GB 6514-1995 Safety regulations for painting operations - Painting process safety and ventilation purification
Some standard content:
GB 6514-1995
This standard is a general standard in the standard system of "Safety Regulations for Coating Operations", and other standards in this standard system are coordinated and matched with it.
This standard mainly refers to the National Fire Protection Association standard NFPA33-89 "Standard for Spray Application Using Flammable and Combustible Materials".
This standard is revised and merged into a standard based on GB6514--86 "Safety Regulations for Coating Operations - Paint Process Safety" and GB6515-86 "Safety Regulations for Coating Operations - Paint Process Ventilation and Purification", replacing the original two standards. This standard has made major adjustments to the original standard in terms of structure and arrangement. Some clauses have been added, deleted and modified in terms of content. This standard was proposed by the Ministry of Labor of the People's Republic of China. This standard is under the jurisdiction of the National Technical Committee for Safety Standardization of Coating Operations. The responsible drafting units of this standard are: Jiangsu Provincial Institute of Labor Protection Science and Technology, and Changzhou Paint Chemical Research Institute of the Ministry of Chemical Industry. The drafting organizations of this standard include: Beijing Labor Protection Science Research Institute, Shanghai Mechanical and Electrical Design Institute, and Yangzhou Qionghua Environmental Protection Engineering Equipment Co., Ltd.
The main drafters of this standard include: Jin Xuefang, Liu Jiyuan, Song Shide, Qin Jiajun, Lu Zheming, Sun Xinyan, He Tianping, and Wu Zhongzhi. 260
1 Scope
National Standard of the People's Republic of China
Safety Code for Painting Operations
Safety, ventilation and air clean-up for painting process
Safety, ventilation and air clean-up for painting process
This standard specifies the general safety and health technical requirements for painting process and its ventilation and purification. GB 6514-1995
Replaces GB 6514~6515--86
This standard applies to the design, installation and use of painting process and its ventilation and purification system. The production and development of coatings should also refer to it. The ventilation and purification of outdoor painting processes for large components such as bridges, buildings, large storage tanks, and ships can also be used as a reference. 2 Cited standards
The provisions contained in the following standards constitute the provisions of this standard through citation in this standard. When this standard was published, the versions shown were valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB3836-83 Explosion-proof electrical equipment for explosive atmospheresGB8978—88 Comprehensive sewage discharge standard
GB 12367—90
GB 12942-—91
GB 14443-93
GB 14444—93
GB14773—93
Safety regulations for painting operations
Safety regulations for painting operations
Safety regulations for painting operations
Safety regulations for painting operations
Safety of electrostatic spray painting process
Safety technical requirements for confined space operations
Safety technical regulations for coating drying rooms
Safety technical regulations for spraying rooms
Safety technical conditions for electrostatic spray guns and their auxiliary devicesSafety regulations for painting operations
GB50058—92Design specification for electrical installations in explosive and fire hazardous environmentsGBJ16—87
GBJ 57—83
GBJ 87—85
Code for fire protection of building design
Code for lightning protection of building
Code for noise control of industrial enterprises
Code for fire extinguisher configuration design of buildings
GBJ 140—90
TJ36—79
Sanitary standard for design of industrial enterprises
3 Definitions
This standard adopts the following definitions.
3.1 Painting process The entire process of paint application in painting operations. Including the mixing of paint, various methods of coating, drying or curing, grinding and puttying.
3.2 Painting operations Location of painting operations The internal area of a factory building or room specially set up for painting operations. Approved by the State Administration of Technical Supervision on December 25, 1995 and implemented on June 1, 1996
3.3 Painting area
GB 6514—1995
Areas where dangerous amounts of flammable and combustible vapors, paint mist, dust or accumulation of flammable residues exist due to painting operations. 3.4 Confined spaces
Refers to closed, narrow, poorly ventilated compartments with only 1 to 2 manholes, i.e., restricted entrances and exits, or poorly ventilated spaces with a depth greater than 1.2m and closed openings that only allow one person to enter and exit. 4 Scope of painting area
4.1 The painting area should generally include the following scope: a) the interior of the spray booth (powder spray booth) and the exhaust system connected to it, b) the enclosed internal space on the painting line; c) other places where paint is directly applied.
4.2 In addition to Article 4.1, areas where there are dangerous amounts of flammable and combustible vapors, paint mist, etc. during painting operations should be included in the scope of the painting area. Part I Paint Process Safety
5 General Requirements
5.1 Painting Workplace
5.1.1 Painting operations should be carried out in the painting workplace or in the designated painting area. 5.1.2 Painting workplaces should not be set up in public buildings such as cultural education, medical care, and residential buildings. Except for those that need to be painted for decoration of the above buildings.
