B.2.5. Completely bounded openings with limited depth of penetration The configuration of some openings may be such that the depth of penetration is a critical issue for determining the entrapment potential. For example, consider a vertical wall or some other barrier behind a step ladder. The entrapment potential depends not only on the dimensions of the opening between adjacent steps but also on the horizontal space between the lower boundary of the opening and the barrier. A child may enter the opening between adjacent steps feet first and may proceed to pass through the space between the rear of the lower step and the barrier and become entrapped when the child’s head is unable to pass through either of these two openings. In effect, there are openings in two different planes, and each has the potential for head entrapment and should be tested. Figure B16 illustrates these two planes for a step ladder as well as for a generic opening. Plane A is the plane of the completely bounded opening in question, and Plane B is the plane of the opening encompassing the horizontal space between the lower boundary of the opening in Plane A and the barrier that should also be tested for entrapment hazards. B.2.5.4.1 Test procedure Step 1: Select the appropriate small torso template based on the intended users of the playground (Figure B3 for toddler playgrounds, Figure B4 for preschool-age and school-age playgrounds). Step 2: Identify all completely bounded openings with limited depth of penetration. Step 3: Place the small torso template in the opening in Plane A with its plane parallel to Plane A; rotate the template to its most adverse orientation with respect to the opening while keeping it parallel to Plane A. Step 4: Determine if the opening in Plane A admits the small torso template in any orientation when rotated about its own axis. No: Pass. The opening is small enough to prevent either head first or feet first entry by the smallest user at risk and is not an entrapment hazard. Yes: Continue. Step 5: Place the small torso template in the opening in Plane B with its plane parallel to Plane B; rotate the template to its most adverse orientation with respect to the opening while keeping it parallel to Plane B. Step 6: Determine if the opening in Plane B admits the small torso template. No: Pass. The depth of penetration into the opening in Plane A is insufficient to result in entrapment of the smallest user at risk. Yes: Continue. Step 7: Place the large head template (Figure B5) in the opening in Plane A with its plane parallel to Plane A. Determine if the opening in Plane A admits the large head template. No: Fail. A child, whose torso can enter the opening in Plane A as well as the opening in Plane B, may become entrapped by the head in the opening in Plane A. Yes: Continue. Step 8: With the plane of the large head template parallel to the opening in Plane B, determine if the opening in Plane B admits the large head template. No: Fail. The largest user at risk cannot exit the opening in Plane B. Yes: Pass. The openings in Plane A and Plane B do not pose an entrapment risk. Handbook for Public Playground Safety 53 Plane B Plane A Plane A Plane B Figure B16. Example of a completely bounded opening with limited depth of penetration
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