Standard No.:	SH/T 3097-2017
English Name:	Specification for design of static electricity earthing in petrochemical industry
Chinese Name:	石油化工静电接地设计规范
Professional Classification:	SH    Professional Standard - Petrochemical
Issued by:	Ministry of Industry and Information Technology
Issued on:	2017-07-07
Implemented on:	2018-1-1
Status:	valid
Superseding:	SH 3097-2000 Code for the design of static electricity grounding for petrochemical industry
Language:	English
File Format:	PDF
Word Count:	15000 words
Price(USD):	450.0
Delivery:	via email in 1 business day

Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative. This Specification was revised by the drafting group according to the requirements of Notice on issuing the plan for the development and revision of the fourth batch of professional standards in 2012 (GONGXINTINGKE [2012] No.252) issued by the Ministry of Industry and Information Technology, through extensive investigation, careful summarization of practical experience, reference to relevant international and foreign advanced standards and extensive solicitation of opinions. This Specification contains five clauses and three annexes, with the main contents as follows: electrostatic earthing area, electrostatic earthing method and requirements of earthing resistance of electrostatic earthing system; general requirements for electrostatic earthing terminal, earthing plate, earthing branch line, earthing main line, earthing electrode and specific connection; general requirements for petrochemical enterprise with area of electrostatic hazards. The following technical deviations have been made with respect to the former edition: ——The nouns and terms are verified and some nouns and terms not used in this Specification are deleted; ——The electrostatic earthing area is specified in detail; ——The setting requirements of special metal earthing plate are modified; ——The requirements for electrostatic earthing connection are modified; ——The clauses for selection of electrostatic earthing materials are added; ——The parameters of volume resistivity are modified; ——The specific requirements for electrostatic earthing of storage tank and piping system are modified; ——Requirements are made more detailed for some clauses. Annexes of this Specification are informative. This standard was issued in 2000 for the first time and revised in 2016 for the first time. This is the first revision. Specification for design of electrostatic earthing in petrochemical industry 1 Scope This Specification specifies the electrostatic earthing area and method as well as requirements for design of electrostatic earthing system of petrochemical enterprises. This Specification is applicable to the design of electrostatic earthing for constructed, extended and renovated engineering of petrochemical enterprises. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB/T 50065-2011 Code for design of ac electrical installations earthing GB 50813-2012 Code for design static explosion prevention in petrochemical powders silo GB 50169-2006 Code for construction and acceptance of grounding connection electric equipment installation engineering GB 50174-2008 Code for design of electronic information system room GB 50611-2010 Code for design of protection of electrostatic discharge in electronic engineering GB 12158-2006 General guideline for preventing electrostatic accidents GB 13348-2009 Safety rules of static electricity with relation to liquid petroleum products 3 Terms and definitions For the purposes of this specification, the following terms and definitions apply. 3.1 static electricity excess or insufficient electrical charge on the surface of an object, which is relatively static for observer, by which the magnetic field effect caused may be neglected compared with the electric field effect, and which may be produced by physical processes such as contact and separation of substances, electrostatic induction, polarization of medium and attachment of charged particles and is produced and accumulated on materials, devices, human bodies, equipment and structures during production, storage and transport 3.2 electrostatic field electric field formed by static electricity around it 3.3 electrified body object or system with unequal amounts of positive and negative charges and showing electrical characteristics to the outside world 3.4 electrified area part of an electrified body where static electricity accumulates 3.5 electrostatic characteristic parameters of substance a) volume resistivity physical quantity characterizing electrical conductivity in objects, which is the resistance value of material per unit cross-sectional area and unit length, expressed in Ω·m b) surface resistivity physical quantity characterizing the conductivity of the surface of an object, which is the resistance value between two opposite sides of a square material, and has nothing to do with the thickness of the object and the size of the square, expressed in Ω c) conductivity physical quantity characterizing the conductivity of materials, whose product with the electric field intensity is equal to the conduction current density, that is, σE = j, expressed in S/m   3.6 electro static electrification, accumulation and dissipation a) electro static electrification process of charging that appears macroscopically due to contact and separation of substances, electrostatic induction, polarization of medium and attachment of charged particles which causes unbalance of positive and negative charges or uneven charge distribution b) electro static accumulation process of electrostatic charge accumulation in which the rate of electro static electrification on an object exceeds that of electro static dissipation due to some electrification factors c) electro static leakage process in which the charges on an electrified body are conducted to the earth through the electrified body itself or other objects, so that the charges disappear partially or completely d) electro static dissipation (decay) process in which the charges on an electrified body partially or completely disappear due to electrostatic neutralization, electrostatic leakage and electrostatic discharge e) stray current any current that does not flow according to specified paths, such as the earth, pipeline in contact with the earth and other metal objects or structures 3.7 electrostatic discharge phenomenon that the dielectric is broken down and discharge is conducted after the energy of electrostatic field reaches a certain level caused by transfer of electrostatic charges between objects with different electrostatic potentials due to direct contact or electrostatic field induction   3.8 material a) electrostatic conductor material with low resistivity, on which it is difficult to accumulate electrostatic charges if it is not insulated from earth and whose volume resistivity is less than or equal to 1×106Ω·m b) electrostatic sub-conductor solid surface