[Rescue Technology] Advantages and Inadequacies of Various Search and Rescue Methods in Building Collapse Accidents

The fire brigade is responsible for the rescue of building collapse accidents and has certain professional advantages and equipment advantages. However, the rescue site cannot be copied, the setting of actual combat training scenes, the lack of practical experience in rescue operations, the combination of human and equipment, and the on-site command and decision-making issues. It has also become a weak link in the rescue operations. Therefore, exploring the laws and rescue techniques for rescue operations of building collapse accidents has become a topic that we need to solve urgently.

I. The unfavorable factors affecting rescue at the scene of building collapse accident

(1) The destruction of facilities such as gas, power supply and water supply attached to buildings results in the coexistence of fire, flooding and hidden dangers of electric shocks.

(2) Uncertainty in the specific location of personnel trapped, different injuries caused by collapse, and different needs for rescue personnel, and the first aid site at the hospital is difficult to intervene.

(3) Disposal teams are diverse and difficult to organize and direct. Rescue forces include local governments, police officers, armed police, fire protection, civil defense, medical institutions, and mechanical engineering departments. Rescue operations are carried out in multiple ways, simultaneously, and in multiple forms. There are numerous complexities, vigilances, and organization and command. How to effectively coordinate and coordinate the various forces and the orderly development of rescue work is a great challenge to the organization and command.

(d) The on-site crowds and family members’ excessive behaviors are likely to affect the search and rescue operations. A large number of people were spotted on the scene of the accident, resulting in an embarrassing environment that greatly interfered with the search and rescue of equipment and dogs, and the rescue operations could not be carried out quickly and effectively.

II. Difficulties to be solved in the rescue of building collapse accidents

(1) From the perspective of the difficulty of the disposal process, the first step in the steps of reconnaissance and intelligence, personnel search and positioning, elimination of secondary disaster hazards, lifting and lifting, and personnel first aid is the search and positioning of trapped persons, followed by exclusion. The danger of secondary disasters is again the demolition of the safe operation of lifting and lifting.

(II) From the perspective of the disposal technology, personnel search and positioning are currently the most difficult and time-consuming. How to accurately and quickly locate trapped persons is the key to the entire rescue work.

Third, the common search positioning method in building collapse accident rescue

(a) Manual search method.

It mainly seeks trapped people by asking insiders, propaganda, and percussion. The search and rescue personnel must be able to understand basic information such as the original safe passage of the collapsed building, the structure of the building, and the approximate location of the trapped person during the search process. Through the clearing of the field after the alert, keeping the relative area quiet, using every pause after the call and percussion, carefully capture the sound and noise from the survivors under the rubble, and identify the location of the sound, determine the on-site marking, and do Good record.

(b) Animal search.

At present, animal search is mainly dog ​​search, which refers to the use of search and rescue dog's sensitive sense of smell to find trapped people buried under the rubble. Some countries in foreign countries are still researching pigs, mice, wasps, and other animals and insects for search training. However, the data show that these animals and insects are more difficult to train, and they do not have the capability of on-site search and rescue.

(c) Instrument search method.

The firefighting force mainly has four types of life detectors: video, audio, radar, and infrared . They search for the signs of life of trapped people through video images, sound waves, electromagnetic waves, and heat energy. There is also a gas life detector that can search based on the site's carbon dioxide concentration. Our fleet is not equipped yet.

Fourth, a brief analysis of the advantages and disadvantages of several search and rescue methods

(1) Manual search

Artificial search personnel are deployed in the buried pressure area and listen, see, knock, shout, and judge are used to directly search the collapsed shallow and narrow areas. Manual search is an efficient and quick method for searching trapped ruins and burying shallow trapped persons. However, it must be noted that under normal circumstances, the living space created by the collapse of houses is very fragile, and the direct stepping on the ruins will increase the load on the ruins. It may cause secondary collapse and cause secondary injury or even death of burying personnel. Pulling net search requires a lot of people to enter the rubble, and people will have a lot of smells and miscellaneous items, which will lead to a sharp decline in the judgment ability of the search and rescue dogs. Large numbers of people will produce loud noises. The use of sound wave detectors will have a greater impact.

(B) search and rescue dog search

Rescue dogs can use their keen sense of smell and dexterous body shape to quickly and efficiently find survivors who have collapsed and buried depths. The rescue dog's hearing is 18 times that of humans. The sense of smell is hundreds of times that of human beings. It has a wide field of vision and has the ability to see objects in low light conditions. When using search and rescue dogs to search, it should be noted that: long-term search will reduce the excitement of search and rescue dogs, so every search 20 minutes after the dog needs to rest for 5 minutes in order to improve the search accuracy; search and rescue dogs can not tell the body and live The smell of humans and the rescue practice of the Wenchuan earthquake proved that the search and rescue dogs are more sensitive to the odors of the body and are louder than those found when survivors are found. Therefore, when using search dogs to search for survivors in the deep ruins, they need to use life detectors, etc. The equipment conducts mutual verification to confirm whether or not the burying person has died. Practice has proved that different search and rescue dogs have different odor sensitivities. Therefore, if the conditions permit, two dogs need to be searched at the same time to verify each other's position. . The effect of dog search depends on the ability of trainers and dogs.

