Session: 10.1 - Boundary layer flows

Paper Number: 158697

158697 - Investigation of Safety Glasses Fogging Due to Mask-Wearing: A Combined Numerical and Experimental Study 

Abstract: 

Wearing masks in safety-critical environments can lead to the fogging of safety glasses, reducing visibility, comfort, and overall task performance. This study investigated the mechanisms governing safety glass fogging under mask-wearing conditions through a combined computational and experimental approach. Multiple mask scenarios were examined, including no mask, no gap (fully sealed), and masks with a top gap that simulates leakage pathways near the nose. Experiments and simulations were conducted at two temperatures (13 °C and a typical laboratory condition of 21 °C) and at 27% relative humidity. Additionally, three breathing rates (double the normal rate, normal rate, and half the normal rate) were considered to assess how different airflow conditions impact condensation on the safety glass surfaces.

A 3-D computational fluid dynamics (CFD) model captured the transient interactions between warm, moist exhaled air and the cooler safety glass surface, accounting for heat transfer, fluid flow, and moisture transport. Temperature and humidity distributions around the face and safety glasses were obtained under various mask fit and breathing conditions. Experimental measurements of lens surface temperature and humidity, conducted in a controlled environment, were used to validate and inform the numerical predictions.

The results indicate that top gaps in the mask strongly influence local airflow and thereby affect condensation on the safety glass. At higher breathing rates, increased airflow carried more moisture towards the lens, while introducing top gaps allowed a greater influx of ambient air that reduced humidity and alleviated fogging. By comparing these different conditions, the study reveals how mask fit, environmental factors, and breathing patterns collectively shape the thermal and moisture environment around safety glasses. These findings enhance our understanding of the thermofluidic and material properties that influence fogging and guide the development of improved mask and safety glass configurations. Optimizing mask geometry, selecting lens coatings, and managing ambient conditions can collectively minimize fog formation, thereby ensuring clearer vision and improved comfort for individuals who must wear masks and safety glasses simultaneously.

Presenting Author: Kian Barari UMass Lowell

Presenting Author Biography: Kian is a PhD candidate in Biomedical Engineering at UMass-Lowell.