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
石油化工静电接地设计规范
1 范围
本规范规定了石油化工企业静电接地的范围、方式及静电接地系统设计的要求。
本规范适用于石油化工企业的新建、扩建和改建工程的静电接地设计。
2 规范性引用文件
下列文件对于本规范的应用是必不可少的。凡是注日期的引用文件，仅注日期的版本适用于本规范。凡是不注日期的引用文件，其最新版本(包括所有的修改单)适用于本规范。
GB/T 50065—2011 交流电气装置的接地设计规范
GB 50813—2012 石油化工粉体料仓防静电燃爆设计规范
GB 50169—2006 电气装置安装工程接地装置施工及验收规范
GB 50174—2008 电子信息系统机房设计规范
GB 50611—2010 电子工程防静电设计规范
GB 12158—2006 防止静电事故通用导则
GB 13348—2009 液体石油产品静电安全规程
3 术语和定义
下列术语和定义适用于本规范。
3.1
静电 static electricity
静电是对观测者相对静止的、处于物体表面过剩或不足的电荷。由它所引起的磁场效应较之电场效应可以忽略不计。静电可由物质的接触与分离、静电感应、介质极化和带电微粒的附着等物理过程而产生，是生产储运过程中在物料、装置、人体、器材和构筑物上产生和积累起来的静电。
3.2
静电场 electrostatic field
静电在其周围形成的电场。
3.3
带电体 electrified body
正负电荷数量不相等，对外界显示电的特性的物体或系统。
3.4
带电区 electrified area
带电体上积聚静电的部位。
3.5
物质静电特征参数
a) 体积电阻率 volume resistivity
表征物体内导电性能的物理量。它是单位横截面积、单位长度上材料的电阻值，其单位为欧·米(Ω·m)。
b) 表面电阻率 surface resistivity
表征物体表面导电性能的物理量。它是正方形材料两对边间的电阻值，与物体厚度及正方形大小无关，其单位为欧(Ω)。
c) 电导率 conductivity
表征材料导电性能的物理量。其与电场强度之乘积等于传导电流密度，即σE=j。电导率的单位为西门子/米(S/m)。
3.6
静电起电、积聚和消散
a) 静电起电 electro static electrification
由于物体的接触分离、静电感应、介质极化和带电微粒的附着等原因，使物体正负电荷失去平衡或电荷分布不均，而在宏观上呈现带电的过程。
b) 静电积聚 electro static accumulation
由于某种起电因素使物体上静电起电的速率超过静电消散的速率而在其上呈现静电荷的积累过程。
c) 静电泄漏 electro static leakage
带电体上的电荷通过带电体自身或其他物体等途径向大地传导而使之部分或全部消失的过程。
d) 静电消散 electro static dissipation (decay)
带电体上的电荷由于静电中和、静电泄漏、静电放电而使之部分或全部消失的过程。
e) 杂散电流 stray current
任何不按指定的通路而流动的电流，这些非指定的通路可以是大地、与大地接触的管线和其他金属物体或构筑物。
3.7
静电放电 electrostatic discharge
具有不同静电电位的物体，由于直接接触或静电场感应引起物体间静电电荷的转移；静电电场的能量达到一定程度后，击穿其间介质而进行放电的现象就是静电放电。
3.8
材料
a) 静电导体 electrostatic conductor
一种具有较低的电阻率，若不与地绝缘则其上难于积聚静电荷的材料。体积电阻率小于或等于1×106Ω·m。
b) 静电亚导体 electrostatic sub-conductor
体积电阻率大于1×106Ω·m，表面电阻率为1×107Ω～1×1010Ω的固体表面。
c) 静电非导体 electrostatic non-conductor
一种具有很高的电阻率，因此能在其上积聚足够数量的静电荷从而引起各种静电现象的材料。
d) 导静电材料 electrostatic conductive material
指金属和碳等电导率大的材料，以及用其他方法(如在绝缘材料中掺入导电材料等)使物体具有导静电性能的材料。
e) 防静电织物 anti-static fabric
通过某种工艺方法，使纤维表面电阻率降低，从而形成或生产出的一种具有防止静电积聚的织物。
3.9
静电安全及灾害预防
a) 静电安全 electrostatic safety
