The test results with steel substrate show that all candidate coatings failed to meet minimum U.S. Navy fire resistance criteria when used as stand-alone coatings. Furthermore, many coatings demonstrated poor adhesion, and fell off from the substrate during the fire test. These data have led the Navy to conclude that intumescent coatings tested in this study are not sufficient to protect shipboard spaces during a fire and are not equivalent when used alone as direct replacement for batt or blanket type fibrous fire insulation (mineral wool, StructoGard) installed aboard U.S. Navy ships. However, U.S. Navy smallscale fire tests have also demonstrated that some of the intumescent coatings, when applied over substrates such as Glass Reinforced Plastic (GRP), did reduce flame spread and smoke generation.

Materials engineering for surface-confined flame retardancy

“…For instance, in structural polymer composites, the use of intumescent coatings is being developed for the thermal protection and thermo-mechanical stabilization of the composites. An early example of the use of several commercial intumescent coatings for the protection of glass-reinforced vinyl ester resin/ balsa wood core sandwich composites was reported by Sorathia et al for military applications [11]. In this paper, small scale fire tests demonstrated a significant reduction of flame spread and smoke density when applied over composites substrates.…”

Investigation of the thermal degradation of polyurea: The effect of ammonium polyphosphate and expandable graphite

“…One of the greatest impediments to the development and application of polyureas in the design and construction of military facilities is their relatively high flammability and their susceptibility to degradation due to exposure to elevated temperatures caused by fire [10], [11], [12] and [13]. One effective way to flame retard polyurea is to use an intumescent system.…”

Generalized pyrolysis model for combustible solids

“…Intumescent coatings are sometimes applied to steel structural members to achieve the fire resistance ratings required by building codes, although the US Navy has concluded that intumescent coatings do not provide a level of fire resistance equivalent to traditional insulation, largely due to poor adhesion characteristics [89]. In addition to being applied as a coating, intumescents are sometimes grafted into composite materials to improve fire performance.…”