American Chemical Society (ACS) Laboratory Safety Practice Test

In a chemical laboratory, the types of materials present typically include flammable liquids, electrical equipment, and various chemical substances. Therefore, having an appropriate selection of fire extinguishers is crucial for addressing potential fire hazards.

Class-A extinguishers are designed for ordinary combustibles like wood, paper, and textiles, which can be relevant in a lab setting if there are any items of this nature present. Class-B extinguishers are essential for flammable liquids such as solvents and oils, which are common in chemical labs. Class-C extinguishers are utilized for fires involving electrical equipment, a fairly common scenario in labs with various electronic devices.

Ordinary combustibles extinguishers are less suitable for a chemical lab environment because they specifically target Class-A materials. Given that chemical labs often contain flammable liquids and electrical equipment, relying solely on extinguishers meant for ordinary combustibles would be inadequate for effectively addressing the broader range of potential fire threats. This makes them less appropriate to have in a lab where specific risks need proper coverage.