DSEAR Risk Assessment

A DSEAR assessment meaning can sometimes be a complicated answer. We have tried to simplify it for you here.

A DSEAR Assessment is a systematic review of a process and substances against strict criteria to determine, first of all if it is explosive, then how to eliminate ignition sources to prevent fire and / or explosions. It also considers the impact and severity of explosions such as the overpressure release and explosion suppression or venting to safe areas.

Furthermore, it identifies the zones which are explosive and defines them into a classification based on likelihood and composition if it is a Powder / Dust or if it is a Gas / Vapor. This is the Hazardous Area Classification (HAC).

The next bit is the most important. What to do with the information from the assessment. We pride our service on a very thorough assessment followed through with all practical and easy to understand recommendations and actions to become compliant.

A DSEAR risk assessment will identify any risks associated with your facility and substances so we can take steps to reduce them together – We will not just give you a list of things to do yourself!
You may see a DSEAR Assessment Example or DSEAR Assessment Template online, but the devil is in the detail. We are happy to give advice on doing the assessment for anyone wanting some pointers. Afterall, our business is about building relationships, not just doing odd jobs.

What is ATEX and DSEAR?

ATEX is the term derived from “AT”mosphere and “EX”plosive which is a European Union directive that sets the expected safety requirements and standards for workplace explosive atmospheres.
The definition of explosive atmosphere can be summarised as the mixture of a flammable or combustible substance (gas, fume, vapour, dust, or powder), that in significant amount of concentration and suspended in air, may ignite when introduced to a source of ignition.

The DSEAR regulations and DSEAR Assessments are the UK implementation of EU standards:

  • ATEX 94/9/EC Directive (The ATEX Equipment Directive) the manufacture of equipment and protective systems designed for use in potentially explosive atmospheres.
  • ATEX 1999/92/EC Directive (The ATEX Workplace Directive) the “minimum requirements for improving the safety and health protection of workers potentially at risk from explosive atmospheres”.

What is a Dangerous Substance?

The DSEAR regulations explain the main characteristics for what is deemed a dangerous substance, but for simplicity, if a substance is classified as flammable (below 60 Degrees Celsius flashpoint) or stored at a temperature of within 60 degrees of its flashpoint (I.E., heated oils), this is classified as a dangerous substance.

The regulations also apply to higher flashpoint substances stored under high pressure – for example, Glycol is a refrigerant substance and has a flashpoint of 100 to 110 Degrees Celsius, however if used under pressure of over 10barg and a leak occurs, this creates a spray and atomises the substance significantly increasing the flammability.

It is important to consider the flashpoint if it is suspended in air AND the pressure it is contained under.

The most effective means to do this is through a DSEAR risk assessment.

Sometimes this can be done as a desktop exercise to determine if it is classified as a Dangerous substance or not – Please contact us for information if this may be the case.

As a general rule and industry standards, the below is a list of the most commonly known industry substances and processes (this is a common list and not a complete list):

  • Oil and solvent based Paints and varnishes
  • Flammable gases (e.g., liquid petroleum gas)
  • Dust from sanding or machining (E.G. wood)
  • Pressurised gases and Cylinders
  • Gas Mains supply
  • Substances that are corrosive to metal
  • Spray booths
  • Flammable Paints and thinners
  • Acetone and solvent cleaners
  • Fuels such as Kerosene, Diesel, LPG, and Petrol
  • A1 Jet Fuels
  • Strong Acids (e.g., >80% Acetic Acid)
  • Food powders and ingredients such as flour and sugar
  • Alcohol production and distillation
  • Welding Gasses
  • Ammonia and some other refrigerant substances and Refrigerant Gasses
  • Biomass fuel dusts
  • Anaerobic Digestion process and gas
  • Biogas Production and Management
  • Chemical manufacturing, Blending, and processing
  • Battery Storage and Charging (Hydrogen)
  • Hydrogen installations and R&D facilities
  • Transport & Logistics
  • Wood and Timber manufacturing and Processing
  • Power Generation
  • Combined Heat and Power (CHP)
  • Coal Mining and Processing

What is NOT a Dangerous Substance?

