A comparison of carbon monoxide yields and particle formation at various global equivalence ratios in vitiated and under-ventilated conditions

Abstract

There have been previous studies comparing experimental methods for the purpose of capturing gaseous yields at a range of global equivalence ratios. However, no work has investigated the capability of the open controlled atmosphere cone calorimeter for collecting such data where its two modes of operation are directly compared. The aim of this study is to compare carbon monoxide yields collected using vitiated and under-ventilated modes of atmospheric control in order to identify the preferable method of replicating carbon monoxide yields reported from larger scale enclosure fire experiments. Cone irradiances of 30, 50 and 65 kW/m2 were applied to PMMA and plywood samples. Vitiated tests were conducted using a mixed air/diluent gas, with an inflow rate of either 100, 150 or 180 L/min, resulting in a reduced oxygen concentration of 17.5 vol. %. Under-ventilated tests were conducted using flow rates of 5, 10 and 20 L/min in an air atmosphere. Particle formations and emissions were also measured using a particle analyser and have been reported herein. Results indicate that the under-ventilated mode of equivalence ratio control offers a more promising method of capturing species yields with favourable comparisons to other bench scale methods.