Simulated Effects of Head Movement on Contact Pressures Between Headforms and N95 Filtering Facepiece Respirators-Part 1: Headform Model and Validation

Lei, Zhipeng; Ji, Xuewu; Li, Ning; Yang, James; Zhuang, Ziqing; Rottach, Dana

doi:10.1093/annhyg/meu051

Cited by 5 publications

(4 citation statements)

References 27 publications

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“…A two-dimensional, isotropic finite element models was developed using ABAQUS CAE 2019. The mask model was compressed with a uniform pressure of 1000 N/m along the 5 mm long upper surface in order to indent the skin and generate a surface pressure with a magnitude similar to those found in literature 29,56,57 . The mask model was then translated by 2 mm to represent the relative motion of facial PPE whilst executing day-to-day tasks.…”

Section: Methodsmentioning

confidence: 99%

A Numerical Analysis of Skin-PPE Interaction to Prevent Facial Tissue Injury

Jobanputra

Hayes

Royyuru

et al. 2021

Preprint

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The use of close-fitting PPE is essential to prevent exposure to dispersed airborne matter, including the COVID-19 virus. The current pandemic has increased pressure on the healthcare system, leading to medical professionals using high-grade PPE for prolonged times, resulting in device-insduced skin injuries. This study focuses on computationally improving the interaction between skin and PPE to reduce the likelihood of discomfort and tissue damage. A finite element model is developed to simulate the movement of PPE against the face during day-to-day tasks. Due to limited available data on skin characteristics and how these vary interpersonally between sexes, races and ages, the main objective of this study was to establish the effects and trends that mask modifications have on the resulting subsurface strain energy density distribution in the skin. These modifications include the material, geometry and interfacial properties. Overall, the results show that skin injury can be reduced by using softer mask materials, whilst friction against the skin should be minimised, e.g. through use of micro-textures, humidity control and topical creams. Furthermore, the contact area between the mask and skin should be maximised, whilst the use of soft materials with incompressible behaviours (e.g. most elastomers) should be avoided.

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Section: Methodsmentioning

confidence: 99%

A Numerical Analysis of Skin-PPE Interaction to Prevent Facial Tissue Injury

Jobanputra

Hayes

Royyuru

et al. 2021

Preprint

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“…Head movements have been found to cause a lower degradation of the protection efficiency of well‐fitting masks (i.e., N95 or FFP) compared with masks providing a lower fit quality (i.e., surgical masks). 39 , 41 A computational framework developed to model and further investigate this aspect 42 , 43 is presented in the modeling section.…”

Section: The Fit Factor As An Indicator Of the Protection Provided By...mentioning

confidence: 99%

“…The method has been further used to calculate the deformation induced by facial expressions and the corresponding changes in contact pressure. 103 The impact of head movements (moving up and down, rotating) has been modeled with a dynamic headform 42 based on observation of real movements. The subsequent contact simulation 43 has led to the calculation of the evolution of the contact pressure at different points of the mask/head contact area upon head movements.…”

Section: Modeling Inward and Outward Leaking Flowsmentioning

confidence: 99%

A critical review on the role of leakages in the facemask protection against SARS‐CoV‐2 infection with consideration of vaccination and virus variants

Wang

2022

Indoor Air

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The protection provided by facemasks has been extensively investigated since the beginning of the SARS‐CoV‐2 outbreak, focusing mostly on the filtration efficiency of filter media for filtering face pieces (FFP), surgical masks, and cloth masks. However, faceseal leakage is a major contributor to the number of potentially infectious airborne droplets entering the respiratory system of a susceptible individual. The identification of leaking spots and the quantification of leaking flows are crucial to estimate the protection provided by facemasks. This study presents a critical review on the measurement and calculation of facemask leakages and a quantitative analysis of their role in the risk of SARS‐CoV‐2 infection. It shows that the pairing between the mask dimensions and the wearer's face is essential to improve protection efficiency, especially for FFP2 masks, and summarizes the most common leaking spots at the interface between the mask and the wearer's face. Leakage is a crucial factor in the calculation of the protection provided by facemasks and outweighs the filtration performances. The fit factors measured among mask users were summarized for different types of face protection. The reviewed data were integrated into a computational model to compare the mitigation impact of facemasks with vaccination with consideration of new variants of SARS‐CoV‐2. Combining a high adoption rate of facemasks and a high vaccination rate is crucial to efficiently control the spread of highly infectious variants.

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“…Strap tension, placement, orientation, friction, and face seal material softness have all been shown to significantly affect contact pressure [ 214 , 215 ]. Additionally, head movements may amplify contact pressure in certain regions of face [ 216 , 217 ]. The tight-fitting straps and head harness can elicit symptoms such as acne [ 218 ], nasal bridge scarring [ 219 ], facial itching, lightheadedness, and headaches [ 220 , 221 , 222 ].…”

Section: Rpd Performance Issues and Challengesmentioning

confidence: 99%

What We Are Learning from COVID-19 for Respiratory Protection: Contemporary and Emerging Issues

Zhang

et al. 2021

Polymers

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Infectious respiratory diseases such as the current COVID-19 have caused public health crises and interfered with social activity. Given the complexity of these novel infectious diseases, their dynamic nature, along with rapid changes in social and occupational environments, technology, and means of interpersonal interaction, respiratory protective devices (RPDs) play a crucial role in controlling infection, particularly for viruses like SARS-CoV-2 that have a high transmission rate, strong viability, multiple infection routes and mechanisms, and emerging new variants that could reduce the efficacy of existing vaccines. Evidence of asymptomatic and pre-symptomatic transmissions further highlights the importance of a universal adoption of RPDs. RPDs have substantially improved over the past 100 years due to advances in technology, materials, and medical knowledge. However, several issues still need to be addressed such as engineering performance, comfort, testing standards, compliance monitoring, and regulations, especially considering the recent emergence of pathogens with novel transmission characteristics. In this review, we summarize existing knowledge and understanding on respiratory infectious diseases and their protection, discuss the emerging issues that influence the resulting protective and comfort performance of the RPDs, and provide insights in the identified knowledge gaps and future directions with diverse perspectives.

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Simulated Effects of Head Movement on Contact Pressures Between Headforms and N95 Filtering Facepiece Respirators-Part 1: Headform Model and Validation

Cited by 5 publications

References 27 publications

A Numerical Analysis of Skin-PPE Interaction to Prevent Facial Tissue Injury

A Numerical Analysis of Skin-PPE Interaction to Prevent Facial Tissue Injury

A critical review on the role of leakages in the facemask protection against SARS‐CoV‐2 infection with consideration of vaccination and virus variants

What We Are Learning from COVID-19 for Respiratory Protection: Contemporary and Emerging Issues

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