This standard specifies the basic requirements for dust explosion prevention in feed processing systems. It is applicable to the design, construction, operation and management of dust explosion prevention in feed processing systems. GB 19081-2003 Safety regulations for dust explosion prevention in feed processing systems GB19081-2003 Standard download decompression password: www.bzxz.net

All technical contents of this standard are mandatory. Foreword
GB19081-2003
This standard is not equivalent to the American Fire Protection Association NFPA61C-1987 "Fire and Explosion Prevention in Feed Processing". This standard is proposed by the State Administration of Work Safety and is under the jurisdiction of the National Technical Committee for Dust Explosion Prevention Standardization. This standard was drafted by Jiangsu Zhengchang Group Co., Ltd.; Wuhan Safety and Environmental Protection Research Institute, Wuxi Research and Design Institute of the State Grain Reserve Bureau, and Dajiang Group Co., Ltd. participated in the drafting. The main drafters of this standard are: Hao Bo, Kong Yunsheng, Hou Yan, Pan Jialiang, Yu Guozhong, Zhou Hao, Jiang Yunzhen, and Cao Kang. I
GB190812003
In the feed processing system, there have been many explosion accidents caused by feed dust in China, endangering the safety of people and property. In order to prevent and reduce the occurrence of feed dust explosion accidents and control the losses caused by dust explosion to a minimum, this standard is specially formulated. This standard proposes economical, practical and advanced protection methods for feed dust explosion prevention, thereby ensuring the safety of people and property. 1 Scope
Safety regulations for dust explosion prevention in feed processing systems This standard specifies the basic requirements for dust explosion prevention safety in feed processing systems. This standard applies to the design, construction, operation and management of dust explosion prevention in feed processing systems. 2 Normative references
GB19081—2003
The clauses in the following documents become the clauses of this standard through reference in this standard. For all referenced documents with a blank date, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, parties to an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For any undated referenced document, the latest version shall apply to this standard GB15577-1995 Safety regulations for dust explosion prevention GB/T15605-1995 Guidelines for dust explosion pressure relief GB17440-1998 Safety regulations for dust explosion prevention in grain processing, storage and transportation systems GB50057-2000 Design code for lightning protection of buildings GB50058-1992 Design code for electrical installations in explosive and fire hazardous environments GBJ16-1987 Code for fire protection design of buildings
3 Terms and definitions
The following terms and definitions apply to this standard. 3.1
Feed
Feedable material that can provide the nutrients required by animals, ensure health, promote growth and production, and does not cause harmful effects under reasonable use. 3.2 bZxz.net
Feed processing
The process of making feed raw materials into finished or semi-finished feed through specific processing technology and equipment. 3.3
Feed processing system is the general term for the equipment, facilities and buildings (structures) used for feed processing. 3.4
Feed dust
Solid feed particles that can settle down in the atmosphere by their own weight but can also remain suspended in the air for a period of time. 3.5
Silos
Vertical cylindrical closed structures for storing bulk materials. 3.6
Feed processing workshops are workshops used to process feed raw materials into feed products. 3.7
Dust explosion prevention and protection are measures to prevent the occurrence of dust explosions and reduce the degree of explosion hazards after dust explosions occur. GB 19081—2003
4 General provisions
4.1 The person in charge of the enterprise shall clearly define the dust explosion hazardous places included in the system, and shall formulate dust explosion prevention implementation rules and safety inspection specifications based on this standard and the actual situation of the unit. 4.2 System operators shall first receive dust explosion safety knowledge education, and can only take up their posts after passing the assessment. 4.3 Fire prevention, explosion prevention and other related facilities should be checked regularly to ensure that they are in good working condition. 4.4 Ventilation, dust removal, explosion relief and explosion prevention facilities shall not be dismantled, changed or stopped without the consent of the safety authority. 4.5 Non-productive open flames should be eliminated in the system, and flammable and explosive items should not be stored in the feed processing workshop. 4.6 Prevent the generation of friction and collision sparks:
- A device for removing iron and other debris from the material should be installed at an appropriate position in the system;- When performing non-hot repair and maintenance operations, it is not advisable to use iron tools to knock on equipment and pipelines, and explosion-proof hand tools should be used. 4.7 Heat-proof surfaces shall comply with the following provisions:
Drying equipment shall use heat-insulating outer coverings; all equipment bearings shall be dust-proof and sealed.