DSEAR (Dangerous Substances and Explosive Atmospheres Regulations) is a UK law that requires employers to protect workers from the risks of fire, explosion, and similar events caused by dangerous substances.

DSEAR applies to all workplaces where dangerous substances are present, stored, used, or handled, including manufacturing, processing, and storage facilities, as well as transport and construction sites.

It does not specify which substances are considered “dangerous.” Instead, it requires employers to identify and assess the risks associated with the substances they use and take appropriate measures to protect workers.

Therefore any substance which is not considered dangerous by the employer as per their risk assessment would not be considered as dangerous substance under DSEAR.

Although the below list has the potential to explode, they are either not relatable to a dangerous substance, or are covered by other regulations and so a DSEAR assessment is not needed for:

Note – These may be possible ignition sources to other DSEAR Zones and so should be considered as part of the scope, but not the reason for a DSEAR Assessment.

  • High Voltage Electricity supply
  • Electrical cabinets
  • Air pressure cylinders (compressed air)
  • Non-flammable pressurised gas cylinders
  • High pressure water (pressure washers)
  • Building materials such as wood, brick, and concrete
  • Office supplies such as paper, pencils, and printer ink

What are Duty Holders Required to do under DSEAR?

The DSEAR Regulations 2002 outline specific for those with responsibility of managing workplaces where potentially explosive atmospheres exist to risk assess the facility, implement suitable control measures and arrangements to be deemed acceptable risk and compliant.

A DSEAR Risk Assessment is a legal requirement for any workplaces that handle, store, and use dangerous substances.

  • Regulation 5: Risk Assessment
  • Regulation 6: Elimination or reduction of risk
  • Regulation 7: Area classification
  • Regulation 8: Accidents, incidents, and emergencies
  • Regulation 9: Training and Information
  • Regulation 10: Identification of containers and pipelines
  • Regulation 11: Duty of co-ordination

Why Do We Need to Do a DSEAR Risk Assessment?

The DSEAR regulations identifies the minimum legal requirements to managing the risk of fire and explosion for hazardous substances and this sets the legal objective to complete a DSEAR Risk Assessment in the first instance. Within the DSEAR regulations, the health, and Safety Executive (HSE) expect the following:

  • Identify the dangerous substances within the workplace and potential risk
  • Implement suitable control measures in order to eliminate or reduce the risk to acceptable levels
  • Implement suitable emergency arrangements to reduce the effects of any incident involving dangerous substances
  • Ensure all policies and procedures to respond to incidents and emergencies
  • Provide suitable training and awareness to employees and contractors on the hazardous substances, areas, and safety arrangements of working within or near hazardous substances
  • Implement suitable identification for hazardous areas and ensure ignition sources are managed or eliminated where possible
  • Ensure appropriate inspection and maintenance systems are in place to maintain good practices

What Are The Benefits Of A Dsear Assessment?

A DSEAR risk assessment will identify the risks associated with your workplace in regard to the substances and the process, to allow appropriate action to be taken. Also, achieving compliance to the DSEAR regulations will demonstrate that the business is managing risk and adopting safe management systems and arrangements.

While working with our clients, we commonly look for the most effective control measures and solutions to achieve compliance, but we also work with clients to ensure we have followed the hierarchy of control as well as the most cost-effective solutions.

How Often Should a DSEAR Assessment be carried out?

As with all other risk assessments and inspections, the DSEAR assessment should be regularly reviewed and updated. Depending on the risk levels of the operations, the HSE generally recommends that DSEAR be updated every 3-5 years.

Normally a DSEAR Assessment should be completed as soon as any potential explosive atmospheres are identified. Ideally in a design sage but more often than not, it is after things are already in place.

If you do have a facility that has a high risk or large volumes of substances, the DSEAR assessment could be reviewed as soon as 6 months after the initial assessment.

That said, however 1 year review after the assessment is most common, and when all actions are closed and compliant, 3-5 years can be very acceptable from there on.

Of course, if things change or you introduce new substances, this will trigger a review, however, if it is a continuation of the initial DSEAR Assessment, the cost is significantly reduced for small changes. A full redo is not needed.

