Wireless sensor monitors health of 'smoke divers'

Dubbed ‘smoke divers’, these firefighters are exposed to high temperatures, physical exhaustion and stress and the wireless sensor lets them know when their bodies are in danger.

According to a statement, the warning system depends on measurements from sensors that monitor an individual’s level of activity and whether he or she is sitting, at rest or lying prone.

It does this by combining data from accelerometers and gyroscopes with heart-rate and skin-temperature measurements. In conjunction, they measure a smoke diver’s level of heat stress.

The system has recently been tested by a group of firefighters on a training field for smoke divers at Rygge Airport in Norway. The aim was to find out how well the warning system, which obtains its data from a sensor system (ESUMS) in the form of a belt fastened closely round the chest, functions in real-life situations.

‘The sensor system was originally financed by US funding for use in medical rehabilitation, but it can also be used in other applications. So far, the results have been very encouraging,’ said project manager Trine Seeberg, a senior scientist at SINTEF, Scandinavia’s largest independent research organisation.

‘The equipment we used worked perfectly and the method correctly identified the risk situations that we simulated, so the trials showed that the method could be a useful way of determining whether or not a smoke diver is in danger,’ Seeberg added.

On the threshold

According to Seeberg, fine tuning remains to be done before the technology can be brought into service; more tests will have to be carried out in realistic situations, and the sensor platform will need to be integrated into smoke divers’ existing safety equipment, possibly in the form of a helmet display.

Seeberg explained that the core of the system is based on algorithms that describe how the body reacts to heat stress and that handle physiological and activity data. These emerged in the course of dialogue with the firefighters and via tests in SINTEF’s physiology laboratory, where activity data plus the heart rate and skin temperature of exercising subjects were measured and logged.

The sensor system currently communicates with the outside world via a second-generation Bluetooth protocol, which is implemented in most smartphones.

The system itself does not have a very long range, so the sensors are connected to a mobile telephone that is also worn by the smoke divers. This in turn sends information in the form of a so-called ‘hazard threshold score’ on a 10-point scale to whoever is monitoring the operation from outside the disaster site.

‘If the score is more than eight, the smoke diver is being exposed to a high level of stress and should abandon the operation, while a score of two shows that the person is in good physical condition and is operating at a level of activity that is not hazardous to health,’ said Seeberg.