Understanding Non Climbable Zones (NCZs) in Pool Barrier Safety 🚱

I’ve seen a few queries online where Non-climbable Zone rules have been misunderstood or misplaced so here’s a brief overview of the NCZ’s and what to check for.

Under AS 1926.1‑2012, there are five distinct Non‑Climbable Zones (NCZ 1–5) designed to prevent children from using barriers as ladders into pools. Please note this article references the 2012 standard – other standards are similar but measurements and rules do differ.

✳️Why Are NCZs Important?

These zones ensure that no horizontal or vertical climbable components—like rails, tree branches, furniture—are within specified clearance areas of the barrier. They’re fundamental to preventing child access, addressing a leading cause of drowning in 0–4 year olds

📝What are the five distinct Non-Climbable Zones NCZ?

NCZ 1 – 900 mm Vertical Plane (External Face of Internal Barrier)

• Measured 900 mm outward, perpendicular from the external face of an internal barrier under 1.8m tall.

• Must be clear of any climbable items or graspable parts. Projects and indentations are considered climbable if they are 10mm or more in depth

• Positioned anywhere within the barrier’s height, including between horizontal elements

  
  

NCZ 2 – Lower Quadrant Outside (Curve Downward)

• A quadrant (arc) with a 900 mm radius downward from the top of NCZ 1, adjacent to NCZ 1.

• This arc must be fully clear of any climbable objects

  
  

NCZ 3 – Upper Quadrant Outside (Curve Upward)

• A 900 mm radius quadrant upward from the top of the barrier.

• This arc must also be fully clear of any climbable objects

  
  

NCZ 4 – Rectangular Zone Inside (For Narrow Vertical Gaps)

• Applies only where the barrier has vertical gaps of 10–100 mm.

• A 900 mm high × 300 mm deep rectangular zone inside, aligned with NCZ 1 elevation.

• Ensures no footholds within the gap that give leverage to climb

  
  

NCZ 5 – Boundary Barrier Quadrant (Top Inside of Boundary Fence)

• Applies when a boundary fence is used as a pool barrier.

• A 900 mm radius quadrant downward from the top inside of this fence forms NCZ 5.

• Ensures the internal side of boundary fences is free of climbable features

🚩Why NCZs Matter

• Child safety: A properly enforced NCZ prevents young children climbing into pools unsupervised.

• Legal compliance: Non‑compliance can result in orders and/or, fines.

• Inspection readiness: NCZs are a crucial part of your pool barrier inspection—failure to meet them is non-compliant.

🔍What is not permitted in a Non-climbable Zone?

• Trees or tree branches – straight trunks with no projects or indentations more than 10mm are ok

• Garden beds or soil build-up

• Climbing plants or vines

• Pool equipment (pumps, filters, heaters)

• Furniture (tables, chairs, benches)

• BBQs or outdoor kitchens

• Play equipment or toys

• Ladders or step stools

• Pot plants or planter boxes

• Pergolas or shade structures (with horizontal elements)

• Storage boxes, bins, or eskies

• Clotheslines or drying racks

• Bikes, scooters, or sports gear

• Decorative objects or statues

Please note this list is some common things I have seen and is not exhaustive!

✅Maintenance Tips to protect your NCZs

• Trim tree branches regularly

• Remove or relocate any climbable items near the barrier

• Avoid storing objects near the pool fence, even temporarily

• Ensure fences and gates are in good repair and not warped or loose

• Always allow wriggle room – fence components move, plants grow. Plan gaps/ fence height etc with room for movement and growth

🧾Summary of NCZ Requirements

• NCZ1 – 900mm area on the outside of the barrier (from the top of the fence downwards)

• NCZ2 – 900mm arc from the top of the barrier downwards externally

• NCZ3 – 900mm arc from the top of the barrier upwards externally

• NCZ4 – 300x900mm zone on the inside if there are gaps between 10-100mm

• NCZ5 – 900mm arc from the top of the barrier downwards internally – only on boundary fences

❓Still not sure?

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