In basic fire safety, portable carbon dioxide (CO2) fire extinguishers are especially suitable and recommended for which type of fire?

Introduction / Context:
Different types of fire extinguishers are designed for different classes of fires, such as those involving solids, flammable liquids, or electrical equipment. Using the wrong type of extinguisher can be ineffective or even dangerous. Carbon dioxide (CO2) fire extinguishers are a common type found in offices, labs, and computer rooms. This question asks you to identify the type of fire for which CO2 extinguishers are especially suitable, a key point in basic fire safety education.

Given Data / Assumptions:

• CO2 extinguishers discharge carbon dioxide gas under pressure.
• They leave no solid or liquid residue after discharge.
• Electrical and electronic equipment can be damaged by water or powder.
• The options mention crackers, electrical fires, bombs, and large structural fires.

Concept / Approach:
CO2 works primarily by displacing oxygen around the fire and by some cooling effect, thereby suffocating the flames. Because the gas does not conduct electricity and does not leave a residue, it is particularly suitable for fires involving live electrical equipment such as computers, switchboards, and servers. Water-based extinguishers can cause short circuits and damage equipment, while powder extinguishers may leave corrosive or messy residues. CO2 is not the best choice for outdoor fires involving fireworks, for bomb-related explosions, or as a general solution for large building fires; those situations often require specialised equipment and professional firefighting services.

Step-by-Step Solution:
Step 1: Recall that CO2 extinguishers release a cold gas that displaces oxygen and does not leave residue. Step 2: Recognise that this makes them ideal for use around sensitive electrical and electronic equipment where cleanliness and non-conductivity are important. Step 3: Examine the option involving crackers and fireworks in open fields, which are usually handled with water or sand and not primarily with CO2. Step 4: Consider that bomb-related fires and explosions are highly dangerous and usually addressed by specialised teams, not standard portable extinguishers. Step 5: Note that large structural fires in buildings often require water, foam, or multiple agents applied by fire services, not just small CO2 extinguishers. Step 6: Conclude that the correct answer is fires involving live electrical and electronic equipment.

Verification / Alternative check:
Fire safety manuals and extinguisher labels typically indicate that CO2 extinguishers are safe for use on Class B (flammable liquids) and Class C (electrical) fires, depending on national classification systems. Offices and server rooms almost always have CO2 or clean agent extinguishers specifically to protect electrical equipment without causing additional damage. Training courses on fire safety emphasise matching extinguisher type to fire class, and they commonly use CO2 examples for electrical panels and computer racks. This confirms that electrical fires are the main recommended use for CO2 extinguishers.

Why Other Options Are Wrong:
Fires caused by fireworks and crackers in open fields are usually handled by preventing ignition and using water, sand, or foam rather than relying mainly on CO2 extinguishers.
Explosions and fires caused by bombs and military explosives involve extreme hazards and are managed by bomb disposal and firefighting professionals, not by typical portable CO2 units.
All types of large structural building fires regardless of cause is incorrect because large fires often require a combination of water, foam, and other agents, and CO2 alone is not sufficient or safe for every situation.

Common Pitfalls:
A common mistake is to assume that any extinguisher can be used on any fire. In reality, using water on an electrical fire can cause electric shock or further damage, and using CO2 in very small unventilated spaces can pose a suffocation risk. Another pitfall is thinking that CO2 extinguishers are "universal" because they look sophisticated and leave no mess. Remember instead that CO2 is especially suited to electrical and electronic equipment fires where non-conductive, residue-free suppression is essential.

Final Answer:
Carbon dioxide fire extinguishers are especially suitable for Fires involving live electrical and electronic equipment where no residue is desired.