How to use sensors to make Hangzhou nanny arson si

How can we stop the similar tragedy of "Hangzhou nanny arson" with the help of sensors

the controversial "6.22 Hangzhou nanny arson case" is not over yet. In the early morning of July 16, another arson case occurred in Changshu, Jiangsu Province, causing 22 deaths. The shocking death figures affect our nerves. Most of the annual fire deaths in most countries in the world occur in houses, and a considerable part of them occur in the night when people are least alert. The main cause of death caused by fire is not burn, but inhalation of smoke

sensor technology may help to stop the tragedy of the "Hangzhou nanny arson case"

this summer, it seems unusual. In addition to the unusual high temperature, some unusual things have happened in it. The controversial "6.22 Hangzhou nanny arson case" is not over yet. In the early morning of July 16, another arson case occurred in Changshu, Jiangsu Province, which caused 22 deaths. The shocking death figures affect our nerves

"6.22 Hangzhou nanny arson" occurred in a real rich community. Eight 25 storey glass curtain wall residential buildings rose from the ground on the East Bank of the Qiantang River. Under the gray blue double-layer glass inside and outside, each building looks neat, dense and impenetrable at first glance, making people unable to imagine the cave with more than 300 flat inside. But in the early morning, a fire on the 18th floor shattered the calm and rich life of all businesses. The fire resulted in the death of four mothers and sons, leaving only Mr. Lin, the male owner of the home. Today, Mr. Lin has been upholding his rights on the road, just to give justice to his family

in addition, it was reported that at more than 4 a.m. on July 16, a fire broke out in a two-story residential building in Yushan Town, Changshu City, Jiangsu Province, killing 22 people and injuring 3. At present, it has been identified as arson, and the suspect has been arrested

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these two fires are man-made arson. Why the suspect set fire is not discussed here. Only from the details disclosed in the report, we should get some warnings from the fire

most of the annual fire deaths in most countries in the world occur in houses, and a considerable part of them occur at night when people are least alert. The main cause of death caused by fire is not burn, but inhalation of smoke. In order to enable people to detect fires as soon as possible, the United States began to apply temperature sensitive fire alarms and household automatic fire alarm systems in residential buildings more than 90 years ago, but the effect is not ideal. Later, when the independent smoke alarm entered the home, people found that its effect was obviously better than the temperature alarm. Since the mid-1970s, the United States has taken the lead in vigorously promoting household independent smoke detectors, and other developed countries have followed suit. Through 40 years of efforts, now most families in major developed countries have installed independent smoke detectors, leaving a lot of experience worthy of our reference

there are two kinds of sensors for the independent smoke detector of civil residence: one is ion sensor, and the other is photoelectric sensor

photoelectric sensor measures the concentration of smoke through a beam of light and a light sensor. When the device is designed, the light beam deviates from the sensor. And make them wear faster. When the smoke enters and passes through the semi-circular ball punch to impact and break through the sample to the induction chamber at a certain impact speed, the smoke particles will scatter part of the light beam onto the sensor. When the concentration of smoke increases gradually, more light beams will be scattered to the sensor. When the light beam reaching the sensor reaches a certain degree, the buzzer will sound

each alarm has reached the test standard, but they have their own advantages. The ion alarm is sensitive to tiny smoke particles, but Alexander aucken, the global automotive director of cyanate, points out that it is faster. When there are open fires (such as burning newspapers) and fast burning fires, there are more small particles of smoke in the air, and the ion alarm will alarm first than the photoelectric alarm. The photoelectric alarm has a faster response to slightly larger smoke particles. When smoldering (such as when the cigarette end ignites the sofa), there will be more slightly larger smoke particles in the air, so the photoelectric alarm will alarm first than the ion alarm. The time interval between these two alarms is not large, but many fires spread very fast, so time is crucial to save lives

the independent smoke fire alarm has simple structure and convenient installation, which is very suitable for residential use. Since developed countries vigorously promoted it in families, they have played an important role in protecting the life safety of residents. Due to the earliest promotion in the United States, the relevant statistical data of official and social organizations are relatively complete. Here, take the data of the United States as an example to illustrate the problem

before 1973, about 6200 people died and 100000 were injured in fires in the United States every year. By 2012, 2855 people died and 16500 were injured in fires in the United States, and the number of deaths and injuries has decreased significantly. Another set of data is that in 1977, only 22% of homes in the United States installed smoke fire alarms. By 2010, 96% of American households had at least one independent smoke alarm. Research and detailed analysis show that these two groups of data are positively correlated

according to the statistics of the American Fire Protection Association from 2005 to 2009, 62% of the death rate of domestic fires in the United States came from families that did not install independent smoke fire detection alarms or did not work normally. In the event of a fire, the chance of escape was 63% higher than that of families that did not install or did not work effectively, In particular, this inevitably has some impact on the accuracy of measurement. Above all, when the fire is very small, the timely alarm of the independent smoke fire detection alarm increases the opportunity of fire fighting and escape in the initial stage, and the mortality rate is only 1%

independent smoke detectors play a great role in the safety of residents. Although they have not been widely used in China, their scope is also expanding, and their effectiveness is increasingly recognized by the government and the public. If they can enter thousands of households, it is believed that many lives can be spared