A material intended to dissipate electrostatic charges must meet at least one of the following requirements:
For a material containing grids or stripes of conductive threads the spacing between conductive threads in one direction must not exceed 10 mm.
Material requirements (standard EN 1149:1995)
For homogeneous materials the surface resistivity after testing must be less than 5 x 1010 Ω
For inhomogeneous materials which are coated or laminated, at least one surface must comply with the requirement for homogeneous materials.
Inhomogeneous materials containing conducting threads must have:
a) at least one surface with no resistances measured to be greater than 109 Ω;
b) a grid pattern of conductive fibres;
c) a maximum spacing of 10 mm between conductive fibres