What are your HEPA filters rated to?

We use regularly maintained and PAT tested cleaning equipment. The HEPA (High Efficiency Particulate Air) filters in our vacuum cleaners are rated at 99.97% efficient at 3 microns. In addition all the cleaning agents we use are COSSH compliant and anti-static dissipative. This means that they will not generate a potentially hazardous electrical charge and they can also help to ground potentially hazardous electrical charges.