0800 808 7799

ATEX Zone 21 Zone 22 Valves

ATEX Certified Explosion Proof Solenoid Valves for Hazardous Gas and Dust Areas.

ATEX encapsulated EEx M II T4 solenoid valves for Zone 21 and 22, ATEX EEx d IIC T4 and T6 Explosion and flame proof solenoid valves and a small range of ATEX EEx ia IIC T4 and T6 intrinsically safe solenoid valves in most voltages, pressures, sizes and materials of construction.

ZoneCategory Presence of explosion atmospheres
Group II Equipment
Zone 0Category 1GContinuous, Frequent
Zone 20Category 1Dfor long periods
Zone 1Category 2GIntermittent
Zone 21Category 2Din normal operation Likely
Zone 2Category 3GOccasional or for short periods.
Zone 22Category 3DNever in normal operation


Hazardous areas for Group II are further divided into Zones, these Zones relate to the predicted occurrence of when an Explosive Atmosphere may be present in the area. These Zones are defined as being:

ColourZonePresence of Gas
Red0Continuously present (During long periods)
Orange1Not Likely to be present (Regular service)
Yellow2Accidentally present (short time service never in regular service)
ATEX Zones
ColourZonePresence of Dust
Red20Continuously present (During long periods)
Orange21Not Likely to be present (Regular service)
Yellow22Accidentally present (short time service never in regular service)
ATEX Zones

Types of ATEX Explosion Proof Protection Available from Connexion Developments Ltd

Protection Symbol020121222DescriptionDrawing
EexmIIT4 "m" Cenelec EN50028   XXXX Encapsulation. Refers to a special casing in which the parts of an electrical apparatus which could ignite an explosive atmosphere by either sparking or heating are encapsulated in a compound in such a way that this explosive atmosphere cannot be ignited
EexiaIICT6 "ia" Cenelec EN50020/39 XXXXXX Intrinsically Safe. Refers to a circuit in which neither sparks or temperature can ignite an explosive atmosphere. If generated under the service conditions specified by the standard regulations (Normal and faulty operating conditions).
EexdIICT2 - 6 "d" Cenelec EN50018   XXXX Flameproof enclosure. Refers to an electrical apparatus whose explosive parts are enclosed in an explosion proof casing. This casing will resist the pressure generated by the internal explosion or an explosive mixture and will prevent the explosion from penetrating to the ambient explosive atmosphere.

Temperature Classes

Group 1

Temperature <150 C or <450 C according to coal dust accumulation on equipment

Group II

Class for Gas (G)Max surface temperature
T1450 °C
T2300 °C
T3200 °C
T4135 °C
T5100 °C
T685 °C

Ignition Temperature for Dusts.

The dust ignition temperature depends on its consistency and its nature. The ignition temperatures for various types of dust are available from reference tables.

 Ignition Temperature
DustsClouds5mm Layer
Aluminium 560°C >450°C
Charcoal 520°C 320°C
Coal Dust (Lignite) 380°C 225°C
Cocoa 590°C 250°C
Coffee Grounds 580°C 290°C
Corn 530°C 460°C
Methyl cellulose 420°C 320°C
Paper Fibre 570°C 335°C
Phenolic Resin 530°C >450°C
Polyethylene 440°C melts
PVC 700°C >450°C
Sugar 490°C 460°C
Soot 810°C 570°C
Starch 460°C 435°C
Toner 520°C melts
Wheat 510°C 300°C

Ignition Temperature for Fuels & Chemicals.

Fuel or ChemicalTemperature
Acetaldehyde 175°C 347°F
Acetone 465°C 869°F
Acetylene 305°C 581°F
Anthracite - glow point 600°C 1112°F
Benzene 560°C 1040°F
Bituminous coal - glow point 454°C 850°F
Butane 420°C 788°F
Carbon 700°C 1292°F
Carbon - bi sulfide 149°C 300°F
Carbon monoxide 609°C 1128°F
Charcoal 349°C 660°F
Coal-tar oil 580°C 1076°F
Coke 700°C 1292°F
Cyclohexane 245°C 473°F
Diethyl ether 160°C 320°F
Ethane 515°C 859°F
Ethylene 490°C 914°F
Ethyl Alcohol 365°C 689°F
Fuel Oil No.1 210°C 410°F
Fuel Oil No.2 256°C 494°F
Fuel Oil No.4 262°C 505°F
Heavy hydrocarbons 750°C 1382°F
Hydrogen 500°C 932°F
Gas oil 336°C 637°F
Gasoline 280°C 536°F
Gun Cotton 221°C 430°F
Kerosene 295°C 563°F
Isobutane 462°C 864°F
Isobutene 465°C 869°F
Isooctane 447°C 837°F
Isopentane 420°C 788°F
Isopropyl Alcohol 399°C 750°F
Light gas 600°C 1112°F
Light hydrocarbons 650°C 1202°F
Lignite - glow point 526°C 979°F
Methane (Natural Gas) 580°C 1076°F
Methyl Alcohol 385°C 725°F
Naphtha 550°C 1022°F
Neohexane 425°C 797°F
Neopentane 450°C 842°F
Nitro-glycerine 254°C 490°F
n-Butane 405°C 761°F
n-Heptane 215°C 419°F
n-Hexane 225°C 437°F
n-Octane 220°C 428°F
n-Pentane 260°C 500°F
n-Pentene 298°C 569°F
Oak Wood - dry 482°C 900°F
Peat 227°C 440°F
Petroleum 400°C 752°F
Pine Wood - dry 427°C 800°F
Phosphorous, amorphous 260°C 500°F
Phosphorous, transparent 49°C 120°F
Production gas 750°C 1382°F
Propane 480°C 842°F
Propylene 458°C 856°F
p-Xylene 530°C 986°F
Rifle Powder 288°C 550°F
Toluene 530°C 849°F
Semi anthracite coal 400°C 752°F
Semi bituminous coal - glow point 527°C 980°F
Styrene 490°C 914°F
Sulphur 243°C 470°F
Wood 300°C 572°F
Xylene 463°C 867°F

Technical Links