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Best practice for good DSEAR documentation

Author : Peter Hodgson, Safety Consultant, ABB.

19 February 2019

The Dangerous Substances and Explosive Atmospheres Regulations (DSEAR) 2002 are concerned with protection of personnel against risks from fire, explosion and similar events arising from dangerous substances used or present in the workplace. The Regulations have been in force for a decade and a half, and yet many operating companies are still unsure whether they are fully meeting the requirements for compliance. 

To help navigate this potential minefield, we take a look at the key requirements of DSEAR, outline how compliance can be achieved and demonstrated, and crucially how to maintain an up to date set of documentation.

A key requirement of DSEAR is the need for a Risk Assessment. This must provide evidence that the employer is aware of all the risks associated with the dangerous substances used on site, and has applied sufficient measures to eliminate the risks or reduce them as far as practicable. The Approved Code of Practice (ACOP) for DSEAR does not specify exactly how this Risk Assessment should be conducted or recorded, but does provide much useful guidance.

Some key points include:
* That the risk assessment must record the nature of the hazard;
* Who might be harmed, and how;
* The measures that are currently in place to address the risk;
* Any additional measures that could be taken; and
* Actions arising from the assessment of the risk.

The HSE’s extensive guidance on risk assessment can be followed in the process of developing DSEAR risk assessments. The ACOP also states that DSEAR risk assessments should not be carried out in isolation from those required under other legislation, such as the Management of Health and Safety at Work Regulations, and that other risk assessments conducted by operating companies, such as fire risk assessments, functional safety studies etc., may cover many of the requirements of DSEAR.

Assessing the risk

A good starting point is to examine the existing process safety risk assessments that are already in place for a site, as it may well be the case that many of the requirements of DSEAR have already been addressed. Many operators of high hazard processes have a suite of risk assessments in place (e.g. HAZOPs, HAZIDs) which will have considered the risks associated with dangerous substances, and DSEAR does not intend to re-invent the wheel. Provided that a recognised process safety risk assessment methodology has been followed, and the risk assessment satisfactorily addresses the requirements of DSEAR, then it can be incorporated into a DSEAR risk assessment.

Many large companies will have their own risk assessment procedures and formats, with risk matrices for categorising hazardous events. These can be used for ranking risks and targeting those that require further action to bring them into the tolerable, as low as reasonably practicable (ALARP) region. At all times, the hierarchy of control should be followed: Eliminate; Reduce; Control; and finally, Mitigate.

It is always preferable to eliminate risks wherever possible. This can be achieved by removing dangerous substances altogether (though this may not be possible where they are required for the process), or by the application of inherent safety principles. Where risks cannot be eliminated, they should be reduced as far as possible. This may be achieved by substituting dangerous substances for others with less volatile properties, by using process containment to limit the potential for flammable atmospheres to form, or use of ventilation to disperse flammable concentrations of gas or vapour, for example.

Control of ignition sources should next be addressed. Every effort must be made to avoid the ignition of flammable atmospheres by correct selection, installation, operation, inspection and maintenance of equipment in hazardous areas. In addition, controlling the generation and accumulation of static electricity and the methods of work processes that are carried out in those locations is also crucial.

Many processes which have been subjected to hazard studies will already have evidence that this hierarchy of control has been applied, and the hazards will be recorded together with their safeguards. However, these hazard studies often focus on the major hazards present within a process, and may not encompass all the risks associated with dangerous substances. It is therefore advisable when conducting a DSEAR risk assessment to ensure that every potential hazard has been considered, regardless of scale.

For example, a hazard study may have identified the potential for a major incident, involving an internal explosion in a process vessel, handling flammable materials, with extremely serious consequences and many safety functions and safeguards in place as a result. However, it may not have considered the risks associated with material handling. Charging powders into a vessel via the manway presents a risk to the operator carrying out the activity, either due to the flammable powder or if the vessel contents are flammable. The consequences can range from a flash fire to an explosion that kills the operator. 

