It depends on what density you need. The formula is length * width * thickness * unit weight = the weight of the glass wool. For example, if it is 20 meters long, 1.2 meters wide, 50 mm thick, and the unit weight is 20kg / cubic, that is to say, 20 * 1.2 * 0.05 * 20=24kg. 48kg / m? means that the weight of one cubic meter is 48kg, you can imagine that with a piece of 50 square millimeter, how many of them can make a piece of cubic meter? You can get the answer by dividing 48, namely 48÷（1÷0.05）=48X0.05=2.4kg
Glass wool has a good sound absorption performance in the high-frequency sound. The main factors affecting the centrifugal glass wool' sound absorption performance are thickness, density and air flow resistance, etc. Density is the weight per cubic meter of materials. 1. with the increase of thickness, the low frequency sound absorption coefficient significantly increases, but there is little change in the high frequency (high frequency absorption is always larger). 2. thickness is the same, the unit weight increases, the low frequency sound absorption coefficient also increases; but when the unit weight increases to a certain extent, the material becomes dense, the flow resistance is greater than the optimum flow resistance, sound absorption coefficient decreases.
First, I want to tell you, regardless of glass wool, rock wool, the unit weight means the weight of the fiber in its volume. 18 kg refers to the weight of glass wool fiber per cubic meter. I think you will understand it through my explaination. That is to say the rock wool is 18 kg. But I have to tell you that, rock wool ≥40KG / M3, this kind of rock wool is not allowed to produce, due to the manufacturing technique. That's all about it since we don't have much time!