Cost and Risk effective Example – Improve ventilation within a boiler container unit

A boiler was installed within a 40m shipping container. This shipping container was sealed and enclosed, and the fuel used was a Propane cylinders stored outside but piped to the burner for ignition and Kerosene fed from the tank outside once the burner had reached temperature.

There were light fittings within the room as well as other electrical points and all of the burner and engine plant was of course not ATEX rated. The whole room was classified as zone 2.

We identified an option to install forced ventilation at high and low levels to the point where the evaporation rate and gas leak pressure was surpassed, and it would not be possible for the room to completely fill with flammable gasses and vapours.

The outcome resulted in reclassifying the unit and instead of all zone 2, the new zone 2 was within 1m of the gas and kerosene pipework connection points, allowing the light fittings and other electrical equipment to remain the same and be compliant.

We were able to do this based on agreement of robust inspection arrangements, gas detection connected to isolation shut off and the improved ventilation arrangements.

This resulted in a significantly reduced cost for the client, and we have followed the hierarchy of control in reducing the risk.

How Much Does a DSEAR Assessment Cost?

The cost of a DSEAR Risk assessment can vary depending on the size and complexity of the facility, as well as the experience and qualifications of the assessor.

A DSEAR assessment is typically carried out by a qualified and experienced consultant, who will assess the facility to ensure that it is compliant with DSEAR regulations and that appropriate measures are in place to minimise the risk of fire or explosion. The assessment will include a review of the facility’s layout, processes, and equipment, as well as an evaluation of the hazardous substances used or stored on site.

The initial costs for conducting a DSEAR (Dangerous Substances and Explosive Atmospheres Regulations) risk assessments at low-risk facilities which are in design stage, such as Property Development wet well pumping stations, start from approximately £2200.

If the assessment necessitates an on-site visit, for a more complex facility, the fees range from £2750 to £4850.

This includes a full On-site inspection and DSEAR risk assessment, Hazardous area classification and detailed action plan. We also provide a detailed handover by revisiting site or via videocall, and wherever needed, ongoing support to implement control measures.

A full report will be issued within 10 to 15 working days of the site inspection.

Please get in touch to chat through the exact details of your project – our specialist Health and Safety support experts will walk you through the full process.

Who can do a DSEAR Assessment?

DSEAR Risk Assessment competency is a very important question.

To be able to complete a DSEAR Assessment, the HSE have stated within their DSEAR ACOP that someone “Competent” must complete the assessment.

This does not really shed much light on the required competency, however having a detailed knowledge of the DSEAR regulations combined with years of experience in high-risk sectors sure will go a long way.

With DSEAR assessor trained staff and over 10 years working in industries with explosive atmospheres, we have time and time again satisfied the HSE of our competence to complete DSEAR Assessments for our clients, so not only will you get a great dsear consultancy service and a service that flows through with all identified actions, but you will also be in very confident and competent safe hands.

What are DSEAR Zones and HAC?

HAC stands for Hazardous Area Classification. This is the detailed calculations that consider all of the substance key information such as ventilation, evaporation rate, release rate, temperature etc to determine how big of a zone exists and how prevalent to determine a zone classification.

A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of Powder / Dust / Fumes / Vapours or Gasses is present continuously or for long periods or frequently.

A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of Powder / Dust / Fumes / Vapours or Gasses is likely to occur in normal operation occasionally.

A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of Powder / Dust / Fumes / Vapours or Gasses is not likely to occur in normal

We then display this in 2 formats. Text to clearly explain the size, extent, and classification of the HAC zone and also secondly, we create a side or overhead plan diagram showing in visual format the extent of the zones.

What is included within the DSEAR Risk Assessment?

The DSEAR assessment typically involves a 1–2-day site visit, where are a specialist consultant will review all management arrangements and walk the whole site looking at storage, handling, and use of dangerous substances to determine a true picture of all activities and risk profile.

We create a register of the substances and review any material safety documentation and any previous or published explosion data. We sometimes have much of this to hand for similar substances from experience with other similar projects.

From there we review the potential ignition sources, release rates and concentrations, temperatures, ventilation, and other control arrangements to determine the risk profile and create the risk assessment and Hazardous area classification.

