Explosion protected products

Explosions can occur wherever flammable gas, liquid or even dust is present and can meet oxygen (in the air). Each substance has different physical properties and characteristics that enable them to be assigned to groups. These groups are particularly important for selecting the right products for the respective area of application. The most important factors for product selection are zone/EPL (Equipment Protection Level) groups, temperature classes and explosion groups. Explosion protected fans and motors from ZIEHL-ABEGG offer the ideal solution for ensuring the safety of your systems. The products comply with all relevant standards and are approved in accordance with the applicable directive. ZIEHL-ABEGG products thus actively contribute to the protection of material assets, workplace safety and, above all, to the health and safety of people and can be used in various applications thanks to our extensive portfolio. ZIEHL-ABEGG would be happy to provide you with active assistance when selecting the right solutions.

Ex product highlights from ZIEHL-ABEGG

P model range

Special applications

Housing fans

FB model range

M model range

AC external rotor motor

MAXventowlet

C model range

ZAbluefin

Plug fan, uninsulated

Explosion protection

For uncontrolled explosions to be triggered in production facilities and work sites, under certain conditions, it is sometimes sufficient for a flammable substance to collide with the oxygen from the ambient air. Special care must be taken with highly flammable gases such as acetylene, hydrogen, ethylene or propane. Explosion protected fans are particularly in demand in chemical factories, refineries, paint shops and paint factories, refuelling and conveyor systems for flammable liquids, gases and solids, as well as in environments with combustible dusts, such as the processing of coal, wood, coffee, cocoa or in grain mills.

Person wearing protective clothing working on blue drums

There are three basic approaches to providing protection against uncontrolled explosions:

Primary explosion protection:

Preventing the formation of explosive atmospheres

Secondary explosion protection:

Preventing the ignition of explosive atmospheres

Tertiary explosion protection:

Mitigating the harmful effects of an explosion

Production equipment used in potentially explosive areas must meet special requirements according to the applicable directives for certification as an “explosion protected” product. Special features are the maximum surface temperature and design measures to prevent impact and friction sparks or electrostatic charges, which could represent a possible source of ignition.

Ignition protection types

For classification according to ignition protection type, a distinction is generally made between:

Electrical equipment

Ignition protection type	Symbol	Standard	Zone	Description
Enhanced safety	Ex eb/Ex ec	EN 60079–7 / IEC 60079-7	1/2	Additional measures ensure an increased level of safety. No impermissibly high temperatures, no sparks or arcs. Examples: Terminal boxes, motors, lights.
Flameproof enclosure	Ex da / Ex db / Ex dc	EN 60079–1 / IEC 60079–1	0 / 1 / 2	The housing is designed in such a way that an internal explosion cannot spread to the surroundings (pressure, gap dimensions). Examples: Motors, transformers, control devices.
Pressurised enclosure	Ex pxb / Ex pyb / Ex pzc	EN 60079–2 / IEC 60079–2	1// 21 1 // 21 2 // 22	The formation or penetration of an explosive atmosphere by an inert gas is prevented in the housing. Examples: Motors, control devices, analysis equipment.
Intrinsically safe	Ex ia / Ex ib / Ex ic	EN 60079–11 / IEC 60079–11	0 // 20 1 // 21 2 // 22	Energy limitation below a critical level. A spark or thermal effect does not have enough energy to ignite the atmosphere. Examples: Measuring technology, fieldbus technology, sensors.
Liquid immersion	Ex ob / Ex oc	EN 60079–6 / IEC 60079–6	1 / 2	Operating media are immersed in protective liquid (e.g. oil), so that a surrounding Ex atmosphere cannot be ignited. Examples: Transformers, resistors.
Powder filling	Ex q	EN 60079–5 I / EC 60079–5	1	Fine-grained filling material (quartz sand) prevents an arc or spark from igniting the surrounding atmosphere. Examples: Sensors, ballasts, transmitters.
Encapsulation	Ex ma / Ex mb / Ex mc	EN 60079–18 / IEC 60079–18	0 // 20 1 // 21 2 // 22	Potting compound prevents arcs or sparks from igniting the surrounding atmosphere. Examples: Mains supply units, fuses.
Ignition protection type “n”	Ex nC / Ex nR	EN 60079–15 / IEC 60079–15	2 / 2	El. equipment is unable to ignite the atmosphere. (Ex nC – enclosed construction / Ex nR – restricted breathing)
Optical radiation	Ex op is / Ex op pr / Ex op sh	EN 60079–28 / IEC 60079–28	0 // 20 1 // 21 1 // 21	Ex op is – Inherently safe, energy-limited optical radiation Ex op pr – Protected, protected against damage and leakage Ex op sh – Deactivation in the event of fibre breakage.
Protection by enclosure	Ex ta / Ex tb / Ex tc	EN 60079–31 / IEC 60079–31	20 / 21 / 22	A suitable housing design prevents the ingress of dust and thus the formation of a dangerous atmosphere inside. Examples: Motors, lights, switchgears.

