Hot work training course includes a theoretical aspects as well as hands on practical fire extinguishing session. This has also often been a good topic for active discussions on courses.
The laconic saying “wrongly extinguished” comes from the story that the fire brigade was late arriving at the scene of a fire and by the time they got there, the volunteers had already extinguished the fire. This self-respecting fire chief was obviously annoyed, so all he could think of to say was the legendary phrase: “Wrongly extinguished!
But.
Without commenting on this particular story or its truthfulness, there is also a lot of validity to the saying. Sometimes this results in unnecessarily large material damage compared to the initial situation and could be like shooting a mouse with a cannon. In other words, while the fire may have been extinguished, and the property saved, it may also have been irreparably damaged in the process. This happens when large amounts of water is hosed into the structure. In fact, when fires that start on the roofs of buildings, the majority of the damage is often caused by the extinguishing water. Fire was on the roof but extinguishing water flooded through several floors and caused structural damages.
Fire develops quickly
Proper initial firefighting and the use of the correct type of extinguisher are crucial. When a fire occurs, there is little time to act. A key factor in managing the situation is the ignition source. Flammable liquids, such as fuels, ignite explosively, whereas solid materials tend to catch fire more slowly. For instance, if a candle is knocked over onto a tablecloth, it could easily ignite a fire that can be controlled by immediately pouring water on it. The situation, however, changes drastically within 2-3 minutes after ignition, making it impossible to contain the fire at this stage due to the heat and smoke generated.
The response time for emergency services in cities is around 10-15 minutes. However, Finland is a sparsely populated country with long distances. On a nationwide scale, according to the fire services’ own statistics, help can be delivered to the accident site within 20 minutes in 90% of cases. https://pelastustoimi.fi/en/rescue-services/rescue-operations
Within 20 minutes, however, the fire has typically escalated to catastrophic proportions at the site and only fire and rescue services might have means to get the situation under control and prevent fire escalating further. For a single business- or realty owner quick emergency preparedness is important. By acting fast we can often put out the fire or at least slow it down until fire brigade arrives and minimise damages.
Safe operations and damage minimization start with advance planning and preparedness. In the event of an emergency, the right type of fire-fighting equipment should be close at hand. Our observations show that the overall situation has improved in recent years and that the fire-fighting equipment on the premises seems to be generally well selected. In the past, it was not uncommon to see, for example, powder extinguishers in domestic appliance stores as the fire extinguishers in the area of the property. In such a situation, the damage caused by a possible electrical fire in one appliance would have been relatively high if anyone had spread a whole 6 kg of powder into the air in twenty seconds.
How to choose the right extinguisher for different situations and locations?
Here is a concise summary of the pros and cons of common fire extinguishers and their suitability for different situations.
Extinguisher types
Class ABC powder extinguisher is a handy tool because it can be used to extinguish a wide range of fires and is very effective. As an ABC class extinguisher, it can be used to extinguish Class A fires, i.e. fires involving solids (wood, textiles, etc.). Class B fires involving non-flammable liquids (solvents, petrol, etc.) and Class C fires involving gases (propane, butane, etc.). It is also suitable for electrical equipment fires up to 1000 volts. The extinguisher is also worry-free because it works in both cold and hot conditions, from -30°C to +60°C.
The powder extinguisher is not affected by seasonal changes and can be stored outdoors without any problems. The effectiveness of powder extinguishers is mainly based on so-called negative catalysis. The extinguishing agent forms a powerful cloud of powder which effectively covers the burning surface, thus interrupting the burning process. The resulting extinguishing layer also prevents re-ignition. Powder extinguishers are also very efficient for their size. However, a powder extinguisher is not a precision weapon. The powder spreads quickly through the air into the surrounding areas and causes a lot of mess. The powder itself is so fine that it can get inside machinery and equipment, often causing it to break down. It should also be remembered that moist powder is corrosive.
