Why is a small opening dangerous if a child's head cannot fit through it?

Because a young child's body can pass through an opening their head cannot, and they then hang by the neck. That is why the concern is a range rather than a maximum: openings smaller than about 3.5 inches will not admit the body, and openings larger than about 9 inches release the head. The gap between is the hazard.

Do I need the official gauges?

For a screening walk you can identify suspect openings with a tape measure and flag them. For an audit, a conformance decision or anything that goes in a record, use the test templates and probes specified in ASTM F1487. Judging a borderline opening by eye is how one gets missed.

What counts as a protrusion hazard?

Anything projecting from a surface that can catch clothing or injure on impact: a bolt extending past its nut, an open S-hook, a broken weld, a hook, a hardware end left uncapped. The test is done with graduated protrusion gauges, and the threshold is tighter on slides and anywhere a child moves at speed.

Should children wear bike helmets on playgrounds?

No. Helmet straps and the helmet itself can catch on equipment, and helmet-related strangulation on playgrounds is a documented reason the practice is advised against. Helmets belong on bikes and scooters, and they should come off before a child gets on play equipment.

Entrapment, protrusion and entanglement checklist

1. Head and body entrapment

Check every opening a child can reach, including ones created by wear, settlement or a repair. The concern is openings that admit a small body but not a head, plus acute angles that can trap a neck or a limb.

Entrapment

Every rigid opening checked against the small and large test templates, not judged by eye
Guardrail and barrier infill gaps checked, including where a rail has bent or a picket is missing
Ladder and stair rungs, and the gap between the top rung and the deck
Gaps between decks, panels, roofs and posts, including those opened up by settlement
Climbing net and rope mesh openings, including where a net has stretched or sagged
Angles between components checked for acute angles below 55 degrees
Partially bound openings, where the ground or the surfacing forms one edge
Openings created by missing or broken parts, or by a non-original repair
Fencing around the site checked, including gates, latches and gaps under rails

0 of 9 checked · · Saved on this device only.

2. Protrusions and projections

Protrusions and projections

No bolt or threaded rod projecting beyond its nut past the allowed limit
All fastener ends capped, with caps present and secure
No open-ended hooks anywhere, including S-hooks on swings and ropes
Swing hanger and chain connectors fully closed, with no gap that can catch fabric
No broken welds, bent brackets, sheared fixings or improvised hardware
Slide entrances and exits checked to the tighter slide threshold
No hooks, eye bolts or attachment points left in place after a component was removed
No sharp edges, burrs, points or splintered timber within reach

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3. Entanglement and strangulation

This is the category that produces the rare but fatal outcomes, and most of it is about what a child is wearing and what has been tied to the equipment.

Entanglement and strangulation

No ropes, cords, leashes, jump ropes or pet leads tied to any part of the equipment
No loose cord, cable or wire hanging anywhere on the structure
Rope and net ends secured, with no loops that can form a noose
Slide hoods and entrances free of projections that can catch a drawstring or a hood
Site signage covering drawstrings, cords, scarves and helmets
Adults and staff briefed to remove bike helmets before children use play equipment
Vegetation, wires and lines clear of the structure and the swing arc

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4. Crush, shear and pinch points

Crush, shear and pinch points

Moving parts checked through their full travel, not at rest
Seesaw and rocker fulcrums, with no accessible pinch at the pivot
Spring rider springs covered or shielded across the full compression range
Spinner and orbiter bearings, with no gap opening up between moving and fixed parts
Gate, hatch and panel hinges checked for finger traps
Chain and cable runs, with nothing that can catch a finger at a pulley or a guide
Play with a moving part by hand, slowly, and look for the gap that appears mid-travel

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Hazard family	How it is found	Typical response
Entrapment	Test templates and probes on every reachable opening	Close, widen or remove the opening
Protrusion	Graduated gauges, tighter limits on slides	Cut back, cap, or replace the fixing
Entanglement	Visual sweep plus signage and clothing policy	Remove the catch point, remove tied items
Crush and shear	Operate the moving part through full travel	Shield, adjust, or take out of use

The four hazard families and the method each one needs. None of them are reliably found by eye alone.

Recording and escalating

Anything in these four categories that is confirmed goes to the top of the severity ranking, because these are the hazards associated with the most serious outcomes. Take the equipment out of use, record the finding with a photograph and a measurement, and record the fix and its date. The records and documentation guide sets out what a defensible log contains.

If any of this is unfamiliar, the underlying detail is in head entrapment and protrusions and entanglement. For the routine walk that covers surfacing, structures and hardware, use the inspection checklist. For sign-off against the current edition of the standard, bring in a qualified inspector, as described in CPSI certification.

Entrapment and hazard checklist