Which type of conduit is commonly used in air-handling spaces?

The correct answer is electrical metallic tubing (EMT) because it is designed to provide protection against physical damage and is non-combustible, making it a suitable choice for air-handling spaces where fire safety is crucial. In these environments, the risk of fire spreading through wiring methods must be minimized, and EMT is effective in meeting those requirements due to its metal construction.

In air-handling spaces, electrical systems must comply with strict regulations to ensure that any material used does not contribute to the spread of fire or produce harmful smoke. EMT's ability to contain electrical wiring securely while not allowing the passage of flames or smoke is why it is preferred in such settings.

Other types of conduits mentioned have limitations in their fire resistance and durability in air-handling areas. For example, flexible plastic conduit and PVC conduit may not provide the same level of fire safety due to their combustible nature, and common plastic pipe is generally not designed for electrical applications, which could lead to code violations and safety hazards in environments that require enhanced fire protection.