The difference between ATEX category 2G and 3G overpressure protection systems lies in their safety level and application scope. Category 2G provides a high protection level for Zone 1 environments where explosive atmospheres occur regularly, whilst category 3G has a normal protection level for Zone 2, where explosive atmospheres rarely occur. The choice depends on your specific risk analysis and operational circumstances.
What do ATEX categories 2G and 3G mean exactly?
ATEX category 2G represents equipment with a high protection level against ignition of explosive gas mixtures. The number “2” indicates category 2 (high safety level), whilst the letter “G” stands for gas (as opposed to “D” for dust). This equipment must withstand two independent faults before a dangerous situation arises.
ATEX category 3G, on the other hand, represents equipment with a normal protection level. These overpressure protection systems are designed to operate safely during normal operation in environments where explosive gas atmospheres may be present. They need only withstand one fault before risk occurs.
The ATEX classification follows a logical system where lower numbers mean higher safety requirements. This system helps engineers and safety specialists in selecting suitable explosion-proof equipment for specific industrial applications.
What safety requirements apply to category 2G versus 3G overpressure protection systems?
Category 2G overpressure protection systems must comply with stricter safety requirements than 3G systems. They undergo more extensive testing procedures and feature redundant safety systems. Certification requires proof that the system remains safe during two independent component or system failures.
For category 3G overpressure systems, the requirements are less stringent, but still important for industrial safety. These systems must demonstrate that they do not form an ignition source during normal operation. Testing procedures focus on temperature control, spark prevention and housing integrity.
Both categories require CE marking and must comply with relevant European standards. Documentation must be traceable and maintenance procedures must ensure the original safety requirements. Regular inspections and calibrations are mandatory for both categories.
In which zones may you use category 2G and 3G equipment?
Category 2G overpressure protection systems are suitable for ATEX Zone 1 and Zone 2. Zone 1 environments are locations where explosive gas atmospheres occur regularly or for short periods during normal operation. Consider areas around process equipment in chemical plants or near filling points.
Category 3G equipment may only be used in Zone 2 environments. These are locations where explosive atmospheres rarely occur and are only present briefly under abnormal conditions. Examples include ventilation outlets or storage areas at a distance from direct process sources.
The zoning is determined by a risk analysis that assesses the probability and duration of explosive atmospheres. This analysis forms the basis for selecting suitable overpressure protection and other explosion-proof equipment for your specific application.
How do you choose between category 2G and 3G for your overpressure protection?
The choice between category 2G and 3G depends on your ATEX zone classification and risk analysis. Begin by determining the explosion risks in your working environment. If explosive gas mixtures can occur regularly, you need category 2G. For environments where this rarely happens, category 3G suffices.
Also consider operational factors, such as:
- The criticality of the process being protected
- The consequences of system failure
- Maintenance possibilities and frequency
- Environmental temperature and conditions
- Budget constraints versus safety requirements
Always consult a qualified ATEX specialist for complex installations. They can perform a thorough risk analysis and advise the most suitable overpressure protection for your specific situation and industrial requirements.
How Presscon helps with ATEX-compliant overpressure protection systems
We provide complete support for ATEX-compliant overpressure systems, from design to maintenance. Our expertise in explosion-proof equipment helps you make the right choice between category 2G and 3G systems for your specific application.
Our services include:
- Risk analysis and zone classification – thorough assessment of your working environment
- System design and engineering – bespoke overpressure protection systems according to ATEX requirements
- Certification and documentation – complete compliance with European standards
- Installation and commissioning – professional implementation by certified technicians
- Maintenance and inspection – regular checks for continued safety
With over 25 years of experience in industrial safety systems, we understand the complexity of ATEX compliance. For applications where vacuum conditions are required, we offer specialised ATEX vacuum overpressure protection that meets the highest safety requirements. Contact us for a thorough analysis of your overpressure protection needs and discover how we can improve your operational safety.
Frequently Asked Questions
How often should I have my ATEX overpressure protection inspected?
The inspection frequency depends on your category and environmental factors. For category 2G systems we recommend annual professional inspections, whilst 3G systems often suffice with inspections every 18 months. Daily visual checks and monthly function tests are essential for both categories to ensure optimal safety.
Can I upgrade existing overpressure protection from 3G to 2G classification?
An upgrade is technically possible, but often requires extensive modifications to the system. The housing, sensors and control electronics must comply with the higher 2G requirements. In most cases replacement is more cost-effective than upgrading, especially since certification and documentation must be completely redone.
What are the most common mistakes when selecting ATEX overpressure protection?
The biggest mistake is underestimating the zone classification through incomplete risk analysis. Other common mistakes are: ignoring environmental temperatures in material selection, insufficient consideration of future process changes, and choosing categories that are too low to save costs at the expense of safety.
How long does the implementation process take for new ATEX overpressure protection?
For standard applications allow 6-8 weeks from order to full commissioning. Bespoke systems can take 10-16 weeks, depending on complexity and certification requirements. Planning ideally begins 3-4 months in advance to accommodate delivery times and any production adjustments.
What documentation do I need for ATEX compliance of my overpressure protection?
Essential documents are: EU declaration of conformity, ATEX certificate, installation drawings, operating instructions in English, maintenance procedures and inspection reports. Additionally, you must prepare an explosion safety document that documents the risk analysis and measures taken in accordance with the ATEX directive.
What happens if my ATEX overpressure protection fails during operation?
In case of failure, the system must be immediately taken out of service until repair and recertification are completed. For critical processes we recommend redundant systems or emergency procedures. Failure analysis is mandatory to determine the cause and prevent recurrence. Document all incidents for compliance and continuous improvement.