What is the simplest type of fire extinguisher?

The simplest type of fire extinguisher is the pump tank water extinguisher. This kind of extinguisher utilizes water as the primary extinguishing agent, making it straightforward in its design and operation. The mechanism typically involves a manually operated pump that draws water from a tank, allowing the user to direct a stream of water at the fire. This simplicity comes from the ease of use; there is no complex mechanism to operate or specialized training required beyond basic fire safety knowledge.

Water extinguishers are particularly effective for Class A fires, which involve ordinary combustibles such as wood, paper, and cloth. Their ease of access and understanding make them a reliable first response tool in many situations. Other types like CO2 extinguishers and foam extinguishers involve more specialized applications and handling. The water mist extinguisher, while useful, involves a more complex technology—producing a fine mist that cools the fire and displaces oxygen, which may not be as immediately straightforward for all users.