F-Gas Exam Categories Explained: Category I vs II vs III vs IV

Why Categories Exist

The F-Gas certification system is not one-size-fits-all. The EU F-Gas Regulation 517/2014 (retained in UK law) establishes four distinct certification categories, each corresponding to a different scope of permitted activities. The category you need depends on the type of work you carry out and the size of systems you work on.

Choosing the right category is important. If you hold a lower category than your work requires, you are operating outside the law. Conversely, if you only perform limited tasks, you may not need to sit the full Category I exam. This guide breaks down each category so you can make an informed decision.

Category I: Full Scope

Category I is the highest level of F-Gas certification and grants the widest scope of permitted activities. If you hold a Category I certificate, you are qualified to carry out:

• Leak checking on all systems, regardless of charge size
• Recovery of F-gases from all systems
• Installation of F-gas equipment
• Maintenance and servicing of all F-gas systems
• Repair of systems containing F-gases
• Decommissioning of F-gas equipment

There are no restrictions on the size of the system or the quantity of refrigerant. Category I is the certificate that most professional HVAC and refrigeration engineers should aim for, as it covers every activity you are likely to encounter in the field.

Who Needs Category I?

• Refrigeration engineers who install and commission systems
• Air conditioning technicians working on split systems, VRF/VRV, and chillers
• Heat pump installers
• Service engineers responsible for full system maintenance
• Anyone who needs unrestricted access to work on F-gas equipment

Exam Requirements

The Category I exam covers all skill groups in the City & Guilds 2079 syllabus. It is the most comprehensive exam, testing knowledge across regulations, thermodynamics, system components, leak detection, recovery, charging, electrical safety, and environmental impact. The exam consists of 40 multiple-choice questions to be completed in 80 minutes, with a pass mark of 60%.

Category II: Limited Charge Size

Category II certification permits all the same activities as Category I, but with a critical restriction: it only applies to systems containing less than 3 kg of F-gas charge (or less than 6 kg for hermetically sealed systems that are labelled as such).

With a Category II certificate, you can:

• Leak check systems with less than 3 kg charge
• Recover refrigerant from systems with less than 3 kg charge
• Install systems with less than 3 kg charge
• Maintain and service systems with less than 3 kg charge
• Repair and decommission systems with less than 3 kg charge

Who Needs Category II?

• Technicians who exclusively work on small domestic or light commercial systems
• Engineers working only with small split systems or portable units
• Those who want a stepping stone before progressing to Category I

Practical Considerations

While Category II covers a useful range of smaller equipment, many employers and clients prefer technicians with the full Category I qualification. The 3 kg charge limit can be restrictive in practice, as many commercial air conditioning systems and refrigeration units contain charges well above this threshold. If there is any chance your work will involve larger systems, Category I is the better investment.

Category III: Recovery Only (Small Systems)

Category III is a specialist certificate focused solely on the recovery of F-gases from systems containing less than 3 kg of charge (or less than 6 kg for labelled hermetically sealed systems).

With a Category III certificate, you can:

• Recover F-gases from small systems (under 3 kg)

You cannot install, maintain, service, repair, commission, or leak check systems under this category. It is a narrow, task-specific qualification.

Who Needs Category III?

• Waste management and recycling operatives who need to recover refrigerant from end-of-life equipment (old fridges, freezers, and small air conditioning units)
• Scrap metal processors handling WEEE (Waste Electrical and Electronic Equipment)
• Anyone whose sole involvement with F-gases is recovering them from small appliances prior to disposal

Exam Requirements

The Category III exam is shorter and covers fewer skill groups than Categories I and II. It focuses primarily on safe recovery procedures, equipment handling, environmental regulations, and personal safety.

Category IV: Leak Checking Only (Large Systems)

Category IV is another specialist certificate, this time focused on leak checking of systems containing 3 kg or more of F-gas (or 6 kg or more for labelled hermetically sealed systems). Note the important distinction: Category IV applies to larger systems, not smaller ones.

With a Category IV certificate, you can:

• Carry out leak checks on systems containing 3 kg or more of F-gas

You cannot install, recover, maintain, service, repair, or decommission systems under this category.

Who Needs Category IV?

• Building maintenance staff who are responsible for routine leak checks on large commercial HVAC systems but do not carry out any refrigerant handling
• Facilities managers who need to perform or oversee mandatory periodic leak inspections
• Compliance officers who physically carry out scheduled leak detection checks

Exam Requirements

The Category IV exam is focused on leak detection methods (both direct and indirect), mandatory leak check frequencies based on CO2 equivalent charge, record-keeping requirements, and the relevant provisions of the F-Gas Regulation.

Comparison Summary

Feature	Category I	Category II	Category III	Category IV
Leak checking	All systems	< 3 kg	No	3 kg and above
Recovery	All systems	< 3 kg	< 3 kg only	No
Installation	All systems	< 3 kg	No	No
Maintenance/Service	All systems	< 3 kg	No	No
Charge size limit	None	< 3 kg	< 3 kg	3 kg and above
Exam difficulty	Highest	Moderate	Lower	Lower

Which Category Should You Choose?

For most HVAC and refrigeration professionals, Category I is the recommended choice. It provides full, unrestricted access to all F-gas activities and is the qualification that employers and clients expect. The exam is more demanding, but with proper preparation it is entirely achievable.

If you are certain your work will only ever involve small systems under 3 kg, Category II may suffice. Categories III and IV are appropriate only for those with very specific, limited roles that do not involve general refrigerant handling or system installation.

Whichever category you pursue, make sure your certification remains current and that you stay up to date with any changes to the regulations. The F-Gas landscape continues to evolve, and ongoing professional development is essential.