What information is needed for the validity period of the explosion-proof certification

Explosion-proof certification refers to the testing and certification of equipment and protection systems used in potentially explosive environments.

There are three main types:

1. ATEX certification: It is a system of conformity assessment of explosion-proof products according to the European Union ATEX directive, which belongs to one of the CE certifications.

2. IEC Ex system: It is an international conformity assessment system for explosion-proof electrical equipment and related services for explosive atmospheres. It is an internationally accepted method to show that explosion-proof electrical equipment or services comply with the IEC TC31 standard.

3. China's explosion-proof product certification: China implements an "explosion-proof certificate" certification system for explosion-proof electrical products. According to the GB3836 and GB12476 series of national explosion-proof standards, a certification system that confirms that the product meets the requirements of the standard through the review of product design drawings and other documents, prototype inspection and experiments, and issuance of an explosion-proof certificate.

Explosion conditions (explosive triangle principle)

Hazardous explosive substances: gas (gas and combustible dust, gas mixture), liquid (flammable liquid, liquid that emits dangerous gas), solid (powder, block)
2. Oxygen (air)
3. Detonation source

Basic methods to prevent explosion

Avoid the formation of an explosive environment (ideal method, difficult to achieve)
5. Eliminate and eliminate possible sources of explosion (practical method)
6. Limit one or a few of these elements to meet the explosion-proof requirements. Such as creating positive pressure, monitoring explosive gas concentration, limiting ignition sources (main means)

Definition of Explosive Hazardous Locations
Explosive hazardous environments will inevitably be formed in the production fields of petroleum, chemical industry, and coal, such as:

1. In coal mines, two-thirds of the places are classified as explosive dangerous places;
2. About 60%~80% of oil extraction sites and refineries belong to explosive dangerous places;
3. In the chemical industry, more than 80% of the production workshops are explosive hazardous locations.
   
   Explosion-proof group and explosion-proof area classification

Explosion-proof group classification
Mining Group I
Non-Mining Group II

Explosion-proof zone classification
Zone 0 (gas) Zone 1 (gas) where the explosive environment persists or occurs frequently
. During the normal operation of the equipment, the explosive environment exists or may exist for a long time, and the frequency is occasional
2 Zone (gas) When the equipment is operating abnormally, an explosive environment exists or may exist in a short period of time. Under normal conditions, the frequency is less likely to occur.
Zone 20 (dust) More than 1000 hours/year or more than 10%/ Period
21 zone (dust) 10~1000 hours/year or 0.1~10%/period
22 zone (dust) less than 10 hours/year or less than 0.1%/period

Explosion-proof category, area and mark
China Explosion-proof Certificate ATEX/IECex
Standard GB 3836 IEC60079 / EN60079
category
Group Zone explosion-proof mark category
Group Zone explosion-proof mark
Mine I MA mark I Category M1 (IM 1) Ex ia I
Ex ia I Ex Ib I
Ex ib I Ex d I
Ex d I Category M2 (IM 2) manufacturing grants the certificate
gas
gas-Ex II 0 area Ex IA II C / B / A II zone 0 (II. 1 G) Ex IA II C / B / A
Ex S Ex S
region 1 Ex ia II C / B / A zone 1 (II 2 G) EEx ia II C/B/A
Ex s EEx s
Ex ib II C/B/A EEx ib II C/B/A
Ex d II C/B/A EEx d II C/B/A
Ex e EEx e
Ex px,py EEx px,py
Ex o EEx o
Ex q EEx q
Ex m EEx m
Ex h EEx s
Ex s
Applicable to all types of zone 0 and 1 Zone 2 (II 3 G) Applicable to all types of zone 0 and 1
Ex nA EEx nA
Ex nC EEx nC
Ex nL EEx nL
Ex nR EEx nR
Ex nZ EEx PZ
Ex PZ
standard GB12476 EN50281
dust
dust-Ex III region 20 is DIP A 20 is III zone 20 is (II. 1 D) Ex 1D
DIP B 20 is
DIP A 21 is zone 21 is (II 2 D) Ex 2D 21 is region
DIP B 21
Zone 22 DIP A 22 Zone 22 (II 3 D) Ex 3D
DIP B 22

Explosive hazardous gas classification

Maximum test safety gap (MESG) or minimum ignition current (MIC) classification

Group China / IEC / ATEX Typical gas ignition characteristics
II Methane from
easy
to
difficult
II II A propane
II B ethylene
II C hydrogen
acetylene

Classification of gas temperature groups

Group safe temperature explosive gas common surface temperature
T1 of 450 degrees or less 46 kinds of hydrogen, acrylonitrile, etc.
T2 less than or equal to 300 degrees acetylene, ethylene and other 47 kinds of
T3 is less than equal to 200 degrees gasoline, crotonaldehyde and other 36 kinds of
T4 less 135 degrees acetaldehyde, tetrafluoroethylene and other 6 kinds of
T5 carbon disulfide
T6 less than or equal to 100 degrees ethyl nitrate and ethyl nitrite less than or equal to 85 degrees

Introduction to common explosion-proof methods

Explosion-proof method IEC standard Explosion-proof method description
EN standard
Chinese standard
Ex d
explosion-proof type IEC 60079-1 When the equipment is in normal operation, put the parts that can generate the detonation source into the explosion-proof
enclosure. The explosion-proof enclosure can withstand the internal explosion pressure. It will not be damaged
and can effectively prevent the explosion from spreading outside the enclosure.
EN 60079-1
GB 3836.2
Ex e
Increased Safety IEC 60079-7 Through the product design
, the detonation source that can produce hot surfaces or electric arcs or sparks is eliminated, thereby achieving the purpose of explosion protection.
EN 60079-7
GB 3836.3
Ex i
intrinsically safe IEC 60079-11 restricts circuit energy through related technologies, so that
sparks or hot surfaces generated by electrical energy in electrical equipment are not enough to detonate substances in an explosive environment.
60079-11 EN
GB 3836.4
Ex m
Encapsulation IEC 60079-18 likely to ignite explosive atmospheres devices or portions thereof plastic seal material
in a substance, the device or part thereof with an explosive environment
quality cut off from , So as to achieve the purpose of explosion-proof.
EN 60079-18
GB 3836.9

Basic knowledge of explosion-proof certification

Ex n

Non-sparking type IEC 60079-15 prevents flammable substances in explosive environments from
contacting the electric spark or arc generated by the equipment by means of magic seed sealing , and at the same time eliminates the hot
surface generated by the equipment , thereby achieving the purpose of explosion protection.
EN 60079-15
GB 3836.8
Ex p

The positive pressure type IEC 60079-2 prevents the equipment or components that will generate the source of detonation in an enclosure. The
enclosure is filled with inert gas to remove the flammable substances in it.
At the same time, the pressure in the enclosure is maintained to prevent external The inflammable substances enter
, so as to achieve the purpose of explosion-proof.
IEC 61241-4
EN 60079-2
GB 3836.5
Ex o
oil immersion type IEC 60079-6 The parts of electrical equipment are completely immersed in the protective liquid, so that
substances in the explosive environment cannot touch the hot surface of the equipment or sparks.
EN 60079-6
GB 3836.6
Ex q
sand-filled IEC 60079-5 bury the parts of electrical equipment in sand, so that the substances in the explosive environment
cannot remove the hot surface or sparks of the equipment.
EN 60079-5
GB 3836.7