The Cygnus 1 Ex Ultrasonic Thickness Gauge stands out because it’s Intrinsically Safe and certified for use in Zone 0 hazardous areas - the most dangerous classification. But what do these certifications really mean? This article breaks down the terminology, regulations, and safety standards that make this device exceptional in its class.

To celebrate our best-performing product, 3 years since launch, we’re offering a FREE* Cygnus S2C-Ex Probe when you order a Cygnus 1 Ex PRO Anniversary kit (includes a Cygnus 1 Ex PRO Gauge and a Cygnus T5B-Ex Probe)!

Understanding Explosive Atmospheres

The term "Ex" refers to explosive atmospheres and is globally recognized in systems designed to prevent explosions.

Hazardous Areas are environments where flammable gases, vapours, or dust may be present in concentrations that can ignite. Equipment used in these areas must meet strict safety standards to prevent sparks or high surface temperatures that could cause explosions.

Global Ex Certification Schemes

Many countries adopt Ex certification schemes based on international standards, mainly those outlined by the IECEx system (International Electrotechnical Commission Explosive). IECEx provides a globally accepted framework to ensure equipment safety in explosive environments.

Here's how some major certification systems align with IEC standards:

Region Scheme Standard

Europe ATEX EN 60079

North America NEC/UL UL 60079

United Kingdom UKEX BS EN 60079

Brazil INMETRO EN 60079

The Cygnus 1 Ex is certified to IECEx, ATEX, and UKEX, and is the only ultrasonic thickness gauge approved for ATEX Zone 0, the highest safety classification. This is equivalent to NEC (UL) Class I Division 1 Group “ALL” in North America.

Zones and Divisions Explained:

Hazardous areas are categorized to define the level of risk:

European and IECEx Zone Classification:

• Zone 0: Explosive atmosphere present continuously or for long periods
• Zone 1: Likely to occur in normal operation
• Zone 2: Unlikely in normal operation, or only for a short time

North American Division Classification:

• Division 1 = Zone 0 or Zone 1
• Division 2 = Zone 2

The most hazardous environment is Zone 0 / Division 1, where explosive gases are nearly always present. These areas require the highest level of protection, which the Cygnus 1 Ex is built to meet.

Why Ex Certification is Superior to Other Testing Methods

You may come across other testing standards, such as MIL-STD-810G, but these do NOT offer the same level of assurance, including;

• Safety by design
• Independent certification body
• Ongoing manufacturer audits
• Multiple fault conditions tested
• Battery safety under fault
• Drop-tested and anti-static materials
• Legal approval for use in Ex zones

MIL-STD-810G merely tests whether a device will cause an explosion during a single test under very specific conditions. It doesn’t consider real-world scenarios like equipment faults, battery issues, or long-term durability. In contrast, Ex certification requires the device to be safe even if something goes wrong.

Final Thoughts

The Cygnus 1 Ex isn't just another ultrasonic gauge - it’s built from the ground up to perform safely in the most hazardous environments on Earth. Designed and manufactured in the UK, it comes with a 3-year warranty and is fully compliant with the world’s most rigorous Ex standards.