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What is ‘Critical Fall Height’ and Why Does it Matter?

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If you’ve been looking at our No Fault website (and if you have, WELCOME!) you may have noticed that each of our playground safety surface products (such as Poured-In-Place (PIP), Loose Rubber Mulch, Bonded Rubber Mulch, and Safety Tiles) have “critical fall heights” associated with them.

“Critical fall height” is the height at which a critical injury can occur. It is based on the “highest designated play area,” or the height of the highest piece of equipment that a child can stand on during normal play.

What’s the purpose? Each year, over 200,000 children are injured in playground falls, and most can be prevented by installing a shock-absorbing surface. An industry standard called American Standard Testing Methods (ASTM) sets the requirements for manufacturers like No Fault, and we take these requirements seriously.

The term “critical fall height” is a combination of fall height and critical height. In this post, we define each of those terms and explain their importance.

What is Fall Height?

According to ASTM, fall height is defined as the “vertical distance between a designated play surface and the protective surfacing beneath it.”

Fall heights vary according to the types of equipment used on the playground. For example, the fall height of climbing equipment, such as a jungle gym will differ from that of a swing set.

Here is a list of fall height measurement criteria for various types of playground equipment:

  • Climbing equipment – highest part of the climber intended for foot support;
  • Upper body equipment – highest part of the equipment;
  • Swing sets – the pivot point;
  • Seesaws – maximum height attainable by the seat;
  • Spring rockers – height of the seat;
  • Composite equipment (where components are connected) – distance from the highest designated play surface to the protective surface.

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What is Critical Height?

Critical height correlates with the impact attenuation, or shock absorbency, of the surface material. Its purpose is to “approximate the maximum fall height that would not result in a life threatening head injury,” according to the Consumer Product Safety Commission.

Depending on the playground surface material being used, critical height measurements vary. For instance, with rubber mulch, if the playground equipment fall height is eight feet, the critical fall height must attain a depth of six inches. If poured-in-place rubber surface is used as a protective safety surface, a depth of 3.5 inches must be achieved.

How Is Critical Fall Height Tested?

Critical fall heights are determined by testing methods that evaluate the shock absorbing properties of the playground surfacing material. This can be laboratory testing or testing in the “fall zone” at the actual play area.

Testers drop an instrumented metal “head-form” onto a sample of the playground surfacing material and record how fast and hard it hits the material. A “head form” is a head-shaped device which has a built-in device for measuring acceleration. The test is repeated from varying heights. These heights determine the thickness of each system needed for protection.

When it comes to installation, you must take into consideration both the depth of safety surfacing and the area of surfacing needed. The surfacing should extend beyond the edge of equipment use area, especially where kids can fall away from the equipment (tumbling out of a swing set seat, for example).

Also, different play equipment will have different fall heights—your equipment manufacturer can tell you what the rating is for each item.

No Fault Safety Surfacing is ASTM Compliant

The use of surfacing materials that have the proper resiliency and impact attenuation is one of the most important factors in reducing injuries from falls.

As we’ve said many times, your children’s safety is our most important concern. When you partner with No Fault, you can rest assured that all our playground safety surface materials are ASTM F-1292 compliant and meet all critical fall height standards and requirements. And if you have any questions … contact us today!

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