One of our goals at TrampolineSafety.com is to compare the performance of different trampoline safety enclosures in the most realistic and accurate manner possible. The most commonly cited standard is from ASTM International, one of the world’s leading standards development organizations. Our goal was to measure trampolines by their published test standard, ASTM F2225-06, and then develop an even more demanding and realistic test. The first thing that we did was to review the existing specification. ASTM F2225-06 defines a test system consisting of a weighted bag which is suspended by a chain as a pendulum. The bag is pulled back in an arc, and then released into the safety enclosure, numerous times, at different locations on the enclosure. The results for the test is either a pass or fail, with a failure consisting of any broken or damaged part of the trampoline or safety enclosure. During our review of the requirements, we realized that the current methodology of testing with a pendulum does not really simulate how a person jumps or falls into the net. For this reason we conceived the need for a release mechanism that would release the swinging mass into the net, just as a jumper falls into net. The next step was to define the requirements for the test system. We quickly concluded that the ideal standard would include a real world free body test.

With the requirements defined, we set out to construct a test machine. Our test system is capable of testing a safety enclosure installed on round trampolines up to 15’ or rectangular trampoline up to 15’ wide and any length with the entry on one end. ASTM F2225-06 defines the impact bag dimensions and also that the weight must match the weight rating of the product while having the bag filled such that the density of the mass is uniform. This was accomplished by filling baggies with sand and wood chips and loading them into the bag such that the bag was full and that the weight matched the max user weight rating for the product. The system that we have constructed is outfitted with two manual winches, one that lifts the impact bag and the other that swings the impact bag back into the release position. A manual release pin is pulled allowing the impact bag to swing into the net, support pole or doorway as prescribed by the test methodology. The free body test was facilitated with the addition of a load release device that was activated as the bag swung towards the net. Like all of the tests of F2225-06, the free body test was carried out such that the center of gravity of the bag would contact at the midpoint of the net or pole.

There were differences between the ASTM test and the free body test in the way that we constrained the frame of the trampoline during testing. In the ASTM standard, the frame is constrained by straps connecting the ground to the upper frame of the trampoline opposite the impact zone, to keep it from sliding on the cement floor of the lab. This could potentially lead to a different result than a backyard trampoline in practice, because the typical trampoline is not held down in this manner. In most cases, the trampoline is placed on either a grass or dirt surface, and it settles over time. When an impact occurs, the force of the jumper’s body into the net causes the trampoline to tip, the nearest leg (closest to the impact zone) is planted into the ground and acts as a pivot point. In our free body test, we secured the lowest part of the nearest leg with a lateral strap, which allowed for this realistic tipping motion. All impacts were captured on video with notes and detailed observations also recorded on the video.

This testing has been performed on the products from several different manufacturers and we have compiled the data here on the TrampolineSafety.com website. These results have been used as one of the components in our Overall Score for the Trampoline Rankings, and are shown in detail in the Safety Testing section. We also continue to be actively involved in creating requirements, defining standards and testing products for compliance.