Protective clothing with anti-static properties is manufactured from fabrics with anti-static fibres. Different types of anti-static fibres are available in the market and have their own performance charactaristics. It is important to know what type of anti-static fibre is applied into the fabric.
In principal there are two different types of anti-static fibre:
Surface resistivity fibres (tested according EN 1149-1)
Metal (Bekinox) and carbon fibres (Negastat P210) are good examples of surface resistivity solutions. To protect the wearer it is very important that the protective clothing is grounded to earth. This can be achieved by a direct line with a ground (wrist bands) or via anti-static shoes and special conductive floors. In some working environments this could be very difficult to achieve.
Core conductive fibres (tested according EN 1149-3)
Carbon is the product that is mainly used as the anti-static component in core conductive fibres (Static-Control™, Negastat P190 and P140 used in Nomex® Comfort). These fibres are able to discharge via corona effect – which means that the static charge is discharged to air and secures more protection in environments where grounding to the earth is impractical.
It is strongly recommend that clothing to protect against static charges should also be fire resisting.