Investigation and Analysis of a Fire Accident in a Large Dying Resident's House

Abstract : This paper introduces the investigation of a fire accident of a large dead man in a residential building. Through analysis of the traces of the fire accident, material evidence, and transcripts, comprehensively identify the fire site, fire point, and cause of fire. The purpose is to investigate the method of investigation of fire accidents and fire prevention measures for residential buildings in the larger dead, for reference by fire scene investigation and fire investigation personnel.

Keywords : residential residence; fire scene; fire investigation; fire investigation

At 4:00 on March 25, 2015, a fire broke out at Room 301, Unit 3, Building 5, Building No. 5, Rongjing Garden, Dawukou District, Shizuishan City. The fire burned out an area of ​​83m2, causing three deaths and a direct property loss of 9,381 yuan.

1 The basic situation of a fire building

Fire building is located at Room 301, Unit 3, Building 5, Rongjing Garden, Dawukou District, Shizuishan City, with a construction area of ​​83m2. The east side is No. 3 building, with Qingshan Road to the west, No. 6 building to the north, No. 8 building to the northeast, and the construction of West Street to the south. The main six floors of the building sit west to the east and are reinforced concrete structures. The 301 room is furnished with three rooms, two rooms and one bathroom. The living room is a fire room. Other rooms have smoke marks. Fire destroyed sofas, fans, wooden cabinets and other items.

2 Site survey

2.1 Environmental Inspection

The fire house is located in Room 301, Unit 3, Building 5, Area 3, and there is a protective fence on the outer side of the window of the kitchen and living room of the 3rd floor of the 3rd floor of the building. There are slight smoke marks on the outside wall of the window. The other windows do not have this phenomenon, and the living room is obviously visible. Excessive traces of fire. Figure 1 and Figure 2 show the plan of the residential fire and the plan of the fire.

Figure 1 Azimuth Diagram of Residential Building

Figure 2 Fire house plan.png

2.2 Preliminary inspection

The living room (300cm x 510cm) is paved with white tiles on the ground . A double leather sofa (44cm x 220cm x 95cm) can be seen at the west end of the north wall at a distance of 20cm from Dongkou Dongfang. The east side of the sofa is on the east side and the east side of the handrail is charred. The east side of the sofa is visible. 17cm × 13cm, 16cm × 8cm irregular roof off the top of the skin, the sofa can see the north side of the north wall 53cm × 40cm × 48cm brown double bedside cabinets, bedside table top drawer east end of the surface split black, the top of the nightstand top surface of patent leather was heated Bubble-shaped, the cabinet can be seen on the top of the burning deformation of the keyboard, the east side of the bedside cabinet can be seen on the ground burning debris, residues from north to south in order are electric fans, air conditioning fans. The wall of the north wall is 51cm away from the east wall, and the deformed socket can be seen from the ground at 35cm. The external plastic shell of the socket deforms like a flow column. The wall coverings were peeled off from the east wall of 85cm and the distance from the ground surface of 57cm to the wall surface of the roof; copper conductors and motors were visible in the ground fans and the wall of the wall was 186cm from the northern end of the east wall. The wall of the wall peeled off, and a double aluminum window was visible in the middle of the east wall. The glass on the north side shattered and fell on the inner sill surface. A single brown sofa was placed on the lower surface of the window at a distance of 113 cm from the north wall. The leather on the northern side of the sofa chair was burned. , wooden frame exposed carbonized. A white refrigerator can be seen on the south side of the single sofa. Smoke marks can be seen on the upper side of the refrigerator and on the surface of the top surface of the refrigerator. The plaster line and fabric curtain residue can be seen between the east side of the refrigerator and the east wall.

2.3 Detailed Inspection and Special Inspection

There is a wall-type five-hole socket 36cm away from the east wall of the living room. The outer surface of the socket is melted and glued to the wall. After the wall socket was photographed and fixed, the wall outlet jack was opened for inspection, and no smoke traces were found on the copper surface of the jack. 10cm on the east side of the bedside table was placed on the north wall with a vertical fan burning residue. After the electric fan was inspected, the upper fan cover fell off and the copper wire was visible in the fan residue. The east side of the wooden skirt wall is 40cm from the north wall and 230cm from the south wall is the bottom of the “U”-shaped mark, and is gradually reduced to the north wall 10cm and the south wall 208cm. The ground floor of the living room is 81cm long, 67cm wide, and 17cm high, and a number of round heating pipes and copper wires are extracted from the floor.

