Fire and Smoke Corrosivity of Metals

The deleterious effects that combustion products, generated dur ing fires, can have on normal construction materials has been well docu mented. The combined effects of fire, corrosive smoke and particulate have been defined as fire corrosivity. While the effects of fire corrosivity are well known little quantitative information is available concerning the mechanisms in volved and the degree to which materials, particularly, metals are susceptible to this attack. Consequently, a study was conducted to begin examining the effects of fire and smoke corrosion on metals. Various metal targets were ex posed to corrosive smoke and fire particulate produced from Polyvinylchloride (PVC) samples burned in a cone calorimeter. The target materials consisted of 304 stainless steel, 1010 carbon steel and 70-30 Cu-Ni alloy. In addition to metal targets, electrical resistance probes were also utilized in the testing to monitor in-situ corrosion. The probe materials corresponded to the metal targets so that a comparison could be conducted. The corrosion probes offer the capability of instantaneously comparing results from similar tests and to con duct in-situ measurements of corrosion rates during a test. After testing, both the metal targets and corrosion probes were sectioned and prepared for analy sis using standard metallographic techniques. The targets and probes were analyzed for corrosion products and depth of attack. As a result of this test it was shown that all the metal targets test proved highly susceptible to the ef fects of smoke corrosivity attributed to the burning of PVC samples. These results are presented and compared by corrosion rates. In addition, the per formance of the corrosion probes in terms of their ability to produce accurate corrosion measurements were evaluated by comparing their corrosion depth measurements to those of the metal targets.