GB 12158-2024General requirements for preventing electrostatic accidents (English PDF)

1 Scope

China's mandatory general requirements for preventing electrostatic accidents. Static electricity is generated wherever two materials separate - liquid flowing through a pipe, powder falling into a hopper, film unwinding, a person getting out of a seat - and in an atmosphere containing flammable vapour or combustible dust the spark that follows is an ignition source that needs no fault and leaves no trace. The measures are all about giving the charge somewhere to go before it accumulates: bonding and earthing everything conductive, controlling the flow rate of liquids into tanks, using conductive or dissipative materials for floors, footwear, clothing, containers and hoses, humidifying where that is practical, and ionising where it is not. The standard sets out those requirements generally, and it is the document the sector-specific rules for fuel handling, powder processing, printing and electronics assembly are built on.

This document specifies the general requirements for electrostatic protection, electrostatic management measures, requirements for area of electrostatic hazards, electrostatic protection measures for solid, liquid, gaseous and powdery materials, human body electrostatic protection measures, as well as analysis and determination of electrostatic accidents to prevent combustion and explosion caused by electrostatic discharge. This document is applicable to the design and management of area of electrostatic hazards. NOTE. protection against other electrostatic hazards (for example, electrostatic shock) may take this as a reference. This document does not apply to the prevention of electrostatic hazards of explosives and powders, electric initiating explosive devices, and fireworks.

2 Normative References

The contents of the following documents constitute indispensable clauses of this document through the normative references in the text. In terms of references with a specified date, only versions with a specified date are applicable to this document. In terms of references without a specified date, the latest version (including all the modifications) is applicable to this document.

GB/T 3684 Conveyor Belts - Electrical Conductivity - Specification and Test Method

GB/T 3836.26-2019 Explosive Atmospheres - Part

26.Electrostatic Hazards - Guidance

GB 6950 Safe Rest Conductivity of Light Fuel Oil

GB 8965.1 Protective Clothing - Flame Retardant Protective Clothing

GB/T 9572 Rubber and Plastics Hoses and Hose Assemblies - Determination of Electrical Resistance and Conductivity

GB 12014 Protective Clothing - Static Protective Clothing

GB/T 15463 Electrostatic Safety Terminology

GB 21148 Foot Protection - Safety Footwear

GB/T 22845 Anti-electrostatic Glove

GB 50058 Code for Design of Electrical Installations in Explosive Atmospheres

GB/T 50493 Standard for Design of Combustible Gas and Toxic Gas Detection and Alarm for Petrochemical Industry

3 Terms and Definitions

The terms and definitions defined in GB/T 15463 and GB 6951 and the following are applicable to this document.

3.1 static conductor Under the conditions of use, the material with a volume resistivity less than or equal to 1 106 m (i.e., the conductivity is greater than or equal to 1 106 S/m) or the solid surface with a surface resistivity less than or equal to 1 107 . NOTE. the volume resistivity and surface resistivity of various materials and surfaces need to be tested in the temperature and humidity environment specified by the standard test method. If the test conditions are optional, the conditions of use refer to the temperature and humidity conditions closest to the environment of use.

3.2 static sub-conductor Under the conditions of use, the material with a volume resistivity greater than 1 106 m and less than 1 1010 m (i.e., the conductivity is greater than 1 1010 S/m and less than 1 106 S/m) or the solid surface with a surface resistivity greater than 1 107 and less than 1 1011 . NOTE. the volume resistivity and surface resistivity of various materials and surfaces need to be tested in the temperature and humidity environment specified by the standard test method. If the test conditions are optional, the conditions of use refer to the temperature and humidity conditions closest to the environment of use.

3.3 static non-conductor Under the conditions of use, the material with a volume resistivity greater than or equal to 1 1010 m (i.e., the conductivity is less than or equal to 1 1010 S/m) or the solid surface with a surface resistivity greater than or equal to 1 1011 . NOTE. the volume resistivity and surface resistivity of various materials and surfaces need to be tested in the temperature and humidity environment specified by the standard test method. If the test conditions are optional, the conditions of use refer to the temperature and humidity conditions closest to the environment of use.

3.4 minimum ignition energy; MIE Under normal temperature and pressure conditions, the minimum electrical energy required to [Source: GB 6951-1986, 1.1]

3.13 relaxation time of charge The time required for the charge (or potential) on a charged body to dissipate to 1/e (about 37%) of its initial value.

3.14 relaxation chamber A thick-diameter pipe section or relaxation storage tank installed in the pipeline system to slow down the flow of charged liquid flowing in the pipe, so that the charge can be thoroughly leaked and attenuated to a safe range.

3.15 time of response; time of rest When producing in a place with electrostatic hazards exist, the interval time required from the equipment stopping operation to the static electricity carried by the material (usually liquid) dissipating to below the safe value, allowing the next operation to be carried out.

3.16 electrostatic discharge The phenomenon that the electric field strength formed by a charged object exceeds the breakdown field strength of the surrounding medium, or contacts with other objects, causing the charge to dissipate or transfer.

3.17 electrostatic accident An unexpected incident that causes casualties or property loss due to electrostatic discharge.

