Hazardous Area Encoder Products
Hazardous locations require encoders, position sensors and other motion control equipment to be designed and certified to operate safely in potentially explosive environments. Flammable gas, vapor, dust or fiber can be ignited by internal electronics in the equipment if it is not properly protected.
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BEI Sensors offers a complete selection of UL and ATEX certified encoders for hazardous areas. Certifications include UL Class I Division 1 and 2, and Class II Division 1 and 2, as well as ATEX Zone 1 and Zone 2. Encoder products with this icon have hazardous area certification for one of the following: explosion-proof, flame proof, intrinsically safe, or non-incendive. |
The tables on this page provide details on BEI Sensors products' certifications. A variety of protection methods is available. The four most common are described below.
Explosion Proof
- The enclosure of the encoder is designed to withstand internal ignition and contain the explosion without damage to the enclosure.
- Heated gases from an explosion that pass through gaps or joints in the assembly will be cooled sufficiently to prevent ignition of gases outside the housing
- Must be connected using gas-tight conduit
- Rated for Division 1 or Zone 1 installations
Flame Proof
- The enclosure of the encoder can withstand internal ignition of volatile gas-to-air mixtures without damage to the enclosure
- Allows for termination using a certified cable glandand cable
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Intrinsic Safety
- Limits the maximum energy that can be delivered into the hazardous location
- Has limitations on the amount of energy that can be stored within the body of the device
- Ensures that - even in double fault condition - the energy that is supplied to or stored in the encoder will not create a spark or heat the surface in a way that would ignite gas, vapor, dust or fiber in the hazardous area
- Must be used with Intrinsically Safe (IS) barrier. NOTE: An IS encoder installed without an IS barrier is not an IS system; in other words, an Intrinsically Safe encoder requires the concomitant use of an Intrinsically Safe barrier.
Nonincendive
- Assures no sparking or hot surfaces will occur in the encoder under normal operating conditions
- Acceptable in Division 2 and Zone 2 installations where explosive agents are present only in abnormal operating conditions
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ATEX and UL Hazardous Area CertifiedNorth American "Explosion Proof" & European "FlameProof" Approvals North American and European "Intrinsic Safety" Approvals North American and European "Nonincendive" Approvals
Hazardous Environment Groups
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Gas Groups |
Dust Groups |
Class I |
Class II |
Division 1 & 2 |
Zone 0, 1 & 2 |
Division 1 & 2 |
A (acetylene) |
IIC (acetylene &
hydrogen) |
E (metals)
(Div 1 only) |
B (hydrogen) |
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F (coal) |
C (ethylene) |
IIB (ethylene) |
G (grain) |
D (propane) |
IIA (propane) |
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North American "Explosion Proof" & European "Flameproof" Approvals
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Encoder Type
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CENELEC/ATEX
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U.S./Canada Class I, Div 1, Group:
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U.S./Canada Class II, Div 1, Group:
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IECEx
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H38
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D
|
|
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H38
(w/ Labyrinth Seal) |
II 2 G Ex d IIB T4 |
C, D |
E, F, G |
Ex d IIB T4 |
H40 |
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D |
|
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HH-X, AH-X |
II 2 G Ex d IIB T4 Gb
IP66 |
C, D |
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Ex d IIB T4 Gb
IP66 |
CAMX, CAUX, CEMX
CEUX, GAMX, GAUX,
GEMX, GEUX, PAUX,
PEUX, NAUX, NEUX, PAMX, PEMX, SAUX, SEUX
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II 2
Ex d IIC T6 Gb
Ex tb IIIC T80 °C
Db IP 6x
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|
|
Ex d IIC T(*) Gb
Ex tb IIIC T(*)°C Db |
CEUX, GEUX, NEUX, PEUX |
I M2
Ex d I Mb |
|
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Ex tb IIIC T(*)°C Db
Ex d I Mb |
North American and European "Intrinsic Safety" Approvals
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Encoder Type
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CENELEC/ATEX
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Class I, Group:
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Class II, Group:
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IECEx |
H20, H25, HS20,
HS25, HS35,
HS45, HH-9,
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II 1 G Ex ia IIB/IIC T4
Ga
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A, B, C, D
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E, F, G
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Ex ia IIB/IIC T4 |
IBM5, IHM5, IHO5, IBO5,
IHK5, IBK5, IHM9, IBM9
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II 1 G
Ex ia IIC T4 Ga
or EX ia IIB T4 Ga |
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Ex ia IIC T4 Ga
Ex ia IIB T4 Ga |
IXM5, IXO5
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I M1
Ex ia I Ma
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Approved Associated Apparatus |
Intrinsic Safety Barrier |
II (1) G [EX ia] IIC |
A, B, C, D |
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Ex nA [ia Ga] IIc T4 Gc |
North American and European "Nonincendive & Non-Sparking" Approvals
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Encoder Type
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Division 2, Groups:
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CENELEC/ATEX
Zone 2/22 |

IECEx |
H20, H25, H25X, HS20, HS25, HS35, HS45, HH_9, HH_B, AH_9, AH_B
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A, B, C, D, F & G
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II 3 G
Ex nA IIB T3 Gc
Ex nA IIB T4 Gc |
Ex nA IIB T3 Gc
Ex nA IIB T4 Gc |
PHU9, PBU9 |
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II 3 G Ex nA
Ex nA IIC T6 Gc |
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DHM5, DHK5, DHO5, KHM5, KHO5, KHK5 |
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II 3 G D
Ex nA IIC T6...T4 Gc
Ex tc IIIC T120°C...T80°C Dc |
Ex nA IIC T6...T4 Gc
Ex tc IIIC T120°C...T80°C Dc |
*Certifications Pending
Additional Resources
Article: Drilling deeper — can position sensors take the heat?
Article: Specifying Encoders for Hazardous Locations
Article: Nonincendive and non-sparking encoders for Division 2 and Zone 2
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