ATEX Solenoid Valve Guide

ATEX Solenoid Valves and ATEX information.

Useful ATEX and safe area classified solenoid valves.

Ex i Intrinsic Safety

Protection in which the electrical energy within the solenoid valve coil is restricted to a level which is below that which could or may cause an ignition or spark and to limit the heat generated by the equipment (Solenoid coil surface temperature).

There are two types of EExi protection, either EExia and EExib.

  • EExia protection allows for the occurrence of 2 faults during operation.
  • EExib protection allows for the occurrence of 1 fault during operation.

Also given as Zone 0 and Zone 20 Category 1, EN50014:1997+A1+A2 + EN50020:1994

ATEX II 2 G EEx ia IIC T6 or T4, Zone 0 Gas and Zone 20 Dust hazardous environments. The T6 temperature rating is a maximum surface temperature of 85°C, T4 is 130°C. It also relates to the maximum ambient temperature this ATEX coil can operate. 

This picture shows a 1/4 BSP 3/2-solenoid valve with an ATEX EExia Nass Magnet coil fitted suitable for the control of compressed air and other inert gases. 

Solenoid valves with ATEX EExiaIICT6 and T4 protection

Ex m Encapsulation.

Protection where by the solenoid valve coil that could potentially cause an ignition is encapsulated within a resin compound so that it prevents contact with a potentially explosive atmosphere of gas or dust. The solenoid valve coil also limits the surface temperature under normal working conditions and there is thermal fuse already installed as a safety device, in this case EExmIIT4 temperature T4 means maximum surface temperature before cut out would be +130°C. It also relates to the maximum ambient temperature this ATEX coil can operate.

Also given as : Zone 1 and Zone 21 Category 2, EN50014:1997+A1+A2, EN50028:1987

EN50271-1-1:1998, Atex II 2 G Eexm II T4 II 2 D IP65 T130°C or Eexm II T6 85°C

Solenoid Valves with ATEX EExmIIT4 protection

Ex d Flameproof.

The solenoid valve coil is contained within a metal enclosure which can withstand the force of an internal explosion and prevent it transmission to the potentially explosive ambient gases or dusts. This method of protection also prevents the ambient hazardous atmosphere from entering the enclosure. Obviously great care and consideration must be taken when performing any maintenance as potentially explosive gases or dusts may enter if opened.

Zone 1 and Zone 21 Categories 2.

Cenelec Standard 50018 EexdIICT6 Flameproof enclosures 

Solenoid Valves with ATEX EexdIIC Flameproof enclosures

Zone

Category

Presence of explosion atmospheres

Group II equipment

zone 0

category 1 G

Continuous, frequent
or for long periods

zone 20

category 1 D

 

zone 1

category 2 G

Intermittent
in normal operation (Probable)

zone 21

category 2 D


 

zone 2

category 3 G

Occasional or for short periods
(never in normal operation)

zone 22

category 3 D

Temperature Classes.

Group 1

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

Group II

Temperature Class for Gas (G)

Permissible surface temperature of electrical equipment

T1

T2

T3

T4

T5

T6

450C

300C

200C

135C

100C

85C

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

Dusts

Ignition Temperature

Clouds

5mm 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

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

Fuel or Chemical

Temperature

(oC)

(oF)

Acetaldehyde

175

347

Acetone

465

869

Acetylene

305

581

Anthracite - glow point

600

1112

Benzene

560

1040

Bituminous coal - glow point

454

850

Butane

420

788

Carbon

700

1292

Carbon - bi sulfide

149

300

Carbon monoxide

609

1128

Charcoal

349

660

Coal-tar oil

580

1076

Coke

700

1292

Cyclohexane

245

473

Diethyl ether

160

320

Ethane

515

859

Ethylene

490

914

Ethyl Alcohol

365

689

Fuel Oil No.1

210

410

Fuel Oil No.2

256

494

Fuel Oil No.4

262

505

Heavy hydrocarbons

750

1382

Hydrogen

500

932

Gas oil

336

637

Gasoline

280

536

Gun Cotton

221

430

Kerosene

295

563

Isobutane

462

864

Isobutene

465

869

Isooctane

447

837

Isopentane

420

788

Isopropyl Alcohol

399

750

Light gas

600

1112

Light hydrocarbons

650

1202

Lignite - glow point

526

979

Methane (Natural Gas)

580

1076

Methyl Alcohol

385

725

Naphtha

550

1022

Neohexane

425

797

Neopentane

450

842

Nitro-glycerine

254

490

n-Butane

405

761

n-Heptane

215

419

n-Hexane

225

437

n-Octane

220

428

n-Pentane

260

500

n-Pentene

298

569

Oak Wood - dry

482

900

Peat

227

440

Petroleum

400

752

Pine Wood - dry

427

800

Phosphorous, amorphous

260

500

Phosphorous, transparent

49

120

Production gas

750

1382

Propane

480

842

Propylene

458

856

p-Xylene

530

986

Rifle Powder

288

550

Toluene

530

849

Semi anthracite coal

400

752

Semi bituminous coal - glow point

527

980

Styrene

490

914

Sulphur

243

470

Wood

300

572

Xylene

463

867