ATEX Solenoid Valves and ATEX information
Solenoid Valves with ATEX EExmIIT4, ATEX EExdIICT4,5+6 and Intrinsically safe solenoid valves with ATEX EExiaIICT6 and T4 protection.
What is ATEX?
ATEX stands for (ATmosphere EXplosive) being a flammable or combustible gases, fluids, mists or dusts in air (with oxygen) so that if there was any ignition source (spark / sufficient heat) the combustion process could ignite the flammable mixture.
There are known limits in which a flammable substance would need to be a certain concentration (not too rich or lean) but sound engineering advice for any application where potentially hazardous media could ever be present is - BE PROTECTED AT ALL COSTS and seek professional advice from an ATEX certified qualified engineer.
The European Union has implemented two harmonised standards for hazardous areas - ATEX 94/9/EC (ATEX 100a) and from April 2016 2014/34/UE and ATEX 99/92/EC (ATEX137). Ratings are classed according to the area or zone being protected.
Below are some ATEX basics relating to ATEX certified solenoid valves, and you can click this link to see our range of ATEX products.
Ex m Encapsulation
Protection whereby 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, EN50028:1987EN50271-1-1:1998, ATEX II 2 G Exm II T4 II 2 D IP65 T130°C or Exm II T6 85°CSolenoid 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.
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 + EN50020:1994ATEX 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.
| 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 |
|
Using ATEX Exm outside.
Firstly, I must emphasize that ATEX EExm encapsulated solenoid coils in general and accordingly the Ex coils are indeed not meant to be subjected to outdoor environmental strain.
Almost all customers know by sound engineering practice that this cannot be achieved without being tested accordingly, however this fact is not stated explicitly in ATEX product documentation.
How does one know or deduct from the facts given?
a) The IP-Code standard EN/IEC 60529 is not referring to environmental conditions, whereas the American NEMA 250 does: Outdoor Corrosion Protection Test, External Icing Test. Thus, it is erroneous to derive from an IP-Code 65 suitability for outdoor applications. Outdoor strains are so diverse that you cannot cope for all conditions prevailing at the possible geographical places with a simple IP test done. No way. You will find that the EN/IEC 60068 series of standards has numerous parts that deal with those kinds of strains, none of them is required for Ex certification.
b) It is true that water protection is required by the Ex standards, some require IPx5, IPx4 but even IPx0 is allowed, see Ex 'e' EN 60079-7. This is not absolute water tightness, and we can deduct that water is not a direct cause for arcing even when in contact with blank current carrying parts (as allowed in 'e' EN 60079-7). You cited "A protection concept whereby equipment that could potentially cause an ignition is encapsulated within a compound or resin to prevent contact with the explosive atmosphere". Yes, it is the explosive atmosphere that must be kept out, this is not water.
c) Note that the tests for IPX5 are very short regarding the period of time that water is applied when compared to water strains outdoor. Water creeping into the coil would cause creeping currents therein. Small amounts will evaporate by thermal energy. This would do no harm. Being exposed frequently and long-lasting to water will lead to degradation of the isolating features with a resulting failure thereof and further current rise, meaning excess power and heat in the coil. In this respect, water is critical must be avoided for a reliable installation. The possible fault of a failing isolation within the coil is covered by the mandatory application of a suitable current fuse, see certificate and operating instructions. Please remind your customer in case you doubt that he follows the prescriptions made.
d) 'Outside usage is possible but not uncovered' had been mentioned below. Well, no. Outside usage does mean more than rain from above as explained earlier, a cover may be helpful in some respect but is not considered to be sufficient. These are our points, though very technical, I hope you will find it explanatory.
try our search Wizard below to find ATEX solenoid valves.
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 sulphide |
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 |
| Iso octane |
447 |
837 |
| Iso pentane |
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 |