5.1.3 Except for large components such as bridges, painting workplaces should generally not be set up in the open air. If they need to be set up, they should comply with the provisions of this standard. 5.1.4 There should be at least two entrances and exits to the painting workplace, and one exit must lead directly to the open air. 5.1.5 The door of the painting workplace should open outwards, and the width of the passage inside should not be less than 1.2m. 5.1.6 The workshop of the painting operation site is generally a single-story building or an independent workshop. If it is arranged in a multi-story building, it should be arranged on the upper floor of the building. If it is arranged in a multi-span workshop, it should be arranged in the outer span. 5.1.7 The fire hazard classification of painting operation production is shown in Table 1. Table 1 Fire hazard classification of painting operation production Type of coating
Coatings and organic solvents with flash point <28℃
Coatings and organic solvents, powder coatings with flash point ≥28℃ to <60℃ Paints with flash point ≥60℃
Fire hazard classification
5.1.8 The fire resistance level, fire protection distance, explosion prevention and safe evacuation measures of the painting operation site shall be implemented according to the production fire hazard category determined in Table 1 and the relevant provisions of GBJ16. 5.2 Hygiene in the painting workplace
5.2.1 The harmful substances in the air of the painting workplace should not exceed the maximum allowable concentration listed in Table 2. Those not listed in Table 2 should comply with the provisions of TJ36.
Xylene
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Table 2 Maximum allowable concentration of main harmful substances in the air of the painting workplace Substance name
Carbon disulfide (skin)
Toluene diisocyanate (skin)
Chromium trioxide, chromate, dichromate (converted to CrO:) Acetone
Butadiene
Organic mercury compounds (skin)
Turpentine
Epichlorohydrin (skin)
Ethylene oxide
Cyclohexane Ketone
Cyclohexane
Benzene (skin)
Styrene
Zinc oxide
Phenol (skin)
Manganese and its compounds (converted to MnO2)
Trichloroethylene
Solvent gasoline
Ethyl acetate
Butyl acetate
Carbon tetrachloride (skin)
Paint dust
Maximum allowable concentration
1The maximum allowable concentration in the table is the value that the harmful substances in the air at the operator's workplace should not exceed. The workplace refers to the place where the operator operates, observes and manages the production process and stays frequently or regularly. If the production operation is carried out in many different places in the workplace, the entire place is considered as the workplace.
2Those marked with "(skin)" are toxic substances that are easily absorbed through the skin in addition to being absorbed through the respiratory tract. 3 The inspection methods for the toxic substances listed in this table shall be carried out in accordance with the national standards for the analysis methods of the corresponding toxic substances. If no national standards have been promulgated, the analysis methods of the industry standards shall be followed. www.bzxz.net
GB 6514--1995
5.2.2 The summer air temperature at the work place of the workers in the painting workplace shall comply with the provisions of Article 49 of TJ36. 5.2.3 The winter air temperature at the work place of workers in the painting workplace shall comply with the provisions of Article 55 of TJ36. 5.2.4 The determination of the hygienic characteristic level of the painting workplace is shown in Table 3. Table 3 Hygienic characteristic level of the painting workplace
Painting operation method
Air spray, airless spray operation
Painting operation containing lead and chromium pigments
Painting operation in a limited space
Painting operation by other methods
Hygienic characteristic level
5.2.5 The production sanitation room in the painting workplace shall be implemented according to the relevant provisions of TJ36 based on the hygienic characteristic level determined in Table 3. 5.3 Noise in the painting workplace
5.3.1 The noise source components such as fans, water pumps, motors and their air ducts and water pipes used in the painting process shall adopt noise elimination and vibration isolation measures to make the noise at the operating position meet the provisions of GBJ87. 5.4 Electrical equipment and ignition sources
5.4.1 Electrical equipment, open flames and ignition sources in the painting workplace shall comply with the provisions of this chapter. 5.4.2 Electrical equipment is generally not installed in the painting area. If it is necessary to install it, it shall comply with the provisions of GB50058. 5.4.3 The explosive gas environment in the painting area is classified as Zone 1 hazardous area. 5.4.4 If the entire painting workplace is classified as the painting area, the space within the vertical and horizontal distance of 3m outside the doors and windows leading to the open air is classified as Zone 2.
