Updated: May 2026
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Author: Veress Árpád · Explosion-protection expert
Explosion protection risk assessment
The explosion protection risk assessment is the systematic survey of explosion risk: it identifies the hazard sources, the zones and the possible ignition sources, evaluates the level of risk, and defines the measures needed to reduce it. It is the professional core of the explosion protection document.
What is the explosion protection risk assessment?
The risk assessment answers where, how large and how acceptable the explosion risk is. It examines two sides together: the probability of an explosive atmosphere forming (described by the zone classification) and the probability of ignition sources being present. The actual risk arises where the two meet.
The steps of the process
- Identifying hazardous substances — which flammable gas, vapour, mist or dust is present, and its properties.
- Probability of an explosive atmosphere — where and how often it may form (zone classification).
- Ignition source analysis — which ignition sources may occur in each zone.
- Evaluating the risk — comparing the probability and the possible consequence.
- Defining measures — prevention first, then constructive protection where necessary.
- Residual risk and documentation — recording the remaining risk and justifying its acceptability.
Ignition source analysis: the 13 ignition sources
Ignition source analysis takes the thirteen ignition source types of MSZ EN 1127-1 in turn and examines which may occur — in normal operation, in an expected malfunction or in a rare malfunction:
- Hot surfaces
- Flames and hot gases
- Mechanically generated sparks
- Electrical equipment
- Stray currents, cathodic corrosion protection
- Static electricity
- Lightning strike
- Radio-frequency electromagnetic waves
- Optical (light-range) electromagnetic radiation
- Ionising radiation
- Ultrasound
- Adiabatic compression and shock waves
- Exothermic reactions (including the self-ignition of dusts)
The goal is that in every zone only an ignition source may remain that is sufficiently improbable relative to the level of the zone.
How do you document it?
The result of the assessment is part of the explosion protection document. For each zone and each ignition source, it must record which measure excludes or reduces the risk, and who is responsible for checking it. This is what makes the assessment auditable.
From the field
In practice
- Location
- a bulk-materials handling plant with dust zones.
- What we found
the risk assessment handled electrical equipment thoroughly, but did not evaluate static electricity and mechanical sparks at the charge-prone plastic components.
- Why it matters
in a dust zone these two frequently omitted ignition sources are the typical trigger. Closing the gap was possible with a few targeted earthing measures and a material change.
Downloadable worksheet and checklist
Risk assessment worksheet + ignition source checklist (PDF) — walks you through the 13 ignition sources zone by zone, so nothing is missed. Download →
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Frequently asked questions
What is the difference between the risk assessment and zone classification?
Zone classification describes the probability of an explosive atmosphere; the risk assessment evaluates this together with the probability of ignition sources, and defines the measures.
What is ignition source analysis?
The systematic identification and evaluation of the possible ignition sources (13 types in total) occurring in the zones.
How often must it be reviewed?
At every change affecting the hazard, and at regular intervals according to the inspection plan.