Explosion Protection Document: Purpose, Requirements and Good Practice
In this article:
Companies handling flammable gases, vapours, mists or combustible dust must assess the risk of explosive atmospheres and document how that risk is controlled. The Explosion Protection Document (EPD) provides this overall demonstration, showing how explosion hazards have been identified, assessed and managed through appropriate technical and organisational measures.
What is the purpose of an EPD?
The EPD should demonstrate where explosive atmospheres may occur and how the associated risks are controlled. The explosion risk assessment must consider the likelihood and duration of explosive atmospheres, potential ignition sources, the substances, processes and installations involved, and the potential consequences of an explosion.
Explosion protection follows a clear hierarchy: prevent the formation of an explosive atmosphere, prevent ignition, and where an explosion cannot be excluded, limit its consequences and propagation.
The EPD brings these elements together by linking hazardous substances and potential release sources with hazardous area classification, ignition source control, technical protection systems, operational measures and emergency arrangements.
Regulatory Context
Explosion protection requirements vary between jurisdictions, but the underlying principles are broadly consistent: organisations should identify explosion hazards, assess the associated risks and implement appropriate preventive and protective measures.
In Europe, Directive 1999/92/EC (ATEX Workplace Directive), and in the UK, the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR), require employers to assess and control risks from explosive atmospheres through appropriate technical and organisational measures, including hazardous area classification and ignition control where applicable, emergency arrangements and training. The ATEX Workplace Directive also requires the preparation and maintenance of an EPD.
For context, see Understanding DSEAR and ATEX: Managing Fire and Explosion Risks, “DSEAR and ATEX Compliance”.
In other jurisdictions, requirements depend on the applicable national law. Recognised international standards and industry good practice such as the IEC 60079 series and the Energy Institute EI15 provide a common technical basis for hazardous area classification, ignition source control, suitable equipment and explosion protection.
The EPD should therefore demonstrate systematic management of explosion risks in accordance with applicable legislation, recognised international standards and relevant industry requirements.
Who needs an EPD?
Where an explosive atmosphere may present a hazard, the requirement for an EPD depends on applicable national legislation, including national implementation of the ATEX Workplace Directive. This can apply across many industries, including oil and gas, chemicals and petrochemicals, hydrogen and biogas, fuel storage, food and agriculture, woodworking, and waste and recycling facilities.
The key consideration is not whether a facility already contains classified hazardous areas, but whether flammable substances can form an explosive atmosphere. The risk assessment determines whether hazardous area classification, additional safety measures and supporting documentation are required.
Where several companies work at the same workplace, their explosion protection activities must also be coordinated.
What should an EPD contain?
There is no mandatory EPD template, but the document should provide a clear and traceable demonstration of how explosion risk is managed. A complete EPD should normally address the following areas.
Scope and facility description
Define the facilities, processes, equipment and activities covered, including relevant interfaces, limitations and responsibilities.
Hazardous substances
Identify flammable gases, liquids, vapours, mists and combustible dusts, together with the properties relevant to explosion risk. Safety data sheets and other applicable technical information should be referenced.
Explosion risk assessment
Assess credible explosion hazards during normal operation, foreseeable abnormal conditions and relevant non-routine activities such as start-up, shutdown, cleaning and maintenance. Consider potential release sources, ventilation, accumulation, ignition sources, consequences and the adequacy of existing safeguards.
Hazardous area classification
Areas where explosive atmospheres may occur in hazardous quantities must be classified according to their frequency and duration. Zones 0, 1 and 2 apply to gases, vapours and mists, while Zones 20, 21 and 22 apply to combustible dust.
The EPD should reference the relevant hazardous area classification drawings, release sources, ventilation assessments and assumptions. A hazardous area classification report is an important input to the EPD, but is not a substitute for it.
Ignition prevention and explosion protection
Credible ignition sources must be identified and controlled. These can include electrical equipment, hot surfaces, flames, mechanical sparks, static electricity, lightning, hot work and temporary equipment. Equipment used in hazardous areas should be suitable for the applicable zone, gas or dust group and temperature requirements.
Where prevention alone is insufficient, suitable consequence-reducing measures should be considered, such as explosion venting, suppression, isolation, explosion-resistant construction, emergency shutdown or physical separation.
Organisational measures and verification
The EPD should address responsibilities, competence, training, operating procedures, work permits, contractor coordination, inspection and maintenance, housekeeping, management of change and emergency preparedness.
Before areas where explosive atmospheres may occur are brought into operation for the first time, explosion safety must be verified by persons with the necessary competence in explosion protection.
When should an EPD be updated?
There is no fixed revision interval. The EPD must be kept up to date and revised following significant changes to the workplace, facility, equipment, organisation, processes or substances used.
A review should also be considered following incidents or near misses, changes to ventilation or detection systems, changes to hazardous area classification, replacement of Ex equipment, new information about substance properties or significant findings from inspections and audits.
The EPD should therefore be treated as a living part of the safety management system, rather than a one-off compliance exercise.
How can ORS Consulting help?
ORS Consulting supports clients throughout the EPD lifecycle, from explosion risk assessment and hazardous area classification to gap assessment, ignition source evaluation and review of existing documentation. Our objective is to help establish an EPD that is technically robust and practical to maintain as the facility evolves.
For further reading, see Common ATEX Misunderstandings and Process Safety: Major Accident Prevention Starts Here, or explore other related articles in ORS Consulting Insights.