We review all documentation and arrangements such as fire risk management, training, electrical inspection, and testing etc and make recommendation on the most effective options to achieve compliance and manage risk.
We model our services around our main goal which is to help the client. We have a strict process to make sure we are representing you, the client and not just causing more hassle to add to your existing ever-long list of things to do.

We achieve this by having a very detailed but VERY clear Risk Assessment template, which includes a fully descriptive and detailed action plan explaining exactly what action to take in order to achieve compliance and acceptable risk levels.

Our Chartered consultants will lead all DSEAR projects and combined with a very detailed understanding of your industry, we undertake an in-depth review of the following:

  • Hazardous Substances and materials
  • Housekeeping and Storage arrangements of dangerous substances
  • Handling and use of dangerous substances
  • Additional process and activities (such as pipework transfer and possible leak points)
  • Emergency Arrangements and procedures
  • Inspection and Maintenance arrangements
  • Sources of ignition, Hot surfaces, and Smoking arrangements
  • Electrical equipment rating within zoned areas
  • Hazardous Area Classification
  • Interconnecting plant and equipment (I.E. Rotary Valves to bagging lines or Shut valve Louvres within LEV ducts)
  • Existing and required control measures
  • Bund Containment and spillage management
  • Management and control of waste substances
  • Fire Risk Assessment, Fire early detection and Fire Fighting arrangements
  • Occupational Health and hygiene arrangements
  • Policies and Procedures around H&S, Management of Contractors and LOTO
  • DSEAR Training
  • Lightning Protection and Earth Connectivity
  • Extraction and Ventilation
  • Planned Preventative maintenance and inspection systems such as Thermal Imaging or mechanical

Please see our Free Resources for a redacted a DSEAR Assessment example report.

Experts in DSEAR Risk Assessments with Over a Decade of Experience

All of our consultants are suitably qualified and registered as members of appropriate bodies.
You will be allocated a Senior consultant with a minimum of Chartered status with IOSH (CMIOSH) to oversee and complete works.

To know more or chat to a consultant, pop an email over to us at [email protected] or call us on – 01656 470044. We are usually in touch within 1 hour of your email. If your query is urgent, contact our senior specialist directly - [email protected]

Example of DSEAR Regulations Policy


DSEAR (Dangerous Substances and Explosive Atmospheres Regulations) is a set of regulations in the United Kingdom that aim to protect workers from the risks of fires, explosions, and other dangerous incidents that may occur as a result of the storage, handling, or use of dangerous substances in the workplace.

The Dangerous Substances and Explosive Atmospheres Regulations (DSEAR) applies to all workplaces where dangerous substances are present and covers a wide range of activities that may pose risks to workers. Some examples of activities that are covered by DSEAR include:
  • The storage, handling, and use of dangerous substances, such as chemicals, flammable liquids, gases, and dusts
  • The transport of dangerous substances within the workplace
  • Processes that involve the use of dangerous substances, such as manufacturing, packaging, and cleaning
  • Work that may generate explosive atmospheres, such as welding, grinding, and spray painting
  • Work that may generate dust explosions, such as food processing, woodworking, and grain handling
  • Work that may generate fire risks, such as the use of hot work equipment, like welding and cutting equipment.

According to the Dangerous Substances and Explosive Atmospheres Regulations (DSEAR) 2002, employers are responsible for ensuring the safety of their employees and others who may be affected by their activities in relation to dangerous substances. As such, DSEAR assessments are required for all workplaces where dangerous substances are present.

This includes workplaces where dangerous substances are stored, handled, or used, as well as workplaces where processes are carried out that may generate explosive atmospheres or dust explosions.

The duration of a DSEAR (Dangerous Substances and Explosive Atmospheres Regulations) assessment can vary depending on the size and complexity of the workplace and the number of dangerous substances present.

For a small and simple workplace with a limited number of dangerous substances, an assessment can be completed in a day or less. However, for larger and more complex workplaces, it may take several days or even weeks to complete the assessment.

It's important to note that the DSEAR assessment is not a one-time event, it's a continuous process, it should be reviewed and updated on a regular basis to ensure that the workplace remains safe and that any new hazards are identified and controlled.

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