Some standard content:
National Standard of the People's Republic of China
Safety regulations for dust explosion prevention and protection1 Subject content and scope of application
This standard specifies the explosion safety requirements for dust explosion hazardous places. This standard applies to the engineering design, management, production, storage and transportation of dust explosion hazardous places. This standard does not apply to underground mines and explosives factories. 2 Reference standards
GB11651 Selection rules for labor protection products
GB/T15605 Dust explosion pressure relief guide
3 Terms
3.1 Combustible dust
Dust that can undergo violent oxidation reactions with gaseous oxidants or air under certain conditions. 3.2 Dust explosion hazardous places
Places where combustible dust and gaseous oxidants (or air) exist. 3.3 Inert gasification
GB15577—1995
A method of filling a place with dust explosion hazard with sufficient inert gas or spreading inert dust on the dust layer to make the dust mixture lose its explosiveness.
3.4 Explosion suppression
When an explosion occurs, the flame is extinguished through physical and chemical effects so that the unexploded dust no longer participates in the explosion. 3.5 Explosion venting
When an explosion occurs in a closed enclosure containing dust and gaseous oxidants or air, before the explosion pressure reaches the ultimate strength of the enclosure, the high-temperature, high-pressure combustion products and unburned materials generated by the explosion are released to a non-hazardous direction through the weak parts of the enclosure so that the enclosure is not destroyed.
3.6 Secondary explosion
When a dust explosion occurs, the shock wave of the initial explosion will lift up the deposited dust again to form a dust cloud, which will be ignited by the subsequent flame and cause a continuous explosion.
4 General Provisions
4.1 Newly built, renovated and expanded enterprises with dust explosion hazardous sites must comply with the provisions of this standard. Existing enterprises that do not comply with the provisions of this standard must formulate a safety technical measures plan and achieve it within a time limit. 4.2 The legal person of the enterprise must be clear whether there are dust explosion hazardous sites in the enterprise and take measures to effectively control dust explosions. 4.3 The enterprise should formulate its own dust explosion prevention implementation rules and safety inspection form in light of the characteristics of its own dust explosion hazardous sites, and conduct dust explosion prevention inspections in accordance with the full inspection form approved by the Anguocha Technical Supervision Bureau on June 19, 1995 and implemented on January 1, 1996. The enterprise shall conduct inspections at least once a quarter, and the workshop (or section) shall be inspected at least once a month. 4.4 Enterprises should earnestly carry out safety production and dust explosion prevention education, popularize dust explosion prevention knowledge and safety regulations, and make employees understand the danger level and explosion prevention measures of dust explosion hazardous places in the enterprise; technical and business training should be carried out for employees, and they are allowed to work only after passing the examination. 4.5 Fireworks are strictly prohibited in dust explosion hazardous places, and the electrical equipment used must be dust explosion-proof. 4.6 The production of dust explosion-proof products must be approved by the Ministry of Labor or its designated unit and a license must be issued. 4.7 Safety, ventilation, explosion-proof, explosion-proof and other facilities shall not be dismantled without the approval of the competent department. 4.8 The safety assessment of construction projects should include dust explosion hazard analysis and explosion prevention measures. 5 Prevent dust clouds and dust layers from igniting
5.1 Prevent bulk powder from spontaneous combustion
5.1.1 Hot powder that can spontaneously combust must be cooled to normal storage temperature before storage. Powders (self-igniting materials) that can self-ignite at room temperature should be stored in inert gas or liquid, or stored in other safe ways. 5.1.2 Under normal storage conditions, when bulk powders that can self-ignite are stored in large quantities, the temperature of the powder must be continuously monitored. When the temperature rises or gas is precipitated, measures must be taken to cool the powder; when the self-ignition process has developed to the point where it may cause combustion or explosion, measures must be taken to stop the development of self-ignition. 5.2 Prevent open flames from igniting hot surfaces
5.2.1 When performing open flame operations in dust explosion hazardous areas, the following regulations must be observed: a. An operation permit approved by the safety person in charge: b. Before the start of open flame operations, combustible dust in the open flame operation area should be thoroughly removed; b.bZxz.net
During the open flame operation and the subsequent cooling period, dust is strictly prohibited from entering the open flame operation area; the section where open flame operations are performed must be separated or isolated from other sections of the equipment. d.