Non-electrical equipment

Ignition protection type	Symbol	Standard	Zone	Description
Constructional safety “c”	Ex h	EN80079-37 / ISO80079-37	0 // 20 1 // 21 2 // 22	Safe in normal operation. The risk of causing ignition due to mechanical faults is minimised to a very small extent. Examples: Fans, pumps, couplings, conveyors.
Ignition source monitoring “b”	Ex h	EN80079-37 / ISO80079-37	0 // 20 1 // 21 2 // 22	Sensors detect impending ignition before the ignition source becomes effective and initiate countermeasures. Examples: Pumps, conveyors.
Liquid immersion “k”	Ex h	EN80079-37 / ISO80079-37	0 // 20 1 // 21 2 // 22	Operating media are immersed in protective liquid (e.g. oil), so that a surrounding Ex atmosphere cannot be ignited. Examples: Submersible pumps, gears.
Flameproof enclosure “d”	Ex h	EN 60079–1 / IEC 60079–1	0 // 20 1 // 21 2 // 22	The housing is designed in such a way that an internal explosion cannot spread to the surroundings (pressure, gap dimensions). Examples: Brakes, clutches.
Protection by enclosure “t”	Ex h	EN 60079–31 / IEC 60079–31	20 / 21 / 22	A suitable housing design prevents the ingress of dust and thus the formation of a dangerous atmosphere inside.
Pressurised enclosure “p”	Ex h	EN 60079–2 / IEC 60079–2	1 // 21 2 // 22	The formation or penetration of an explosive atmosphere by an inert gas is prevented in the housing. Examples: Pumps.

Oil tanker next to an oil rig at sea at sunset

Explosive areas

The zone describes the probability of an explosive atmosphere occurring and how long it is present. There are basically two types of atmospheres, the gas atmosphere and the dust atmosphere.

Gases, mist, vapours

Zones

Equipment protection level (EPL)

Dusts

Zones

Equipment protection level (EPL)

Temperature class

For applications in explosion-protected areas, electrical equipment is divided into groups T1 to T6 according to its maximum surface temperature. The equipment must be set up in such a way that its maximum surface temperature (according to EN 60079) is below the lowest ignition temperature of the potentially explosive atmosphere.

Temperature class	T1	T2	T3	T4	T5	T6
Max. surface temperature	≤ 450°C	≤ 300°C	≤ 200°C	≤ 135°C	≤ 100°C	≤ 85°C
IIA	Acetone, ethane, ethyl acetate, ammonia, benzene, benzenamine, formic acid, methane, methyl chloride	Methanol, propane, ethyl alcohol, n-butane, n-butyl alcohol	Petrol, turpentinol, diesel fuel, aviation fuel, fuel oils, n-hexane	Acetaldehyde		Ethyl nitrite
IIB	Blue Acid	Ethylene	Dimethoxymethane	Ethyl Ether
IIC	Hydrogen	Acetylene			Sulphur Carbon

Explosion group

Gases, vapours and combustible dusts are divided into different groups according to their flammability:

Gas: Categorisation according to minimum ignition energy or safe gap value

Dust: Division according to type of dust

Marking

The marking of explosion protected fans and motors is not uniformly regulated on a global scale, but is similar in many countries. In Europe, marking according to the ATEX directive (comparable to IECEx) applies:

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CE mark confirms conformity with the European directives applicable to this product
0102
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Number of the notified body (NB) responsible for certifying the manufacturer’s quality system
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European symbol for marking explosion-proof devices
II
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European Equipment Group Identifier (I = underground + associated surface installations // II = other installations)
2G
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European Equipment Category Identifier
Ex
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Standard-specific Ex marking
db eb
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Ignition protection type(s) of the device
IIC
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Equipment group
T4
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Temperature class
Gb
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Equipment protection level (EPL)
PTB 08 ATEX 3060
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Type examination certificate number (NB – year – ATEX – serial number // ATEX could also be indicated by “.”)
X
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Marking for devices with “special conditions” during use or “U” for incomplete devices

Guidelines & Certifications

ATEX

The ATEX Product Directive (ATmosphères EXplosives) 2014/34/EU stipulates the conditions under which products may be placed on the market that are used in potentially explosive areas.

