What is the required size for the personnel entry opening on horizontal ducts?

What is the required size for the personnel entry opening on horizontal ducts?

• A. 24 in. x 24 in.
• B. 18 in. x 18 in.
• C. 16 in. x 16 in.
• D. 20 in. x 20 in.

Answer: (D)

Access for maintenance inside horizontal ducts has to be large enough for a worker to enter and work comfortably. The minimum opening specified is 20 inches by 20 inches. This size provides room for a person wearing typical PPE and bringing in tools, while allowing enough maneuvering space to position, rotate, and operate inside the duct. If the opening is smaller, entry, movement, and tool access become difficult and unsafe, which is why smaller options aren’t considered acceptable as the required minimum. Larger openings are permitted, but the 20x20 inch size is the standard minimum to meet practical access needs.

Access for maintenance inside horizontal ducts has to be large enough for a worker to enter and work comfortably. The minimum opening specified is 20 inches by 20 inches. This size provides room for a person wearing typical PPE and bringing in tools, while allowing enough maneuvering space to position, rotate, and operate inside the duct. If the opening is smaller, entry, movement, and tool access become difficult and unsafe, which is why smaller options aren’t considered acceptable as the required minimum. Larger openings are permitted, but the 20x20 inch size is the standard minimum to meet practical access needs.