The surface allowable temperature of equipment or devices (such as light sources, heaters, etc.) that are in direct contact with dust clouds must be lower than the 5.2.2
minimum ignition temperature of the corresponding dust layer.
5.2.3 Places, equipment and devices where flammable or explosive dust exists shall comply with the following provisions: 5.2.3.1 The bearings of process equipment shall be dustproof and sealed; if overheating is possible, detectors that can continuously monitor the bearing temperature must be installed. 5.2.3.2 Belt drive should not be used; if belt drive is used, a speed difference sensor and an automatic anti-skid protection device must be installed. When sliding friction occurs, the protection device should ensure automatic shutdown. 5.2.3.3 Bucket elevators must be equipped with safety protection devices. 5.3 Preventing arc and spark ignition
5.3.1 Appropriate lightning protection measures should be taken in dust explosion hazardous places. 5.3.2 When there is a danger of static ignition, the following regulations must be observed: 5.3.2.1 All metal equipment, device casings, metal pipes, brackets, components, parts, etc. should generally be directly grounded by static electricity; if direct grounding is inconvenient or the process does not allow it, it can be indirectly grounded through static conductive materials or products. The direct static grounding resistance is not greater than 100Ω, and the indirect grounding resistance is not greater than 10°0.
5.3.2.2 Apparatuses directly used to hold powders, pipes (belts) for conveying powders, etc. should be made of metal or anti-static materials. 5.3.2.3 All metal pipe connections (such as flanges) must be bridged. 5.3.2.4 Operators should take anti-static measures. 5.3.2.5 It is prohibited to eliminate static electricity by using a directly grounded metal conductor or screen in contact with high-speed flowing powder. 5.4 Preventing ignition by friction and collision sparks
5.4.1 When dust clouds can be ignited by sparks generated by accidental collisions (such as collisions between metal debris and internal parts of process equipment), measures must be taken to prevent collisions from occurring.
5.4.2 At the feed point of the process flow, magnets, pneumatic separators or sieves that can remove debris from the mixed materials should be installed to prevent debris from colliding with the equipment.
GB 15577-1995
5.4.3 Sparks generated by friction between aluminum, magnesium, titanium, zirconium, etc. or powders containing these metals and stainless steel are particularly dangerous ignition sources. When powders of the above metals or alloys are present, friction sparks must be prevented. 5.4.4 For process equipment containing dust that is particularly easy to ignite, it must be ensured during inspection and maintenance that no friction and collision sparks are generated in the section containing such dust.
5.4.5 Grinding and cutting with rotating grinding wheels and rotating cutting discs is strictly prohibited without the same protective measures as for open flame operations. 5.5 Inertization
5.5.1 In process equipment that produces or handles powders that are particularly easy to ignite, the dust cloud must be inerted with inert gas. 5.5.2 In equipment such as mills and mixers that process or handle powders, it should be determined whether to use inert gas inerting based on their dust explosion characteristics.
5.6 Strictly controlling the dust concentration to be outside the dust explosion concentration range is an effective explosion prevention measure. In special cases, such as in powder exhaust systems and in small rooms used for powder electrostatic spraying, the dust concentration must be controlled to be higher than the upper limit of the dust explosion concentration.
6 Reduce the damage caused by the initial explosion
6.1 Segmentation and isolation
6.1.1 The connection of process equipment must ensure that each equipment can be easily separated and moved without open flame operations. 6.1.2 When designing process equipment, technically feasible isolation must be considered to prevent the explosion of a certain equipment from spreading to adjacent equipment. 6.2 Protective parking during explosion
6.2.1 In an emergency, it must be possible to remotely cut off the power supply to all motors. 6.2.2 Depending on the size of the workshop, several switchboards with interchangeable remote control motor power supplies can be installed. The switches must be properly marked, preferably with self-luminous signals.
