In the aftermath of events such as a factory explosion, earthquake, or a terrorist bomb, man-made structures are often reduced to rubble piles, sometimes of immense dimensions. For victims trapped deep inside, their rescue depends on the actions of firefighters and USAR teams and the effectiveness of the procedures, equipment and techniques they deploy. If fire is involved, USAR teams often have to wait for the fire services to bring a situation under control before they can move in to start their search and rescue efforts.
While first responders and medium and heavy USAR teams are typically some of the first on the scene in the aftermath of a disaster, the discipline and procedures they follow and the equipment they employ in their efforts, can mean the difference between life and death for those trapped and still alive beneath the rubble. With such victims potentially conscious or unconscious, possibly able to speak, or totally unable to communicate, getting USAR teams to work as fast as possible is of paramount importance. That said, it’s only possible for these teams to begin their SAR efforts once any fires have been extinguished, or near extinguished and the rubble pile then made safe by engineers and shoring teams.
It’s an unfortunate fact in the case of fires, that it may be many days before firefighters can bring a situation under control sufficiently for others to begin their work, although they will take a lead from fire teams and when absolutely necessary sometimes work alongside them before deploying fully. But when they do go in, it’s at this point that the steps and drills USAR teams follow and the equipment they use, can make the difference between life or death for those awaiting rescue. 298
Inside the SAR toolbox
At the disposal of the USAR team are a specialist set of technical tools used to ‘listen’ for and locate victims trapped in the rubble pile. These include the latest seismic and acoustic listening devices often used alongside telescopic cameras. These can include heat detecting sensors, but together this toolbox delivers the latest and most effective tech for finding live victims in the voids of a rubble pile once the firefighters have done their job.
Sound vibrations generated by a victim travel through the solid parts of a structure or ground and are picked up by seismic/acoustic sensors, placed on flat surfaces, such as concrete, or wood. They can be pushed into the ground using screw-in spike attachments, or attached to steel structures at any angle or in any plane using magnetic attachments. The operator’s display interface provides seismic results in visual form and audio results in the headphones; the system allows the operator to review all feedback enabling him to pinpoint the victim’s location. The display panel shows the differing seismic signal strengths coming from each sensor, which appear in a way similar to a graphic equalizer and by seeing which sensor delivers the strongest signal the operator can direct the team to move the other sensors until they home in on the victim’s location.
If a victim is alive but unconscious, many seismic systems, however, may miss them as they need to make some kind of noise or movement to be detectable. At the same time, the acoustic detector will pick up sounds such as voices or breathing and can, therefore, detect an unconscious, though breathing victim. Some systems use two acoustic search probes simultaneously giving the operator a stereo comparison of any noises; airborne sound waves have been shown to travel within and under layers of debris in a rubble pile but become attenuated before they escape to the surface. Certain, well known devices in the industry have addressed this by their configuration – attached either to rigid telescopic booms on which they can be pushed into the void, or to flexible cables on which they can be lowered into the rubble. Two-way intercom-based communications between rescuers and trapped victims are also integrated into some leading acoustic sensor systems. 680
In mentioning the key USAR tools to be employed during a rescue when fire and USAR teams are working alongside one another, it would not be complete without citing the initial, very basic but proven steps when teams typically begin their search by calling out and listening for any responses or sounds. This will often be followed by the use of specially trained dogs to sniff out and locate victims. The Federal Emergency Disaster Management Agency (FEMA) in the US trains dogs for use in mass-casualty events, for both domestic and overseas disasters. Some canines are trained to discriminate between different kinds of scents and for different scenarios, e.g. rubble, water, forest and avalanche searches, although USAR dogs will alert on any human or cadaver scent and are generally non-scent discriminating.
When fire and disaster mix – a case study
An explosion on 17 July, 2015 at the Wood Treatment Limited wood mill in Bosley, Cheshire, UK, caused a major fire and the structural collapse of many buildings on the site. The event occurred at around 0900hrs requiring the deployment of some 15 fire appliances and by 1030hrs when fire teams had deployed it was ascertained that two explosions had taken place, four employees were missing and 35 injured were taken to hospital.
