“When the use of a wrist strap system is impractical, the [ESD] floor and [ESD] footwear shall be the primary means of ESD control.” [EN 61340-5-1 clause 5.5 EPA working practices]

“Most people do not stand solidly on both feet, it is important that paths to ground are made in the heel and toe area of both feet. Where toe and heel straps are used as ESD footwear, once these are worn outside the EPA, particularly on carpets, they are likely to accumulate fluff and become ineffective; this requires that they be checked or replaced on every visit to the EPA [ESD Protected Area].