6.2.3 Remote control switches must be installed where they can still be operated when fire and explosion occur in the workshop. 6.3 The workshop should be protected by an automatic explosion suppression system. 6.4 Restraining the deflagration pressure
6.4.1 When producing and handling powders that can cause explosions, if there is no automatic explosion suppression system and no pressure relief measures, all process equipment must be sufficient to withstand the overpressure generated by internal explosions. At the same time, the connecting parts between the process equipment (such as pipes, flanges, etc.) should also have the same strength as the equipment itself; the connecting parts between high-strength equipment and low-strength equipment must be equipped with explosion-proof devices. 6.4.2 All powder discharge pipes and connecting pipes between different process equipment should be sufficient to withstand the overpressure generated by internal dust explosions. 6.5 Explosion relief
6.5.1 When the strength of the process equipment is not sufficient to withstand the pressure generated by a fully developed internal dust explosion, an explosion relief port must be set. The size of the explosion relief port should be based on GB/T15605 or dust explosion standard tests and actual inspections to ensure that the maximum explosion relief pressure that may be reached in the event of an accidental explosion does not exceed the maximum internal pressure that the container can withstand. 6.5.2 For process equipment with inline pipes, the generally recommended design indicators should be able to withstand an internal overpressure of at least 0.1MPa. 7 Prevention of secondary explosion
7.1 Prevent powder from escaping from production equipment
7.1.1 The joints, inspection doors, baffles, explosion vent covers, etc. of process equipment should be tightly closed to prevent powder from leaking into the workshop. 7.1.2 The pressure when there is powder in the process equipment should be lower than the environmental pressure outside the equipment. 7.2 Effective dust removal in special places
7.2.1 Effective safety dust removal measures must be taken in special places where dust leakage cannot be completely prevented (such as where powder enters and exits process equipment). 7.2.2 Effective protective measures must be taken in places where powder is manually loaded. 7.2.3 The place where packaging is carried out must be cleaned regularly. 7.3 Packaged powder products should be sent to a separate storage room as soon as possible. 437
7.4 Do a good job of routine cleaning
GB15577—1995
7.4.1 All production workshops and storage rooms that may accumulate dust should be cleaned in time. 7.4.2 It is forbidden to use compressed air for purging. 8 Personal protection and emergency education
8.1 Personal protection
8.1.1 Production personnel must use labor protection supplies in accordance with the relevant provisions of GB11651. 8.1.2 In places where inert gases are used in the process flow or toxic gases can be released, respiratory protection devices that can purify the air must be equipped. 8.1.3 In the workplace, it is strictly forbidden for production personnel to wear clothes made of chemical fiber fabrics close to their skin. 8.2 Rescue
8.2.1 Enterprises must prepare a rescue plan for dust explosion accidents and report it to the competent authorities for approval. 8.2.2 Under the close cooperation and guidance of the local fire department, all employees should be trained in fire fighting and rescue regularly. 9 Fire Fighting
9.1 It is forbidden to use fire fighting methods that can raise deposited powder to form dust clouds. 9.2 When extinguishing fire, a nozzle with good atomization effect must be used to ensure that the extinguishing agent can form dust clouds and liquid mist curtains. 9.3 The extinguishing agent should be correctly selected according to the physical and chemical properties of the dust. 9.4 If the burning material can generate explosive gas when in contact with water, it is forbidden to use water to extinguish the fire. 9.5 Fire fighting facilities and extinguishing agents must be available at all times. 10 Structure and layout of buildings (structures)
10.1 Process equipment with dust explosion hazards or buildings (structures) with explosive dust should be separated from each other and leave enough safety distance.
10.2 The building should be a single-story building, and the roof should be a light structure, or an "anti-explosion" structure can also be used. 10.3 Structure of multi-storey buildings
10.3.1 Multi-storey buildings should adopt frame structures. Where such structures cannot be used, explosion vents with sufficient area must be set on the wall.
10.3.2 If windows or other openings are used as explosion vents, it must be ensured that they can effectively vent explosions when an explosion occurs. 10.4 Dangerous process equipment in the factory should be located at a higher position in the building and close to the outer wall. 10.5 Equipment, beams, racks, etc. must have a surface structure that is easy to clean and should not have an upward splicing plane. 10.6 Evacuation routes
10.6.1 There must be a sufficient number of evacuation routes in the work area. The number and location of evacuation routes shall be determined by the design department and approved by the competent department. 10.6.2 Evacuation routes must be equipped with obvious road signs and emergency lighting. 10.7 Particularly dangerous process equipment should be set in open air places outside the building. Additional notes:
This standard was proposed by the National Technical Committee for Dust Explosion Prevention Standardization. This standard was drafted by the Safety and Environmental Protection Research Institute of the Ministry of Metallurgical Industry. The main drafters of this standard are Zhang Zhongqi, Zhou Hao, Feng Zhibin, Zhao Danli, Pang Qizhi, Li Xiaofei, and Wang Honghan.
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