In an emergency when the ventilating current is reversed, how should doors that affect ventilation be maintained?

In an emergency when the ventilating current is reversed, how should doors that affect ventilation be maintained?

• A. Self-closing
• B. Left open
• C. Operated manually by workers
• D. Locked shut

Answer: (A)

When ventilation can reverse direction in an emergency, the air paths must stay as the system was designed to prevent dangerous backflow and spread of contaminants. Self-closing doors ensure these air controls stay in place automatically, even if power or visibility is lost. They close after passage and stay closed, preserving the intended flow and isolation between zones without requiring people to operate them in a dangerous situation. Leaving doors open or relying on manual operation introduces the risk of uncontrolled air movement and contamination spreading, while locking doors shut would block necessary ventilation.

When ventilation can reverse direction in an emergency, the air paths must stay as the system was designed to prevent dangerous backflow and spread of contaminants. Self-closing doors ensure these air controls stay in place automatically, even if power or visibility is lost. They close after passage and stay closed, preserving the intended flow and isolation between zones without requiring people to operate them in a dangerous situation. Leaving doors open or relying on manual operation introduces the risk of uncontrolled air movement and contamination spreading, while locking doors shut would block necessary ventilation.