Void ratio is the volume of water that can be stored in the tank. There are two types of volume, gross volume, and net volume. If you think you have attenuation create the 1m x 1m x 1m. That is the area of volume of that space is 1m cubed, most attenuation creates for structural stability have something in the middle. For example with a couplet max system, you have an area inside the system that’s going to be taking up plastic. That is essentially the area within that 1m cubed, as an example, which won’t store water, because a percentage of that area will be taken up by the plastic. Void ratio is basically the percentage of empty space, therefore the percentage of water that can be held. Most crate systems are about 5% plastic inside, so for every 1m cubed of water, 1m cubed of space would hold 950 litres of water rather than 1000 litres of water. That is a 95% void ratio. Graf EcoBloc Maxx holds 96% void ratio, so we can hold 960 litres of water for every meter cubed of space. Our flex and light systems can go up to 97, depending on circumstances, which is a good void ratio. This can help mass plan the design of tanks. If it’s a level 22 tank, that’s not going to make a big difference, but if you have a tank which is designed at a 95% void ratio, which is 1000 cubed or 1500 cubed. Because of our improved void ratio, we can shave quite a bit. We can hold the same amount of water in less space, in less crates. Which is, of course, saving. But there are lots of positive elements in the higher void ratio. Void ratio is basically the volume of water that can be held. Gross volume is the area, and in terms of basic length, width, by height. Volume ratio is the actual amount of water that can be stored in that space.
