They say smoke detectors can save lives in a pinch. So, should you install smoke alarms in your home or not?
How much does the presence or absence of smoke detectors in a fire affect a successful escape?
Last year, our local fire and rescue detachment conducted an “experiential fire simulation experiment” to tell you the answer with experiments.
Firstly, let's get familiar with the classification and working principle of smoke detectors
Smoke detectors: commonly known as smoke detectors, we can see this product everywhere, whether it is an underground station, office buildings, shopping centres, hotels, shops, warehouses, server rooms, houses, etc. We can see it when we look up. Also known as smoke detectors, smoke detectors, smoke detectors, smoke probes and smoke sensors.
Classification of smoke detectors:
According to the principle class classification: ion type, photoelectric type
By transmission method: stand-alone, bus, relay, wireless.
Difference between ionic and photoelectric:
Ionic: more sensitive to small smoke ions, high sensitivity to smoke detection, generally used in places with high smoke detection requirements, such as laboratories, high speed trains.
Photoelectric: Sensitive to slightly larger smoke ions, poor response to grey smoke and black smoke. We are more common smoke detectors are basically photoelectric, such as offices, underground stations, shopping centres, etc.
Structure and main functions of photoelectric smoke detectors.
As shown above, the ASD426A smoke detector from anssin.
The smoke alarm pictured above is designed using the photoelectric smoke sensing principle to prevent fire by monitoring the concentration of smoke with a built-in photoelectric smoke sensor.
The smoke moves upwards and as it rises to the bottom of the ceiling and enters the maze detector in the smoke inlet area of the alarm, the smoke particles are partially scattered by light, the denser the smoke, the more light is scattered onto the photoelectric receiving element.
When a certain amount of light is scattered on the sensor receiving element, the device will alarm and a buzzer will sound to indicate a fire and at the same time a red light will flash to indicate a fire.
The working principle of photoelectric smoke detector.
The labyrinth of smoke detectors is the core component of smoke detectors, when a fire occurs, smoke enters the labyrinth through the smoke inlet slit, the smoke scatters the infrared emitted by the infrared transmitter tube, so that the infrared is received by the receiver tube, the labyrinth converts the light signal into an electrical signal, thus the smoke detection function.
The working principle of the labyrinth:
In the case of infrared emitting and receiving tubes without smoke due to the structure of the labyrinth, the receiving tube is unable to receive the light signal from the infrared emitting tube.
The infrared light from the infrared emitter is scattered by the smoke particles and the intensity of the scattered light is proportional to the concentration of smoke.
The intensity of the infra-red light received by the infra-red photosensitive receiver tube changes with the concentration of smoke, the greater the concentration, the stronger the light signal received. The receiver tube converts the light signal into an electrical signal, which is then converted into an alarm signal through the circuit.re
01
Simulated bin fire
Smoke sensing is almost 50 seconds faster than human reaction after a fire,Lasted at least 15 minutes in a closed room.
This simulation was placed in a local farmer’s house that was about to be demolished, three storeys high.
The fire started in a living room on the third floor, with two bedrooms attached to the front and back. As required by the experiment, the door to one bedroom was closed while the other was left open, and smoke alarms were installed in both rooms.
At 10.20am, the firefighters “lit the fire” in the living room and started the clock.
Simulated bin fire
Soon after, the first set of smoke detectors located in the living room alarmed for 26 seconds.
At this point, the visibility in the living room dropped significantly; the room I with the open door was also flooded with smoke and visibility began to drop; but in the room II with the closed door, apart from a slight smoke burrowing through the door, the reporter felt no significant change in the room and visibility remained normal.
The second set of smoke alarms, 44 seconds, was located in the bedroom with the door open. Visibility in the room drops significantly and the reporter begins to evacuate; visibility in the living room is almost zero; but the situation in room II remains unchanged significantly.
At 1 minute 12 seconds, the smell of smoke was so strong in the room with the door open that it began to affect normal human breathing and movement.
