Api574 my self study notes

API RP 574 In-house training Inspection Practices for Piping System Components

My Self Study Notes

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西沙群岛- 临近 友邦和睦的蓝色疆土

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内部培训 管道系统部件的检查实践 Fion Zhang/ Charlie Chong

Foreword 诸言 API RP 574 此建议(RP)的做法它的目的是： 补充API 570 关于API规范的修订, 重申等; 一般来说,至少每隔 5年 API 标准进行审查和修订,重申或撤 回,该审查周期可能被一次性长达 2年 的延长.审查和修订后 6个月生效. 在修订后至生效期间选用此”建议-RP”,用户有 必要声明所运用的版本.

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Contents 1 Scope 范围 2 Normative References 规范性引用文件 3 Terms, Definitions, Acronyms, and Abbreviations 术语，定义 4 Piping Components 管道元件 5 Pipe-joining Methods 管道连接方法 6 Reasons for Inspection 检查原因 7 Inspection Plans 检验计划 8 Frequency and Extent of Inspection 检查的频率和程度 9 Safety Precautions and Preparatory Work 安全注意事项和筹备工作 10 Inspection Procedures and Practices 检查程序和做法 11 Determination of Minimum Required Thickness 最低所需厚度的测定 12 Records记录 Annex A (informative) External Inspection Checklist for Process Piping 工艺管道的外部检查清单

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1 Scope 范围 这RP描述管道与管道配件的检查方法以帮助检查员履行 API 570 工作. 此RP不包括特种项目的检查, 如仪表和控 制阀.

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2.Normative References 规范性引用文件

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3. Terms, Definitions, Acronyms, and Abbreviations 术语,定义,缩略语和缩写

Please refer to text 请参考文本

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4 Piping Components 管道元件 4 Piping Components 4.1 Piping 4.2 Tubing 4.3 Valves 4.4 Fittings 4.5 Flanges 4.6 Expansion Joints

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4.1 Piping 管道

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4.1 Piping 管道 两种最常见的碳钢管道所用材料在石化行业 ASTM A53 , ASTM A106 业界中采用无缝或纵缝电阻焊接( ERW) 有两个考虑: • 经济角度 • 焊缝增快腐蚀 大于NPS16 管道一般为纵向焊缝管 碳钢及合金管道一般 “按照标准尺寸” 制造至

NPS48

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4.1 Piping 管道 碳钢及合金管道一般 “按照标准尺寸” 制造至 NPS48

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Pipe wall thicknesses are designated as: (1) pipe schedules in NPS up to 36 in.

(2) The traditional thickness designations: • Standard weight, (ST) • Extra strong, and (XS) • Double extra strong (XXS) differ from schedules and are used for NPS up to 48 in.

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4.1.1.2 Pipe wall thicknesses are designated as pipe schedules in NPSs up to 36 in. (914 mm). The traditional thickness designations- standard weight, extra strong, and double extra strong—differ from schedules and are used for NPSs up to 48 in. (1219 mm).  NPS1/8 ~ NPS36 管道厚度按照 pipe schedules “管配编制表制” 与传统的 厚度标识.  NPS1/8 ~ NPS48 管道厚度按照传统的厚度标识 “标准体重” / “额外的强” / “双超强”

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NPS14 或更大 实际OD=NPS标记

NPS12 或更小 实际OD≠NPS标记

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Joint Efficiency 连接效率 ASME B31.3 Table 302.3.4

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大于NPS16 管道一般为纵向焊缝管

Ej ? 连接效

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Ej

连接效

?

大于NPS16 管道一般为纵向焊缝管 Fion Zhang/ Charlie Chong 574-4

Ej

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连接效

?