5.4.5 For closed or semi-closed painting process equipment, the space within the vertical and horizontal distance of 3m outside the open surface is classified as Zone 2. 5.4.6 The partition wall between the adjacent workshops of the painting area shall be a solid wall of non-combustible body. The door on the partition wall shall also be a non-combustible body. 5.4.7 The classification of hazardous areas of adjacent places separated from the painting area by partition walls with doors is shown in Table 4. Table 4 Division of hazardous areas of explosive gas atmospheres adjacent to the painting area Adjacent areas separated by partition walls with doors
Painting area
One partition wall with doors
Two partition walls with doors
(through corridors or suites)
Non-explosion hazardous areas
The distance between the door frames of the two partition walls should not be less than 2 m Only one partition wall with doors, the horizontal distance outside the door is within 7.5m as Zone 2. 5.4.8
When it is necessary to heat flammable substances such as paint, hot water, steam and other heat sources should be used. It is strictly forbidden to use stoves, electric stoves, gas stoves and other open flames. 5.4.9
Cotton yarn, rags and other items stained with flammable substances such as paint should be placed in a metal box (barrel) with a lid, and removed and handled during the shift. It is strictly forbidden to throw them randomly. 5.4.10
The explosive dust environment in the painting area is classified as 11 hazardous areas. 5.4.11
There should be safety signs prohibiting fireworks at the entrance of the painting area and other places where open flames and sparks are prohibited. 5.4.12
5.4.13 When the painting equipment, storage containers, ventilation ducts and material conveying systems are shut down for maintenance, if open flame operations such as electric welding, gas welding, blowtorches, etc. are required, they should be reviewed and approved by the enterprise's safety and technology department, and the fire safety system should be strictly implemented and the safety operating procedures should be followed. 5.4.14 Firefighting equipment should be installed near the painting area in accordance with the provisions of GBJ140, and regularly inspected to maintain effective status. 5.5 Preparation and transportation of paint
5.5.1 Paint and auxiliary materials
5.5.1.1 When paint and auxiliary materials enter the factory, they should have complete, accurate and clear product packaging marks, inspection certificates and instructions. 5.5.2 Coating preparation
5.5.2.1 Coating preparation should be done in a dedicated paint preparation room, which should comply with the provisions of 5.4.1, 15.1 and 15.5. 5.5.2.2 When the amount of solvent-based coating used is small (generally less than 20 kg), it is allowed to prepare it on site in the painting area. 264
5.5.3 Coating transportation and treatment
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5.5.3.1 Pipes for conveying coatings, solvents and thinners should be well connected and no leakage is allowed. 5.5.3.2 When there is no centralized material supply system, the remaining coatings and auxiliary materials should be returned to the paint room or poured into a closed container after the work is completed. 5.5.3.3 Coatings and auxiliary materials and their containers that cannot be used any more should be placed in designated waste dumps and properly disposed of in a centralized manner. 5.5.3.4 Waste liquid coatings and auxiliary materials are strictly prohibited from being poured into the sewer. 5.5.3.5 A certain amount of paint and auxiliary materials are allowed to be stored in the painting workplace, but the amount should not exceed the amount used in a single shift. 6 Air spraying
6.1 Except for very large workpieces, air spraying should be carried out in the spray room. 6.2 The safety and technical requirements of the spray room should comply with the provisions of GB14444. 6.3 The workplace with multiple spray rooms should be separated from other adjacent non-painting workplaces by non-combustible partition walls. 7 Airless spraying
7.1 Except for very large workpieces, airless spraying should be carried out in the spray room. 7.2 The safety and technical requirements of the spray room should comply with the provisions of GB14444 and 6.3. 7.3 The booster cylinder, components, pipelines, valves, etc. in the airless spraying device should be subjected to hydraulic pressure test and air tightness test according to the provisions of high-pressure pipe fittings. In addition to passing the above tests, the minimum radius of curvature of the matching high-pressure hose should not be less than 2.5 times the diameter of the hose when the pipeline is arranged. 7.4 The spray gun for airless spraying shall be equipped with a self-locking safety device, and the spray gun shall be able to self-lock during spraying intervals. 7.5 The air inlet end of the compressed air-driven airless spray device shall be equipped with a pressure-limiting safety device, and an overpressure safety alarm device and a grounding device.
7.6 Under no circumstances should the nozzle of the pressurized airless spray device be aimed at the human body, power supply, or heat source, nor should the pressure be tested with the palm of the hand. 8 Electrostatic spraying
8.1 The safety and technical requirements of the electrostatic spraying process shall comply with the provisions of GB12367. 8.2 Electrostatic spraying room
8.2.1 Electrostatic spraying shall be carried out in the electrostatic spraying room. 8.2.2 The safety and technical requirements of the electrostatic spraying room shall comply with the relevant provisions of GB14444 and GB12367. 8.2.3 The entrance and exit of the electrostatic spraying room should be equipped with a steel Class A fireproof door and a door closer. 8.2.4 The door of the electrostatic spray booth should be interlocked with the power supply of the electrostatic generator to cut off the power when the door is opened. 8.3 High-voltage electrostatic generator
8.3.1 The power socket of the high-voltage electrostatic generator should be a dedicated structure. The grounding terminal in the socket should be connected to the dedicated ground wire. The neutral wire should not replace the ground wire.
The high-voltage output of the high-voltage electrostatic generator and the high-voltage cable connection terminal should be equipped with a current limiting safety device, and the shielding wire of the high-voltage cable should be firmly connected to the dedicated ground wire.