3 Fire cause identification

3.1 Determination of the fire time

At 4:00 pm on March 25, 2015, the “119” Command Center of Shizuishan City took the police and was located in Building 301, Unit 3, Building 5, Building 5, Rongjing Garden District, West Street, Dawukou District. After investigation and investigation, it was learned that Room 401 was awakened at about 3 o'clock on March 25th, and it smelled of burnt smell. After the neighbors checked and determined that Room 301 was on fire, they called the third son of Room 301 in Room 301; After attending the inspection at 3:30 am, Garden Security Tian received a telephone call from 601 households and learned that 301 households had caught fire and then arrived at the scene. After on-site inspection: 301 indoor walkways, kitchens, halls have smoke traces, smoke marks evenly, fire burned living room sofas, fans, wooden cabinets and other items, living room window aluminum window frame part of the melting. Combining information such as fire damage, smoke traces, fire development rules, and inquiries made by the policeman Liu, security Tian, ​​and a neighbor, etc., it was determined that the time of the fire was about 2:30 on March 25, 2015.

3.2 Identification of Fire Parts

After investigating the interview, none of the relevant personnel on the scene saw an open flame. His neighbors described one of the deceased lying on the side of the hall, heading towards the entrance door, and the foot toward the living room; the second of the deceased was in the aisle at the entrance to the bathroom and headed towards the room. In the northeast direction of the hall, the foot is in the southwest direction; the three of the dead lie in the bed in their bedroom. Of the three deceased persons, except for one person who had a burn, no other signs of burn were seen in the other two deceased persons. After on-site inspection, the living room of Room 301 was placed on the north wall from west to east with two-seat sofas, nightstands, and vertical fans. The armrests and backrests on the east side of the two-seat sofa are overheated, and the traces of overheating and heat deformation from west to east are reduced. The cortex on the east side of the sofa is burned, the internal wood frame is carbonized, and the upper part of the east handrail is located 60cm×13cm east of the cortex and its interior. The sponge burned, the underlying wooden frame was exposed and the surface charred. The carbonization of the wood frame at a distance of 30 cm from the ground and 40 cm from the north wall is serious. The depth of carbonization is about 3 cm, and the lower cortex burns. Comprehensive recognition of the fire fire site is located in the northeast corner between room 301 living room north wall double sofa and east wall single sofa, as shown in Figure 3.

3.3 Identification of Fire Points

After investigation and interview, Dawukou District Fire Squadron conducted firefighting on the living room of Room 301 and found Mars between the living room's north wall double sofa and the East Wall single sofa. The water basin was used to collect water and spilled to the northeast corner. The family members designated on the site that there are electric fans, foot tubs, and air-conditioning cooling fans in the northeast corner of the living room. After on-site inspection, one third of the electric fan base at the northeast corner of the living room was burned and lost. The outer layer of the strut was burnt and lost. The exposed metal rod was over-oxidized and discolored. The head and the strut broke open; the foot tub was heated. Deformation, discoloration, adhesion to black combustion residue; on-site extraction of a melt (81cm × 67cm), the bottom was light yellow melt, the rest of the smoke traces, the upper part of the whole fire, there are black residues; on-site extraction of the round Metal discoloration occurs in the shape of the heating tube, and two multi-stranded copper wires are connected to the end, and the surface insulation layer falls off. After the inspection and appraisal of circular heating pipes and residual copper conductors, the "Technical Appraisal Report" of the Tianjin Fire Evidence Identification Center of the Fire Bureau of the Ministry of Public Security concludes that the melting marks at the ends of the copper conductors are electro-thermal effects. Therefore, it is considered that the starting point for the fire is the northeast corner of the living room, 40 cm from the north wall and 9 cm from the east wall.

4 Fire cause identification

4.1 Exclude the possibility of fire caused by artificial fire

After investigation visit, room 301 of household Chen had a good relationship with his neighbors, his physical condition was good, and he had no suicidal tendency; Chen Mou went home from work and prepared to apply for a driver’s license; Chen’s daughter attended the sixth primary school in Dawukou District. And the neighbors all reflect that they are obedient and sensible. In the process of sorting out the 301-room house, the family of the deceased found more than 200 yuan in cash and purse in the purse of Chen’s daughter’s woman’s house. After on-site inspection, the entrance door of Room 301 was in good condition and the outer window fence was intact. After fixing the position of the residue at the burning point of the living room, the residue on the surface of the tile joint under the residue was wiped and extracted with absorbent cotton. After inspection by the public security criminal investigation department, no residue of combustion aid was found. Comprehensive analysis eliminates the possibility of fire caused by artificial fire.

