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DSEAR: Hazardous Area Classification for Gases and Liquids

28 January 2025

HSE runs three different courses to help employers comply with the Dangerous Substances and Explosive Atmospheres Regulations (DSEAR).

  • DSEAR: Gases and Liquids
  • DSEAR: Hazardous Area Classification for Gases and Liquids
  • DSEAR: Controlling Dust Explosion Risks

While there is some overlap between the courses delegates can attend one or more courses depending on which area of DSEAR they are interested in.


DSEAR requires that areas where accidental releases of dangerous substances could occur are identified and classified according to the likelihood of the formation of a flammable atmosphere.

Within classified areas, sources of ignition should be controlled. This course is designed to provide delegates with the knowledge to carry out straightforward hazardous area classification in accordance with commonly used standards or to act as an intelligent customer when contracting others to deliver this role.

The 'DSEAR: Hazardous Area Classification for Gases and Liquids' course is aimed at those with some existing experience of DSEAR and hazardous area classification, whereas the 'DSEAR: Gases and Liquids' is an entry level course.

Learning outcomes

Delegates will be provided with information that will help them to:

  • Understand how the regulations apply in relation to hazardous area classification
  • Know what standards are available for area classification​
  • Understand which area classification standards are most applicable to them and understand which are applicable to their business
  • Be able to perform a straightforward area classification study​
  • Be able to act as an intelligent customer when commissioning hazardous area classification

What the course will cover

Delegates will be introduced to DSEAR and the classification of hazardous substances and will look at the relevance of the physical/chemical properties of gases, liquids and flammable mists to area classification. The classification of hazardous areas by zone will be explained, including the concept of a zone of negligible extent (NE). Delegates will look at the importance of ventilation in area classification and the concept of Vz based methods. Delegates will look at hazardous area classification standards and codes and be given an overview of what equipment to use in classified areas. Finally, delegates will look at the national and international standards and guidance commonly used in area classification including practical examples of their use.

Who should attend?

This course is suitable for those who require a detailed understanding of the process of hazardous area classification, including process safety engineers, electrical engineers and health and safety practitioners.


The course will be run at the HSE Science and Research Centre in the spa town of Buxton.

Buxton is in the heart of the Peak District and has good links to major roads and motorways, mainline train stations and Manchester International Airport.

Details of hotels in the Buxton area can be found at


£690 per person (includes course notes, lunch and refreshments).

Book Course

Please note that all courses must be paid for via credit card at the time of booking.

Some of our training courses can also be delivered in-company, please contact us to discuss your requirements.

Telephone: +44 (0)203 028 3704

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