Conveyor belts for use in underground installations - Electrical and flammability safety requirements; German version EN 14973:2015
1Key Takeaways
This European Standard specifies the electrical and fire safety requirements for conveyor belts used in underground mining environments (including flammable and non-flammable environments). Conveyor belts conforming to this European Standard are designed for use in conveying systems in flammable environments such as co…
2Expert Interpretation
A comprehensive analysis of DIN EN 14973:2016-02, the fire safety standard for conveyor belts in underground mines, covers electrical safety requirements, fire performance testing, explosion-proof classification, and implementation key points. This detailed explanation of the safety regulations and technical requirements for conveyor belts in flammable and explosive environments provides professional guidance for mining equipment selection and safety management.
DIN EN 14973 Standard Overview and Technical Evolution
DIN EN 14973:2016-02, "Electrical and fire safety requirements for conveyor belts used in underground mines," is a key standard from the European Committee for Standardization (CEN) for the safety of conveyor equipment in mines. Published in February 2016, it supersedes the 2009 edition and primarily adds the laboratory fire tunnel test as an alternative to the fire spread test.
Standard Scope and Classification System
This standard applies to conveyor belts used in flammable and non-flammable environments in underground mines, specifically Group I, Category M2 equipment (as defined in EN 13463-1:2009). The standard divides conveyor belts into three main categories:
| Category | Application environment | Safety devices | Maximum drum temperature |
|---|---|---|---|
| Class A | General underground use with restricted access hazards only | No requirement | No restrictions |
| Class B1 | Potentially explosive atmosphere | Without additional safety devices | 450°C |
| Class B2 | Potentially explosive atmosphere | With additional safety devices | 450°C |
| Category C1 | Presence of combustible dust or conveyed material | Without additional safety devices | 325°C |
| Category C2 | Presence of additional fuel sources (fire load) | With additional safety devices | 325°C |
Electrical Safety Requirements and Test Methods
According to the EN ISO 284 test requirements, all conveyor belts used in underground mining must have a surface resistance of no more than 300 MΩ, which is a key indicator for preventing explosions caused by static electricity buildup.
Frictional heating test requirements
Drum friction test in accordance with EN 1554:2012:
- Class A conveyor belt: Glowing is permitted but flames are not permitted
- Class B1 conveyor belt: Neither glowing nor flames are permitted, and the roller temperature must not exceed 450°C
- Class C1 conveyor belt: Neither glowing nor flames are permitted, and the roller temperature must not exceed 325°C
Fire performance test system
The standard establishes a multi-level fire performance test system, including:
1. Anti-ignition performance test (EN ISO 340)
For Class A, B1, B2 and C2 conveyor belts, the total afterburn time of the six specimens must be less than 45 seconds, and the afterburn time of a single specimen must not exceed 15 seconds. Category C1 has stricter requirements, and the average afterburning time of the intact specimen with the surface shall not exceed 18 seconds.
2. Fire spread test
Four-level test method is adopted:
| Test method | Applicable standard | Qualification standard | Applicable category |
|---|---|---|---|
| 2m single burner test | EN 12881-1 Procedure A | Undamaged length ≥100mm | A, B1, B2 |
| Dual burner test | EN 12881-1 Procedure B | Entire width undamaged | All categories |
| Propane stove test | EN 12881-1 Procedure C | Undamaged length ≥ 600mm or temperature rise ≤ 140°C | All categories |
| Fire tunnel test | EN 12881-2 | Fire spread not exceeding 10m | Category C2 |
| Laboratory fire tunnel test | EN 12881-1 Procedure D | See Table 1 requirements | Limited scope |
Implementation recommendations and risk assessment
According to the requirements of Appendix A of the standard, the implementation process should focus on:
1. Hazard identification
- Risk of static electricity accumulation and discharge
- Risk of ignition due to localized frictional heating
- Conveyor belt ignition caused by small fire sources
- Risk of fire spreading along the conveyor belt
2. Risk Assessment Method
A risk assessment should be carried out in accordance with EN ISO 12100, using the methodology provided in EN 31010. The risk assessment needs to consider:
- The likelihood of the hazard occurring
- The severity of the consequences
- The effectiveness of existing safety measures
3. Certification Recommendations
According to the recommendations in Annex C, for conveyor belt series with the same structure and materials, a family certification approach can be adopted, where only the lowest and highest tensile strength specifications need to be tested.
Conformity with EU Directives
This standard supports the essential requirements of the following EU directives:
| Directive number | Directive name | Conformity chapter |
|---|---|---|
| 94/9/EG | Equipment and protective systems for potentially explosive atmospheres | Chapters 4, 5, 6, 7 and 8 |
| 2006/42/EG | Machinery Directive | Essential Requirements 1.5.6 and 1.5.7 |
Technical evolution and updated content
Major updates to the 2016 edition compared to the 2009 edition:
- New Test Procedure D: Laboratory fire tunnel testing has been added as an alternative to the fire spread test
- Technical Content Revisions: Test requirements and technical parameters have been comprehensively revised
- Editorial Improvements: The readability and implementability of the standard have been improved
The implementation of this standard is of great significance to ensuring the safe operation of underground mine conveying systems, especially in places such as coal mines where flammable and explosive atmospheres exist. Conveyor belt manufacturers, mine operators, and regulatory agencies should fully understand and strictly implement the requirements of this standard.