4 General Requirements...

5 Electrostatic Management Measures

5.1 General Requirements The relevant organizations of the area of electrostatic hazards shall adopt necessary management measures to standardize the various processes and links of electrostatic protection, and the electrostatic protection technology and methods, equipment, appliances and personnel behaviors therein.

5.2 Organizational Management The relevant organizations of the area of electrostatic hazards shall clearly define the highest manager of electrostatic protection and the electrostatic protection management implementation department.

5.3 Documents An electrostatic hazard control scheme shall be formulated in the area of electrostatic hazards and become part of the internal management normative documents of the organization. Its content shall at least include.

---Possible electrostatic hazards;

---Manifestations of electrostatic hazards;

---Causes of electrostatic hazards;

---Control measures of electrostatic hazards;

---Personnel training plan;

---Verification of anti-electrostatic measures;

---Relevant records of electrostatic protection behaviors.

5.4 Personnel Personnel working in the area of electrostatic hazards shall receive regular anti-electrostatic hazard training. The training shall be combined with the actual work of the organization, and the content shall include training on laws, regulations, standards, implementation methods of anti-electrostatic measures, necessary drills and knowledge supplements. Non-operating personnel entering the area of electrostatic hazards, including but not limited to short-term visitors, maintenance personnel, cleaning personnel, etc., shall be equipped with publicly available individual anti-electrostatic equipment. Before entering the area of electrostatic hazards, experienced staff shall inform relevant regulations.

5.5 Identification Related organizations of the area of electrostatic hazards shall identify specific information of electrostatic sensitive objects within the range of operation, identify the range of the area of electrostatic hazards, electrostatic hazardous links, electrostatic protection personnel, supplies, equipment and facilities.

5.6 Inspection In the work, key data shall be monitored and recorded in real time in accordance with the electrostatic hazard control plan, and the monitoring device shall be regularly measured by a qualified third-party institution. The frequency of inspection, testing and measurement depends on the purpose, durability and risk of failure of the controlled object. An inspection mechanism for electrostatic protection management shall be established, and corrective measures shall be taken in a timely manner for problems and non-conformities found during the inspection.

5.7 Signs and Records All areas of electrostatic hazards shall have obvious hazard signs. The signs shall indicate the rating of the area of electrostatic hazards and the entrance and boundaries of the area of electrostatic hazards. The area of electrostatic hazards shall have signs, such as earthing points, anti-electrostatic items that shall be used, necessary clothing, electrostatic hazardous zone and activity restrictions, etc. Electrostatic sensitive objects and anti-electrostatic packaging / equipment containing electrostatic sensitive objects shall be posted with clear and explicit risk level signs. All work shall be recorded and preserved.

6 Area of Electrostatic Hazards

6.1 Division of Area of Electrostatic Hazards When there are explosive mixtures that can be ignited or detonated by static electricity in the environment, or when explosive mixtures that can be detonated by static electricity are directly processed, handled, etc. in the environment, the environment is an area of electrostatic hazards. In accordance with the probability of explosion accidents caused by static electricity in the workplace, the area of electrostatic hazards is divided into Zone 0, Zone 1, Zone 2 (explosive gas atmosphere) and Zone 20, Zone 21, Zone 22 (explosive dust atmosphere). The division of each zone shall be carried out in accordance with GB 50058.

7 Solid Material Protection Measures

7.1 When non-metallic electrostatic conductors or electrostatic sub-conductors are connected to metal conductors, the area of close contact shall be greater than 20 cm2.

7.2 All constituent parts of the overhead piping system shall maintain reliable electrical connections. Outdoor systems shall also satisfy the requirements of relevant national lightning protection regulations.

7.3 Earthing conductors used on vibrating and frequently moving devices shall not use stranded wires or metal chains, but bare stranded wires or braided wires over 6 mm2.

7.4 When using dissipative coating materials to coat non-anti-electrostatic materials, pay attention to the following properties of the coating materials.

a) It shall be ensured that the dissipative coating cannot be washed off, wiped off, or become ineffective over time. Otherwise, such coating is only suitable as a temporary measure to reduce the accumulation of electrostatic charge.

b) When adding materials to make the surface absorb moisture to improve surface conductivity, it shall be noted that if the ambient humidity is too low (relative humidity is less than 30%), the materials may become insulating materials and accumulate electrostatic charge.

c) The dissipative additives used in anti-electrostatic packaging materials shall match the packaged products. If the product absorbs the dissipative additives that it contacts, then, it may cause product contamination and / or loss of packaging dissipative properties.

7.5 For the conveyor belts used to convey or transport solid materials, the materials conveyed to the stub bar or chute through the end of the conveyor belts can carry a large amount of charge, and attention shall be paid to the risk of electrostatic ignition. The conveyor belts used for different occasions and their speed requirements shall comply with the requirements of Table

3.Table 3 does not apply to conveyor belts that dissipate charge through the mode of corona discharge. It shall be noted that conductive or dissipative conveyor belts cannot remove the charge carried by insulating conveyed objects. Table 3 -- Requirements for Conveyor Belts Belt Speed Zone

0 Zone

20 Zone

21 Zone 22 II C II A and II B MIE 10 mJ MIE > 10 mJ adhesive used to connect the conveyor belts does not interrupt the conductive path.