The installation moved five metres. Is the hazardous-area classification still valid?
“The equipment is unchanged. We only moved it five metres.”
In explosion safety, the word only deserves investigation.
Hazardous-area classification does not belong to a machine in isolation. It describes where and how often an explosive atmosphere may occur, based on the source of release and its surroundings. Five metres away, ventilation and dilution may behave differently. A wall, air intake, pit, drain, canopy or adjacent unit can change dispersion. New ignition sources, cable routes, bonding arrangements and equipment interactions can change the risk as well.
Relocation does not automatically invalidate the existing classification. It does mean that continued validity must be demonstrated.
ATEX Workplace Directive 1999/92/EC requires the employer to assess explosion risks, coordinate protective measures and keep an explosion protection document. Its measures must be reviewed whenever significant changes, extensions or conversions occur in the workplace, work equipment or organisation of work. Whether five metres constitutes a significant change depends on consequences, not distance alone. National transposing law may set more specific inspection and documentation duties.
A sound management-of-change review compares the original assumptions with the new installation. Are the substance, operating conditions and grade of release unchanged? What is the availability and effectiveness of ventilation at the new position? Can vapour collect in a low point or travel towards an opening? Are the equipment category or EPL, gas group and temperature class still suitable? Have bonding, cable entries, protective systems and the installation’s initial inspection been re-established and recorded?
IEC 60079-10-1 supports classification of areas where flammable gas or vapour hazards may arise. IEC 60079-14 covers design, equipment selection, installation and initial inspection, while IEC 60079-17 covers inspection and maintenance in service. These standards provide technical methods; they do not remove the employer’s legal duty to review the risk and update the evidence.
After a move, the useful question is not “How far did it travel?” It is “Which assumptions behind our classification have changed?”
What apparently minor relocation has caused the biggest hazardous-area surprise at your site?
Sources
- Directive 1999/92/EC — protection of workers at risk from explosive atmospheres
- Directive 2014/34/EU — equipment for potentially explosive atmospheres
- European Commission ATEX overview and guidance
- IEC 60079-10-1:2020 — classification of gas areas
- IEC 60079-14:2024 — design, installation and initial inspection
- IEC 60079-17:2023 — inspection and maintenance