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直缝电阻焊管

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ERW / Ej

= 0.85

连接效

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Ej

=1

连接效

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Ej 连接效= 0.80~1.0 (单面破口) Ej 连接效= 0.85~1.0 (双面破口)

SSAW Welded Pipe 螺旋焊管道

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Ej

= 0.8 ~ 1.0 (单) / 0.85 ~1.0 (双)

连接效

SAW Welded Pipe 埋弧焊 直缝焊接 (单或双面焊接) Fion Zhang/ Charlie Chong 574-4

管道/容器/结构支撑 Fion Zhang/ Charlie Chong 574-4

没有 NPS 13

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4.1.1.3 Allowable tolerances in pipe diameter differ from one piping material to another. Table 3 lists the acceptable tolerances for diameter and thickness of most ASTM ferritic pipe standards

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4.1.1.3 Allowable tolerances in pipe diameter differ from one piping material to another. Table 3 lists the acceptable tolerances for diameter and thickness of most ASTM ferritic pipe standards. The actual thickness of seamless piping can vary from its nominal thickness by a manufacturing tolerance of as much as 12.5 %. The under tolerance for welded piping is 0.01 in. (0.25 mm). Cast piping has a thickness tolerance of +1/16 in. (1.6 mm) and –0 in. (0 mm), as specified in ASTM A530

无缝管道的实际制造厚度公差变化高达12.5 % 焊接管道的下公差为 0.01英寸 (0.25mm) 铸铁管道 ASTM A530的厚度公差: 正公差 1 /16英寸(1.6毫米) 和负公差 -0英寸(0毫米)

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4.1.1.4 Cast iron piping is generally used for nonhazardous service, such as water; it is generally not recommended for pressurized hydrocarbon service.

The standards and sizes for cast iron piping differ from those for welded and seamless piping. 铸铁管道一般用于无害的服务, 不合适压力油气管道.

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学习学习: 标的是厚度负公差, 正公差要求？

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学习学习: 标的是厚度负公差, 正 公差？ 没有正公差要求!

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4.1.2 Fiber Reinforced Plastic (FRP) Pipe 纤维增强塑料(FRP)管 4.1.2.3 FRP管道包括典型的服务应用

服务水,工艺水,冷却介质,食用水,污水/ 灰水,非危险废物,无害的水渠，无害 的通风口,化工,消防环形水管,消防水 雨淋系统,生产和压舱水.

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4.1.2.4 ~ 4.1.2.9 ASME B31.3 Chapter VII 和 AWWA 里有 FRP 相关的设计要求但不提供详细与 正确的腐蚀屏障,树脂,制造,接头,特定的应用程序选择指导. 为此很多生产商开发 自己的规格,材料,量,制造要求和设计因素. 影响 FRB 运用与质量的因素有：          

维修人员缺乏对选用的材料与生产熟悉 不同的生产技术,材料选择对最终产品物理性能带来很大的差别 各树脂,固化机理,对温度限制. 内垫腐蚀屏障. 紫外线的降解. 每个接头链接方法有它的优点和缺点. 链接人员资格一样重要. 无损检测的限制. 管附件支撑如阀门,三通等需要不同于金属管道的分析. 检验人员对生产, 固化机理, 检验方法与要求的认识.

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4.1.2.8 ……Standardized FRP piping systems commonly called “commodity piping” are manufactured for a variety of services and are sold as products with a predetermined design, resin, corrosion barrier and structure…… 回顾上一节的很多不确定因素：

标准化的FRP管道系统通常被称 为“商品管道”…….

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4.1.3 Small-bore Piping (SBP) 小口径管道 小于或等于NPS 2的管件或管组件 4.1.4 Linings 内衬

内衬一般为金属和非金属两种 内衬功能有：  减少腐蚀  侵蚀  产品的污染  管壁温度

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金属内衬工艺有三种

爆炸复合方法 Clad pipe 复合管 has a metallic liner that is an integral part of the plate material 轧制或爆炸 (1) rolled or explosion before fabrication of the pipe

bonded

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They may instead be separate strips of metal fastened to the pipe by welding referred to

(2) strip lining 通过焊接固定到管道分体垫片内衬

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Corrosion-resistant metal can also be applied to the pipe surfaces by various

(3) weld overlay processes. 一体的堆焊方法

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非金属内衬工艺 Some common nonmetallic lining materials for piping are concrete, castable refractory, plastic, and thin-film coatings 混凝土, 耐火浇注料, 塑料和薄膜涂料

耐火浇注料

混凝土

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薄膜涂料 塑料

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4.2 Tubing 管子

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小管子套管通常是在小直径的，主要用于热交换器，仪表 管道，润滑油服务，蒸汽跟踪，和类似的服务. 其表示大小 是与实际的OD而非NPS

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4.3 Valves

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4.3 Valves 4.3.1 General The basic types of valves are gate, globe, plug, ball, diaphragm, butterfly, check, and slide valves.

