Many dusts are prone to the build-up of static electricity. Flour is perhaps one of the best known. Historically explosions from handing powder in them were fairly common, perhaps one of the most famous was in Washburn, UK, A Mill where 18 people were killed and 6 mills were destroyed in total.
To reduce these dangers anti-static filter media were developed, allowing the dissipation of any charge which might build up on the bags. This is an essential aspect of Atex certified installations.
The technology is based on the incorporation of electrically conductive fibers into the needlefelt, this can either be by blending the fibers in with the actual media or by the incorporation of a conductive scrim into the center of the textile. The latter technique ensures conductivity as the grid is controlled throughout every part of the felt.
Several fibers are used to impart static dissipation, the most reliable is stainless steel as this has excellent thermal and chemical resistance and can therefore withstand all the conditions which the fibers can handle.