A New Perspective on Hydrogen Chloride Scavenging at High Temperatures for Reducing the Smoke Acidity of PVC Cables in Fires. II: Some Examples of Acid Scavengers at High Temperatures in the Condensed Phase

In the European Union, according to Regulation (EU) n. 305/2011, cables permanently installed in residential and public buildings need additional classification for acidity. EN 60754-2 is the test method for assessing acidity, and three classes are provided: a1, a2, and a3 (less performant). The research on PVC compounds with low smoke acidity helps to produce cables in the best additional classes for acidity, giving the PVC cables the possibility to be used in medium and high fire risk locations. This paper shows the behavior of some acid scavengers at high temperatures performing EN 60754-2 in isothermal conditions at different temperatures between 400 degrees C and 950 degrees C. The test apparatus is a tube furnace where the test specimen is burnt, and the released gases are trapped in bubbling devices containing double deionized water. pH and conductivity are measured, the efficiency of the acid scavengers is assessed, and chemical analysis of the ashes is performed. That allows us to understand why some substances succeed and others fail in trapping hydrogen chloride (HCl). The most important conclusion in this paper is that the higher the temperature, the lower the performance of the acid scavenger, showing that HCl concentration in the gas phase depends strongly on the heating conditions of the test specimen.