Graphene-based sensor can help detect when firefighters’ protective clothing is no longer safe

A University of Alberta researcher is working with Canada-based Davey Textile Solutions and other industry partners to reduce the risk of faulty protective gear used by firefighters, with a graphene-based sensor that can detect the gradual breakdown in garments from exposure to heat, moisture and ultraviolet (UV) light.

These fibers age silently and lose their performance, so this sensor technology is a breakthrough in terms of safety for workers exposed to heat and flame, said clothing and textiles scientist Patricia Dolez, the project’s lead researcher and an assistant professor in the U of A Faculty of Agricultural, Life & Environmental Sciences (ALES).

Damage to the garments may not be visible to the naked eye before performance is reduced considerably, according to Dolez. Firefighters have no good way to know how safe their clothing really is—you can’t tell just by looking at it.

Once fully developed, the sensor patch would provide a way to assess the garment without destructive testing—for example, having to cut out samples to test the fabric’s condition through conventional methods such as strength testing.

The sensor patch uses graphene to form conductive tracks on the patch’s surface. When exposure to heat, moisture or UV light exceeds a certain level, the graphene track is disrupted and loses its electrical conductivity.

Firefighters would use a simple voltmeter to check the safety levels of their clothing on the sensor patch—a result that comes within seconds.

The sensor has been provisionally patented and is still under development. It comes at an optimal time, Dolez said, as the National Fire Protection Association (NFPA) prepares to upgrade its recommendations on garment maintenance because of an underlying threat of diseases such as cancer, which can be caused by fire-associated harmful substances leaching into the fabric.

The current recommendation is to wash firefighting garments twice a year, but the problem is all the existing data that determines when the clothing needs to be replaced is based on that once- or twice-a-year washing, she said.

New NFPA recommendations are expected to increase the laundering frequency to after each exposure to a firefighting incident, which means the monitoring technology also needs to be amped up. The sensor is important to be able to gauge what the garment is going through with each washing.

Davey Textile Solutions, one of five industry partners working with Dolez, manufactured the fire-resistant fabrics that will be used as part of the sensor patch. The company is producing reflective trims for protective garments.

The sensor could also be used in the oil and gas, electrical, construction and mining industries, said Lelia Lawson, research and development specialist for Davey Textile Solutions.

This is an example of how we try to be ahead of the curve to provide new proactive items to the marketplace, said Lawson, noting that one of the biggest questions for clients in heavy industry is knowing when to retire personal protective equipment (PPE).

The sensor takes the ambiguity out of that question.

The sensor research, which began in 2018, also includes the expertise of Jane Batcheller from the U of A Department of Human Ecology and Hyun-Joong Chung, associate professor in the Department of Chemical and Materials Engineering.