Out of rubble

Engineers from across Europe are working on a life-saving location device that aims to provide rapid detection of buried casualties during search-and-rescue operations.

The work is part of a four-year Second Generation Locator (SGL) for the Urban Search and Rescue (USaR) Project, involving research from 21 partners in areas such as optical sensors, wireless communication, bioethics and thermal image analysis.

As part of the project, Loughborough University is contributing its expertise in chemical detection through work being undertaken by Prof Paul Thomas and his team at the Centre for Analytical Science. The research aims to provide accurate chemical profiles of humans facing life-threatening situations.

Thomas explained: ‘Our role in the project is to provide some ground truths. We want to replace assumptions and theory with known data so that it can be used to properly specify SGL systems that can screen ruins for signs of life. We hope these SGL systems will not only provide detailed analysis of a collapsed building, but also support rescue teams in making difficult decisions about where and how long they should concentrate their efforts.’

According to Thomas, there is usually a 24-hour window when people that are injured and trapped can be saved, followed by a three-day window for those that are unhurt. By analysing the levels of carbon dioxide and ammonia, chemical sensors could detect whether a trapped person is still alive faster than traditional methods.

Thomas said: ‘One of the designs the project has come up with is a sensor that you put down on site. This pumps air out of the ruin, which is collected on an absorbent trap that enables us to collect any vapours that are present from humans. Once we’ve sampled a large volume of this air it is injected at a very concentrated pulse into a variety of sensors that are able to analyse its chemical profile.’

The effectiveness of this sensor will rely largely on the diversity and accuracy of chemical profiles supplied by Loughborough. Existing data is currently based on mathematical calculations and assumptions. However Thomas’ team has constructed two void simulators in the hope of backing up its theory.

‘Our simulation of a collapsed building is in the form of a long glass tank that’s put inside an aluminium shell. This acts as a heat sink for us to control the temperature. We’ve fitted lots of panels of different materials with holes drilled out of them so that air will go in a tortuous pathway passing over different surfaces and depths.’

‘We’re looking for volunteers to lie down in this enclosed space,’ Thomas continued. ‘Our ultimate aim is to analyse someone’s chemical profile over 24 hours. The participants are provided with just enough conditioned air to support life. We can also change the temperature and humidity and from that we can build up a profile of what sort of chemicals are released. Pending ethical approval, we’re hoping to begin these trials by the end of the year.’

Ellie Zolfagharifard