What are DSEAR Assessments?

The Dangerous Substances and Explosive Atmospheres Regulations (DSEAR) require employers to assess all potential risks to employees and others whose safety may be affected by the use or presence of a dangerous substance at the workplace.

The regulations concentrate on preventing or limiting the harmful effects of fires, explosions and similar energy-releasing events and corrosion to metals.

The main requirements for complying with DSEAR are:

• Undertaking a risk assessment that includes identifying sources of flammable atmospheres and suitable control measures; and
• Performing Hazardous Area Classification calculations to identify where flammable atmospheres may be present and where ignition sources need to be controlled.
• Employees are provided with appropriate information and training.

These are the types of substances that fall under the regulations:

• Use of flammable gases, such as acetylene, for cutting and welding
• Handling and storage of waste dusts from woodworking operations
• Handling and storage of flammable wastes including fuel oils
• Storage and use of flammable solvents and paints
• Storage and use of flammable gases, e.g. LPG
• Storage and use of highly flammable liquids, petroleum spirit

(The list above is not comprehensive)

Click here to read some frequently asked questions about fire safety.

DSEAR assessment approach

A three-stage approach should be used for undertaking an assessment.  This is as follows;

1. Hazard identification;

During this stage all substances and processes that potentially could create an explosive atmosphere should be reviewed. This includes, where applicable, flammable gases and vapours, combustible powders/dust and other substances that can under specific conditions create an ‘explosion type’ event, e.g. dusts. The review should cover the full ‘life span’ of the substances from delivery, storage and use to dispatch/disposal within the areas under consideration.

2. DSEAR based risk assessments;

DSEAR based risk assessments should be undertaken on the situations identified within Stage 1. The assessments should identify the processes where there is the potential for an explosive atmosphere to be created in both normal and reasonably foreseeable fault conditions. For each process or collection of similar processes the assessments consider the likelihood and consequences of an explosive atmosphere being created and ignited but should also consider what further controls, if any are in place to mitigate the consequences should ignition occur. This mitigation, if appropriate should cover controls to prevent the propagation of the explosion or minimise the damaged caused.

3. Hazardous area classification

A HAC should be undertaken for those fixed locations where explosive atmospheres potentially could arise to address residual risk that is left after applying the hierarchical principals of the regulations.

The purpose of the HAC is to ascertain the extent to which an explosive atmosphere occurs, which will determine the level of protection required to prevent sources of ignition.

Hazardous areas are classified in terms of Zones based on the probability, or frequency and duration of the occurrence of an explosive atmosphere.The Zones are outlined within Schedule 2 of the regulations.Where the likelihood of an explosive atmosphere can be reduced to a negligible extent by engineering controls, there is no need to establish a ‘Zone’ as such.

Hazardous area classification (Zoning)

For gases, vapours or mists:

• Zone 0:  A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapour or mist is present continuously, or for long periods, or frequently.
• Zone 1: A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapour or mist is likely to occur in normal operation occasionally or is likely to persist for a period of time.
• Zone 2:  A place in which an explosive atmosphere consisting of a mixture with air of dangerous substances in the form of gas, vapour or mist is not likely to occur in normal operation but if it does occur, will persist for a short period only.

For dusts:

• Zone 20: A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is present continuously, or for long periods or frequently.
• Zone 21: A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is likely to occur in normal operation occasionally.
• Zone 22: A place in which an explosive atmosphere in the form of a cloud of combustible dust in air is not likely to occur in normal operation but, if it does occur, will persist for a short period only.

The above Zoning classifications relate to the likelihood of a release of a flammable material.

Equipment and protective systems for all places in which explosive atmospheres may occur must be selected in accordance with the requirements contained in the Equipment and Protective Systems Intended for Use in Potentially Explosive Atmospheres Regulations 1996

Who is responsible?

The employer is responsible for ensuring that the standard of equipment and protective systems provided are appropriate to the hazard classification of the zone. The access point to places so classified should be marked with the appropriate sign.

The signage displayed must be triangular and have black letters on yellow background with black edging and the yellow portion must take up at least 50% of the area of the sign.

In summary, compliance with the regulations requires a risk assessment to be undertaken, and all 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.

Assessments and therefore risks will vary according to the level of knowledge, experience, training and competency of the individual undertaking the assessment. In many cases it may be beneficial and cost effective to seek advice and assistance from experienced professionals.