Phil's Turf Talk Why is sand important in artificial turf

Why is there sand in artificial grass?
Many people are confused as to why there is sand in most artificial grass installations, in fact, many people believe the sand goes under the turf before it is installed rather than in it. It is the final step in the installation process but one of the most critical for a number of different reasons:,
Keeping the artificial turf fibres upright
The sand layer supports the base of the artificial grass fibres helping keep them upright and preventing excessive premature wear. For a standard 35mm landscaping grass, as an example, the bottom 15mm of the pile should be filled with kiln dried silica sand.
Weighs the turf down
Many artificial turf products (depending on the pile height) use somewhere in the vicinity of 13-18kgs of sand per square meter. You can imagine how this affects the overall weight of the product and is the main reason it is difficult to reuse or move artificial turf once it has been installed. This heavy top layer assists keeping the turf in place, especially where the turf may exposed to excessive wind.
Acts as a drainage medium
Artificial Turf, when installed correctly, is designed to withstand heavy rain. The sand layer assists by acting as a drainage medium - soaking up and dispersing this water, helping it drain freely through the turfs backing and into the base-course layer below. Within minutes of a significant rain event you should be able to walk on your artificial turf and not notice any pooling of water.
Helps with ball bounce on a sports court
Sand infill is integral to the artificial turf system. Infill provides ballast, and it is important to install the correct ratio of sand to meet the ball bounce and roll requirements for the predominant sport being played on the turf surface.
Keeps the grass cooler
Sand assists in keeping the turf cooler. Sand has a low heat capacity, but it retains water unlike nylon or polyethylene. In the peak of midday summer temperatures, a simple water sprinkling can help to reduce the temperature of the turf significantly.
Fire ratings
Only artificial grass with sand infill is tested to be fireproof and suitable for indoor use. This is due to the sand having an extinguishing effect, which prevents fire from spreading.