这是IEEE标准844.4的第一版™/CSA C293。4、IEEE/CSA管道阻抗加热标准和设备设计、安装、测试、调试和维护应用指南，是由IEEE和CSA集团共同制定的协调标准。IEEE对阻抗加热的要求之前已在IEEE Std 844中发布。本标准是将最初的IEEE Std 844分解为单独的要求和应用指南的五个项目之一。本标准应与IEEE Std 844.3结合使用™/CSA C22。2第293.3号，IEEE/CSA管道和设备阻抗加热通用标准、测试、标记和文件要求。 由于阻抗加热系统与电力、控制和报警系统相关，因此在使用本标准时，应参考其他标准（其中一些标准在第2条中列出）。本标准无意取代任何现行标准或推荐做法，在应用本标准或任何其他标准时，应始终使用合理的工程判断。本标准与行业惯例相关联；它不是设计指南或详尽的程序手册。本标准中包含的附件为资料性附录。1.1概述本标准分为七条。 第1条规定了范围和目的。第2条列出了适用本标准时有用的其他标准的参考。第3条引用了IEEE Std 844.3/CSA C22中的定义。2号293.3。第4条规定了阻抗加热的设计指南。第5条提供了安装注意事项和指南。第6条涉及阻抗加热系统的现场测试、启动、调试和运行。第7条规定了维护和维修指南。本标准还包含附件。附件A提供了参考书目。附录B提供了管道热损失计算方法。 附录C提供了加热和冷却计算方法。附录D提供了确定绝缘水泥等效厚度的方法。附录E提供了阻抗加热设计的设计输入参数示例。附录F给出了安装要求记录的示例。附录G显示了可用于记录系统调试的表格示例。附录H给出了预防性维护记录的示例。附录I显示了本标准中涵盖的绝缘阻抗导体类型。1.2范围本标准规定了钢或钢合金管道和设备的阻抗加热系统的应用。 它为一般工业应用中这些系统的设计、安装、维护和维修提供了建议。本标准适用于拟安装在具有爆炸性环境的普通和危险场所的阻抗加热系统。危险地点包括:加拿大:2区；22区；或第一类第二分部；第二类第二分部；CSA C22中所述的III类2类。1.美国:一级2区；22区；或第一类第二分部；第二类第二分部；NEC中所述的III类2类。本标准与其他公认规范和标准一起使用时，旨在涵盖整个阻抗加热系统，包括系统设计、规范、安装、操作、测试、调试和维护。 本文件还讨论了以下对阻抗加热系统性能重要的相关系统:a）隔热系统；b） 电力供应系统；c） 电气接地系统；控制和监控系统。1.3目的本标准旨在帮助用户指定、安装、操作、调试期间测试和维护阻抗加热系统:a）保持设计温度；b） 提供电气、热力和机械耐久性和可靠性；andc）减少对用户和周围环境的危害。本标准中的设计信息、选择参数和数据并非旨在为阻抗加热系统提供完整的设计基础。 本文提供的信息为以下方面提供了指导:选择最佳阻抗加热系统设计；制定加热管道或设备的设计标准和约束条件，以帮助确保系统兼容性准备规范，以获取阻抗加热系统的报价；以及开发阻抗加热系统的安装、操作、测试、调试和维护信息。

This is the first edition of IEEE Std 844.4™/CSA C293.4,IEEE/CSA Standard for Impedance Heating of Pipelines and Equipment—Application Guide for Design, Installation, Testing, Commissioning, and Maintenance, which is a harmonized standard jointly developed by IEEE and CSA Group. The IEEE requirements for impedance heating were previously published in IEEE Std 844. This standard is one of five projects to break up the original IEEE Std 844 into separate requirements and application guidelines.This standard should be used in conjunction with IEEE Std 844.3™/CSA C22.2 No. 293.3,IEEE/CSA Standard for Impedance Heating of Pipelines and Equipment—General, Testing, Marking, and Documentation Requirements. Since impedance heating systems are interrelated with electric power, control, and alarm systems, other standards (some of which are listed in Clause 2) should be referred to when using this standard.This standard is not intended to supersede any current standards or recommended practices, and sound engineering judgment should always be used when applying this or any other standard. This standard correlates industry practices; it is not intended to be a design guide or an exhaustive procedure manual. The annexes that are included in this standard are informative.1.1 GeneralThis standard is divided into seven clauses.Clause 1 provides the scope and purpose.Clause 2 lists references to other standards that are useful in applying this standard.Clause 3 references definitions that are found in IEEE Std 844.3/CSA C22.2 No.293.3.Clause 4 establishes the design guidelines for impedance heating.Clause 5 provides installation considerations and guidelines.Clause 6 covers field testing, start-up, commissioning, and operation of impedance heating systems.Clause 7 provides maintenance and repair guidelines.This standard also contains annexes.Annex A provides bibliographical references.Annex B provides pipe heat loss calculation methods.Annex C provides heat-up and cool-down calculation methods.Annex D provides a method to determine equivalent thicknesses of insulating cements.Annex E provides an example of design input parameters for an impedance heating design.Annex F presents an example of a record for installation requirements.Annex G shows an example of a form that can be used to document the commissioning of the system.Annex H presents an example of a preventive maintenance record.Annex I shows the insulated impedance conductor types covered in this standard.1.2 ScopeThis standard provides for the application of impedance heating systems for steel or steel alloy pipe and equipment. It provides recommendations for design, installation, maintenance, and repair of these systems in general industry applications. This standard applies to impedance heating systems intended to be installed in ordinary and hazardous locations with explosive atmospheres.The hazardous locations include the following:In Canada: Zone 2; Zone 22; or Class I, Division 2; Class II, Division 2; Class III, Division 2 as described in CSA C22.1; andIn the USA: Class I, Zone 2; Zone 22; or Class I, Division 2; Class II, Division 2; Class III, Division 2 as described in the NEC.This standard, when used with other recognized codes and standards, is intended to cover impedance heating systems in their entirety, including system design, specification, installation, operation, testing, commissioning, and maintenance.This document also addresses the following associated systems that are important to the performance of impedance heating systems:a) Thermal insulation systems;b) Electric power supply systems;c) Electric grounding systems; andd) Control and monitoring systems.1.3 PurposeThis standard is intended to aid the user in specifying, installing, operating, testing during commissioning, and maintaining impedance heating systems that:a) Maintain design temperature;b) Provide electrical, thermal, and mechanical durability and reliability; andc) Reduce hazards to the user and the surroundings.Design information, selection parameters, and data in this standard are not intended to provide a complete design primer for impedance heating systems.The information presented provides guidelines for the following:Selecting the optimum impedance heating system design;Establishing design criteria and constraints for the heated pipeline or equipment to help ensure system compatibilityPreparing specifications to obtain quotations for impedance heating systems; andDeveloping information on installation, operation, testing, commissioning, and maintenance of the impedance heating system.