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Hazardous Area Classification for Gases and Liquids

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26 October 2023

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

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.


The Dangerous Substances and Explosive Atmospheres Regulations (DSEAR) require 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 course covers

  • The classification of hazardous substances
  • The relevance of the physical/chemical properties of gases, liquids and mists to area classification
  • The classification of hazardous areas by zone, including the concept of a zone of negligible extent (NE)
  • The importance of ventilation in area classification and the concept of Vz
  • The Quadvent approach to area classification
  • The national and international standards and guidance commonly used in area classification including practical examples of their use
  • An introduction to equipment for use in explosive atmospheres

Who should attend

This course is suitable for those who may be asked to carry out hazardous area classification as part of a DSEAR assessment including process safety and electrical engineers, and health and safety practitioners.

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

For a higher level introduction to hazardous area classification the DSEAR - Gases and Liquids course would be more appropriate.


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 mainline train stations and Manchester International Airport. This course can be run at your site or local area by arrangement.

Details of hotels in the Buxton area can be found at


£675 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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