8.3.3 The high-voltage electrostatic generator should be equipped with a control and protection system to automatically cut off the power supply when the working system fails or is overloaded. 8.4 Electrostatic spray gun and paint supply device
8.4.1 The safety technical requirements of the electrostatic spray gun should comply with the provisions of GB14773. 8.4.2 The safety distance between the electrostatic spray gun and other conductors and the workpiece should be at least twice the maximum distance of the spark discharge under the voltage.
8.4.3 The minimum distance between the electrostatic spray gun and the grounded equipment and grounded parts should be greater than three times the distance between the electrostatic spray gun and the workpiece. 8.4.4 No other conductors and cables should be set within 800mm around the paint supply pipeline, and safety signs should be hung. 8.4.5 High-voltage cables used for electrostatic spraying should be shielded. High-voltage cables without shielding layers should be suspended and installed, and the minimum distance from the surrounding distribution lines and conductors should be 800mm when the electrostatic voltage is 100kV or below. 265
9 Powder electrostatic spraying
9.1 Powder spraying room and powder recovery device
GB6514--1995
9.1.1 Powder electrostatic spraying should be carried out in a powder spraying room that complies with the provisions of Chapter 18, and the operator should operate outdoors. 9.1.2 The body of the powder spraying room must be made of flame-retardant or non-combustible materials, with smooth inner walls and no bumps. 9.1.3 The maximum concentration of dust in the exhaust duct at the powder spray booth outlet should not exceed 50% of its lower explosion limit concentration. If the lower explosion limit concentration is unknown, the maximum concentration should not exceed 15g/m. 9.1.4 The metal frame of the powder spray booth and the workpiece should be reliably grounded. 9.1.5 Fire alarm devices and automatic fire extinguishers should be installed in the automatic spraying powder spray booth. The alarm device should be interlocked with shutting off the compressed air, cutting off the power supply, starting the automatic fire extinguisher, and stopping the workpiece transportation. 9.1.6 For the assembly line operation of automated production, interlocking control should be adopted between the powder spray booth and the recovery device to prevent mutual explosion transmission. When there is a fire at one end, the connection channel should be able to be quickly and automatically cut off. 9.1.7 Pressure relief devices should be installed in both the powder spray booth and the powder recovery device. 9.1.8 The setting and installation of the powder conveying pipeline should avoid the formation of static electricity accumulation. 9.2 Spraying device and powder supply device
9.2.1 The high-voltage electrostatic generator should be equipped with an automatic control system with constant field strength powder spraying. Under the set working conditions, if the distance between the spray gun and the workpiece changes within the permitted range, the current value should not exceed 10% of the set value. 9.2.2 After the high-voltage electrostatic generator and connecting cable are matched with the powder spray gun, when the voltage is adjusted to the maximum value, there should be no sparks when the short circuit to the ground. 10 Electrophoretic painting
10.1 The electrophoretic tank should be equipped with partition facilities and ventilation and exhaust devices. And it should be equipped with a safety or protective interlock device to prevent personnel from electric shock accidents.
10.2 The rectifier system of electrophoretic painting should be separately installed in the enclosure facilities. Operation and maintenance should be handled by a dedicated person. 10.3 The wastewater to be discharged by electrophoretic painting should be purified, and the purified wastewater should comply with the provisions of GB8978. Flood coating, shower (flow) coating, and ling coating
Dip coating, shower coating, and roller coating production lines should generally be equipped with partition protection facilities. 11.1
The design and operation of dip coating, shower coating, and roller coating production lines should ensure safe operation. 11.2
11.3Fire alarms and automatic fire extinguishers should be installed in the workplaces of dipping, pouring and rolling coating. 11.4Paint collection devices should be installed where paint drips from workpieces, and local exhaust devices should be installed. 11.5Workpieces entering the drying room should comply with the provisions of 14.4. 11.6Ventilation and exhaust devices should be installed in dipping tanks, pouring and rolling coating devices. The ventilation and exhaust devices of pouring coating should be automatically interlocked with the paint supply pump. 11.7The dipping tank should be equipped with a tank cover made of non-combustible materials. When the dipping tank is not working, the tank cover should be able to be tightly covered. 11.8When the dipping tank and the drying room share the same factory building, the distance between them should not be less than 7.5m. Except for the diffused paint tank of water-based paint. 11.9Large dipping tanks and pouring paint devices should have underground storage tanks outdoors. When not working, the paint liquid should be placed in the storage tank. In the event of a fire, the paint liquid should be quickly discharged into the storage tank. Except for water-based paint. 12 Manual painting
12.1 Manual painting refers to manual brushing, rolling, finger painting, scraping putty, grinding, etc. 12.2 Manual painting work sites should be equipped with ventilation devices and demarcated painting areas. : 12.3 When manually painting large fixed equipment, local exhaust devices should be installed. 12.4 When manually brushing, rolling, and applying, the operator should wear solvent-resistant gloves and masks. 12.5 When dry grinding, the operator should wear a dust mask. 266
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12.6 Solvents used to clean painting tools should be solvents with low toxicity and low volatility. 13 Painting operations in confined spaces
