Polycarbonate versus Acrylic for ice hockey spectator shielding (part 2)
In the first part of this blog series we showed that 0.47″ Polycarbonate is 20-25% more flexible than the same thickness Acrylic under simulated hockey player impact conditions. This increased flexibility could potentially lead to a reduced number of player concussions and reduce concussion severity.
In this article we will discuss how the thickness of the shielding affects the flexibility. Acrylic is traditionally used at a thickness of 0.47″. As Acrylic can break, it is not advisable to go thinner than this for spectator shielding. Indeed, some hockey arenas even increase the thickness to 0.545″ to prevent breakage, unfortunately increasing the rigidity in the process.
Polycarbonate does not suffer from the same breakage problems as Acrylic, therefore it is possible to reduce the thickness without having the risk of material breaking. To see how reducing the thickness of the Polycarbonate affected the flexibility, we tested 0.47″, 0.39″ and 0.31″ Polycarbonate under simulated hockey impact conditions (a 180lb weight hitting the shielding at a speed of 14mph). We found that 0.39″ Polycarbonate was 40% more flexible than 0.47″ Polycarbonate. We also found that 0.31″ Polycarbonate was 45% more flexible than 0.47″ Polycarbonate. We concluded that the largest benefit in flexibility was in reducing the Polycarbonate from 0.47″ to 0.39″ and that further reductions to 0.31″ only had marginal benefits.
Overall changing from 0.47″ Acrylic to 0.39″ Polycarbonate increased the flexibility by over 60%; a significant change from a player safety perspective. Even with this increased flexibility and reduced thickness, the Polycarbonate would virtually eliminate the current breakage issue.
Another factor to consider for arena safety is that changing from 0.545″ x 50″ x 80″ Acrylic to 0.39″ x 50″ x 80″ Polycarbonate would reduce the weight of each sheet from over 90 lbs per sheet to 65 lbs per sheet. This decrease is very significant when considering the safety of arena personnel lifting the panels into place and when considering the consequences of a panel falling into the crowd following an impact by the players.
One consequence of the increased flexibility of the panel is there is slightly increased movement of the panel in the frame. A 0.47″ Acrylic sheet moved 0.34″ in the frame whereas the 0.39″ Polycarbonate moved 0.71″ in the frame. This increased movement needs to be considered when designing the frame and HighLine can provide assistance if required.