What is a DSEAR Risk Assessment?
A DSEAR Risk Assessment is a systematic evaluation of the risks posed by dangerous substances and explosive atmospheres within your workplace. It identifies potential hazards, assesses the likelihood and severity of incidents, and defines effective control measures to mitigate risks.
When is a DSEAR Risk Assessment Required?
A DSEAR risk assessment is a legal requirement wherever a dangerous substance could be present in the workplace - dangerous substances include flammable liquids and vapours, flammable gases, combustible dusts, and also include substances with the potential energy for releasing events, corrosion, and exothermic thermal runaway reactions. Learn more about dangerous substances here.
Whenever new processes are introduced - such as production lines, process equipment, or procedural operations - a DSEAR risk assessment should be carried out. The risk assessment should be considered as a live document and reviewed if any alterations are made to the process, including if different materials are used, so that any new hazards which may have been introduced are assessed and mitigated.
The purpose of the risk assessment is to allow employers make informed decisions on how best to eliminate or reduce the risks to As Low As Reasonably Practicable (ALARP) and demonstrate that a structured approach has been followed when considering the safety of personnel and the control measures required.
What Does a DSEAR Risk Assessment Involve?
Regulation 5 of DSEAR has specific requirements for what should be included in a DSEAR risk assessment. The assessment must consider the following:
Hazardous properties of the dangerous substances
Circumstances of the work
Effect of existing safeguards and mitigation measures
Likelihood of an explosive atmosphere being present (typically taken from the Hazardous Area Classification).
Likelihood of effective ignition sources being present - EN 1127-1 contains 13 ignition categories which are typically used in assessments. ATEX equipment is also considered here - you can learn more about what ATEX markings mean here.
Anticipated effects of a fire or explosion - this depends on various parameters, such as quantity of the substances, congestion, confinement, and process conditions
Interconnected equipment and areas where fire or explosions could spread or propagate
Activities, such as maintenance, where there is potential for high risk - these are usually not covered in a DSEAR assessment as they are task-specific and typically form part of a Safe Systems of Work (SSOW) or Permit to Work (PTW) system on site
An important part of a DSEAR risk assessment is selecting an appropriate Basis of Safety (BoS) for each process. The basis of safety essentially defines the principles and control measures used to prevent fire and explosions and is a summary of why the process is safe to operate.
The findings of a DSEAR risk assessment must be recorded if there are five or more employees.
How is DSEAR Risk Assessment Carried Out?
Step 1: Gather Data
The first step in a DSEAR risk assessment is to gather information on your site, processes and substances used. This includes:
Material properties (dusts, gases, and vapours)
Process descriptions and operating conditions
Drawings (site layout, PFDs, and/or P&IDs)
HAC documentation
Potential ignition sources
ATEX equipment asset register
Fire and explosion protection system details
Occupancy of areas
Emergency response plans
If there is an existing process, it is recommended that a site visit is carried out to see the facility in person. Conducting an assessment remotely can be tempting due to the potential cost savings, but it can lead to hazards being overlooked or improperly assessed.
Step 2: Conduct Risk Assessment
A risk assessment should be conducted for every unit operation or process where a dangerous substance could be present. These mainly apply to fire and explosion hazards, but corrosion and pressurised releases must also be considered. Regulation 5 of DSEAR requires the following parameters to be assessed:
Scale and anticipated effects of the hazard
Likelihood of an explosive atmosphere being present
Likelihood of effective ignition sources being present (guidance on ignition sources can be found in EN 1127-1)
Potential for escalation to connected areas and equipment
Safeguards and mitigation measures in place
Although not required by DSEAR, the occupancy of the area is usually taken into consideration. The likelihood and severity of the event should then be recorded - typically, a risk matrix is typically used to rank the risks, although a qualitative approach may be appropriate for less hazardous operations.
For new processes at the design stage , a desktop-based DSEAR risk assessment is typically carried out. This based on the design information and should feed into the design process to eliminate and mitigate hazards as much as possible. A desktop-based assessment should be reviewed periodically throughout the design stage to capture any changes - a common mistake is for the risk assessment to be conducted at the start of the project and not reviewed which can mean that key risks have not been assessed or adequately mitigated, resulting in costly remedial actions and delays. Installations being used for the first time will require the overall explosion safety to be verified, which typically happens during the commissioning stage - learn more here.
Step 3: Determine if the Risks are ALARP
Regulation 6 of DSEAR places a duty on employers to ensure that risk is either eliminated or reduced as far as is reasonably practicable. A risk matrix will typically be calibrated to show unacceptable, tolerable if ALARP, and broadly acceptable risks. If risk reduction measures are identified and not implemented, the reasoning behind this should be robustly recorded to show why the measure is grossly disproportionate in terms of cost, time, and/or effort to the risk reduction benefit it would achieve. This process is called an ALARP demonstration, and is a key part of risk assessment. If the risks are not deemed to be ALARP, then additional safeguards or mitigation measures should be implemented, or the process design should be reviewed.
Regulation 6 prescribes a prioritised list of risk reduction measures which broadly aligns with the engineering hierarchy of controls (Elimination, Substitution, Engineering Controls, Procedural Controls, PPE). The regulations split these control measures into two lists - control measures (i.e. measures to stop the hazard being realised) and mitigation measures (i.e. measures to mitigate the harm caused by the event after it has occurred). The control measures are to be applied so far as is reasonably practicable in the order in which they appear.
Control Measures (in order of priority):
Eliminate the dangerous substance or substitute it with a less hazardous substance
Reduce the quantity of substances to a minimum
Avoid or minimise release of the substance
Control the release of a substance at source
Prevent the formation of an explosive atmosphere (e.g. through effective ventilation)
Avoid ignition sources
Avoid adverse conditions that could give rise to harmful effects
Segregate incompatible substances
Mitigation Measures:
Minimise the number of personnel exposed
Avoid propagation of fires and explosions
Pressure relief
Explosion suppression
Explosion containment
PPE
A common mistake that is made is procurement of ATEX rated equipment without first trying to prevent an explosive atmosphere from forming in the first place. This not only goes against the regulations, but can add significant capital and operational expense that could be avoided by first eliminating or reducing the hazardous zones.
How Often Should a DSEAR Risk Assessment be Reviewed?
A DSEAR risk assessment should be reviewed periodically - we recommend every 3-5 years to capture any creeping changes. However, it should be reviewed if any of the following are changed:
Materials - new materials may be more hazardous, or have different explosive properties that mean existing ATEX equipment and protection systems are no longer suitable
Process Conditions - changing the process conditions could mean that an explosive atmosphere is more likely to form (e.g. increasing the temperature above the flash point of a liquid, changing the ventilation rates, or pneumatically conveying powders vs gravity feed), introduce new ignition sources, or chemical reaction hazards
Process Equipment - new process equipment may not be compatible with the existing materials (e.g. installing a non-ATEX or incorrectly specified ATEX replacement pump) ,
After an Incident - and if there is a fire or explosion incident (or near miss) at the site, then the risk assessment should be reviewed to ensure that the root cause of the incident has been identified and will not be repeated
Who is Responsible for a DSEAR Risk Assessment?
Ultimately, the employer is responsible for ensuring that a suitable and sufficient DSEAR risk assessment is in place and that its key findings have been shared with all employees. However, every employee still has a legal responsibility and duty of care under the Health & Safety at Work Act 1974 (HASWA).
Expert Support for DSEAR
Our team supports clients across the UK with all aspects of DSEAR compliance, including:
If you need clarity or guidance, get in touch - we’re here to help.