13.1 Painting operations in confined spaces refer to the decoration of confined spaces themselves or fixed equipment and facilities located in confined spaces. In addition, confined spaces should not be used as painting work sites. 13.2 Paint stripping operations in confined spaces shall also comply with the provisions of this chapter. 13.3 When there is only one entrance and exit in a confined space, an additional process opening should be opened. 13.4 The safety and technical requirements for confined space operations shall comply with the provisions of GB12942. 14 Drying and curing
14.1 Painting equipment should not be used alternately for drying and curing of paint. The following situations may be excluded. 14.1.1 If the painting equipment is also used for natural air drying and curing of paint, the air temperature for drying and curing should not be higher than the ambient temperature, and the ventilation system should comply with the provisions of 15.5. 14.1.2 Intermittent painting operations, including automotive recoating spray booths, may be used alternately for drying and curing of paint when they comply with the relevant provisions of this standard and the following provisions: a) The inner surface of the painting area (especially the ground) should be kept free of flammable residues; b) A temperature safety protection device should be installed, and the heating device should be automatically turned off when the set temperature exceeds 93°C. c) Paint mist shall not fall on fixed radiant heating devices in the painting area. d) Interlocking devices shall be provided for the painting equipment, drying equipment and ventilation system. The painting equipment shall not be operated when the heating equipment is in operation or when there are portable radiant heaters in the painting area. The ventilation system shall always be in operation when the painting or drying equipment is in operation and shall comply with the provisions of 15.3 and 15.5.
e) Other flammable materials shall not be brought into the painting area. 14.2 Thermal systems that use open flames or may produce sparks during drying shall not be installed in the painting area. They may be installed near the painting area when equipped with an interlocking ventilation system designed as follows: a) the drying space must be thoroughly ventilated before the heating system is started; b) the provisions of 15.5 shall be complied with at any source of ignition; c) the heating system can be automatically shut down in the event of ventilation failure. 14.3 Paint collection devices shall be provided in the leveling section of the painting operation and local exhaust devices shall be provided. 14.4 There shall be no residual paint dripping from the workpieces entering the drying room. 14.5 The safety and technical requirements of the drying room shall comply with the provisions of GB14443. 14.6 The naturally dried painted workpieces shall be placed in a place approved by the enterprise's safety and technical department. If it is indoors, it should be a special room; if it is outdoors, there shall be no open flames or sparks within 5m around. Part 1 Ventilation and purification of painting process
15 General requirements
15.1 In order to prevent harmful substances such as gas, smoke, and dust from escaping indoors, the painting process should first adopt local exhaust. When it is impossible to use local exhaust or the use of local exhaust still cannot meet the requirements of 5.2.1, comprehensive ventilation should be adopted. 15.2 When the pollutants containing harmful gases, smoke, and dust discharged by the exhaust system affect the air quality of the surrounding environment of the workshop or the nearby residential areas, purification treatment, recycling or comprehensive utilization measures should be taken before they are discharged into the atmosphere to meet the national comprehensive emission standards for air pollution and the local total emission standards of relevant provinces and cities. 15.3 At the beginning of the painting operation, the fan should be turned on first, and then the spraying equipment should be started. At the end of the operation, the spray equipment should be turned off first, and then the fan. When the ventilation system stops operating or fails, the automatic control device should immediately cut off the power supply and send a signal to the operator. 267
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15.4 Industrial enterprises may choose to adopt purification measures such as activated carbon adsorption, catalytic combustion, thermal combustion or liquid absorption according to process conditions and pollution conditions to ensure that the air quality in the workplace and the surrounding environment meets the requirements of Articles 5.2.1 and 15.2. 15.5 In ventilation and purification equipment and systems, the volume concentration of flammable and explosive gases and vapors should not exceed 25% of their lower explosion limit concentration. The dust concentration should not exceed 50% of its lower explosion limit concentration. 16 Local exhaust
16.1 The local exhaust system for painting operations should be equipped with devices to remove paint mist or recover dust. 16.2 The exhaust hood for local exhaust should meet the following requirements: a) The exhaust hood should be set at the pollution source;
b) The air suction direction of the exhaust hood should prevent harmful substances from flowing through the operator's breathing zone; c) The form, size and position of the exhaust hood should be determined according to the volatility and specific gravity of the discharged pollutants and the operation method of painting. 16.3 The process equipment and process that emit harmful substances should be sealed first. When it is impossible to use a closed or semi-closed device, a side suction type, an umbrella type, a blowing and suction type exhaust hood or a slot side exhaust hood should be used according to production conditions and ventilation effects. 16.4 Mechanical exhaust systems that frequently discharge harmful gases should be equipped with bypass exhaust ducts. So that harmful gases can continue to be discharged when the ventilation equipment stops operating.
