TIFR develops country’s first low-cost device to test efficacy of masks
The Tata Institute of Fundamental Research (TIFR), Mumbai, has recently developed India’s first low-cost testing equipment to assess the efficacy of face masks.
Considering the shortage of personal protective equipment (PPE), including masks, TIFR is also studying how masks can be reused post decontamination.
N95 masks are designed for 95% filtration efficiency for very small 0.3 micrometre (µm) sized particles, while surgical or cloth masks are meant mainly for protection from relatively larger droplets of infectious material emitted during coughing, sneezing or talking, according to the
Union health ministry.
A team of scientists led by professors Arnab Bhattacharya and Shankar Ghosh of TIFR, along with Ronak Sutaria of air quality research group Respirer Living Sciences (RLS), built a prototype — mask integrity test resource (MITR) — using air quality measurement units and other components to develop a setup that measures fine particle (0.3µm) filtration through N95 masks. This was built using home-made items such as a vacuum cleaner, boxes, bottles, and a plastic ball (used as a mannequin).
“We estimate that such a unit could be built for ₹30,000-₹50,000 ranging from the most basic one to a slightly advanced unit within the country,” said Bhattacharya.
“Commercially available units that need to be imported cost over ₹10 lakh. At the same time, recent US Federal Emergency Management Agency (FEMA) guidelines restrict PPES export, which will impact the availability in India.”
For the project, different types of N95 and surgical masks being used by Tata Memorial Hospital were supplied to TIFR, and were tested using this equipment. The filtration efficiency could drop significantly if the mask was not well fitted, and allowed leaks from the side, Bhattacharya said, while cautioning that these experiments were done using a rudimentary set up on a plastic ball.
“While we expect a better fit for the human face, we found that even if the best N95 masks are used, unless the mask is worn properly or well-sealed from the sides, it can be dangerous for frontline workers,” he said.
The TIFR scientists also evaluated the filtration efficiency of several materials used at home for masks – from folded handkerchiefs to cotton T-shirts. “Even home-made masks could have 50-60% filtration efficiency, comparable with surgical masks, and are good for everyday use by the public,” said Bhattacharya.
The testing protocol plays a critical role in evaluating the efficiency of masks across intensive care units (ICUS) and health care facilities, said Sutaria. “Many hospitals across India are currently facing a severe shortage of facemasks, leading to the manufacture of varying quality. The existing mask testing equipment available from the US costs upto ₹90 lakh,” he said, adding that such a low-cost set up could also help in quickly comparing the quality of masks, with the risk of the market being flooded with inferior quality products.
The other aspect of TIFR’S research looked at reusability of masks after disinfecting them. According to N95decon.org, an international consortium of scientists for N95 mask decontamination, alcohol-based disinfectants, soaps, bleach solutions, ethylene oxide etc. though effective in virus inactivation could degrade the filtration efficiency or leave hazardous residues.