At 5 minutes and 03 seconds, visibility in the open door room is almost zero.
What about the closed door group?
At 10 minutes 55 seconds after the ignition, the smoke detection device in the closed room started to alarm. But at around 8 minutes after the ignition, the reporter in the closed room could already smell the pungent smoke (and hear the alarm in the living room).
It is worth noting that although a small amount of smoke seeped through the cracks into the closed room, the general air environment was maintained in such a way that escape was possible.
02
Simulated electric vehicle fire
The smoke response is more pronounced after the fire has started.The smoke was so thick that it only lasted for a maximum of three minutes.Once the smoke had cleared and the staff had reset all the individual smoke sensing alarms, the experiment began again.
After igniting the electric vehicle, the timer began.The electric car burns to produce a lot of black smoke.
The smoke alarm time in the living room was 24 seconds and visibility was almost zero in the area above 1.5m above the floor at the scene due to the large amount of smoke from the burning electric car, while visibility in room I also decreased significantly and the smoke from room II through the doorway was much more pronounced than in the first experiment.
The smoke pouring out of Room I caught the firefighters off guard
The alarm in the open room was 36 seconds and the freestanding smoke sensor alarm in Room I began to alarm and visibility was almost zero; visibility in Room II began to drop significantly and some of the journalists involved in the experiment began to evacuate.
After 1 minute and 18 seconds of alarming in the closed room, the freestanding smoke sensor alarm in Room II started to alarm and visibility in the room was less than half a metre except at a location above 1 metre above the ground, and visibility was dropping very quickly.
The smoke in Room II is becoming more and more visible
The smoke alarm time was 24 seconds in the living room, 36 seconds in the open room and 1 minute 18 seconds in the closed room, all of which were well ahead of the human response time.
Electric car quickly burnt to a hollow shell
03
Fire safety advice
It is recommended that smoke alarms are installed in the home
Installing smoke detectors can maximise the likelihood of a person escaping.
It is easy to see from this experiment that if the bedroom door is closed when sleeping, then the smoke sensor in the living room is able to react 7-8 minutes earlier than a human being can sense a fire.
If the door to the room is not closed when sleeping, then the smoke sense in the living room is able to sense the onset and spread of smoke about 50 seconds earlier than the human body.
If the living room is on fire, a person with the door to the room open will know about 6 minutes earlier than a person with the room closed. At the same time, however, the best time for a person to escape is approximately 5 minutes. Conversely, a closed room door gives you enough time to call for help and actively start saving yourself.
These two diagrams show a common situation in a fire: smoke rising up and layering, which is why the emphasis has always been on crawling to escape in a fire.
04
The overlooked stand-alone smoke alarm
No wiring required, just battery power
Once smoke is present in the early stages of a fire, it can be sensed
The role of smoke detection is actually overlooked by many people. Consider installing a freestanding fire smoke detector alarm in your home if conditions allow, as this can play an important role in the timely detection of fires, especially at night.
If you live in an environment where fire and electricity are dense, especially in public living rooms and kitchens, installing smoke detectors can maximise the possibility of escape.
The installation of freestanding smoke detection alarms should include the public areas of the above buildings and premises, bedrooms and other resting rooms in residential buildings, living rooms, living rooms, dining rooms, internal walkways, the upper part of the evacuation staircase on each floor, and other rooms and parts with fire hazards.
SD-431
SD-436
05
"Smart Smoke Sensor"Text Here
Unlocks even more new features
Providing accurate data on fire starts
The “Smart Smoke Sensor”, which Anssin has been promoting, can be linked to the mobile phones of up to five people.
In the event of a fire, firefighters, the community and even the elderly person’s family will be the first to know about the fire, and will be able to pinpoint the location of the alarmed smoke sensor, making it easier for rescue services to get to the scene in the first place.
The only substances that caught fire in the experiment were rubbish bins or electric cars,Real fires are more complex and dangerous than experimental situations Installing smoke detectors can Maximise the chances of a successful escape.
What are you waiting for?