17 Ventilation in spray booths
17.1 The spray booth should be equipped with mechanical ventilation and paint mist removal devices. 17.2 The ventilation of the spray booth shall comply with the provisions of Chapter 4 of GB14444-93. 18 Ventilation of the powder spray booth
18.1 The powder spray booth shall be equipped with mechanical ventilation and powder recovery devices. 18.2 The purification efficiency of the powder purification and recovery device in the powder spray booth shall ensure that the surrounding environment is not polluted. 18.3 The powder outlet of the powder purification and recovery device shall take measures to prevent dust from flying to ensure that the maximum allowable concentration of dust in the working environment air complies with the provisions of 5.2.1.
18.4 The exhaust outlet of the powder spray booth shall be consistent with the direction of powder diffusion as much as possible. 18.5 The wind speed at the opening of the powder spray booth should be 0.3~0.6m/s, and the opening area includes the operating hole, catenary entrance and exit, etc. 18.6 The workplace where the powder spray booth is set up should be prevented from interfering with the air flow. 18.7 The inner wall of the powder spray booth and the conveying pipeline should be smooth and have sufficient wind speed to avoid dust accumulation. 18.8 The fan in the powder spraying room should be interlocked with the spray gun to cut off the power when there is no wind. 18.9 When the purified gas discharged by the powder purification and recovery device is directly returned to the operation area, its dust concentration should comply with the provisions of 21.3. 19 Drying room ventilation
The drying room ventilation should comply with the provisions of Article 5.1 of GB14443-93. 20 Comprehensive exhaust
20.1 When the painting process and equipment are not fixed and local exhaust cannot be used, comprehensive exhaust should be used in the painting area. 20.2 In special circumstances, for large-area painting operations, due to the wide emission surface, organized comprehensive exhaust should be used to prevent the operator from being in the polluted airflow.
20.3 When the vapors of several solvents (aromatic hydrocarbons, alcohols, acetates, etc.) are released into the air at the same time, the comprehensive ventilation volume should be calculated according to the sum of the air volumes required to dilute each gas to the maximum allowable concentration. 20.4 The amount of harmful gases dispersed into the painting workplace, when there is no process design data or it is impossible to calculate by calculation, the air exchange volume required for comprehensive ventilation can be determined according to the measured data or empirical data of similar workshops and the number of ventilation times of the room. 268
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20.5 When the comprehensive exhaust system exhausts harmful gases and vapors, its air intake should be located in the area with the highest concentration of harmful substances. The flow direction of the airflow organization of the comprehensive exhaust system should avoid harmful substances flowing through the operator's breathing zone. 21 Air supply system
21.1 Painting workplaces with local exhaust or comprehensive exhaust should be naturally replenished; when natural replenishment cannot make the harmful substances in the indoor air meet the requirements of 5.2.1 or the room temperature is too low to affect production, a mechanical air supply system should be installed. 21.2 The painting workplace is in a dusty environment, and the mechanical air supply system should be equipped with an air filter. 21.3 The content of harmful substances in the air delivered to the workshop by the mechanical ventilation system shall not exceed 30% of the maximum allowable concentration specified in Table 2. 21.4 The location of the air inlet of the mechanical ventilation system shall meet the following requirements: a) It shall be located in a place with clean outdoor air; b) It shall be located downwind of the wind direction with the lowest frequency throughout the year at the exhaust outlet, and should be 2m lower than the exhaust outlet; c) The bottom of the air inlet shall not be lower than 2m from the outdoor floor; d) If the air inlet and the exhaust outlet must be located at the same height above the roof, the horizontal distance between them shall not be less than 10 times the pipe diameter and shall not be less than 10 ㎡.
e) When harmful substances in the workplace are discharged through the skylight, the air inlet should not be set on the roof of the workplace. 21.5 The air delivered by the mechanical ventilation system shall be delivered to the work area or the work place where workers often stay. 21.6 Reasonably organize the air flow of air intake and exhaust to prevent air containing harmful substances from flowing through the work area that does not contain or contains only a small amount of harmful substances. 22 Ventilation Ducts
22.1 The ventilation system of the painting workplace should be openly installed; the air inlet and exhaust outlet should be equipped with wire mesh and should be directly connected to the outdoors where sparks cannot fall; the regulating valve and other movable parts on the air duct should be made of non-flammable materials determined by the design department. 22.2 The lightning protection measures for the exhaust duct should comply with the provisions of GBJ57. 22.3 The ventilation duct used in the painting process should not be connected to the ventilation duct used in other processes or the smoke window flue for conveying combustible materials. 22.4 For ventilation systems that need to adjust the air volume, air volume measurement holes should be set at the cross-section where the air flow is relatively stable in the air duct. 22.5 In order to observe the air temperature in the air duct of the high-temperature exhaust system, temperature measurement holes and thermometers should be set on the air duct. 22.6 Effective measures should be taken for the air inlet and exhaust devices and air inlet and exhaust ducts to prevent the deposition of pollutants, and they should be cleaned regularly. 22.7 When the temperature of the air delivered by the ventilation and purification equipment and pipelines increases or decreases significantly, or when freezing is likely, insulation, heat preservation or antifreeze measures should be taken.
