This article provides the importance of fire safety to pharmaceutical and other allied industries. Before moving on to Fire Types and Extinguishers, let us look into the basic aspects of fires and safety.
Industrial Safety has got utmost importance. Safety stands on two most important pillars, i.e. Risk and Hazard. Let’s see the difference between the two.
Hazard is something that can cause harm or damage to business assets or humans. Examples of hazards: Chemicals, Electricity, Noise, Fire, Stress, working on height or in a confined space, etc.
Whereas, Risk is the probability of any hazard actually causing harm. The risk depends on the ‘n’ number of factors that can put us in danger. For example, in a gasoline storage area, an electrical spark can cause harm in terms of fire but the probability of happening incidence is a risk.
So, we can say that fire is a hazard and poses a potential risk if not addressed properly. Anyway, this article focuses on Fire types and their applicable extinguishers.
What Is Fire? How It Differs From Flame?
Fire: Rapid oxidation of material because of the process of chemical combustion, liberating different energies such as light, heat, smoke, and chemicals.
Whereas, Flame: Visible portion of the fire that can be seen through the naked eyes. Red-Orange flame shows incomplete combustion while blue flame shows complete combustion.
To understand the fire types, let’s see how fire starts and the elements that cause the fire when they come in contact with each other.
You might have heard of the term ‘Fire Triangle‘ earlier, let us see it again.
There are 3 necessary elements required to cause a fire.
- Source of Ignition (Heat)
- Fuel (Wood, Plastic, Clothes etc.)
According to the above diagram:
- All elements (Heat, Fuel, and Oxygen) depend on each other.
- The fire can cause if and only if all elements are present at the same time.
- Fire will not ignite if any one of the elements is absent.
Hence, avoiding fire requires a tool that eliminates any one component from the fire triangle and ultimately breaking the fire triangle.
Let us understand the 5 classes of fire and their applicable extinguishers that’ll answer the following questions.
- What are the fire types or classes?
- How do we decide the classes?
- Which type of extinguisher mitigates a particular fire type?
Fire Types and Extinguishers
Refer below the matrix representing fire class or type and associated extinguishers.
Following are the types of available fire extinguishers.
- Dry Powder
- Wet Chemical
As seen in the above matrix, no single fire extinguisher can eliminate all classes of fire. Instead, each fire extinguisher has its importance in handling distinct classes of fire.
Compatible to mitigate Class A fires. Includes fire due to wood, paper, cardboard, coal, fabrics, or dry pulps. Installed near to exit place of hospitals, offices, etc.
When water is sprayed on the fire has a cooling effect, reducing heat transfer (remember fire triangle) gradually eliminating heat element.
Label color on fire extinguisher is Red.
There are 3 types of water extinguishers:
- Jet: Extend less surface area, consuming more time and water to mitigate fire.
- Spray: Covers more surface area requires less time to diminish fire but may require more water.
- Mist: They are lightweight and have proper flow control. The rate of spraying ranges between 250-300 microns of water droplets forming a layer of heat with high precision. Droplet size of fewer than 250 microns can cause water droplets to evaporate and cannot mitigate the fire. On the other hand, higher particle size result in more water wastage. Sometimes able to handle Class B fires when added suitable additives.
Dry Powder Extinguishers
They are compatible to mitigate Class A, B, C, D, and E fires. Not recommended for use in confined spaces which may cause more confusion, difficult cleaning, and suffocation issues. We may find these types of fire extinguishers in the chemical, pharmaceutical, petroleum industries, etc.
Just like a water type they too cause barriers but in between oxygen and fuel, which ultimately breaks the fire triangle.
Label color on fire extinguisher is Blue.
They are compatible to mitigate Class B and E fires. We can find these types of fire extinguishers in paint industries or construction sites wherever flammable liquids or electrical fire hazards may occur.
Carbon dioxide is typically stored in a liquid form. When released from the nozzle, converts into gas. CO2 gas, when comes in contact with the fire, replaces the oxygen with the help of high pressure. This eliminates the oxygen in the fire triangle, which results in a mitigated fire.
Label color on fire extinguisher is Black.
Compatible to mitigate Class A and B fires. These types of extinguishers found in all places mentioned in the water extinguisher plus flammable metals.
Foam when applied on fire, reduces the heat and creates the barrier between fuel and heat, eventually mitigating the fire.
Label color on fire extinguisher is Cream White.
Wet Chemical Extinguishers
Compatible to mitigate Class A and F fires. Found in commercial and industrial kitchens and restaurants as wet chemicals effectively handle the fires caused by combustible cooking media such as oils and fats.
Wet chemicals when sprayed, convert to foam and form a barrier between oils and heat, which mitigates the fire gradually.
Label color on fire extinguisher is Yellow.
As we’ve seen, each fire type to mitigate requires a different extinguisher. Therefore, the selection or application of fire extinguishers should be considered on a detailed and optimized analysis of suitability, cost, resources, and then bringing out effective solutions.