Gas and vapours (Ex01 – Ex04)

Gas and vapours (Ex01 – Ex04)

The CompEx Ex01-Ex04 Gas and vapours qualification has been developed for electrical and instrument technicians working in hazardous locations where gases or vapours can form explosive atmospheres.


This qualification is suitable for practicing electrical or instrument technicians who are involved in installing, inspecting and maintaining certified Ex electrical equipment in locations where gases and vapours can potentially create a hazardous area.

Entry requirements

  • Practicing competent electrical technicians
  • Practicing competent instrument technicians
  • Electrical/instrument engineers with previous practical experience
  • Prior CompEx certification supported by employer sponsored letter.


Approximately 5 days, however; some international centres offer a 6-day course to further support candidates where English is not their first language.


The 5-day course includes:

  • 3 days of guided learning (theoretical 15-20 hours, practical 4-6 hours)
  • 2 days of assessment

This course has been developed in consultation with industry to ensure the core competence of existing and potential workers who operate in these environments.

The qualification consists of four units, which cover the minimum requirements for safe working practices in hazardous locations.

Candidates will learn about the safety considerations that should be applied to work areas that contain potentially explosive or flammable atmospheres and the factors that are used to classify their location.

The course includes instruction on how to read hazardous area certification, labelling and documentation, and also informs candidates about the main protection concepts, categories and levels that are applied to certified Ex electrical equipment.

Successful candidates will demonstrate the knowledge and skills to meet the requirements highlighted in the IEC 60079 series of standards and the relevant national standards and directives. This qualification focuses on the minimum specifications identified in IEC60079:0, IEC60079:10.1, IEC60079:14 and IEC60079:17.

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Key learning objectives

Candidates that successfully complete the Ex01-Ex04 qualification will be able to:

  • Identify the correct national regulations, directives, and IEC standards which relate to hazardous areas.
  • Demonstrate a basic knowledge of the main protection concepts, categories and protection levels that apply to equipment certified for use in hazardous areas.
  • Recognise the elements that make up a hazardous atmosphere and the precautions required.
  • Demonstrate an underpinning knowledge of how certified Ex electrical equipment including Ex ‘d’, ‘e’, ‘n’, ‘p’, ‘m’, ‘o’, ‘q’, ‘s’, Intrinsic Safety (IS) maintains its protection concept and how it is to be selected, installed, inspected and maintained.
  • Identify the correct test value readings for IS and non-IS installations and equipment.

Qualification details

Candidates who are successful in both the theory and practical assessments will receive a CompEx Certificate in Core Competence.


Assessment is undertaken using both practical assessments and an online examination that covers the four separate CompEx units.

Online exam

Candidates must undertake a multiple-choice online examination that consists of 60 questions answered over 1.5 hours.

Practical assessment:

Candidates are required to undertake four practical assessments (one per unit):
  • Ex01 – 3 hours 45 minutes
  • Ex02 – 1 hour 30 minutes
  • Ex03 – 3 hours
  • Ex04 – 1 hour 15 minutes

Candidates have been certified for CompEx 01 - 14 across all these Countries

Make an enquiry

If you would like to make an enquiry about the CompEx Scheme or require further information about any of our qualifications, please contact us by completing our enquiry form.

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