with volume resistivity greater than 1×106Ω·m and surface resistivity ranging from 1×107Ω to 1×1010 Ω c) electrostatic non-conductor material with very high resistivity, on which a sufficient amount of electrostatic charge may be accumulated to cause various electrostatic phenomena d) electrostatic conductive material material with high electrical conductivity, such as metal and carbon, and materials that make objects have electrostatic conductivity by other methods, such as doping conductive materials into insulating materials e) anti-static fabric fabric with the function of preventing electro static accumulation which is produced through a certain process to make the surface resistivity of fibre be reduced 3.9 electrostatic safety and disaster prevention a) electrostatic safety situations and conditions under which people injury, equipment damage or property loss due to electrostatic phenomenon do not occur in the production process and environments (systems)   b) electrostatic accident phenomenon or event that causes the production system, equipment, technological process, materials and products to fail or damage (such as productivity slowdown, poor product quality, and even failure and destruction) due to the action of some electrostatic phenomenon c) electrostatic disaster phenomenon or accident such as property loss, personal casualty caused by electrostatic discharge, such as fire, explosion, electrostatic shock and secondary accident caused thereby d) electrostatic shock pathophysiological effects when the human body is passed through by the instantaneous impulse current generated by the electrostatic discharge generated from electrified body to human body, from electrified body with static electricity to earthing conductor or between human bodies e) secondary accident personnel injuries caused by falling from high altitude or touching other obstacles due to the imbalance of human body caused by electrostatic shock; or phenomenon or event that causes the consequences of existing fires and explosions to be worse f) area of electrostatic hazards general designation of working areas whose space exists explosive mixture that may be detonated by static electricity, or where such explosive mixture is directly processed, treated and operated 3.10 electrostatic earthing a) electrostatic earthing earthing set to prevent the dangerous effects of static electricity on people and equipment b) electrostatic earthing system external lead-out channel through which the charge on the electrified body leaks and dissipates to the earth c) direct electrostatic earthing earthing method for earthing objects through metal conductors d) indirect electrostatic earthing earthing method for earthing objects through non-metallic conductive materials or anti-static materials and anti-static products e) connection measures to electrically connect objects without good conductive paths to each other so that they are at the same potential f) classification on resistance of electrostatic earthing 1) leakage resistance of static electricity total resistance of the measured point of the object to the earth when the object is not charged 2) earthing resistance of static electricity resistance of electrostatic earthing system to earth, in which, the resistance between equipment shell and earth is called earthing resistance of static electricity, and that between earthing electrode and earth is called earthing electrode-to-earth resistance 4 Basic requirements 4.1 Electrostatic earthing area 4.1.1 Electrostatic earthing measures shall be taken when equipment, piping, operating tool and human body might produce and accumulate static electricity and thereby cause electrostatic hazards in production, processing, storage and transport: a) Equipment, gas holder and storage tank for producing, processing and storing inflammable and explosive gases and liquids; b) Piping and various valves for conveying flammable and explosive liquids and gases; c) Tank trucks (tankers), oil tanks, loading stages and rails, crane pipes, equipment and pipelines for loading and unloading flammable and explosive liquids and gases; d) Equipment and pipelines for producing and transporting combustible dust. 4.1.2 The following parts shall be earthed for the purpose of electrostatic earthing: a) Conductors that are installed inside the equipment and cannot normally be inspected from the outside; b) Metal parts mounted on insulated objects; c) Conductors used in conjunction with insulated objects; d) Conductors insulated by coatings or powders; e) Conductors which are prone to corrosion and consequent poor contact; f) Conductors suspended on the liquid surface. 4.1.3 The earth terminals of various static electricity eliminator shall be earthed as required. 4.1.4 Special electrostatic earthing measures may not be taken in the following cases (except for computers, electronic instruments, etc.): a) The metal conductors have been electrically connected to the earthing systems for lightning protection, electric protection, stray current protection, electromagnetic shielding, etc.; b) The metal conductors, such as buried metal structures, metal pipework, and reinforcements of structures are in a tight mechanical connection, and there is sufficient electrostatic conductivity between the metal contact surfaces in any case. 4.1.5 Metal pipe sections that have been cathodically protected shall not be electrostatically earthed. 4.1.6 In addition to this Specification, the design of electrostatic earthing shall also meet the requirements of the current relevant mandatory standards of the nation. 4.2 Electrostatic earthing method 4.2.1 Direct electrostatic earthing: The electrostatic conductor shall be earthed directly with a metal conductor.

Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 Basic requirements 4.1 Electrostatic earthing area 4.2 Electrostatic earthing method 4.3 Earthing resistance of electrostatic earthing system 4.4 Electrostatic earthing terminal and earthing plate 4.5 Electrostatic earthing branch line and connecting line 4.6 Electrostatic earthing main line and earthing electrode 4.7 Selection of electrostatic earthing materials for electrostatic earthing main lines and earthing electrode 4.8 Electrostatic earthing connection 5 Technical requirements 5.1 Fixed equipment 5.2 Storage tank 5.3 Piping system 5.4 Railway platform and tank truck 5.5 Bus station and tank truck 5.6 Pier 5.7 Powder processing, storage and transportation equipment 5.8 Spouting devices of gas and vapour 5.9 Chemical fibre equipment 5.10 Measures for discharging static electricity of human body 5.11 Electrostatic earthing of computer room and electronic instrument room Annex A (Informative) Test method of electrostatic earthing Annex B (Informative) Precautions in electrostatic earthing Annex C (Informative) Typical figures for electrostatic earthing connections Bibliography Explanation of wording in this Specification