Rubber and Plastic Products Processing System Dust Explosion Prevention Safety Specifications

8.2 Key Technical Requirements for Dust Collectors

Bag dust collectors must meet six core requirements:

1. Operating Mode: Negative pressure dust collection is preferred; spark detection is required on the main duct during positive pressure.
2. Explosion Control Measures: Multiple measures must be combined; explosion isolation must be used in conjunction with other measures.
3. Differential Pressure Monitoring: Differential pressure alarms must be installed at the inlet and outlet, and data must be recorded.
4. Ash Discharge Control: The ash hopper must be equipped with an airlock ash discharge device and monitoring for abnormal operation.
5. Ash Collection Cleaning: Ash collection hoppers must be cleaned regularly.
6. Structural Design: The inner wall of the ash hopper must be smooth for easy material discharge.

Article 8.2.2 stipulates that dry dust collectors should, in principle, be installed outdoors, unless flameless explosion venting or an explosion venting duct ≤3m is used. This has a direct impact on the plant layout design.

8.3 Duct Design Specifications

The main duct must be made of steel. Non-metallic materials must be flame-retardant and electrostatically conductive. The key parameter, **design velocity**, must be calculated based on a dust concentration ≤25% LEL, requiring accurate understanding of dust characteristics during the design phase.

8.5 Operation Control Logic

The start-up and shutdown sequence of the dust removal system is clearly defined for the first time: **start before process equipment**, and materials can only enter after the design velocity is reached; **shut down 10 minutes after process equipment**. The control cabinet must be located in a safe location free from explosion hazards.

Technical Guidelines for Combined Application of Explosion Control Measures

Chapter 9 systematically summarizes the application conditions and technical requirements of various explosion control measures:

Important principle: Clause 9.4 explicitly prohibits the use of observation windows, cleaning holes, and maintenance holes as explosion vents. This requires enterprises to specifically design explosion venting devices that meet the standards when selecting and modifying equipment.

Key Points of Operational Safety Management

10.2 Full-Process Control of Hot Work Operations

Hot work operations are a high-risk process, and the standard stipulates the following full-process control requirements:

• Preparation before operation: Spray water to remove accumulated dust within a radius of ≥10m; remove accumulated dust inside the equipment; start the dust removal system for ≥10min to remove suspended dust
• Isolation measures: Stop the equipment handling dust and connected dust removal systems; seal and isolate connecting pipelines (close valves or disconnect and seal pipes); when working on the top of the silo, close the openings within a 10m radius and cover them with non-combustible materials
• Process monitoring: Recover the cut parts in a timely manner and check that no hot objects fall into the equipment
• Post-operation management: Clean up the site and monitor for ≥1 hour; prohibit dust from entering during the cooling period; check the inside of the equipment after welding and cutting to confirm that there is no smoldering

10.3 Dust Cleaning Specifications

Special attention should be paid to the characteristics of rubber and plastic dust during cleaning operations:

1. Choice of Cleaning Method: Compressed air blowing is prohibited when there are hot surfaces or open flames.
2. Explosion-proof Electrical Equipment: Electrical equipment used for cleaning must be dust explosion-proof.
3. Special Material Handling: Rubber, plastic, and synthetic resin dust cleaning requires humidification, and non-sparking tools should be used.
4. Steam/Compressed Air Use: Turn off or remove electrical equipment and other ignition sources before blowing.

Standard Implementation Recommendations and Compliance Path

Phase 1: Current Status Assessment and Gap Analysis (1-2 months)

Enterprises should establish a special working group to conduct a comprehensive gap analysis in accordance with the requirements of Chapter 11 of the standard:

1. Hazardous Area Reclassification: Assess the compliance of existing area classification according to the method in Appendix A, and establish zoning description documents.
2. Dust Removal System Inspection: Check whether dust collectors, ducts, and fans meet the requirements of Chapter 8, paying particular attention to the combined application of explosion control measures.
3. Process Equipment Assessment: Verify the integrity of explosion-proof measures for key equipment such as internal mixers, crushers, and granulators.

Phase Two: Technical Transformation and System Upgrade (3-6 months)

Based on the gap analysis results, formulate a priority transformation plan:

Phase Three: Continuous Improvement and Compliance Maintenance (Long-Term)

Establish a normalized management mechanism based on standard requirements:

• Dynamic risk assessment mechanism: Re-classify hazardous areas when process equipment changes
• Equipment maintenance system: Regularly inspect flameless explosion relief devices, explosion-proof valves, and other explosion-proof equipment
• Personnel training system: Conduct specialized training for high-risk operations such as hot work and dust cleaning
• Record and file management: Completely preserve zoning documents, risk assessment records, maintenance records, etc.

Industry Impact and Future Outlook

The implementation of AQ4232-2025 will have a profound impact on the rubber and plastics industry: