Describe the Narrabri distribution barrier design for standard height.

• A. 12 bags, hung in 2 rows
• B. 11 bags, hung in 2 rows
• C. 11 bags, in 2 rows 0.3m apart
• D. 11 bags, hung in 2 Rows 0.5m apart

Answer: (D)

The standard height Narrabri distribution barrier is achieved by using eleven bags hung in two rows with a 0.5-meter gap between the rows. This setup creates a uniform barrier surface across the opening, giving the required height and continuity to block or control the intended flow. The two-row arrangement adds thickness and stability, ensuring the barrier remains effective under operational conditions, while the 0.5-meter spacing defines the gap between rows so the barrier maintains its shape and performance. Deviating from this by changing the bag count or spacing would move away from the established height and cross-section, reducing consistency with the standard.