基本类型的阀门有:

闸阀, 截止阀, 塞,.球, 隔膜, 蝴蝶, 截流和滑阀. 压力温度等级规范,阀体厚度和其它设计数据根据有:

ASME B16.34 or API 599, API 600, API 602, API 603, API 608, or API 609, as applicable.

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4.3.2 Gate Valves 闸阀 闸阀由一个阀体它包含一个闸门用于中断(干扰)流。这种类型的阀门,通常用 于在全开或全闭的位置. 大于2” 的闸阀一般阀体端口和连接端口一样大小这 种闸阀叫” full-ported valve“. 另一种”reducing port valve” 的阀体端口小于连 接端口, 这种阀门不合适用作隔断阀泄压装置

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Gate Valves 闸阀

闸阀的阀门,通常用于在全开或全闭的位置. 阀体端口和连接端口一样大小这种闸阀叫 “Full-ported valve”. 另一种 “Reducing port valve” 的阀体端口小于 连接端口, 这种阀门不合适用作隔断阀泄压 装置

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闸阀 “Reducing Port Valve”

”Reducing port valve” 的阀体端口小于连接端口, 这种阀门不合适 用作隔断阀泄压装置 Fion Zhang/ Charlie Chong 574-4

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4.3.3 Globe Valves 截止阀-(不叫调节阀吗?) 截止阀是用来用于调节流体流动, 包含一个阀体一个圆盘和盘轴平行移动并能关 闭状态时圆盘接触到阀门底座. 除了真空阀, 流向普遍向上(失效关闭) 对于细节流服务,圆盘和底座, 非常陡峭, 这种特殊类型的截止阀被称为”针阀”

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细节流服务,圆盘和底座, 非常陡峭, 这种特殊类型的截止阀被称为”针阀”

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”针阀”

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4.3.4 Plug Valves 旋塞阀 塞阀由一个圆锥或圆柱形插头紧贴到相应形座圆锥.旋塞阀通常用作隔断阀，以 关闭流体. 该阀是关闭的插头通过转动四分之一圈

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4.3.5 Ball Valves 球阀 球阀通常用作隔断阀,以关闭流.球阀通常配备有弹性合成橡胶类的 体座材料，高压球阀为提供了良好的关断特性全金属可被广泛应用.

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球阀

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4.3.6 Diaphragm Valves 隔膜阀 甲隔膜阀是一个无衬垫的阀，它包含一个由柔性材料制成的隔膜，当阀杆 拧下来, 它迫使弹性膜片对座位/坝, 来达到调节与截流效果 这些阀门不广泛应用于石化行业, 但在腐蚀性的服务和低于约 250oF/121oC 温度环境下也常应用做为防漏阀.

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截流与 调节隔膜阀

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4.3.7 Butterfly Valves 蝶阀

蝶阀构造为阀体中放置一个由阀杆摆动的竖立盘. 蝶阀是最常用在低压服务的 粗流量控制. 各种阀座位的材料和结构设计用来确保高压与低压紧密关闭. 大的蝴蝶阀一般机械操作的. 机械特性是为了防止关断服务时阀盘猛撞阀座. 运用范围:

 一般用在低压粗流量控制  高压与低压关断

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蝶阀

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4.3.8 Check Valves 单向阀 单向阀是用来自动防止回流.止回阀的最常见的类型是:    

摆动圆板/半球塞 升降活塞 球塞 弹簧半圆板止回阀

摆动圆板/半球塞 Fion Zhang/ Charlie Chong 574-4

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升降活塞

弹簧半圆板止回阀 Fion Zhang/ Charlie Chong 574-4

球塞

弹簧半圆板止回阀 球塞 Fion Zhang/ Charlie Chong 574-4

升降活塞

升降活塞

摆动圆板/半球塞

摆动圆板/半球塞 Fion Zhang/ Charlie Chong

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4.3.9 Slide Valves 滑阀 是一家专门闸阀: 滑阀一般用于腐蚀性或高温服务. 它由一台 对座滑动板构造的特殊阀. 滑动板上下升降影响固定节流孔的大小 来调节或截流. 用在高温流体的滑阀内部通常覆盖耐侵蚀耐火材料.

