ATEX zones 1, 2, 21 and 22: which lighting is permitted

Gas zones and dust zones: what the numbers mean

ATEX brings together the European rules on equipment and workplaces with an explosion risk: the equipment directive 2014/34/EU and the workplace directive 1999/92/EC. The employer records in an explosion protection document where an explosive atmosphere can occur and how often. That zone classification decides which luminaire you may install.

Gases, vapours and mists fall under zones 0, 1 and 2, combustible dust under zones 20, 21 and 22:

• Zones 0 and 20: explosive atmosphere present continuously or for long periods, such as inside a tank or silo.
• Zones 1 and 21: occasionally in normal operation, such as around filling points, sieves or mixers.
• Zones 2 and 22: not in normal operation and otherwise only briefly, such as a storage hall next to a process.

The EXORA range is certified for zones 1, 2, 21 and 22. Zones 0 and 20 require category 1 equipment; in practice lighting is rarely installed there.

How to read the Ex marking

Example for gas: II 2G Ex db eb IIC T6 Gb, for dust: II 2D Ex tb IIIC T85°C Db.

• II: surface industry (group I is mining).
• 2G or 2D: category 2, for zone 1 or 21. Category 3 is for zone 2 or 22.
• db, eb, tb: the type of protection, see below.
• IIC or IIIC: gas or dust group. IIC also covers hydrogen and acetylene, IIIC conductive dust. A higher group covers the lower ones.
• T6 or T85°C: maximum surface temperature. T6 is 85 °C, T4 135 °C, T3 200 °C.
• Gb or Db: equipment protection level, b for zone 1 or 21, c for zone 2 or 22.

The rule: the category is equal to or higher than the zone requires, the gas or dust group covers the substance present, and the temperature class lies below the ignition temperature. A luminaire for zone 1 may therefore also be installed in zone 2, but not the other way round.

What makes an Ex luminaire different from an IP65 luminaire

An ordinary IP65 high bay keeps dust and water out, but has never been tested for a spark or hot spot inside. An Ex luminaire has, through a type of protection:

• Ex d (flameproof enclosure): an ignition stays within the housing.
• Ex e (increased safety): no sparks or hot parts, often combined with Ex d for the driver.
• Ex n (non-sparking): for zone 2 only.
• Ex t (enclosure): for dust zones, dust-tight with a limited surface temperature.
• Ex m (encapsulation): driver and LED module fully potted.

In concrete terms: a housing of die-cast aluminium or glass-fibre reinforced polyester, toughened glass, a limited surface temperature even in a warm hall and a certified cable entry. LED helps: the low operating temperature makes T6 or T85 °C achievable, where a discharge lamp often stayed at T3. EXORA runs from 40 to 200 W; the 100 W high bay delivers 17,000 lm at 5000 K, the 40 W linear luminaire 6,400 lm.

Applications: chemicals, grain and paint shops

Chemicals: zone 1 is common around filling stations, pumps and tanks, with the rest of the hall often zone 2. Gas group IIB covers most solvents; hydrogen or acetylene calls for IIC. As a guideline, 200 to 300 lux in process areas and 500 lux at operating positions is usual; the lighting calculation gives the exact value.

Grain, flour and animal feed: zone 21 arises in silos and at elevators, with the surrounding storage often zone 22. Organic dust falls into group IIIB. A dust layer on a warm luminaire ignites much sooner than a dust cloud; the installation standard applies a 75 °C margin below the smouldering temperature of a 5 mm layer. Choose a low temperature class, a smooth washable design and at least IP65.

Spray booths and paint shops: zone 1 usually applies inside the booth and in the extraction ducts, with zone 2 around it. As a guideline, spray work calls for 750 lux or more on the workpiece with good colour rendering. Luminaires inside the booth itself must be category 2, or be mounted outside the zone behind a sealed window. For the surrounding zone 2 the explosion-protected linear luminaire fits, arranged symmetrically to avoid shadows.

Junction boxes, cable glands and installation

An Ex luminaire is only explosion-protected if the whole chain is. The installation standard EN IEC 60079-14 requires that junction boxes, glands and stopping plugs are also certified for the zone and the type of protection:

• Ex e junction box to split or loop through; the EXORA range includes one with two stopping plugs.
• Cable glands matching the cable type (armoured or not) and the type of protection. An Ex d gland on an Ex e box is generally allowed, not the other way round; follow the gland certificate.
• Unused entries closed with a certified stopping plug, never with a plastic cap.
• Equipotential bonding of all metal parts, and the specified tightening torque applied.

After handover comes an initial inspection and then periodic inspection in accordance with EN IEC 60079-17. The installer must be demonstrably competent in explosion-protected installations; include that in your estimate.

How to choose from the EXORA range

• Zones 1 and 21, high halls: high bay 100 W, 17,000 lm, 100° beam, IP65, from around 6 metres.
• Zones 1 and 21, yards and facades: floodlight 100 W, Type II optic, IP66, IK10, for loading bays and tank pits.
• Zones 2 and 22, low rooms and surrounding areas: linear luminaire 40 W, 6,400 lm, 120° beam, IP65.
• Accessories: Ex junction box with stopping plugs and cable glands.

All EXORA luminaires are ATEX and IECEx certified, with a 5-year warranty from European stock, from 65 to 849 euros excluding VAT. Lichtplein supplies businesses only. If in doubt, send the zone drawing from the explosion protection document with your enquiry.

Frequently asked questions