Covid-19: The OPPBTP compares the effectiveness of a face shield and a type I consumer mask

Construction professionals have often expressed discomfort and severe constraints related to wearing a mask against Covid-19, due to the physical efforts of their activity, and more particularly during periods of high heat.

While masks of all kinds were lacking in the spring of 2020, face shields have been investigated especially as they have a number of advantages: transparency, ease of communication and lip reading. But in the absence of sufficient scientific data, the public authorities have not authorized the wearing of a face shield as a replacement for a mask, in France and in many other countries. In order to analyze the possibility of offering another alternative to the general public mask, the OPPBTP wished to study the comparative performance between category I general public masks and various types of face shields in order to protect against Covid-19. .

The Organization therefore called on the National Metrology and Testing Laboratory (LNE) to carry out an original study that was interesting in terms of its results. In fact, this study asserts equivalent levels of protection, under the conditions of the tests carried out, between the different types of face shields and for category 1 barrier masks conforming to the AFNOR Spec S76-001 standard.

The OPPBTP wished to make its contribution with this study, which complements other work and studies carried out internationally to feed scientific knowledge with the objective of providing construction professionals with the most suitable protection solutions.

Similar splash protection for consumer masks and face shields

The tests were carried out by the National Metrology and Testing Laboratory (LNE) on two mannequins and for four types of products (general public type mask and three different visors) according to different test configurations (projection modes of particles and position of the emitting and receiving heads relative to each other).
56 tests were carried out for three types of breath (normal breath, sustained breath and sneezing) and according to different configurations: 4 different pieces of equipment and 4 different positions between the heads.

The results obtained for these specific configurations show that all the equipment tested offers a level of anti-projection protection of between 96,73% and 99,93%.

For particles of size 2,5 μm, the level of spray protection is between 98,56% and 99,93%.

In configurations where the general public mask has been tested, the level of projection protection is similar to that of face shields

A study to be completed to go further

In order to go further and to be able to clearly define whether the face shield can replace the mask in all situations related to Covid-19, additional studies are certainly necessary. The OPPBTP is ready to collaborate and continue the tests and exchanges with the stakeholders concerned.

The full report is available here