指在生产过程及各种环境(系统)中，不发生由于静电现象而导致人的伤害、设备损坏或财产损失的状况和条件。
b) 静电故障 electrostatic accident
由于某种静电现象的作用，导致生产系统、设备、工艺过程、材料、产品等发生故障、损害(如生产率下降、产品质量不良，以至失效、破坏等)的现象或事件。
c) 静电灾害 electrostatic disaster
由于静电放电而导致发生财产损失或人员伤亡的危害、损害的现象或意外事件(如火灾、爆炸、静电电击以及由此而造成的二次事故等)。
d) 静电电击 electrostatic shock
由于带电体向人体，或带静电的人体向接地的导体，以及人体相互间发生静电放电，其所产生的瞬间冲击电流通过人体而引起的病理生理效应。
e) 二次事故 secondary accident
由于静电电击使人体失去平衡，导致人员由高空坠落或触及其他障碍物而引起的伤害；或造成已存在的火灾、爆炸的后果进一步扩大等危害的现象或事件。
f) 静电危险场所 area of electrostatic hazards
空间存在可由静电引爆的爆炸性混合物，或对其进行直接加工、处理和操作等工艺作业场所的统称。
3.10
静电接地
a) 静电接地 electrostatic earthing
为防止静电对人身和设备等的危险作用而设的接地。
b) 静电接地系统 electrostatic eatrhing system
带电体上的电荷向大地泄漏、消散的外界导出通道。
c) 直接静电接地 direct electrostatic earthing
通过金属导体使物体接地的一种接地方式。
d) 间接静电接地 indirect electrostatic eatrhing
通过非金属导电材料或防静电材料以及防静电制品使物体接地的一种接地方式。
e) 连接 connection
将彼此没有良好导电通路的物体进行导电性连接，使相互间大体上处于相同电位的措施。
f) 静电接地的电阻分类
1) 静电泄漏电阻 leakage resistance of static electricity
物体在不带电的情况下，物体的被测点对大地的总电阻。
2) 静电接地电阻 earthing resistance of static electricity
静电接地系统的对地电阻。设备外壳至大地的电阻称为静电接地电阻，接地体至大地的电阻称为接地体对地电阻。
4 基本规定
4.1 静电接地的范围
4.1.1 在生产加工、储运过程中，设备、管道、操作工具及人体等，有可能产生和积聚静电而造成静电危害时，应采取静电接地措施：
a) 生产、加工、储存易燃易爆气体和液体的设备及气柜、储罐等；
b) 输送易燃易爆液体和气体的管道及各种阀门；
c) 装卸易燃易爆液体和气体的罐(槽)车，油罐，装卸栈桥、铁轨，鹤管，以及设备、管线等；
d) 生产、输送可燃粉尘的设备和管线。
4.1.2 在进行静电接地时，应包括下列部位的接地：
a) 装在设备内部而通常从外部不能进行检查的导体；
b) 安装在绝缘物体上的金属部件；
c) 与绝缘物体同时使用的导体；
d) 被涂料或粉体绝缘的导体；
e) 容易腐蚀而造成接触不良的导体；
f) 在液面上悬浮的导体。
4.1.3 各种静电消除器的接地端，应按要求进行接地。
4.1.4 在下列情况下，可不采取专用的静电接地措施(计算机、电子仪器等除外)：
a) 当金属导体已与防雷、电气保护、防杂散电流、电磁屏蔽等的接地系统有电气连接时；
b) 当埋入地下的金属构造物、金属配管、构筑物的钢筋等金属导体间有紧密的机械连接，并在任何情况下金属接触面间有足够的静电导通性时。
4.1.5 当金属管段已作阴极保护时，不应静电接地。
4.1.6 静电接地设计，除应符合本规范外，尚应符合国家现行有关强制性标准规范的规定。4.2 静电接地方式
4.2.1 直接静电接地：静电导体应采用金属导体进行直接接地。
4.2.2 间接静电接地：为使金属以外的静电导体、静电亚导体进行静电接地，将其表面的局部或全部与接地的金属体紧密相接的一种接地方式。
4.2.3 静电非导体除应间接静电接地外，尚应配合其他的防静电措施。
4.3 静电接地系统的接地电阻
4.3.1 静电接地系统静电接地电阻值不应大于106Ω。专设的静电接地体的对地电阻值不应大于100Ω，在山区等土壤电阻率较高的地区，其对地电阻值不应大于1000Ω。
4.3.2 当其他接地装置兼作静电接地时，其接地电阻值应根据该接地装置的要求确定。
4.4 静电接地端子和接地板
4.4.1 应在设备、管道的一定位置上，设置专用的接地连接端子，作为静电接地的连接点。4.4.2 接地连接端子的设置应符合下列要求：
a) 不易受到外力损伤；