22.8 For exhaust pipes with a diameter of less than 300mm, inspection holes should be set every 3m or so during the laying length, but the distance between the inspection holes on large-diameter air ducts can be increased. Inspection holes should be set at the bends of the pipes. 22.9 The setting of the air ducts of the ventilation system should be tight, airtight, and easy to disassemble and clean. 22.10 The air duct bracket should be firm and reliable, and the bracket should be able to withstand the weight of the air duct itself and the dynamic load of the air duct. 22.11 For air ducts that transport high-temperature gases, when their surface temperature is 80~~200℃, they should be kept at a distance of more than 0.5m from the flammable structures and equipment of the building, and at a distance of more than 0.25m from the fire-resistant structures and equipment. 22.12 The horizontal distance between the exhaust duct with a wall temperature higher than 80℃ and the duct conveying flammable and explosive gas, steam, and dust shall not be less than 1m. The duct conveying hot gas shall be laid on the duct conveying gas at a lower temperature. The duct conveying gas above 80℃ or flammable and explosive gas shall be made of non-combustible body.
22.13 Electric wires, gas pipes, heat pipes and pipes conveying liquid fuel shall not be installed on the wall of the ventilation duct or pass through the duct. 22.14 When the duct passes through a flammable roof or wall, the duct shall be covered with fire-resistant materials or the duct shall be emptied around. 22.15 The ventilation duct shall not pass through the fire wall. If it must pass through the wall, a fire damper shall be installed at the passing point. The duct and its insulation material within 2m on both sides of the fire wall shall be made of non-combustible body. The gap through which the duct passes shall be filled with non-combustible body. 22.16 Dry dust collectors and filters used to filter explosive dust should be arranged in the negative pressure section of the system. 22.17 The positive pressure section of the local exhaust system for exhausting explosive gas and vapor mixtures should not pass through other rooms. 269
23 Fan room
GB6514—1995
23.1 The fan room should be separated from other rooms and should not be used for other purposes. 23.2 Air supply and exhaust equipment should not be arranged in the same fan room. Exhaust equipment should not be arranged in the same fan room as ventilation equipment for other rooms without explosion hazards.
23.3 When determining the fan air volume, the air leakage of the duct and equipment should be added. Generally, 5%~10% is added for the supply and exhaust system; 10%~15% is added for the dust removal system.
23.4 When determining the fan air pressure, the pressure loss additional value should also be considered. Generally, the supply and exhaust system shall add 10% to 15%; the dust removal system shall add 15% to 20%.
24 Activated carbon adsorption purification
24.1 To purify the room temperature organic gas discharged from the painting operation, the activated carbon adsorption method can be used, and the desorption method can be steam desorption, hot gas desorption, etc. The concentration of harmful gases after adsorption shall comply with the provisions of 15.2. 24.2 A thermometer, a temperature alarm and a fire-proof water pipe shall be installed in the adsorber. When the temperature of the activated carbon layer reaches 150°C, an alarm shall be sounded immediately, and the fan and the adsorber inlet valve shall be closed. If the temperature continues to rise, the water pipe valve shall be opened and water shall be drained to cool down. 24.3 A pressure gauge and a pressure relief pipe (or safety valve) shall be installed on the top of the adsorber. 24.4 A gas sampling pipe shall be installed at the gas outlet of the adsorber to regularly measure the gas concentration. When the concentration of harmful gases exceeds the specified value, the adsorber shall be stopped and desorption shall be performed.
24.5 A pressure gauge should be installed on the air duct at the gas outlet of each adsorber to measure and adjust the exhaust volume passing through each adsorber. 24.6 A filter to remove impurities, dust, etc. should be installed in the pipeline before the fan. The filter should be equipped with a pressure gauge. When the resistance of the filter exceeds the maximum resistance allowed by the design, it should be cleaned immediately. 24.7 A bypass exhaust duct should be installed in front of the filter. When the adsorption purification system fails or the work is completed, the exhaust duct valve should be opened immediately to temporarily exhaust the harmful gas to prevent poisoning or explosion accidents caused by excessive concentration. 24.8 A flame arrester should be installed after the filter. When steam desorption is used, a safety exhaust pipe should be installed on equipment such as oil-water separators, oil storage tanks, and gas-liquid separators.
