A rate of change in velocity over time.

Access Ramp

A ramp that is used to gain access to a play surface or playground area.


This term is used to describe any part of play equipment that can be contacted by any part of the body or any area that can be entered and used in any way.

Accessory Toy

A toy that is attached to a larger piece of equipment that is removable from the larger structure.

Adjacent Platform

Two platforms that share a vertical plane but are different heights.


Any accessory used to reduce the risk of equipment tipping over after being installed. They can also be used to prevent the lifting of the legs of any equipment.

Aliphatic Binder

This binder is clear in color and will not affect the color of the rubber granules used in the surface. This kind of binder is more UV resistant as well as being more resistant to chemicals used in pool water. This kind of water is best for use on areas with high levels of UV exposure, around pools, or in surfaces using lighter colored rubber granules.

Aromatic Binder

These binders are a dark, amber color. These will darken the color of the rubber granules used in the surface. The binder will also darken over time and is less resistant to certain chemicals and so is not recommended for use around pool areas.


Cable is made by multiple strands of metallic wire that are twisted or lain together.

Climbing Equipment

Climbing equipment is defined as being play equipment that requires users to maintain three points of contact while using it.

Completely Bounded Non-Rigid Opening

An opening in any part of playing equipment that is defined by flexible openings. These flexible openings can deform during normal use.

Completely Bounded Rigid Opening

Any opening in any part of playing equipment that is defined by openings that are not flexible.


A portion of play equipment that has a specific use and generates specific equipment and that cannot stand alone.

Composite Play Equipment

Equipment that is made up of two or more pieces of equipment that are attached or functionally linked in order to create one unit incorporating more than one kind of play activity or multiple play surfaces.

Critical Height

The distance below which a life-threatening injury is not expected to occur if a child falls. The critical height is dependent on the type of surfacing included in the playground area.

Crush and Shear Point

A juncture at which someone could experience a contusion, laceration, abrasion, amputation, or other kinds of trauma while using the play equipment.


The time rate of a reduction of velocity.

Designated Play Surface

Any elevated surface designed for standing, walking, sitting, or otherwise playing. This term also applies to any flat surface that is tilted less than 30 degrees and is larger than 2.0 inches squared.

Drop Height

The distance from which a certified playground safety inspector will drop a headform to the surface to test the critical height.

Early Care and Education Facility

A setting in which care is provided for eleven or more children.


A condition in which the user of the playground equipment’s clothes or something around their neck becomes caught and entwined on a part of the equipment.


A condition that impedes the withdrawal of a body part that has passed through an opening in a piece of equipment.

Fall Height

The distance between the tallest designated play surface on a playground and the ground below. The fall height for swings is determined by the height of the pivot point for the swing. Check the specific code referring to different playground equipment as well as manufacturer information.

Fully enclosed Swing Seat

A Suspended Device upon which a user sits that has non-removable supports on all sides which are intended to support the user and prevent them from falling while using the swing.


Acceleration due to gravity at sea-level.


The maximum acceleration due to gravity that is experienced from an initial impact.


The striking surface of the testing apparatus used by certified playground inspectors.

Head Injury Criteria

A measure of impact severity which takes into consideration the time over which deceleration occurs, the duration of peak deceleration, and the peak level of deceleration.

Impact Attenuation

The ability of a surface to disperse and absorb the force of a body that impacts it.

Impact Velocity

The velocity of a falling body immediately before impacting a surface, or the velocity at which a falling body impacts a surface.

Loose Fill System

A surfacing system for a playground that includes small, individual pieces of the surfacing material that are not bonded together. The material must be tested for impact attenuation and must meet CPSC and ASTM requirements as well as providing the proper critical height for a playground area.

Surface System

The system composed of all the materials that contribute to the absorption of impact force. Surface systems are designed to reduce the likelihood of life-threatening injuries occurring from falls in and around playground areas.

Theoretical Drop Height

Calculating the theoretical drop height equates the velocity of the headform dropped curing inspection to a height that would generate that same velocity at sea-level with no friction to reduce the movement of the headform as it falls.

Unitary System

A surfacing system for a playground that incorporates more than one material that has been bonded together to create one cohesive surface. The material must be tested for impact attenuation and must meet CPSC and ASTM requirements as well as providing the proper critical height for a playground area.