GB 7692-2012Safety code for painting - Safety, ventilation and air clean-up for pretreatment process of painting (English PDF)

Note Note on the printed English title

The English title on the cover of the document is printed as Safety code for painting-Safety, ventilation and air clean-up for pretreatment process of painting, but the separator between the first two words of the subtitle is set with the Chinese enumeration comma rather than an ordinary comma. The wording has not been altered; only that separator has been rendered as a comma so that the title can be reproduced in Latin typography.

Foreword Foreword

The foreword states that, with the exception of 6.2.3, 6.2.5, 6.3.3, 6.3.4.3 and 6.3.5, all the technical content of the standard is mandatory, and that the standard was drafted according to the rules of GB/T 1.1-2009.

The standard is one of the Safety code for painting series of national standards, of which twelve had been issued: GB 6514-2008, Safety of the painting process and its ventilation and air clean-up; GB 7691-2003, General rules for safety management; GB 7692-2012, Safety of the pretreatment process of painting and its ventilation and air clean-up; GB 12367-2006, Safety of the electrostatic spray painting process; GB 12942-2006, Technical requirements for safety of work in confined spaces; GB/T 14441-2008, Terminology; GB 14443-2007, Technical requirements for the safety of coating drying rooms; GB 14444-2006, Technical requirements for the safety of spray painting booths; GB 14773-2007, Technical conditions for the safety of electrostatic spray guns and their auxiliary devices; GB 15607-2008, Safety of the powder electrostatic coating process; GB 17750-2012, Safety of the dip coating process; GB 20101-2006, Technical requirements for the safety of organic waste gas clean-up installations.

The main technical changes with respect to GB 7692-1999 are listed as: references to national standards added, removed and updated; the definition of the pretreatment process of painting improved; the definition of confined space and the content of table 1 of the former standard deleted; 5.2.8 and 5.2.9 of the former standard merged; clause 9 on the steel pretreatment line deleted, together with 9.4, 9.5 and 9.6, with editorial changes to the retained content; a provision added requiring operators to wear eye protection and to keep an adequate safety distance from one another; the way the range of values for the volume of the shot blasting room in table 3 of the former standard is presented improved; some provisions of the former standard revised and consolidated; the structure of the whole standard adjusted.

The standard was proposed by the State Administration of Work Safety and is under the administration of the Subcommittee on Painting of the National Technical Committee on Work Safety Standardization (SAC/TC 288/SC 6).

Relationship Relationship to previous standards

The cover carries the indication that this standard replaces GB 7692-1999.

The foreword adds that the previous editions of the standards replaced by this document were issued as GB 7693-1987 and as GB 7692-1987 and GB 7692-1999.

1 Scope

This standard lays down the general safety and technical requirements for the pretreatment process of painting and for its ventilation and air clean-up.

This standard applies to the design, the installation, the acceptance and the use of the pretreatment process of painting and of its ventilation and air clean-up systems.

2 Normative references

The documents listed below are indispensable for the application of this document. For dated references, only the edition cited applies; for undated references, the latest edition, including all amendments, applies.

GB/T 2493 Test method for rotation of grinding wheels; GB 2494 Bonded abrasives - Safety requirements; GB 2894 Safety signs and guideline for the use; GB/T 3608 Classification of work at height; GB/T 3805 Extra-low voltage (ELV) - Limit values; GB 3883.1 Safety of hand-held motor-operated electric tools - Part 1: General requirements; GB 4053.3 Safety requirements for fixed steel ladders and platforms - Part 3: Industrial guard-rails and steel platforms; GB 6514-2008 Safety code for painting - Safety, ventilation and air clean-up for painting process; GB 8978 Integrated wastewater discharge standard; GB/T 11651 Code of practice for selection of personal protective equipment; GB 12942 Safety code for painting - Technical requirements for safety of work in confined spaces; GB/T 14441-2008 Safety code for painting - Terminology; GB 14443 Safety code for painting - Technical requirements for the safety of coating drying rooms; GB 14444 Safety code for painting - Technical requirements for the safety of spray painting booths; GB 16297 Integrated emission standard of air pollutants; GB 20101 Safety code for painting - Technical requirements for the safety of organic waste gas clean-up installations; GB 50016 Code for fire protection design of buildings; GB 50058 Code for design of electrical installations in explosive and fire hazardous environments; GB 50140 Code for design of extinguisher distribution in buildings; JB/T 7992 Bonded abrasives - Test methods for appearance, dimensional and form tolerances.

