Setting Up Your Gym Floor for Bleachers
It’s time for a confession. In athletic facility design, spectators can sometimes be treated as an afterthought. It’s not that we don’t realize the importance of spectators in designing a gym space. It’s just easy to become preoccupied with the players on court.
Let’s be clear. It isn’t wrong to emphasize athletes when it comes to gym flooring. They engage with the floor directly and thus require more from it. Athletes are jumping, diving, pivoting, and running on the surface. It’s why we test sports floors for shock absorption, ball rebound, and surface friction (see ASTM F2772). By comparison, the audience at a sporting event is a bit more…well, sedentary.
Spectators sit on bleachers, which affect gym flooring in a more indirect fashion, but no less important. Bleachers come in many forms, from the portable tip-and-roll variety to motorized telescoping designs. All of which require some forethought when it comes to the floor underneath.
Let’s examine the science of “just sitting there” a little more closely. Bleachers of all types exert static loads on the floor. Static loads are the weight applied to the underlying surface when the weight does not move. If a bleacher system is stationary, static loads are the only concern. On the other hand, portable bleachers exert rolling loads in addition to the static loads as they are rolled into position for use.
In resilient flooring like Abacus’ Padenpor or Tarkett’s Omnisports, static load tolerance is typically measured in PSI, utilizing the ASTM F970 testing standard. With a confirmed static tolerance, you can use the surface area of the bleachers and weight capacity to calculate whether a particular floor is up to the task. It’s important to note that the PSI tolerance set by the ASTM F970 standard does not mean the floor will be free of indentations. There is an acceptable threshold of 5 mil, which means the floor will indent at stated PSI value. Does that matter? If bleachers are movable like the tip-and-roll design, then perhaps. It would mean the slight indentation could be visible. You might consider making a conservative estimate of the weight you are willing to put on the floor, whether it is a bleacher or other heavy equipment.
The other consideration with portable bleachers is rolling load tolerance. That parameter is measured according to ASTM F2753. Also referred to as dynamic load tolerance, rolling loads add the complexity of lateral motion to the downward force of weight on the floor. Here, it is advisable to consult with your flooring provider to get a sense of the floors performance when it comes to rolling load. Resilient sports floors from various manufacturers will have unique characteristics. For example, some floors will indent more but recover faster and more completely. Other floors might have a lesser initial indentation, but recover at a slower rate.
Here’s where design and planning come into play. If you have all the information about the type of bleachers and equipment that will be used in a gym, as well as the static and rolling load tolerances, you might want to incorporate a “bleacher block” system. This process usually adds a high density rubber based mat underneath the floor in the areas where bleachers and equipment will be used. It fortifies the specific areas where load tolerances need to be higher. There are also complete sports floor systems, like Omnisports HPL (high point load) that can increase load tolerance across the entire playing surface as well. A prime example of this is the recent installation of Omnisports HPL at the Empire State Building. This sort of floor offers a degree of versatility when it comes to bleachers and movable equipment.
The most important aspect of designing for both sports and spectators is consulting with a flooring professional. At Abacus Sports Installations, we have more than 30 years of experience in athletic flooring of all types. Please contact us for a consultation.