4.8 The electrical design of the system to prevent electrical sparks shall comply with the relevant provisions of Chapter 3 of GB50058-1992. 4.9 Anti-static measures and anti-static grounding shall comply with the requirements of 5.3.2 of GB15577-1995. 4.10 Dust cleaning shall comply with the following provisions: A well-maintained and clean room is the best measure for explosion prevention. A regular cleaning system should be established, especially for cleaning of rotating and heating parts;
It is advisable to use vacuum dust collection devices for cleaning operations, and it is not advisable to use compressed air for cleaning operations. 4.11 After the equipment in the feed processing system is stopped and before maintenance, the accumulated materials inside the equipment and the dust outside the equipment should be removed first. 4.12 Explosion-proof safety inspections should be carried out regularly according to the implementation rules and safety inspection specifications for dust explosion prevention. 5 Open flame operation
5.1 Open flame operation should not be carried out during system operation. 5.2 Enterprises should divide fire and explosion prevention operation areas according to specific circumstances, and clarify the approval departments and authorities for handling open flame operations in each area. 5.3 Before carrying out open flame operation, approval should be obtained from the unit's safety or fire department. The open flame operation site should be supervised by a dedicated person and equipped with sufficient fire extinguishing equipment.
5.4 Welding or cutting can only be carried out after the operation line is stopped and reliable safety measures are taken. 5.5 Buildings in the fire and explosion prevention operation area should be cleaned within a radius of 10m from the open flame operation site, and the ground should be wetted with water, and all doors and windows should be opened.
5.6 When working on a pipeline connected to a closed container: a) If there is an isolation valve, ensure that the valve is tightly closed; b) If there is no isolation valve, the pipelines on both sides of the ignition point should be removed and the pipe openings should be closed or the pipelines should be isolated with isolation plates. 5.7 When open flame operation is carried out on the top of the silo, all silo roof holes and ventilation and dust removal ports within a radius of 10m from the open flame operation point should be covered and covered with flame retardant materials.
5.8 After open flame operation, monitoring should be carried out at any time until the working parts cool down to room temperature. 5.9 After welding, the workpiece must be completely cooled before painting and other production operations can be carried out. 6 Requirements for buildings (structures)
6.1 General
The fire protection design of feed processing system buildings shall comply with the relevant provisions of GBJ16-1987. 6.2 Civil engineering design
The following buildings (structures) should not be arranged within 10m around the feed processing workshop: 6.2.1
Buildings (structures) that are prone to disasters such as fuel depots and chemical warehouses; a)
b) Office buildings, staff dormitories, canteens, conference rooms and other buildings with dense crowds. Feed processing workshops should take lightning protection measures in accordance with the relevant provisions of GB50057-2000. 6.2.2
6.2.3 Each silo should be equipped with a manhole or cleaning port, and should be able to prevent dust from escaping from the silo. 6.2.4
The grain inlet room should be open or semi-open. The floor, walls and roof of the warehouse and feed processing workshop should be flat and easy to clean. 6.2.5
GB 19081-2003
The fire resistance level, number of floors, floor area, fire protection distance, explosion relief and safe evacuation of the feed processing workshop should comply with the relevant provisions of Chapter 3 of GBJ16-1987.
6.3 Fire prevention and fire fighting in the general plan
6.3.1 When the feed processing workshop is arranged together with the raw material warehouse, auxiliary material warehouse, finished product warehouse and other buildings, the feed processing workshop should be located on one side or corner of the plane, and should not be arranged in the center of the plane. 6.3.2 Circular fire passages should be set around the feed processing workshop and silos. 6.3.3 Water pump connectors and ground fire hydrants shall be installed near the factory area, and the distance between outdoor fire hydrants shall not exceed 120m. 6.4 Indoor fire prevention and fire fighting
Fire hydrants shall be installed in feed processing workshops, silo grain inlet rooms, silo bottom floors, finished product warehouses, raw material warehouses, and auxiliary material warehouses. The amount of water used for indoor and outdoor fire fighting shall comply with the relevant provisions of Chapter 8 of GBJ16-1987. 6.5 When windows are used as explosion vents, they shall be opened outwards. 7 Electrical design
Division of feed dust hazardous places and locations 7.1
The classification of feed dust hazardous places and locations is shown in Table 1. Classification of feed workshop dust hazardous places and locations Table 1
Dust environment
Sealed silo
Raw material silo, silo
Silo to be crushed in feed processing workshop Indoor elevator
Indoor pulse dust collector
Indoor cyclone separator
Imperial grain pit
Crusher room
Fan room
7.2 General requirements
Electrical equipment and lines should be set up and laid in areas without dust explosion hazards; if it cannot be avoided, it should comply with the relevant provisions of Chapter 3, Section 4 of GB50058-2000. 7.2.2 The production operation of feed processing shall be equipped with electrical interlocks that meet the requirements of process operation and ensure safe production. The electrical interlocks include: electrical interlocks between production lines; electrical interlocks between various electrical equipment in production operation; emergency stop of production lines.
