Quantification of soot deposit on a resistive sensor: Proposal of an experimental calibration protocol

Abstract

During a fire in an industrial facility, the main consequences concerning aerosol are the production of large amount of soot and potential resuspension of hazardous material in particulate form. Soot deposition quantification on walls in a room during a fire is essential for the prediction of aerosol quantities that can be transported in the ventilation ducts and clog high efficiency particulate air filters. For this purpose, accumulative resistive sensors, initially developed for monitoring Diesel Particulate Filters (DPF), have been used to quantify soot particles that are deposited on its sensing side. After validation of the fabrication process via electrical measurements, the sensor response has been studied under different polarization voltages and an experimental protocol for soot quantification has been qualified. Thanks to those protocols, it was first demonstrated that the polarization voltage has no influence on the deposition velocity. Then, the resistive sensor was calibrated at polarization voltages of 10 V and 0.1 V. For 0.1 V, results are less repeatable and do not allow to propose a correlation between conductance and deposited mass. Better repeatability was found for a polarization voltage of 10 V allowing to propose and develop a calibration procedure aiming to correlate sensor conductance and deposited mass of aerosol. Indeed, it was proved that the sensor has a blind zone, in terms of conductance, for mass deposit ranging from 0 to 230 mg/m 2 . A linear calibration curve with a good sensitivity of 2.49 µS.mg -1 .m 2 was obtained for deposited mass between 230 and 1630 mg/m 2 .

An innovative method for soot deposit quantification using a CO2 sensor: Application to fire studies in research facilities

“…Mensch & Cleary (2018) used resistive sensors for a first attempt to quantify soot deposits formed by thermophoresis within a temperature gradient imposed between thermally regulated rectangular flow chanel. According to this literature review, corresponding soot deposited mass per surface area are ranging from 20 to nearly 350 mg.m -2 , values confirming the relevance of the quantification method introduced by Kort et al (2021). Nevertheless, additional measurements, carried out during real-scale and confined fire experiments (Kort et al, 2019) have demonstrated that significantly higher mass deposit (up to 25 g.m -2 ) could be obtained under realistic conditions, limiting the range of application of the quantification method introduced by Kort et al (2021).…”

“…According to this literature review, corresponding soot deposited mass per surface area are ranging from 20 to nearly 350 mg.m -2 , values confirming the relevance of the quantification method introduced by Kort et al (2021). Nevertheless, additional measurements, carried out during real-scale and confined fire experiments (Kort et al, 2019) have demonstrated that significantly higher mass deposit (up to 25 g.m -2 ) could be obtained under realistic conditions, limiting the range of application of the quantification method introduced by Kort et al (2021). Thus, the aim of this work is to develop an additional measurement devices able to quantify such high soot deposit contamination levels in a direct, non-invasive, representative and complementary way to the quantification method proposed by Kort et al, (2021).…”

“…Nevertheless, additional measurements, carried out during real-scale and confined fire experiments (Kort et al, 2019) have demonstrated that significantly higher mass deposit (up to 25 g.m -2 ) could be obtained under realistic conditions, limiting the range of application of the quantification method introduced by Kort et al (2021). Thus, the aim of this work is to develop an additional measurement devices able to quantify such high soot deposit contamination levels in a direct, non-invasive, representative and complementary way to the quantification method proposed by Kort et al, (2021). This first experimental approach for an in situ quantification of soot deposition on walls during fires (Kort et al 2021) is based on a resistive sensor previously developed in our consortium (Grondin et al, 2015).…”

“…For this purpose and due to the lack of quantitative soot deposition data under realistic fire conditions, an innovative method for soot quantification in experimental facilities devoted to fire research has been developed. This method is based on the quantification of gases emitted during regeneration of a resistive sensor surface and has a higher detection limit than the electrical conductance quantification method previously proposed and validated by (Kort et al, 2021). A proof of feasibility has been shown for two types of soot and a prediction curve has been proposed for deposited masses which vary between 16 and 350 µg (1304 mg.m -2 and 28525 mg.m -2 ).…”

Dry aerosol particle deposition on indoor surfaces: Review of direct measurement techniques

“…These sensors are sensitive to ambient conditions, such as relative humidity and the orientation of the sensors is also important (Kort et al 2019(Kort et al , 2021. with the mass loading.…”