The Master Glossary of Hazardous Areas & Explosion Protection
This glossary is designed to be your essential one-stop shop for demystifying the complex terminology and abbreviations that define the hazardous area landscape.
We’ve organized the most critical concepts into a logical flow to help you understand the key concepts, and how they pertain to the mobile technology that powers your field operations.
Section 1: Foundations & Regulatory Framework
This section defines the legal and international frameworks that mandate safety standards in hazardous locations.
|
Term |
Category |
Detailed Definition |
|
ATEX |
Regulatory |
The European Union framework (Directives 2014/34/EU and 1999/92/EC) for equipment and worker safety. Mandatory for products sold in the EU. |
|
IECEx |
Regulatory |
An international certification scheme based on IEC standards. It aims to harmonize "Ex" standards globally to facilitate international trade. |
|
Hazardous Area |
Environment |
Any location where flammable gases, vapors, mists, or dusts can mix with air to create an explosive atmosphere under atmospheric conditions. |
|
Notified Body |
Authority |
An independent, accredited organization (e.g., Intertek, SGS, UL, CSA) that audits manufacturers and issues "Ex" certificates. |
Section 2: The Environment (Zones)
Zones are the first step in risk assessment. They define how likely an explosion is to occur based on time and frequency.
|
Zone (Gas) |
Zone (Dust) |
Occurrence Frequency |
Frequency Detail |
|
Zone 0 |
Zone 20 |
Continuous |
Hazard is present constantly or for long periods (>1,000 hours/year). |
|
Zone 1 |
Zone 21 |
Occasional |
Hazard is likely to occur during normal daily operations (10–1,000 hours/year). |
|
Zone 2 |
Zone 22 |
Rare |
Hazard is unlikely to occur; if it does, it persists for a very short time (<10 hours/year). |
Section 3: Material Hazards (Groups & Temps)
Even if a Zone is "Rare," you must know "What" is in the air. This section classifies substances by how easily they ignite.
Gas & Dust Groups
|
Group |
Representative Substances |
Relative Hazard |
|
Group I |
Methane, Coal Dust (Firedamp) |
Underground Mining Only |
|
Group IIA |
Propane, Petrol, Acetone, Ammonia |
Low (Highest energy required to ignite) |
|
Group IIB |
Ethylene, Town Gas, Coke Oven Gas |
Medium |
|
Group IIC |
Hydrogen, Acetylene, Carbon Disulphide |
Highest (Extremely easy to ignite) |
|
Group IIIA |
Combustible Flyings (Cotton, Rayon, Lint) |
Low |
|
Group IIIB |
Non-Conductive Dust (Grain, Sugar, Wood, Flour) |
Medium |
|
Group IIIC |
Conductive Dust (Aluminum, Magnesium, Graphite) |
Highest (Conductivity increases risk) |
Temperature Classes (T-Classes)
Applies to Gas environments. The device surface must never exceed the Auto-Ignition Temp (AIT) of the gas.
|
T-Class |
Max Surface Temp |
Example Substances |
|
T1 |
450°C |
Methane, Hydrogen |
|
T2 |
300°C |
Ethanol, Butane |
|
T3 |
200°C |
Petrol, Diesel, Jet Fuel |
|
T4 |
135°C |
Standard for most mobile devices/tablets. |
|
T5 |
100°C |
N/A (Less common requirement) |
|
T6 |
85°C |
Maximum Safety (e.g., Carbon Disulphide). |
Section 4: Protection Concepts & Methods
This is the core "How." These engineering philosophies determine whether a device prevents an explosion or simply survives one.
The Two Primary Philosophies
|
Philosophy |
Principle |
Context for Mobile Devices |
|
Intrinsically Safe (IS) |
Prevention: Limits the energy (current/voltage) to ensure no spark or heat can occur. |
Found in Native Ex iPhones/Androids. Allows for light, slim devices. |
|
Explosion Proof (Ex-Proof) |
Containment: Uses a heavy-duty enclosure to contain an internal blast and cool flames. |
Usually found in Ex Cases. Results in heavier, bulkier equipment. |
Specific Protection Methods (Ex Codes)
|
Code |
Name |
Principles / Fault Tolerance |
Typical Zones |
|
Ex ia |
Intrinsic Safety |
Safe with two simultaneous component faults. |
0, 1, 2 |
|
Ex ib |
Intrinsic Safety |
Safe with one component fault. |
1, 2 |
|
Ex ic |
Intrinsic Safety |
Safe during normal operation (no faults). |
2 |
|
Ex d |
Flameproof |
Enclosure withstands internal pressure; cools exiting gases. |
1, 2 |
|
Ex e (eb, ec) |
Increased Safety |
Robust construction; prevents arcs/sparks from starting. |
1, 2 |
|
Ex m (ma, mb) |
Encapsulation |
Electronics "potted" in resin to exclude gas/dust. |
0, 1, 2 |
|
Ex p (px, py, pz) |
Pressurized |
Clean air/inert gas keeps hazardous air out. |
1, 2 |
|
Ex t (ta, tb, tc) |
Dust Tight |
Protection by enclosure specifically for dust layers/clouds. |
20, 21, 22 |
|
Ex n (nA, nR) |
Non-Sparking |
Low-cost method specifically for Zone 2. |
2 |
Section 5: Certification & Marking
This is the "decoder ring" for the stickers found on the back of iPads and iPhones.
|
Code / Suffix |
Meaning |
Detailed Context |
|
Category 1 / 2 / 3 |
ATEX Level |
1: Zone 0/20; 2: Zone 1/21; 3: Zone 2/22. |
|
EPL (Ga, Gb, Gc) |
IECEx Level |
Ga: Highest Gas protection; Gc: Normal Gas protection. |
|
EPL (Da, Db, Dc) |
IECEx Level |
Da: Highest Dust protection; Dc: Normal Dust protection. |
|
X-Condition |
Specific Rule |
Found at end of Cert #. Means you must read the manual (e.g., "Charge only with Brand X cable"). |
|
U-Component |
Incomplete Part |
Found at end of Cert #. Means the part is not safe to use unless built into a system. |
|
CE + 4 Digits |
Notified Body |
e.g., "CE 0539" (UL). Confirms the factory is audited for Ex production. |
Section 6: Hardware & Physical Protection
Specific jargon related to the physical build of mobile devices and their environmental durability.
|
Term |
Hardware Type |
Definition |
|
Native Ex Device |
Smartphone/Tablet |
A device engineered internally to be Ex i. Usually thinner and lighter. |
|
Ex Case |
Accessory |
A certified housing (often Ex d or Ex t) that makes a consumer device safe. |
|
Ruggedized |
Durability |
Refers to drop/shock resistance (MIL-STD-810H). Does not mean it is ATEX certified. |
|
IS-Barrier |
Charging |
A safety circuit in a "Safe Area" that cleans power before it enters an Ex device. |
|
IP67 / IP68 |
Sealed |
6: Dust-tight (Mandatory for most dust zones); 7/8: Immersion in water. |
|
Antistatic |
Material |
Materials (often on iPad cases) designed to prevent the buildup of static electricity. |
How to read a Marking String (Example)
CE 2460 Ex II 2 G Ex ib IIC T4 Gb
- CE 2460: European Conformity + Notified Body ID.
- Hexagon Ex: Explosion protection symbol.
- II 2 G: Group II (Surface), Category 2 (Zone 1), Gas.
- Ex ib: Protection Method (Intrinsic Safety for Zone 1).
- IIC: Gas Group (Hydrogen/Acetylene safe).
- T4: Temp Class (135°C).
- Gb: EPL (High protection for Gas).