Non-conductive plastic hard hats are worn for head protection in the chemical industry, even in hazardous zones, where, in principle, they can cause incendive discharges.
- The clean room garments required when working in GMP-compliant areas, in particular the boot covers, prevent the wearer from being reliably grounded, even though the flooring may be adequately conductive.
- Corrosion protection measures such as painting, other surface coatings and glass linings of piping prevent reliable potential equalisation and grounding of flanges and pipe spools. In extreme cases, the accumulation of electrostatic charge and the resultant breakdowns can even negate the original purpose of coating. Examples of this are the damaged glass linings in reactor vessels [2] and the breakdown of PTFE linings in process piping.
- The use of aluminium-laminated plastic bags is another example of two conflicting objectives, i.e. the product quality requirements and prevention of ignition hazards.
It must be decided on a case-by-case basis which of the objectives or protective goals takes precedence, and what additional measures, if any, are necessary.