GB/T 51374-2019 in English
VALIDStandard for electrical installation engineering construction and acceptance in explosives and powders atmosphere
- Issued on:2019-06-05
- Implemented on:2019-10-01
- File Format:PDF
- Delivery:Via email within 5 business days
$650.00
本标准适用于火炸药及制品研制、生产、加工、处理、转运或储存环境的电气安装工程施工及验收。
Introduction
Analysis of the core content of the standard
Scope of application and division of hazardous areas
This standard applies to electrical installation projects in the research/production/storage environment of gunpowder, explosives and their products. According to the degree of explosion risk, hazardous places are divided into:
| Category | Characteristics | Typical area |
|---|---|---|
| Class F0 | Long-term presence of explosive dust | Explosive crushing workshop |
| Class F1 | Normal operation may cause explosion | Drug mixing workshop |
| Class F2 | Only fire risk | Finished product temporary storage |
Note:Different types of areas require electrical equipment with corresponding explosion-proof levels.
Key installation technical requirements
1. Installation of explosion-proof electrical equipment
- Flameproof (d) equipment must maintain the integrity of the flameproof surface, and the fastening bolts must have spring washers
- Positive pressure (pD) equipment should be ventilated before power supply, and the ventilation volume should be ≥5 times the pipeline volume
- Intrinsically safe (iD) circuits must use blue cables, and the distance from non-intrinsically safe circuits should be ≥50mm
2. Laying of electrical lines
| Laying method | Technical requirements | Applicable to hazardous locations |
|---|---|---|
| Steel pipe wiring | Thread engagement ≥ 5 threads (Φ≤32mm) | F0/F1/F2 |
| Cable tray | Filling rate ≤40%, grounding every 30m | F1/F2 |
| Isolation seal | Sealing box is installed 450mm away from the equipment | F0/F1 |
Lightning protection and grounding system
Typical problem solution:
The measured grounding resistance of an explosive production line is 8Ω. After correction by the seasonal coefficient (1.55 in October):
R equivalent = 8 × 1.55 = 12.4Ω > 10Ω (design requirement)
Add vertical grounding electrodes (≥Φ15mm galvanized round steel) to make the measured value ≤6.5Ω.
Grounding electrode selection requirements:
- Vertical grounding electrode: galvanized round steel ≥Φ15mm or galvanized steel pipe ≥Φ25mm
- Horizontal grounding electrode: galvanized flat steel ≥50mm² (3mm thick)
- Electrostatic grounding wire: ≥6mm² copper core soft wire for vibration equipment
Implementation points and common misunderstandings
Special attention:
- Branch cables are prohibited in F0 areas, and the air tightness of steel pipes requires a 10kPa pressure test
- When converting from the old to the new explosion-proof mark, tD A21 corresponds to the original DIP A21 (see Appendix A)
- Intrinsically safe circuit grounding requires single-point grounding, and the shielding layer must not be grounded repeatedly
Key indicators for acceptance
| Item | Standard value | Test method |
|---|---|---|
| Insulation resistance | ≥2MΩ(lamp) | 500V megohmmeter |
| Grounding resistance | ≤10Ω(common) | Seasonal coefficient correction |
| Steel pipe sealing | 1kPa(F2)/10kPa(F0) | Air pressure stabilization 15min |
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