Playground Equipment and Surfacing
Core concepts
Equipment safety turns on fall height, entrapment, entanglement, and sharp or protruding hazards. Know that fall height is measured from the highest designated play surface, not the top of a guardrail or the peak of a roof. Surfacing must attenuate impact for that fall height; critical height is the maximum fall height for which a surface provides acceptable protection. Loose-fill surfaces (sand, pea gravel, wood mulch, shredded rubber) attenuate well but require depth maintenance and are displaced by use; unitary surfaces (poured rubber, tiles) are consistent but can degrade and are costly.
Entrapment criteria use probe dimensions: openings that admit a small torso but trap the head are the classic hazard, and questions often hinge on distinguishing an opening that is too small to enter from one that is large enough to pass through. Entanglement hazards include protruding bolts, open S-hooks, and gaps that catch clothing or drawstrings.
Traps
A frequent trap is assuming any soft-looking surface is adequate - grass, packed dirt, and asphalt are not impact-attenuating regardless of appearance. Another is measuring fall height from the wrong reference point. Watch for equipment where a single opening is compliant in one orientation but not another.
Rule of thumb
Match surfacing to the highest fall height, then add maintenance margin. Loose fill loses depth with use; specify and inspect for depth at the point of highest fall height, not at the edge of the area.