Understanding smoke and the importance of smoke detectors for safety

How is smoke composed?

The exact composition of smoke from a fire varies depending on the source of the fire and the materials burned. The main constituents of smoke are as follows:

• Nitrogen (N2): approximately 40-60%
• Carbon dioxide (CO2): approximately 20-30%
• Hydrocarbon gases (CH4, C2H2, C2H4, C2H6): approximately 10-15%
• Carbon monoxide (CO): approximately 5-10%
• Water vapour (H2O): approximately 5-10%
• Oxygen (O2): approximately 3-5%
• Ash, solid particles and soot: approximately 1-5%.

These figures vary according to the situation and the type of fire. Early smoke detection is crucial to prevent the risks associated with fire. Good detection allows you to react quickly in the event of a fire starting, before it spreads and causes significant damage. It is therefore essential to have reliable detection devices that comply with current safety standards to ensure the safety of the home and its occupants. These devices will trigger an alarm in the event of smoke, which will warn the occupants and encourage them to evacuate. These standards guarantee that the devices meet the performance criteria necessary for effective protection against the risk of fire and ensure that the alarm will be sufficient to prevent any danger.

Where does the smoke come from?

It is important to realise that in France, a domestic fire breaks out every 2 minutes. In 1 in 4 cases, the fire is caused by poorly maintained electrical equipment or installations. On average, there are 10,000 fire victims per year, including 800 deaths. In 75% of cases, death occurs through asphyxiation due to smoke from the flames.

The smoke produced during a domestic fire can come from various sources. These include fires:

• Electrical and electronic: caused by short circuits, overloaded sockets, faulty appliances
• Kitchen fires: caused by cooking errors, grease or oil fires
• Fuel fires: such as wood, paper and cardboard, plastic, etc.

It is important to understand how the various safety devices work in order to guard against the dangers of fire. Indeed, the proper functioning of smoke detectors and other safety devices is essential to prevent fires and protect occupants. It is also essential to ensure regular maintenance of electrical installations and to follow safety instructions. By ensuring that smoke detectors and all installations are properly maintained, it is possible to reduce the dangers associated with fire and ensure the safety of the home and its inhabitants.

How does smoke affect the body?

What are the effects?

The smoke produced by a fire can have serious consequences because of the particles it contains. Fine particles can penetrate deep into the respiratory tract and lungs. Once inhaled, smoke causes:

• An increase in heart rate
• Irritation of the respiratory system
• An increased risk of asthma, bronchiolitis, bronchitis and cancer.

Smoke also contains toxic substances such as carbon monoxide (CO) or sulphur dioxide (SO2), which affect the eyes, skin and nervous system. Carbon monoxide (CO), in particular, is an odourless, colourless and invisible gas that is dangerous. If inhaled in high doses, it can cause various symptoms such as dizziness, nausea and headaches, and can even be life-threatening.

Smoke therefore represents a serious threat to the lives of the occupants of a building. It is therefore crucial to take appropriate safety measures to protect your life and avoid any exposure to its dangers. Make sure your home is equipped with reliable smoke detectors to ensure your safety and that of your family.

What should I do if I see smoke?

In order to protect your health and safety against possible asphyxiation due to smoke, here is what to do in case of fire:

1- Evacuate the premises as quickly as possible, covering your nose and mouth with a handkerchief or piece of clothing to protect yourself from toxic gases.

2- Call the emergency services by dialling 18 or 112.

3- Stay away from the source of smoke and heat until help arrives. If you are near the exit or on a floor below the fire, get out.

Otherwise, if you are on a higher floor or even on the same landing, stay where you are and take the appropriate steps to protect yourself:

• Close the doors;
• Spray and seal the door with wet cloths if smoke is coming through it;
• Wait for help by standing at a window;
• Crawl on the floor and cover your nose and mouth with a damp handkerchief if smoke is entering the room.

These measures will protect you and minimise the dangers of smoke and heat inhalation.

How to avoid the risk of fire?

It is important to carry out certain tasks to avoid smoke inhalation and prevent fires in the home:

• Have installations and other electrical appliances regularly maintained.
• Carry out minor repairs such as changing a faulty power socket or replacing a bare wire.
• Avoid overloading multi-sockets to avoid the risk of overheating.
• Have the chimney swept once a year.
• Store flammable products and other combustible materials in safe places and outdoors.
• Check the fire extinguishers.
• Have a system of smoke detectors (DAAF) installed.
• Set up a remote monitoring system to enhance security and ensure a rapid response in the event of an incident.

These detection and remote monitoring systems will help to ensure the safety of the home and its occupants by providing a rapid warning in the event of smoke. The audible alarm signal triggered by these detectors ensures a quick and efficient evacuation, thus reinforcing the overall fire protection system. This audible signal, combined with remote monitoring, is crucial for warning occupants and ensuring a quick response to an emergency situation.

What does the law say about smoke detectors?

Smoke detection is crucial to ensure the safety of people in buildings. Fixed smoke detectors are devices designed to detect the presence of smoke in the air. They play a key role by triggering audible alarms in the event of suspected smoke. This detector device alerts occupants to evacuate the premises. In France, since 8 March 2015, the law requires every owner to install a smoke detector (DAAF) in all homes. This device must be EN 14604 certified and bear the CE marking. This standard guarantees that the product has passed sufficient performance tests and complies with safety requirements.

The smoke detector should preferably be installed on the ceiling. In apartment buildings, it is recommended that each owner installs a smoke alarm on each floor. For large dwellings, it is better for the owner to install several devices to ensure optimal safety. To guarantee that it works properly, it is recommended that you test and dust the detector's installation and carry out regular maintenance at least once a year, which increases the product's lifespan and ensures that it works properly.

Smoke is an asphyxiating and toxic gas. That is why it is important for the owner to be able to detect it quickly to avoid suffering its consequences. The type of smoke detection system is something that should not be taken lightly, as the duration of smoke detection can influence the speed with which the alarms are triggered.

Smoke detectors are designed to detect the early stages of a fire. They thus ensure the safety of a home and its occupants. The type of detector installation to be used depends on the characteristics of the dwelling and its specific security needs. The battery life of the smoke detector should also be checked by the owner to ensure reliable long-term detection, with proper maintenance, and to enable the alarms to be triggered correctly.