Final answer:
Fan blades must be guarded when they are less than 7 feet above the floor to prevent accidental injuries.
Step-by-step explanation:
When the blades of a fan are less than 7 feet above the floor, they must be guarded to prevent accidental contact and potential injury. This safety regulation is important to adhere to in both residential and commercial settings. Ensuring the blades of a ceiling fan or any other type of fan are properly guarded helps minimize the risk of injury due to their operation, especially in environments where individuals might inadvertently come into contact with them due to their height proximity.