4.2 Exclude the possibility of fire caused by careless use of fire

The main basis is as follows: After investigation, the deceased had a smoking behavior. No flammable flammable products were found outside the cortex sofa except the cortex sofa. In the field test, the lit cigarette was placed on a leather sofa until the cigarette was completely extinguished and the leather sofa could not be ignited. After on-the-spot investigation, no residual cigarette case, cigarette butt, and lighter residue were found in the 301 indoor living room's fire area. There were no traces of fire in other rooms and only smoke marks. The comprehensive analysis excludes the possibility of igniting flammable materials such as flammable materials and flammable materials due to fire.

4.3 can not rule out the possibility of fire caused by electrical line failure

After investigation visits, Chen had the habit of using electric heating feet in the foot bath. After on-site inspection, the air switch of Room 301 was tripped and turned off. No other power supply was tripped, and plugs of useful electrical equipment were plugged into the wall outlet of the northeastern corner of the living room and remained in the fire after the plug was connected to the plug. Found heat pipes and strands of copper strands with melting marks, and sent them to the Tianjin Fire Evidence Identification Center of the Ministry of Public Security Fire Department. After the identification and confirmation, the broken ends of the multi-stranded copper conductors of the heating pipe are melted by electrothermal effect. mark.

5 Analysis of Causes of Disasters

5.1 Inhabitants have low awareness of fire hazards in electrical equipment

A number of electrical devices are placed at the fire site, and some devices are high-power electrical devices. They are prone to fire due to electrical faults or short circuit of electrical wires. The resident population (especially the elderly and children) has a weak sense of fire safety in the family, lack of fire safety knowledge, and lack of safety awareness in the use of electricity in the fire. It is not possible to better place the electricity equipment to stand alone or use the electrical equipment after power off. .

5.2 There are more combustibles around the fire point

There are powdered herbal medicines placed on the fire site, sponge wood frame sofas in the outer leather, and electric devices are placed on the corners of the two sofas in the fire area of ​​the living room. Fabric curtains made of fiber materials are placed above the electric equipment. Therefore, the combustibles in the fired residence are relatively concentrated, and there are potential dangers and objective conditions for fires caused by inadvertent use of fires and malfunctions of electrical lines. In addition, the indoor airtightness is good, combustible materials cannot be completely burned, and the conditions for the continuous production of toxic gases such as CO are formed, causing great harm to the life of occupants.

5.3 Relatively Closed Living Environment

Due to the influence of anti-theft and other factors, residential doors and windows are locked to form a confined space, and the indoor oxygen content is relatively low. After the fire, CO is generated due to incomplete combustion. After sleeping at night, the accommodation personnel encounter sudden fire and can easily become CO poisoning. Persons lose their ability to save themselves and escape, which can easily lead to casualties. The three deaths in the fire accident were CO poisoning.

6 Precautions for Fire Occurrence in Residential Buildings

(1) Strengthen the use of fire, electricity, and gas management in residential buildings for civil buildings. Leading by government agencies to strengthen the management ability of the neighborhood committees and public security police stations, organizing civil affairs, comprehensive management, safety supervision, culture and other departments to set up special fire inspections, carry out hidden investigations and daily firefighting management, and urge residents to timely carry out old and aging wires. Change or casing protection, safe use of electricity, fire, gas.

(2) Fire-fighting training actively penetrated into residential areas. The residents' fire safety education is included in the social fire safety training work. In a variety of well-informed forms, extensive education and training on residential fire, electricity, and gas use are conducted to effectively improve the people's self-defense and self-rescue capability.

(3) Strengthen community fire safety publicity work. Through the township (street), administrative village (community) and the villagers grid staff to strengthen the management of fire safety "grid", and vigorously carry out daily fire management and advocacy work. Strengthen the publicity work of fire prevention in urban and rural areas, open up new fronts for rural fire safety publicity and education, widely disseminate information on fire safety in rural areas, and provide rural families and schools with diverse forms of fire protection knowledge, from fire fighting, home use, fire, and gas use. It has effectively improved the ability of the people to prevent themselves and save themselves.

(4) Strengthen the fire safety management of residential properties. Aggregated residential buildings have become a trend in today’s society. As a property company that manages residential communities, it is closer to fire safety management, and it is reasonable to implement some fire safety management responsibilities in property management, and it can find and resolve existing safety problems in a timely manner.

This article comes from "Fire Investigation and Analysis" and was reorganized and edited by China Rescue Equipment Network.