7.2.3 All electrical equipment shall be equipped with short circuit and overload protection. 3
GB 19081—2003
7.2.4 The control room shall control all process operations and shall have the function of real-time monitoring of the working conditions of on-site operating equipment. 7.2.5 The main control room shall be equipped with signal communication with each floor. 7.3 Electrical equipment
7.3.1 Lighting fixtures shall be selected according to the classification of hazardous places. The lighting of feed processing workshops shall be centrally controlled by floor. 7.3.2 When inspecting the equipment and facilities in Zone 20 and Zone 21, dust-tight and dust-proof dust explosion-proof lamps shall be used respectively. 7.3.3 Electrical equipment that may generate sparks during normal operation, such as sockets, lighting distribution boxes, etc., should be arranged outside the explosive dust area. 7.3.4 The cables used in the lines of mobile electrical appliances used in Zone 20 and Zone 21 should comply with the requirements of GB50058-1992. 7.3.5
The distribution cabinets and control cabinets should be concentrated in the control room, which should be separated from the production workshop by walls and spring doors. 7.3.6
For the temperature groups of electrical equipment installed in Zone 20 and Zone 21, see Table 2. Table 2 Temperature groups for electrical equipment installed in silos and feed processing workshops Temperature groups
Electrical equipment in Zone 20 and Zone 21 should be selected according to Table 3. Table 3 Selection of electrical equipment
Hazardous locations
Category of enclosure
Explosion-proof mark
DIPDTT2
Note: DT is a dust-tight enclosure with an enclosure protection level of IPex; DP is a dust-proof enclosure with an enclosure protection level of IPsx. 7.4 Electrical circuits
7.4.1 Electrical circuits shall comply with the provisions of 6.3 of GB17440--1998. T2
DIPDPT2
7.4.2 Electrical circuits shall be laid in an environment with a low explosion risk or away from dust release sources. 7.4.3 In an explosive dust environment, the rated pressure of insulated wires and cables used in low-voltage power and lighting circuits shall comply with the requirements of GB50058---1992.
7.4.4 The selection of insulated wires and cables in an explosive dust environment shall comply with the requirements of GB50058---1992. 7.4.5 When insulated wires are used for electrical lines in explosive dust areas, steel pipes shall be used for wiring. When cables are used, bridges shall be used for laying. 7.4.6 When cable bridges are used, non-armored cables may be used, and necessary rodent prevention measures shall be taken. 7.4.7 Electrical lines in explosive dust areas are not allowed to have intermediate joints. When electrical pipelines and cable bridges pass through walls and floors, the holes shall be strictly blocked with non-combustible fillers.
7.5 Lightning protection and grounding
7.5.1 The lightning protection and grounding design in feed dust explosion hazard areas shall comply with the relevant provisions of GB50057-2000. 7.5.2 The lightning protection of feed processing workshops shall be designed as a second-class lightning protection building, and other buildings shall be designed as a third-class lightning protection building. 7.5.3 Buildings in explosive dust areas may use structural steel bars of buildings (structures) to form lightning protection devices. Electrical equipment in zones 20 and 21 shall adopt the TN-S grounding system. 7.5.4
7.5.5 Each section of the metal shell of the equipment, racks and pipelines in Zone 20 and Zone 21 shall be bridged to form a good passage and shall not be interrupted. 7.5.6
The grounding electrode, down conductor and lightning arrester shall be reliably welded from bottom to top to ensure a good electrical passage. 7.5.7
The working grounding, protective grounding and lightning protection grounding of the power system and the grounding of the automatic control system should be combined to set up a joint grounding, and the grounding resistance value shall be the minimum value.
8 Process design and equipment
8.1 General provisions
8.1.1 The minimum width of various passages in the production workshop should be considered in process design: non-operating passage: 500mm;
-operating passage: 800mm;
main passage: 1000mm.