Consequently, it is important to examine all processes involving dangerous substances. An analysis of the process steps can identify all points at which there is the potential for a flammable atmosphere to form, and potentially be ignited. All the hazards can then be identified and the safeguards designated. This is the purpose of carrying out a DSEAR risk assessment, after all – to ensure that personnel are protected from the hazards associated with the processes involving dangerous substances.

Importantly, since 2015 DSEAR has also covered compressed gases, substances corrosive to metal, and the upper flashpoint for materials being classified as flammable has been raised from 55°C to 60°C, due to the Classification, Labelling and Packaging Regulations. This means that a DSEAR risk assessment must cover the use of compressed gas cylinders and also diesel. The advice regarding these substances is that the fundamental risk associated with these materials has not changed. Provided a diligent operating company was already addressing the risks associated with these materials under the Management of Health and Safety at Work Regulations, then their current procedures and safeguards associated with these materials can be incorporated into the DSEAR risk assessment.

Area classification

Only when a DSEAR risk assessment has been carried out and the hierarchy of control has been applied should Area Classification be focussed on. This is because Area Classification is aimed at ensuring control of ignition sources; it identifies the areas where a residual risk of forming a flammable atmosphere exists, after everything has been done to reduce the risks as far as practicable.

DSEAR regards the Area Classification of a process as an integral part of the risk assessment documentation, and dictates that the DSEAR documentation must be reviewed at regular intervals. The frequency of review is not defined in the Regulations, but it is advised that it should depend on the nature of the risk, and the likely degree of change. Therefore, for a high hazard process, or one that is frequently reconfigured, a shorter interval between reviews would be appropriate.

Also, the DSEAR documentation should be reviewed whenever significant changes occur. It is therefore important to ensure that your Management of Change (MoC) process includes prompts to identify whether the proposed change affects the risks associated with dangerous substances, and if so, that the DSEAR risk assessment and Area Classification are reviewed accordingly. It may be necessary to review the MoC process and the competencies of those authorised to handle such reviews, in order to ensure this requirement can be demonstrably fulfilled. The ACOP also states that the DSEAR risk assessment should be reviewed whenever there is reason to suspect it may be invalid. This may be the case if a site has an incident involving dangerous substances. Even a near miss should prompt a review to ensure that the risks were correctly identified, with nothing overlooked, and consider whether additional safeguards need to be introduced.

Frequency and periodic review

Since there is no defined frequency for the regularity of reviews, it is important to define an interval that is frequent enough to demonstrate a commitment to maintaining compliance with the regulations. Good practice would be to identify an interval that is manageable for the process without being so frequent that adhering to the programme is impractical, or that the review becomes rushed and ineffective; whilst also ensuring that it is not infrequent.

If we consider the frequency at which other process safety documentation is required to be reviewed, that can help to influence the definition of a suitable interval. Regulation 10 of COMAH requires that safety reports are fully reviewed every five years; the Offshore Installations (Safety Case) Regulations also require a five yearly review. The British Standard 60079 Explosive atmospheres Part 14: Electrical installations inspection and maintenance’ specifies that fixed equipment inspection intervals should not exceed three years without the basis for the extension being documented.

With this in mind an interval of three years can be seen as good practice and consistent with the requirements of other relevant standards. If a longer interval was justified then no more than five years would be advisable, based on typical requirements for major process safety related documentation.


In conclusion, compliance with the regulations requires a DSEAR risk assessment to be carried out, including compressed gases and substances corrosive to metal, and all DSEAR documentation to be regularly reviewed and updated. Applying the hierarchy of control, ensuring risk assessments meet the key requirements of DSEAR, and defining a sensible interval for reviews enables compliance to be demonstrated and maintained.

About the author

Peter Hodgson is a Safety Consultant with ABB. He has over 10 years of experience in the ATEX and DSEAR field, including Hazardous Area Classification, DSEAR Compliance, and Mechanical Equipment Risk Assessment, in many industries including oil & gas, chemicals, paints and coatings, material handling, pharmaceuticals and offshore.

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