Aer-Flo Floating Silt Curtain, Type 3 DOT, 3'x50'
Type 3. DOT is a special adaption of the Type 2 barrier. Approximately 20 % of the area of the barrier skirt fabric is replaced with a polypropylene filter fabric conforming to some State DOT specifications. The filter fabric is inserted to reduce the pressure on the curtain while retaining silt. In actual practice, a filter fabric which is woven tightly enough to retain silt will not significantly reduce pressure on the curtain. Conversely, if the filter fabric is woven loose enough to reduce the pressure on the curtain, it will not be able to retain most silt and sediment particles. In addition, the filter fabric cannot be heatsealed, and must be sewn into the curtain, resulting in a reduction in curtain strength and longevity.