8.1.2 Open chutes (troughs) and equipment should not be used indoors. GB19081—2003
8.1.3 Mechanical equipment should have sufficient strength and rigidity to avoid sparks caused by breakage, distortion, collision, friction, etc. during operation. 8.1.4 A complete ventilation and dust removal system should be equipped. The dust concentration in the air in the feed processing workshop, silo feeding room, and upper and lower corridors of the silo should be lower than 10mg/m3, and the dust concentration discharged into the atmosphere should be lower than 120mg/m3. 8.2 Bucket elevator
8.2.1 Bucket elevators should be equipped with safety protection devices such as slippage and deviation, and the emergency interlock shutdown device should be able to be activated immediately when a fault occurs. 8.2.2 The casing, head, base and connecting pipe of the bucket elevator should be sealed and dust-proof, and the seals should be made of non-combustible materials.
8.2.3 Bucket elevators should be equipped with explosion relief ports. The location and area of ​​the explosion relief ports should comply with the relevant provisions of GB15605--1995. The explosion relief port on the top of the machine head should be led to the outside, and the length of the duct should not exceed 3m. 8.2.4 There should be an inspection port at the head of the elevator. 8.2.5 The driving wheel of the elevator should be covered with rubber, and the spare bucket belt should have flame retardant and anti-static properties. 8.2.6 An appropriate material cleaning port should be set at the machine base, and it can be used to check the machine base, bottom wheel, reel and bucket belt. 8.3 Chute, pipe fittings, buffer bucket
The connection of chute, pipe fittings, and buffer bucket should be detachable, but must be sealed after installation. 8.4 Buffer device
The chute for conveying materials should have a buffer device at the elbow. 8.5 Screw conveyor and scraper conveyor
Screw conveyor and buried scraper conveyor should not leak dust to the outside. When the discharge port is blocked or the scraper chain breaks, the machine should be able to stop immediately and alarm.
8.6 Discharging machine
When the feeding port of the discharging machine is connected to the silo, the sealing should be done to prevent dust leakage. The connecting flange should be lined with non-metallic sealing gaskets and fastened with bolts. The gate should be easy to open. The connection of the discharging port of the discharging machine and the hose connection should also be well sealed. 8.7 Batching scale, mixer and buffer hopper
The batching scale, mixer and buffer hopper should be connected by a connecting pipe. Mixers of 2t/batch and above can be equipped with independent dust spraying prevention devices. 8.8 Air compressor
Air compressors should preferably use screw and vane air compressors. 8.9 Heating device
8.9.1 Heat transfer devices using air, steam or heat transfer liquid vapor should be equipped with pressure reducing valves. 8.9.2 Heaters and pumps for heat transfer media should be located in a separate room without explosion hazard or in a building with flame retardant (or non-combustible) structure.
8.9.3 The enclosure of the heat exchanger should be made of non-combustible materials and should have suitable openings for cleaning and maintenance. 8.9.4 Heat exchangers should be placed in suitable locations and arranged in a certain way to prevent flammable dust from entering the induction coil or other hot surfaces. 8.9.5 The heating device of the heat transfer system should be equipped with suitable working control devices. 9 Pneumatic conveying
9.1 When a fire occurs, the pneumatic conveying system should be shut down quickly. 9.2 Bag dust collectors should be equipped with special explosion vents. 9.3 Pulse bag dust collector:
- The dust accumulation and damage of the filter bag should be checked regularly; anti-static filter materials should be selected; the oil-water filter, air storage tank and air bag on the dust collector in the compressed air system should be discharged 1 to 2 times per shift; 5
GB19081-2003
- When it is necessary to stop, first stop the fan, and after a period of time, stop the fan and pulse controller to keep the filter bag clean after each stop. The cleaned dust should be discharged from the ash hopper. 9.4 The suction pneumatic conveying fan should be located after the last dust collector. 9.5 Compressed air pneumatic conveying equipment should be closed to prevent dust leakage. 10 Ventilation and dust removal system
According to the process requirements, the ventilation and dust removal system should adopt multiple independent systems. An independent dust removal system should be set up at the feeding port. 10.1
10.2 Try to shorten the length of the horizontal air duct and reduce the number of elbows. Horizontal pipes should be connected with flanges. 10.3 Each silo top should be equipped with an exhaust hole or a small silo top dust removal device. 10.4 An air volume adjustment device should be installed at the appropriate position of each air suction duct. 10.5 To prevent pipe blockage, a suitable pipe wind speed should be selected, generally between 12m/s and 20m/s. 10.6 All dust-generating points should be equipped with suction hoods, which should be as close to the dust source as possible. 10.7 Pulse bag dust collectors should meet the requirements of 9.3. 10.8 The fan should be located after the last dust collector. 6
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