Hazardous-Area Equipment (Ex)

Quick pick (TL;DR)

Get the area classification first: Zone 0/1/2 (gas) or 20/21/22 (dust), gas group (IIA/IIB/IIC), temperature class (T1–T6).
Then match equipment: Ex ia (intrinsic safety) for Zone 0 & instruments; Ex d (flameproof) or Ex e for Zone 1 power; Ex n / Ex t for Zone 2 / dust.
The equipment's gas group & T-class must be ≥ the area requirement, with ATEX/IECEx certification.

Step 1 — Classify the area

Parameter	Options	Meaning
Zone (gas)	0 / 1 / 2	Frequency of hazard
Zone (dust)	20 / 21 / 22	Dust hazard
Gas group	IIA / IIB / IIC	Ignition energy
Temp class	T1 (450°C) – T6 (85°C)	Max surface temp

Step 2 — Match protection method

Ex type	Principle	Typical zone
Ex ia / ib	Limit energy	Zone 0 / 1 (instruments)
Ex d	Contain explosion	Zone 1 (power, motors)
Ex e	No arcing parts	Zone 1 (terminals)
Ex p	Pressurization	Zone 1/2
Ex n / Ex t	Non-sparking / dust	Zone 2 / dust 21/22

Step 3 — Decode an Ex marking

Nameplate vs area requirement

Area requirement Zone 1 , gas group IIB , T3 , ambient 40°C Equipment marking Ex db IIC T4 Gb (ATEX/IECEx) Check each field Ex db (flameproof) suits Zone 1 → OK IIC ⊇ IIB (covers it) → OK T4 (135°C) ≤ T3 (200°C) → OK Gb = Zone 1 EPL → OK Result → suitable (equipment exceeds the area)

Each field must meet or exceed the area — IIC covers IIB, T4 satisfies T3, Gb suits Zone 1.

Common mistakes

Wrong gas group for the area.
Non-certified glands on Ex d.
Surface temp exceeds T-class.

Requisition & datasheet

Zone, group, T-class, ambient.
Method, EPL, IP, certification, gland.

Frequently asked questions

What should I know about Hazardous-Area Equipment (Ex)?

Get the area classification first: Zone 0/1/2 (gas) or 20/21/22 (dust), gas group (IIA/IIB/IIC), temperature class (T1–T6). Then match equipment: Ex ia (intrinsic safety) for Zone 0 & instruments; Ex d (flameproof) or Ex e for Zone 1 power; Ex n / Ex t for Zone 2 / dust. The equipment's gas group & T-class must be ≥ the area requirement, with ATEX/IECEx certification.

Which standards or codes apply?

IEC 60079 series (-0 general, -1 Ex d, -7 Ex e, -11 Ex i, -2 Ex p, -10 classification, -14 installation), ATEX 2014/34/EU, IECEx, NEC 500/505.

Standards — IEC 60079 series; ATEX; IECEx; NEC 500/505.