24.9 A thermometer, pressure gauge, steam flow meter and steam pressure reducing valve should be installed on the steam pipeline used for desorption. 24.10 A thermometer, flow meter and gas concentration alarm should be installed on the hot gas pipeline used for desorption. 24.11 All equipment and wiring methods that may generate static electricity in the adsorption purification system shall comply with the provisions of GB3836. 24.12 After the construction of all equipment is completed, they shall be subjected to pressure resistance test. Only when they fully meet the requirements can they be installed. 25 Catalytic combustion purification
25.1 The concentration of harmful gases after catalytic combustion shall comply with the provisions of 15.2. 25.2 The catalytic combustion device shall be equipped with a thermometer or gas concentration alarm. When the temperature or gas concentration reaches the maximum limit, the alarm shall be immediately sounded, the preheating heater shall be turned off, the bypass exhaust pipe shall be opened, and the workpiece shall be stopped from entering the spraying system. The catalytic combustion equipment shall be equipped with a pressure relief device. 25.3 The preheating chamber shall be equipped with a temperature alarm or indicating device. When the design maximum temperature is exceeded, a signal shall be immediately issued and heating shall be stopped at the same time. The heating system shall be interlocked with the ventilation system. If the ventilation system fails, the heating system shall be automatically shut down. 25.4 When purifying organic waste gas containing sticky substances, a filter must be installed before the catalytic combustion device. When the filter resistance reaches the maximum resistance allowed by the design, it shall be handled immediately. 25.5 The installation and operation of the bypass exhaust duct in front of the catalytic combustion device shall comply with the provisions of 24.7. 25.6 A flame arrester shall be installed between the coating drying room and the catalytic combustion equipment. 25.7 The temperature of the gas passing through the fan shall be lower than the specified temperature of the fan. A regulating valve shall be installed in front of the fan to make the air volume adjustable. 25.8 The heat insulation and thermal insulation materials of the catalytic combustion equipment system shall be made of non-combustible bodies. 25.9 The equipment, electronic control devices and wiring methods used in the catalytic combustion system shall comply with the provisions of 24.11. 270
GB6514-1995
25.10 The joints between the catalytic combustion device and the pipeline shall be tight and leak-proof, and an airtightness test shall be carried out after installation. 25.11 When the catalytic combustion device starts working, the fan should be started for 2~3 minutes to discharge the organic gas accumulated in the equipment and the air duct, and then the preheating equipment should be started. When the work is terminated, the preheating equipment should be turned off first, and the fan should continue to run, and then turned off after the remaining organic gas is exhausted. Finally, open the main electrical switch and open the bypass exhaust duct valve. 26 Thermal combustion purification
26.1 The preheating chamber should be equipped with a temperature alarm. When the temperature exceeds the designed maximum temperature, the alarm will be immediately sounded, the heating will be stopped at the same time, and the bypass exhaust duct valve will be opened. The heating device should be interlocked with the fan, and the heat source should be automatically cut off when the fan stops running. 26.2 The concentration of combustion products in the combustion chamber should comply with the provisions of 15.2. The combustion chamber should be equipped with a temperature alarm. When the gas temperature after combustion exceeds the designed maximum temperature, the alarm will be immediately sounded, the heating system will be turned off, the workpiece will be stopped from continuing to enter the painting system, and the bypass exhaust duct valve will be opened at the same time. 26.3 A flame arrester should be installed on the pipeline in front of the thermal combustion device, and a pressure relief device should be installed on the combustion device. 26.4 The setting and operation of the bypass exhaust pipe in front of the thermal combustion device shall comply with the provisions of 24.7. 26.5 The boiler or production furnace that also serves as a waste gas treatment should be used all year round. The amount of waste gas treated should be less than the blast volume of the boiler or furnace and should not affect the normal operation of the boiler or furnace. 26.6 When designing a thermal combustion device, it should be considered that the substances contained in the waste gas will not dirty the heat transfer surface of the heat exchanger or boiler; if these substances are contained, a filter should be installed to remove them, and it should be cleaned in time when the maximum resistance allowed by the design is exceeded. 26.7 The heat insulation and thermal insulation materials used in the thermal combustion system shall comply with the provisions of 25.8. 26.8 The fan setting of the thermal combustion device shall comply with the provisions of 25.7. 26.9 The installation of thermal combustion devices and pipelines shall comply with the provisions of 25.10. 26.10 The equipment, pipelines, electrical equipment and wiring methods that may generate static electricity in the thermal combustion system shall comply with the provisions of 24.11. 26.11 The operating procedures for starting and stopping the operation of the thermal combustion device shall comply with the provisions of 25.11. 27 Liquid absorption purification
27.1 The concentration of harmful gases after liquid absorption purification shall comply with the provisions of 15.2. 27.2 The treatment device for waste absorption liquid shall be designed at the same time as the absorption device and ensure safety. 27.3 The liquid pump in the absorption purification system shall be interlocked with the fan. At the beginning of work, the liquid pump should be turned on first, and then the fan; at the end of work, the fan should be turned off first, and then the liquid pump.
27.4 The equipment and pipelines that may generate static electricity in the absorption purification system shall comply with the provisions of 24.11. The liquid pump used shall be explosion-proof. 27.5 The purification room shall meet the requirements of fire prevention and explosion prevention. 27.6 The installation of absorption purification equipment and pipelines shall comply with the provisions of 25.10. 271
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