What is used to seal unused ductwork in protected areas?

What is used to seal unused ductwork in protected areas?

• A. Metal plates caulked and screwed in place
• B. Duct tape
• C. Rubber grommets
• D. Plastic wrap

Answer: (A)

In protected areas, unused ductwork must be closed with a fire-rated closure. A metal plate sized to cover the duct opening is installed, fastened with screws, and the gap around it is sealed with an approved firestop caulk or sealant. This combination creates a durable barrier that preserves the fire-resistance rating of the surrounding assembly and prevents smoke, heat, and air from bypassing the protected area. Other options lack the necessary fire resistance or permanence and can fail under heat or over time, making them unsuitable for maintaining the integrity of the protected space.

In protected areas, unused ductwork must be closed with a fire-rated closure. A metal plate sized to cover the duct opening is installed, fastened with screws, and the gap around it is sealed with an approved firestop caulk or sealant. This combination creates a durable barrier that preserves the fire-resistance rating of the surrounding assembly and prevents smoke, heat, and air from bypassing the protected area. Other options lack the necessary fire resistance or permanence and can fail under heat or over time, making them unsuitable for maintaining the integrity of the protected space.