Playground Drainage for Synthetic Turf Not all drainage is created equal! AirDrain offers 100% vertical drainage and has 92% air void. This combination effectively collects and redirects water easily. Additionally, AirDrain raises the entire profile a full 1â€, letting gravity drain the entire playground quickly and efficiently. The combined effect of AirDrain is a more stable surface area, reduced expenses for repairs and more play time. A drainage system should allow for water to quickly drain away from the surface and be directed to exit drains, thus allowing a shorter turnaround time for the continuation of play. AirDrain provides drainage which is unmatched in the industry â€“ up to 40gpm/sf â€“ allowing the surface to be free of water. AirDrain is only limited by the drainage capacity of the profile above and the capacity of the exit drains. For playgrounds constructed with AirDrain the grid is installed on top of a 1.125â€ or 2.125â€ poly green foam pad which is placed directly onto the properly prepared subbase of concrete, asphalt or compacted aggregate. This creates a 1â€ air void and allows for maximum drainage.