What is an EPD?
What is an EPD?
The Explosion Protection Document (EPD) is the central compliance document required by the ATEX Workplace Directive (1999/92/EC) for any workplace where explosive atmospheres may occur. It's not just a form to fill in—it's the comprehensive record that demonstrates you've systematically identified, assessed, and controlled explosion risks at your site.
Legal Requirement
Article 8 of the directive mandates that employers draw up and maintain an EPD before work begins in areas where explosive atmospheres may be present. The document must be revised whenever the workplace, work equipment, or organisation of work undergoes significant changes, extensions, or conversions. The EC ATEX Guidelines emphasise that this isn't a one-time exercise—the EPD must be a living document that reflects your current situation.
What the EPD Must Demonstrate
At minimum, the EPD must show three things: that explosion risks have been identified and assessed, that adequate protective measures are in place, and that the workplace and equipment are designed, operated, and maintained with due regard for safety. In practice, this means the document brings together several key elements:
- Risk assessment results: Documenting what flammable substances are present, how and where explosive atmospheres could form, what ignition sources exist, and how significant the risks are
- Zone classification: Plans and drawings showing which areas are classified as Zone 0, 1, 2 (gases) or Zone 20, 21, 22 (dusts), with justification for each classification
- Equipment verification: Records confirming that equipment installed in each zone has the appropriate category certification for that zone
- Protective measures: Documentation of the technical and organisational measures in place—ventilation systems, earthing and bonding, permit-to-work procedures, worker training
Zone Classification Documentation
Zone drawings form a critical part of the EPD. EN/IEC 60079-10-1 specifies that zone documentation should include drawings showing zone extent in three dimensions (plans, elevations, and sections), data sheets listing flammable materials and their properties, records of release sources with their grades and release rates, and details of the ventilation arrangements that influence zone extent. These drawings should be to scale, clearly labelled, and kept current whenever process or layout changes occur.
Operational and Organisational Measures
The EPD should reference or include operational procedures for normal and abnormal conditions, the permit-to-work system for hot work and equipment opening, inspection and maintenance schedules for Ex equipment, emergency response plans, and training records showing that workers understand the risks and procedures. The directive specifically requires coordination when workers from multiple employers are present—this coordination must be documented in the EPD.
Who Prepares the EPD?
The employer is legally responsible for the EPD, but preparing it properly requires competent persons with knowledge of both the process and explosion protection principles. In practice, this often means collaboration between operations staff (who understand the process), safety engineers, and sometimes external explosion protection specialists. What matters is that whoever prepares it has the competence to do so correctly, and the employer takes responsibility for the final document.
Keeping the EPD Current
An outdated EPD is almost as bad as no EPD at all. The document must be reviewed and updated when processes change (new materials, different quantities, altered flow rates), when equipment is modified or replaced, when layout changes affect zone classification, after any explosion-related incident or near-miss, and at regular scheduled intervals even if nothing has obviously changed. The EPD should include a revision history showing when it was last reviewed, what triggered the review, and what changed.
Combining with Other Documentation
The directive allows employers to combine the EPD with existing risk assessments and documentation produced under other legislation—the safety report under the Seveso Directive, for example, or the general risk assessment required by the Framework Directive (89/391/EEC). This avoids duplication while ensuring all explosion-specific requirements are addressed. The key is that the EPD-specific content must be identifiable and complete, regardless of the format you choose.