b) 便于检查维修；
c) 便于与接地线相连；
d) 不妨碍操作；
e) 尽量避开容易积聚可燃混合物以及容易锈蚀的地点。
4.4.3 静电接地端子有下列几种：
a) 设备、管道外壳(包括设备支座、耳座)上预留出的裸露金属表面；
b) 设备、管道的金属螺栓连接部位；
c) 接地端子排板；
d) 专用的金属接地板。
4.4.4 专用金属接地板的设置应符合下列要求：
a) 金属接地板可焊(或紧固)于设备、管道的金属外壳或支座上。
b) 金属接地板的材质，应与设备、管道的金属外壳材质相近。
c) 用于管道静电接地引下线的金属接地板的截面不宜小于50mm×10mm，管道跨接用的金属接地板的截面不宜小于50mm×6mm；最小有效长度宜为60mm。如管道有保温层，该板应伸出保温层外60mm。
d) 设备接地用的金属接地板的截面不宜小于50mm×10mm，最小有效长度对小型设备宜为60mm，大型设备宜为110mm。如设备有保温层，该板应伸出保温层外60mm或110mm。
e) 接地用螺栓规格不应小于M10。
f) 当选用钢筋混凝土基础作静电接地体时，应选择适当部位预埋200mm×200mm×6mm钢板，钢板上再焊专用的金属接地板。预埋钢板的锚筋应与基础主钢筋相焊接。
4.5 静电接地支线和连接线
4.5.1 静电接地支线和连接线，应采用具有足够机械强度、耐腐蚀和不易断线的多股金属线或金属体，规格可按表4.5.1确定。
表4.5.1 静电接地支线、连接线的最小规格
设备类型 接地支线 连接线
固定设备 16mm2多股铜芯电线
φ8mm镀锌圆钢
12mm×4mm镀锌扁钢 6mm2铜芯软绞线或软铜编织线
大型移动设备 16mm2铜芯软绞线或橡套铜芯软电缆 —
一般移动设备 10mm2铜芯软绞线或橡套铜芯软电缆 —
振动和频繁移动的器件 6mm2铜芯软绞线 —
4.5.2 在振动和频繁移动的器件上使用的接地导体不应采用单股线及金属链。
4.6 静电接地干线和接地体
4.6.1 静电接地干线和接地体应与其他用途的接地装置综合考虑，统一布置。可利用保护接地干线、防雷电感应接地干线作为静电接地干线使用，否则应专门设置静电接地干线和接地体。
4.6.2 静电接地干线的布置，应符合下列要求：
a) 有利于设备、管道及需要在现场作静电接地的移动物体的接地；
b) 静电接地干线在装置内宜闭合环形布置，不同标高层或两个闭合环之间的接地干线应至少有两处连接。
4.6.3 下列接地干线或线路不得用于静电接地：
a) 三相四线制系统中的中性线；
b) 整流所各级电压的交流、直流保护接地系统；
c) 直流回路的专用接地干线。
4.6.4 静电接地体的设计应符合下列要求：
a) 当静电接地干线与保护接地干线在建构筑物内有两点相连时，可不另设静电接地体；
b) 应充分利用自然接地体以及其他用途的接地体；
c) 腐蚀环境中，宜根据腐蚀介质及腐蚀环境类别选用复合型耐腐蚀材料。
4.7 静电接地干线和接地体静电接地材质的选择
4.7.1 静电接地材质可选用镀锌钢材、复合型防腐接地材料等。
4.7.2 当选用镀锌钢材时，钢材规格可按表4.7.1确定。
表4.7.1 静电接地干线和接地体用钢材的最小规格
名称 单位 规格
地上 地下
扁钢 截面积
厚度 100mm2
4mm 160mm2
4mm
圆钢 直径 φ12mm φ14mm
角钢 规格 — 50mm×5mm
钢管 直径 — 50mm
4.7.3 当选用复合型防腐接地材料时，静电接地干线和接地体用复合型防腐接地材料的最小规格可按照表4.7.2确定。
表4.7.2 静电接地干线和接地体用复合型防腐接地材料的最小规格
名称 单位 规则
地上 地下
复合型防腐扁钢 截面积
厚度 100mm2
4mm 100mm2
4mm
复合型防腐圆钢 直径 φ12mm φ12mm
复合型防腐角钢 规格 50mm×5mm 50mm×5mm
4.7.4 条文所规定的材质选择是针对石油化工装置的一般要求，对于特殊物料装置，应根据其工艺产品特性确定接地材质的选型。
4.8 静电接地的连接
4.8.1 接地端子与接地支线连接，应采用下列方式：
a) 固定设备宜采用螺栓连接；
b) 有振动、位移的物体，应采用挠性线连接；
c) 移动式设备及工具，应采用电瓶夹头、鳄式夹钳，专用连接夹头或磁力连接器等；
d) 不应采用接地线与被接地体相缠绕的方法。
4.8.2 静电接地体的连接应符合下列要求：
a) 当采用搭接焊连接时，其搭接长度应是扁钢宽度的2倍或圆钢直径的6倍，焊接处应进行防腐处理。
b) 当采用螺栓连接时，其金属接触面应去锈、除油污，并加防松螺帽或防松垫片；
c) 当采用电池夹头、鳄式夹钳等器具连接时，有关连接部位应去锈、除油污。