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滑阀

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4.4 Fittings 配件

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4.4 Fittings 配件 4.4.1 Metallic Fittings 金属配件 管道配件是用于连接管段，改变流动的方向，或允 许流被转用或添加其他配件.

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4.5 Flanges 法兰

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4.5 Flanges 法兰 4.5.1 Metallic Flanges 金属法兰

ASME B16.5 各种材料的法兰盘至 NPS 24 ASME B16.47 各种材料的法兰盘至 NPS 26 ~ NPS 60.

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法兰连接面

滑面法兰

凸面法兰 沟槽法兰 Fion Zhang/ Charlie Chong 574-4

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Welding Neck Flange 对焊法兰

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Lap-Joint Flange 搭接法兰

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Socket Welded Flange 承插焊法兰

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Slip-on Flange 平焊法兰

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Blind Flange 盲板法兰

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Thread Flange 螺纹法兰

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4.6 Expansion Joints 膨胀弯

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Expansion joints are devices used to absorb dimensional changes in piping systems, such as those caused by thermal expansion, to prevent excessive stresses/strains being transmitted to other piping components, and connections to pressure vessels and rotating equipment. While there are several designs, those commonly found in a plant are metallic bellows and fabric joint designs.

Metallic bellows can be single wall or multilayered, containing convolutions to provide flexibility. Often, these joints will have other design features, such as guides, to limit the motion of the joint or type of loading applied to the joint.

Metallic bellows are often found in high-temperature services and are designed for the pressure and temperature of the piping system. Fabric joints are often used in flue gas services at low pressure and where temperatures do not exceed the rating of the fabric material.

常见的是 (1) 金属波纹管和 (2) 织物接头. 金属膨胀弯可以运用于高温与压力的管道. 织物或非金属接头用于低压与材料允许的工作温度下.

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5 Pipe-joining Methods 管道连接方法 5 Pipe-joining Methods 5.1 General 5.2 Threaded Joints 5.3 Welded Joints 5.4 Flanged Joints 5.5 Cast Iron Pipe Joints 5.6 Tubing Joints 5.7 Special Joints 5.8 Nonmetallic Piping Joints.

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5.1 General 概要

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5.1 General 常见的用于组装管道元件连接方法  焊接  螺纹连接  法兰连接 5.2 Threaded Joints 螺纹接头一般都限制在非关键服务的辅助管道一般小于NPS2 24英寸(610毫米)和更小的螺纹接头依照标准连接方法(见ASME B1.20.1) 螺纹接头毗邻旋转设备或其他高振动来源是特别容易受到由于

疲劳导致失效

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Threaded Joint Fittings

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5.3 Welded Joints 焊接接头

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5.3 Welded Joints 焊接接头 5.3.1 General 大致 对焊连接方法除了小口径NPS2 或更小和需要时常做定期检验的管 线外,是主要的管道连接方法.

5.3.2 Butt-welded Joints 对接接头 在石化行业对焊连接是最常见.

5.3.3 Socket welded Joints 承插焊接接头 承插焊接接头注意事项有确保足够的对接间隙来容纳管道或配件的 膨胀与收缩.

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5.3.4 Welded Branch Connections 焊接分支连接

   

缺少阀门或管道支撑, 振动, 热膨胀和 其它配置因素

导致过度的结构负荷与高于正常的应力, 这集中应力可能会 导致疲劳开裂或其他故障.

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5.4 Flanged Joints 法兰接头

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5.4 Flanged Joints 法兰接头 法兰接头是由螺栓连接某种形式的垫圈阀座表面之间的两个法兰作 为密封连接: 法兰,面有; 凸面, 沟槽, 滑面三种.

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5.5 Cast Iron Pipe Joints

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5.5 Cast Iron Pipe Joints 铸铁管接头可:

       

flanged, packed, sleeve, hub-and-spigot-end or hub-and-plain-end, or bell-and spigot-end or bell-and-plain-end type.

Push-on joints with rubber or synthetic ring gaskets are available.  Clamped joints are also used.  Threaded joints are seldom used for cast iron.