(III) Instrument search

The advanced life detector is a technical guarantee to improve the search efficiency of personnel and minimize the casualties of trapped persons. The current life search equipment equipped by the firefighting force mainly includes: visual life detectors, infrared life detectors , acoustic wave vibration detectors, and radar life detectors . However, at any site, commanders and fighters' mastery and proficiency in the operation of the instrument will directly affect the search and rescue speed and success rate. The accumulation of a large number of rescue workers at the site of the collapse is a major factor that seriously affects the search and rescue of trapped persons.

1 , visual life detector: also known as optical life detector, it is the use of optical instruments with light irradiation to observe and detect life, can solve the problem of life detection in poor visibility. This kind of instrument can convert the light radiation emitted or reflected by an object into an electric signal. After signal processing, the image of the object is reproduced to achieve the purpose of search and rescue. When there is a blockage, you can use a certain gap or punch in advance, use the universal joint to probe the optical probe in depth. Its advantage is that it is simple and intuitive to use. The disadvantages are the need for lighting, inconvenient for the detection of objects that are shadowed and buried deeper, and the limited working environment. There must be voids or voids with a diameter of not less than 5 cm.

2. Infrared life detector: Similar to the visual life detector, except that it does not require light, it can perform passive life detection under dark conditions, which solves the problem of life detection under the condition of insufficient illumination, and is especially suitable for shallow-buried personnel in the early stage of an accident. The rapid discovery. The disadvantage is that it can not penetrate with deeper object detection and buried detection.

3 , acoustic vibration detector: also known as the audio life detector , is the use of sound or vibration sensors, the use of air as a carrier of various sound waves or other media as a carrier of various types of vibration, through the recognition of other people's voice to carry out. This method can directly use a person to hear a person's cry for help or a percussion sound. The disadvantage is that it requires a quiet surrounding environment. At the same time, a plurality of contact sensors are required to be used in combination to prevent sound interference. Undetectable survivors cannot be detected. The monitoring range is small. The sound wave is 7.5 meters and the vibration is 23 meters . It requires the victim to send a recognizable sound, which is very difficult for infants and young children.

4. Radar Life Detector: It integrates radar technology and biomedical signal detection technology. It uses pulsed electromagnetic waves, penetrates blocking media, and detects reflected waves after human vital signs such as breathing and heartbeat. It can detect body's breathing and body movement signals within a certain distance and penetrate a certain thickness of non-metal wall, and perform intelligent analysis and judgment, so as to realize the function of partition wall exploration. It has strong penetrating ability, and is not affected by environmental temperature, hot objects and sound interference compared with optical, infrared and audio detection technologies. It is widely used in search and rescue work for earthquakes, landslides, collapses and other disasters. . The disadvantage is that different types of machines have different penetrative forces on the steel-concrete structure. When used in the field, they cannot interfere with the source (living people) within 6 meters of the instrument's radiation range . Otherwise, serious interference will occur, directly affecting the detection result. .

V. Application of Search and Positioning Technology in Rescue of Building Collapse Accidents

( 1 ) Application of Canine and Radar Life Detector in Search and Rescue of Buildings on Collapsed Sites

In the search and rescue of a building collapse site, search and rescue dogs are generally first searched for a wide range of areas. After determining the basic goals, life search equipment is used for accurate search and investigation. With the help of electromagnetic waves, radar life detectors can penetrate a certain thickness of obstructing medium, such as reinforced concrete, brick-concrete structure ruins, etc., to detect the living breath of human survivors, and to detect various micro motions caused by human life activities, such as Breathing, heartbeat and other information, so as to identify the existence of life, to achieve the purpose of finding survivors.

(2) The initial orientation of the artificial or rescue dog and the accurate positioning of the radar life detector are the better methods used in search and rescue practice.

From several successful search and rescue cases, it can be seen that the initial orientation of the artificial or rescue dog, combined with the accurate positioning of the radar life detector, is a better method used in practice. Give full play to the characteristics of rapid maneuvers of artificial and rescue dogs, and then accurately position the advanced detection equipment, maximize the search and rescue effectiveness, and also shorten the search and rescue time, which has greatly promoted the rescue work. The burying personnel strive for the greatest possible survival.

The information in this article comes from the Internet and was reorganized and edited by China Rescue Equipment Network.