In the printed list, GB 3883.1 is cited with the part number written out in Chinese characters, while the neighbouring citation of GB 4053.3 uses a numeral for the same purpose. The inconsistency belongs to the original document.

3 Terms and definitions

The terms and definitions given in GB/T 14441-2008 and the following apply to this document.

3.1 Pretreatment process of painting. The whole sequence of operations carried out in a painting operation before the coating material is applied, comprising rust removal, degreasing, chemical pretreatment, dust removal and removal of old paint. It can be divided into mechanical pretreatment, by spraying, shot blasting or abrasive grinding with pneumatic tools, and chemical pretreatment and organic solvent treatment, by degreasing, pickling, neutralising, surface conditioning, phosphating, passivating, anodising, silane treatment, rinsing and similar operations.

3.2 Location of pretreatment operation. The site set aside for pretreatment work and the specific space around it.

3.3 Pretreatment area. The area where, because of the pretreatment work, hazardous quantities of flammable and combustible vapours, mists of various chemical substances, dust, or accumulated combustible or corrosive residues are present.

4 Extent of the pretreatment area

4.1 The pretreatment area for painting shall in general include the following: the inside of the body of mechanical spraying and shot blasting rooms and the shot collecting, lifting and dust removal systems connected to them; the process tanks of chemical pretreatment, the closed inner space of the combined washing machines on the flow line and the exhaust systems connected to them; organic solvent washing tanks, high-pressure washing, ultrasonic washing tanks, vapour washing installations, electrostatic dust removal installations and the exhaust systems connected to them.

4.2 Besides the areas of 4.1, the areas where hazardous quantities of flammable and combustible vapours or of corrosive liquids and gases are still present in the pretreatment work shall also be counted within the extent of the pretreatment area.

5.1 Safety of the pretreatment process - General requirements

5.1.1 Pretreatment work shall be carried out at the location of pretreatment operation or inside the marked pretreatment area.

5.1.2 Except for very large components, the location of pretreatment operation should not in general be set in the open air; where it has to be, it shall comply with the provisions of this standard.

5.1.3 The location of pretreatment operation shall be sited on the upwind side of the direction of the least frequent wind of the year for the plant area, and shall be separated from the machining, welding, assembly and other operations connected with the production process.

5.1.4 The location of pretreatment operation shall be laid out on the side of a single-storey or multi-storey building close to an outer wall.

5.1.5 Locations of pretreatment operation with organic solvent degreasing or removal of old paint belong respectively to fire hazard production categories A and B. The fire protection of the location shall comply with the relevant provisions of GB 50016.

5.1.6 Locations with organic solvent degreasing or removal of old paint shall be well ventilated; smoking and the introduction of sources of ignition are prohibited; battery vehicles, motor vehicles and metal-wheeled trolleys shall not enter during the work; the operators shall wear antistatic working clothes and antistatic working shoes.

5.1.7 At locations of chemical pretreatment the floor shall be laid with corrosion-resistant material and shall be even, non-slip, easy to clean and impervious to standing water. The waste water shall be discharged to the waste water treatment system. Where an immersion pickling process is used, effective anti-corrosion measures shall be taken for the inner walls, columns, roof trusses and roof of the building.

5.1.8 The pumps, fittings and piping systems matched to high-pressure jet washing installations, and the bodies and rubber hoses of shot blasting rust removal or old paint removal installations, shall undergo pressure resistance tests and sealing performance tests according to the relevant national provisions.

5.1.9 Hand-held lighting fittings used in pretreatment work shall comply with the relevant provisions of GB/T 3805.

5.1.10 The summer air temperature at the location of pretreatment operation shall be calculated from the difference between the indoor and outdoor temperatures of the workshop. The limit of that difference shall comply with 5.1.2.2 of GB 6514-2008. In winter, local heating shall be provided as required by production and by the state of the mechanical exhaust in the closed manual working areas, so that the temperature of the working environment is kept not lower than 12 °C.

5.1.11 The maximum allowable concentration of harmful substances in the air at the location of pretreatment operation shall comply with 5.1.2.1 of GB 6514-2008.

5.1.12 Mechanical rust removal or removal of old paint shall be provided with an independent exhaust system and dust removal installation; the total dust content of the air in the breathing zone of the operators shall be less than 8 mg per cubic metre.

5.1.13 The hygiene characteristic grade of the location of pretreatment operation is grade 2.

5.1.14 The location of pretreatment operation shall be provided with emergency flushing water equipment with an uninterrupted water supply.