Its main purpose is to protect people who work in potentially explosive areas or who could be affected by explosions.

IECEx

Similar to the ATEX Directive within the EU, IECEx standards define the marking of Ex products internationally with the aim of harmonising international regulations and establishing mutual recognition.

FAQs

Ex motors

Is approval from a notified body required for an explosion protected motor?
There is no general rule here, it depends on several factors. IECEx applications always require approval from a notified body. In Europe (ATEX), this is not mandatory for Zone 2 (EPL Gc) products; the manufacturer can issue a manufacturer’s declaration here. For Zone 1 (EPL Gb) or Zone 0 (APL Ga) products, approval from a notified body is mandatory. A declaration of conformity is required in all cases.
Can a PTC thermistor triggering device from ZIEHL-ABEGG be used in a potentially explosive atmosphere?
No, the PTC thermistor triggering devices are not suitable or approved for use in potentially explosive atmospheres. The devices must be installed in the safe area.
Do you need a PTC thermistor triggering device to operate a fan with ZIEHL-ABEGG external rotor motor?
Yes, a PTC thermistor triggering device is mandatory for operating the ZIEHL-ABEGG Ex e external rotor motor. You can find the right device here.
Can fans driven by an Ex d (or Ex de) internal rotor motor be operated on a frequency inverter?
ZIEHL-ABEGG can take this into account so that motors are selected that may operated on the frequency inverter. It is important that ZIEHL-ABEGG is informed that frequency inverter operation is desired or required at this point. However, the information in the operating instructions for the motor is decisive – these instructions must be observed. If necessary, thermal monitoring via a PTC thermistor and a corresponding PTC thermistor triggering device must be used when operating on a frequency inverter. You can find the right devices here.
Can fans powered by ZIEHL-ABEGG Ex e external rotor motors be operated on a frequency inverter?
No, the ZIEHL-ABEGG external rotor motors have not been tested for operation on a frequency inverter and may therefore not be operated on a frequency inverter. However, the motors can be voltage-controlled so that the speed can be changed via a corresponding control unit. You can find the right devices here.

Ex fans

Is approval from a notified body required for an explosion protected fan?
There is no general rule here, it depends on several factors. IECEx applications always require approval from a notified body. In Europe (ATEX), this is only required for Zone 0 (EPL Ga) products. For Zone 1 (EPL Gb) products, it is sufficient to file the technical documentation with a notified body. For Zone 2 (EPL Gc) products, it is sufficient to archive the technical documentation internally.
What information does ZIEHL-ABEGG need in order to be able to select a suitable fan?
ZIEHL-ABEGG requires at least the following information to select an explosion protected fan:
- Operating point (volume flow and pressure)
- Ambient temperature (e.g. -20 to +40°C)
- Zone or EPL (e.g. Zone 1 or EPL Gb)
- Gas group (e.g. IIB)
- Temperature class (z.B. T3)
- Other special customer requirements
When do you need an explosion protected fan?
Explosion protected products – in this case fans – are always required if the risk analysis carried out by the operator of a system and the resulting explosion protection document specifies the use of explosion protected devices in order to ensure the safe operation of a system. It is therefore the responsibility of the employer/operator to determine whether explosion protected devices must be used and, if so, which ones. The legal basis in Europe is Directive 1999/92/EC.
What distinguishes an Ex fan from a non-Ex fan?
Ex fans are designed to fulfil the requirements of the standard for explosion protected fans (DIN EN 14986). This includes, for example, the use of certain approved material pairings between stationary and rotating parts, and distances between rotating and stationary parts must also comply with specific limit values. When selecting coatings (paint), care must be taken to ensure that they cannot become electrostatically charged. There are many other design features that must also be taken into account.
Can repairs be carried out on an Ex fan?
The manufacturer should be contacted first if repairs are necessary. There are minor repairs that may be carried out under own responsibility, but there are other repairs that may only be carried out by the manufacturer. It is therefore essential to clarify in advance what type of repair is involved.
Can impellers or blades made of high performance composite material be used in potentially explosive areas?
Yes, but not every blade or impeller made of high performance composite material can be used in potentially explosive areas. ZIEHL-ABEGG uses special high performance composite materials for these applications, which meet the requirements for potentially explosive areas. These requirements specify, among other things, that the high performance composite materials must not continue to burn independently and must not become electrostatically charged.