Class AB foam extinguisher contains water and foam. The foam extinguisher is best suited for extinguishing liquid fires. I also consider this to be the best option for every home as a primary extinguisher. The foam extinguisher is about as effective as a powder extinguisher, but it does not cause the same mess and the destruction of electronic equipment. The foam extinguisher is frost-sensitive and should be kept indoors during the winter. Unless you have gas stoves, refrigerators and other appliances in your home, I would recommend a foam extinguisher indoors and a powder extinguisher outdoors. Sometimes less effective but environmentally friendlier water extinguisher could be considered 27A34B*40F. Class F refers to kitchen grease
Pictures from one of our Fire fighting practise. Task was to extinguish liquid fire (diesel) with a hand held extinguisher. On the first picture Foam extinguisher
This picture extinguishing with powder. Notice how powder dust in the air. It spreads quite far.
These stationary extinguishers should be inspected by an authorised fire extinguisher service centre according to the inspection period stated in the label. Indoor and immobile extinguishers typically every 2 years, others once a year.
A CO2 or carbon dioxide extinguisher is a Class B extinguisher. It is designed to extinguish flammable liquids by suppression, as the gas discharged from the extinguisher replaces the oxygen required for combustion with carbon dioxide. The gas discharged is very cold and close to -80 degrees Celsius. The advantage of the CO2 extinguisher is that it does not create a mess around the extinguisher. The extinguisher is not very efficient in terms of its power rating. If you compare the 89B rating of a 6 kg extinguisher to flammable liquids, the equivalent rating for a physically similar sized powder or foam extinguisher could be 233B. These numbers refer to amount of liters of flammable liquid. (in laboratory test mix of water and heptane. 89 liters versus 233 liters of burning liquid)
On the downside, the power rating is limited to flammable liquids, and the use of the extinguisher to extinguish, for example, burning clothing could become life-threatening if the person wearing the clothing were to gasp gas into his lungs. At the same time, it should be borne in mind that the escaping gas causes frostbite on contact with the skin. CO2 extinguishers are often used in electrical rooms because the gas does not cause a mess or damage to surrounding equipment.
Fire blankets. This fire extinguisher is good and cheap and should be a standard feature in every kitchen. It is well suited to extinguishing grease fires, for example. A grease fire is an unfortunate example of improper extinguishing. If you make the mistake of ‘extinguishing’ a grease fire with water, the water quickly evaporates and a vapour throws the burning grease around, turning the kettle into a veritable pillar of fire.
Conclusion:
Fire alarms and fire-fighting equipment are an important part of home security. The investment is not even that big when you think about what it protects. However, when choosing extinguishers, it is worth considering the circumstances and placing them in a location where they are easily accessible. It would be a good idea to practice using the extinguishers so that you can do the job if a situation, even if it is pressurised, should ever arise. Practising will give you confidence in the situation and also help you to assess whether the fire is already at the stage where evacuating yourself and others is really the only and right option.
Been there, done that – my own experience of an initial firefighting situation
In real life, the undersigned has twice extinguished an incipient fire with a fire blanket. In both cases, major damage was very possible, but by doing the right thing, the damage was relatively minimal.
The first time was an electrical appliance fire in a cooker hood. Something went suddenly wrong when the appliance was put into operation in a summer place after the winter. It would have taken the fire brigade an estimated half an hour to arrive, so the situation would have been over in a bad way if you had only been able to call for help. A powder extinguisher was also available and within reach at the time, which gave me the security and confidence that the situation would be resolved, but fortunately as I considered my options I did not need to use it. The fire blanket did the job and if the powder extinguisher had been used indoors, it would have taken quite a while to clean up. After this episode, the indoor powder extinguisher was replaced with a foam extinguisher and today there is a CO2 extinguisher and a foam extinguisher in the hallway of the property. There is a fire blanket in the kitchen.
On the second occasion, a grease fire started in a large gas barbecue. This too was overcome, although there were also elements of disaster when one of the guys grabbed a pint of water and approached the barbecue. Brisk shout ”NO!” and he stepped back. This would have been specifically the wrong way to extinguish fire.
Here is a link to a video example of why a grease fire should not be extinguished with water, but with a blanket or kettle lid, for example.
Enclosed a safety demonstration with a grease fire. How to do it and especially what NOT to do
You can learn how to use fire extinguishers on a course such as a basic fire-fighting course or on a hot work license training course. We have also organised fire-fighting exercises and fire-fighting demonstrations tailored to corporate recreation days, for example.
