"Shenhai" sprogimui atsparus
The explosion-proof marking in explosion-proof lighting fixtures is a label that describes the explosion-proof grade, temperature group, type, and applicable areas of the lighting fixture.
Explanation of Explosion-proof Marking:
As per GB 3836 standards, the explosion-proof marking of lighting fixtures includes:
Explosion-proof Type + Equipment Category + (Gas Group) + Temperature Group.
1. Explosion-proof Type:
Table 1 Basic Types of Explosion-Proof
| Explosion proof form | Explosion proof form sign | Explosion proof form | Explosion proof form sign |
|---|---|---|---|
| Ugniai atsparus tipas | EX d | Sand filled type | EX q |
| Didesnis saugos tipas | EX e | Encapsulation | EX m |
| Barotropic type | EX p | N tipo | EX n |
| Jaičiausiai saugus tipas | EX ia EX i | Special type | EX s |
| Naftos invazijos tipas | EX o | Dust explosion-proof type | EX A EX B |
2. Equipment Category:
Electrical equipment for sprogmuo gas atmospheres is divided into:
Class I: For use in coal mines;
Class II: For use in explosive gas atmospheres other than coal mines.
Class II explosion-proof “d” and intrinsic safety “i” electrical equipment are further divided into IIA, IIB, and IIC classes.
Electrical equipment for degiosios dulkės environments is divided into:
Type A dust-tight equipment; Type B dust-tight equipment;
Type A dust-proof equipment; Type B dust-proof equipment.
3. Explanation of Explosion-proof Marking:
The ability of an explosive gas mixture to propagate an explosion indicates its level of explosion hazard. The greater the ability to propagate an explosion, the higher the danger. This ability can be represented by the maximum experimental safe gap. Additionally, the ease with which explosive gases, vapors, or mists can be užsidegė also indicates the level of explosion hazard, represented by the minimum igniting current ratio. Class II explosion-proof or intrinsic safety electrical equipment is further classified into IIA, IIB, and IIC based on their applicable maximum experimental safe gap or minimum igniting current ratio.
Table 2 Relationship between the Group of Explosive Gas Mixtures and the Maximum Experimental Safe Gap or Minimum Igniting Current Ratio
| Dujų grupė | Maximum test safety gap MESG (m m) | Minimalus uždegimo srovės koeficientas MICR |
|---|---|---|
| IIA | MESG≥0,9 | MICR＞0,8 |
| IIB | 0.9＞MESG≥0.5 | 0,8≥MICR≥0,45 |
| IIC | 0,5≥MESG | 0,45＞MICR |
4. Temperature Group:
The ignition temperatūra of an explosive gas mixture is the limit temperature at which it can be ignited.
Electrical equipment is classified into T1 to T6 groups based on their highest surface temperature, ensuring that the maximum surface temperature of the equipment does not exceed the permissible value of the corresponding temperature group. The relationship between temperature groups, equipment surface temperature, and the ignition temperature of degus gases or vapors is shown in Table 3.
Table 3 Relationship between Temperature Groups, Equipment Surface Temperature, and Ignition Temperature of Flammable Gases or Vapors
| Temperature level IEC/EN/GB 3836 | The highest surface temperature of the equipment T [℃] | Lgnition temperature of combustible substances [℃] |
|---|---|---|
| T1 | 450 | T＞450 |
| T2 | 300 | 450≥T＞300 |
| T3 | 200 | 300≥T＞200 |
| T4 | 135 | 200≥T＞135 |
| T5 | 100 | 135≥T＞100 |
| T6 | 85 | 100≥T＞8 |
5. Requirements for Setting Markings:
(1) Markings should be prominently placed on the main body of the electrical equipment;
(2) The markings must remain clear and durable under potential chemical corrosion. Markings such as Ex, sprogimui atsparus tipas, category, and temperature group can be embossed or debossed on the visible parts of the casing. The material for the marking plate should be chemically resistant, such as bronze, brass, or stainless steel.