Applications

Directives & standards

What is ignition protection type Ex nA?
The ignition protection type Ex nA is a zone 2 ignition protection type for non-sparking production equipment. The corresponding standard is DIN EN IEC 60079-15 or IEC 60079-15. Due to the similarity between ignition protection type Ex nA and ignition protection type Ex eb, ignition protection type Ex nA will no longer be available from 19/04/2022. Instead, there is the ignition protection type Ex ec, for which the DIN EN 60079-7 applies in Europe and the applies IEC 60079-7 on IECEx level.
Which standards are relevant for Ex motors at IECEx level?
The ignition protection type used is decisive for motors. IEC 60079-0 and IEC 60079-14 apply to all motors. IEC 60079-7 must also be complied with for Ex eb and Ex ec motors. IEC 60079-1 also applies to Ex db motors.
Which standards are relevant for Ex motors in Europe?
The ignition protection type used is decisive for motors. DIN EN IEC 60079-0, die DIN EN 60079-14 and DIN EN 1127-1 apply to all motors. In addition, DIN EN 60079-7 must be complied with for Ex eb and Ex ec motors. DIN EN 60079-1 also applies to Ex db motors.
Which standards are relevant for fans at IECEx level?
IECEx fans are subject to similar standards as ATEX fans – SO 80079-36 and ISO 80079-37. DIN EN 14986, which applies in Europe, does not exist at IECEx level.
Which standards are relevant for Ex fans in Europe?
DIN EN 14986 applies for Ex fans in Europe. In addition, the basic standards of non-electrical explosion protection DIN EN ISO 80079-36 and DIN EN ISO 80079-37 apply. ZIEHL-ABEGG explosion protected fans naturally meet these standards and thus comply with Directive 2014/34/EU.
Do ATEX standards have to be complied with in Europe?
No, the standards do not necessarily have to be complied with. It can also be ensured by other means that the product meets the requirements of the ATEX Directive. However, the assumption principle applies in Europe – i.e. if a standard is met, it is assumed that the corresponding directive will also be fulfilled. It is therefore advisable to comply with the relevant standards and simplify the conformity assessment.

Markings & groupings

What does the "X" after the certificate number of an explosion protected device mean?
If the device is marked with an "X", special conditions must be observed, for example during installation or operation. These special conditions are mentioned in the certificate and must be observed accordingly to ensure safe operation. One such special condition can, for example, be the requirement for PTC monitoring for a motor if an operating mode other than S1 is present, or similar.
What does the "U" after the certificate number of an explosion protected device mean?
A device with a "U" certification is an incomplete device. Such devices must not be used in potentially explosive areas without additional measures. An example of this is an explosion protected circuit breaker, which must be installed in a correspondingly approved Ex e housing casing so that it can be used in Ex areas.
No information on the ambient temperature is provided on the name plate. What temperatures can the device be operated in?
If no information on the ambient temperature is provided on the name plate, the standard temperature range -20 to +40 °C applies. As soon as the ambient temperature range of the device deviates from this, this must also be marked on the name plate.
What does it mean if a device is marked with gas group IIB+H2?
The IIB+H₂ marking means that the product may be used in an atmosphere IIB and is also suitable for hydrogen (H₂), which actually falls into group IIC.
Can a device approved for Zone 21 (EPL Db) be used in Zone 22 (EPL Dc)?
Yes, higher requirements must be met to achieve equipment protection level Db for Zone 21 than for equipment protection level Dc for Zone 22.
Can a device approved for Zone 1 (EPL Gb) be used in Zone 2 (EPL Gc)?
Yes, higher requirements must be met to achieve equipment protection level Gb for Zone 1 than for equipment protection level Gc for Zone 2.
Can a device marked with dust group IIIB be used in an IIIA atmosphere?
Yes, to achieve dust group IIIB, higher requirements must be met than for IIIA, so this is permitted.
Can a device marked with gas group IIB be used in an IIA atmosphere?
Yes, to achieve gas group IIB, higher requirements must be met than for IIA, so this is permitted.
Can a device of temperature class T4 be used in an atmosphere with temperature class T3?
Yes, to achieve temperature class T4, higher requirements must be met than for T3, so this is permitted.