5.1.15 Mechanical pretreatment for rust removal shall limit the use of dry sand blasting; shot blasting and shot peening processes shall be used.

5.1.16 Benzene shall not be used in pretreatment work. Toluene, xylene and petrol shall not be used in large-area degreasing and old paint removal work, nor other toxic substances or substances with a low flash point.

5.1.17 The quantity of chemicals stored in a pretreatment workshop or section shall not exceed the consumption of two working shifts. The chemical storage cabinet shall be close to the point of use.

5.1.18 The operators of pretreatment work shall wear personal protective equipment according to GB/T 11651; when manual shot blasting is carried out they shall wear an enclosed rubber protective suit and an air-supplied hood.

5.1.19 The discharge of the soaking water, the spray water and the various chemical waste liquids produced in chemical pretreatment work shall comply with the relevant provisions of GB 8978.

5.1.20 The various wastes produced in pretreatment work shall be properly disposed of.

5.1.21 Measures for damping, sound insulation, silencing and sound absorption shall be taken for the fans, water pumps, motors and other noise-producing components and for the air ducts and water pipes used in the pretreatment process. The noise at the pretreatment location shall comply with the relevant provisions of 5.1.2.6.2 of GB 6514-2008.

5.1.22 Electrical equipment should in general not be installed inside a pretreatment area where organic solvents are used. Where it must be installed, it shall comply with the relevant provisions of GB 50058.

5.1.23 In a pretreatment area where organic solvents are used, the explosive gas environment of the area is classified as a zone 1 hazardous area. Outside its doors and windows opening to the open air, the space within a horizontal distance of 3 m and a vertical distance of 1 m is classified as zone 2.

5.1.24 The inside of a closed or semi-closed pretreatment process installation in which organic solvent washing is carried out with good ventilation is zone 1; outside its open face, the space within a horizontal distance of 3 m and a vertical distance of 1 m is classified as zone 2.

5.1.25 Flammable and explosive materials shall not be stacked within 15 m around a working position where organic solvent degreasing or old paint removal is carried out, nor within 5 m around a working position where rust removal with pneumatic tools is carried out.

5.1.26 Stoves, electric furnaces, gas furnaces, oil-burning furnaces and other open-flame heating equipment shall not be used at a location of pretreatment operation where organic solvents are used.

5.1.27 A no-smoking safety sign shall be posted at the entrance to a location of pretreatment operation where organic solvents are used; fire-fighting equipment shall be provided according to the relevant provisions of GB 50140, inspected periodically and kept in working order.

5.2 Safety of the pretreatment process - Organic solvent and vapour degreasing

5.2.1 When degreasing with a combustible organic solvent, the storage batteries or other power supply devices shall first be removed from the product or the component; the working location shall be provided with a warning sign and equipped with a combustible gas concentration meter, and measurements shall be taken periodically.

5.2.2 Vapour degreasing washing shall be carried out in a semi-enclosed tank, with strict measures to prevent the escape of the washing liquid vapour; the lining material of the inner wall of the tank shall be stainless steel, ceramic, flame-retardant unsaturated polyester resin fibre reinforced plastic or other suitable material.

5.2.3 The vapour degreasing washing installation shall be provided with automatic monitoring of the temperature and the liquid level of the washing liquid and with monitoring of the cooling water supply to the condenser; the scale division of the temperature measuring instrument shall be not greater than 0.5 °C.

5.3 Safety of the pretreatment process - Mechanical pretreatment

5.3.1 Mechanical rust removal should preferably use shot blasting and shot peening, so that the process is enclosed and the working conditions improved.

5.3.2 The wire brushes, scrapers and hammers used for manual rust removal shall be checked for reliability before work. The spacing between adjacent operators shall be greater than 1 m.

5.3.3 Manual rust removal work carried out at 2 m or more above the ground shall follow the requirements of GB/T 3608.

5.3.4 Hand-held electric grinding tools used for rust removal shall comply with the relevant provisions of GB 3883.1.

5.3.5 Pneumatic or electric grinding tools used for rust removal shall have their linear speed limited according to the abrasive disc material and the wire buffing wheel selected. A no-load trial run shall be carried out before work to check the reliability of the electric tool; during the work the wear of the abrasive shall be checked frequently and the tool shall not be used beyond the limit. The relevant provisions of GB 2494 shall also be met. The operators shall wear eye protection and keep an adequate safety distance from one another.