The explosion had been caused by the ignition of wood dust produced in the process to make wood-laminate flooring. Quantities of heating oil, kerosene, acetylene were also present adding to the combustibles and asbestos added to the other dangerous constituents in the mix. This presented dangerous conditions for both the fire fighters and the USAR teams who had to wait on the sidelines until the fires were out before setting about their work. The Cheshire Fire Brigade described as ‘fully developed’, fires in several areas including a four-storey building that had collapsed among the devastation. The possibility of further explosions meant the fire services had to proceed carefully, with water the main fire-fighting element. 1000
By the evening on day one, the large multi-agency team now gathered, including Merseyside and Lancashire USAR teams, would need to remain for several days before they would be able to deploy using their Searchcam 3000s and LD3-4 Delsar life detection systems from Savox Communications. Once the fires were under control these devices would be used on many occasions in the days ahead.
Some of the USAR shoring teams worked with the fire services to ensure structures were safe for the firefighters to do their job and gain access to areas where fires were burning in isolated places. At the end of day one the Cheshire Fire Brigade spokesperson was quoted as saying its crews were ‘working tirelessly to ensure that search and rescue teams could safely access the site’ as soon as possible to search for those missing’.
Specialist USAR teams were only able to began initial assessments some 24 hours after the disaster struck, with dogs employed at a very early stage thereafter together with the basic search methods outlined above, followed by the first uses, where possible, of the Savox search and rescue cameras and life-detection systems. These two solutions are almost de facto industry solutions in use all over the world.
During the second night, USAR teams discovered a body that in an area that had been identified as of interest by one of the SAR dogs. On day three, demolition and specialist heavy lifting gear cleared a path to the centre of the site for the USAR teams whose efforts continued through the next week alongside the firefighters who continued to douse the site with water. It was at this stage that USAR changed to one of search and recovery and by lunchtime on 21st July a second body was found. On the morning of the 27th July, a fresh USAR team from West Yorkshire arrived on site to replace the crews from Lancashire who, like their Merseyside counterparts, had attended since the start. The Merseyside USAR group remained and continued working with the West Yorkshire team. A full two weeks after the incident began on 31st July the USAR teams were still working 24/7 to locate the missing with firefighters continued to monitor and cool the site. 1381
Right equipment at the right time
In an event like Bosley Mill, deploying the right SAR equipment at the right time is down largely to the efforts and coordination of the fire department on the scene and whose efforts must ensure the safety of both its own teams and the USAR operatives.
Dogs employed at an early stage are responsible for a many victim-location SAR successes and while no live victims were pulled from the rubble on this occasion the location of deceased workers was aided by the canines. In addition, deployed at Bosley were technical search tools, including Delsar seismic/acoustic life-detection equipment and SearchCam 3000 telescopic cameras, which were used in combination during the SAR phase. Once the recovery phase had begun, however, the SearchCam 3000 alone was employed in the search for the missing.
Recognized in the industry as probably the most powerful such tool available for USAR purposes, Delsar offers full frequency spectrum monitoring that enables an operator to detect everything from the lowest frequency hum, to the highest pitched screech. However, as with all such seismic sensors operating in a wet situation where the fire brigade uses vast amounts of water to drench a fire, water ‘dripping’ throughout a rubble pile can cause false alerts because it can sound like a person tapping on a hard surface. USAR operators have to use their experience to distinguish between regular water dripping in a post-fire scenario and the tapping of a person, which is often less regular.
Communicating around the rubble
Operators of technical USAR kit have, until relatively recently, not had a sophisticated means of communicating with other members of the USAR team or fire fighters working alongside them. This made telling everyone to be quiet on detection of a victim, or getting other members of the USAR team to move sensors around the pile, very difficult. A new communications solution – the SR100-Rescue from Savox Communications – is now enabling life detection operators to communicate with other members of the USAR team more effectively who, in turn, can communicate with fire fighters around them over a two-way radio solution that links directly into their other search tools. It also enables the team to communicate directly with command and control elements of a USAR deployment, which has not, previously, been possible.
For more information, go to www.savox.com
About the Author
Mikael Westerlund is Chief Strategic Officer at Savox Communications.