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bell-and spigot-end

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Sleeve Joint / Clamped joints

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Packed Joint

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5.6 Tubing Joints 小管接头

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5.6 Tubing Joints 小管接头

小管线道可以通过焊接, 软钎焊, 钎焊或通过扩 展或压缩配件连接

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5.7 Special Joints 特殊接头

采用独特的垫圈，夹具，和特别的螺栓连接等: 优点有:     

更高的压力和温度 更小的尺寸 易于安装 要求不那么严格的, 强度增加

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5.8 Nonmetallic Piping Joints 非金属管道接头

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5.8 Nonmetallic Piping Joints 非金属管道接头 5.8.1 General 大纲 在 API570 / 574 只要一类非金属管道: FRB/GRP 玻璃纤维增强塑料 Some common joint designs in FRP pipe systems include a bell-and-spigot, butt-and-wrap, taper-taper and flange-flange. 一些常见的玻璃钢管道系统的连接设计有:    

钟插口, bell-and-spigot 对接和滚扎, butt-and-wrap 锥锥, taper-taper 法兰对接. flange-flange

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纯粹参考学习

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5.8.2 Bell and Spigot/Taper-taper

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5.8.2 Bell and Spigot /Taper-taper

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Bell and Spigot

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5.8.3 Butt and Wrap

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Butt and Wrap

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5.8.4 Flange-flange 法兰法兰

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6 Reasons for Inspection 检查的原因 6 Reasons for Inspection 6.1 General 6.2 Safety 6.3 Reliability and Efficient Operation 6.4 Regulatory Requirements

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6.1 General

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6.1 General The primary purposes of inspection are to identify active deterioration mechanisms and to specify repair, replacement, or future inspections for affected piping. These actions should result in increased operating safety, reduced maintenance costs, and more reliable and efficient operations. API 570 provides the basic requirements for such an inspection program. 检验的主要目的是为确认管道的损坏机理 (和程度) 从而有效的确定:

维修 更换 安排未来检验 这些行动应导致增加了(1)操作的安全性, (2)降低了维护成 本 (3) 更可靠更高效的操作

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6.2 Safety 安全

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6.2 Safety 安全 Adequate inspection is a prerequisite for maintaining this type of piping in a safe, operable condition. In addition, federal regulations such as OSHA 29 CFR 1910.119 has mandated that equipment, including piping, which carries significant quantities of hazardous chemicals be inspected according to accepted codes and standards which includes API 570. 充足的检查是保持管道安全性与可操作性的先决条件 OSHA 29 CFR 1910.119 规定设备, 包括带有显着的数量危险化学品 管道应当根据公认的规范和标准(包括API 570)的检查.

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6.3 Reliability and Efficient Operation 可靠性和高效运行

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6.3 Reliability and Efficient Operation 可靠性和高效运行 Thorough inspection and analysis and the use of detailed historical records of piping systems are essential to the attainment of acceptable reliability, efficient operation, and optimum on-stream service. Piping replacement schedules can be developed to coincide with planned maintenance turnaround schedules through methodical forecasting of piping service life.

(1) 彻底的检查和分析, 并使用管道系统的 (2) 详细历史记录，实现可接受的可 靠性，高效的运作，和最佳流服务是必不可少的。 通过预测管道使用寿命, 配合设施维修周转安排, 开发管道更换时间表达到管 道可靠地,高效的运作.

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6.4 Regulatory Requirements 法定要求

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6.4 Regulatory Requirements 法定要求 API 570 was developed to provide an industry standard for the inspection of in-service process piping. It has been adopted by a number of regulatory and jurisdictional authorities. In addition, in some areas other requirements have been specified for the inspection of piping. Each plant should be familiar with the local requirements for process piping inspection.

API570它已经通被一些法规和司法当局采纳为安全标准. 每个化工设施应该熟悉当地法定机构对工艺管道检验要求

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总结: Reasons for Inspection 检查的原因

 操作的安全性 (人员/设备/环境)  降低了维护成本  更可靠更高效的操作

+  符合国家与地方法定要求

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7 Inspection Plans 检验计划 7 Inspection Plans 7.1 General 7.2 Developing an Inspection Plan 7.3 Monitoring Process Piping 7.4 Inspection for Specific Damage Mechanisms 7.5 Integrity Operating Envelopes

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7.1 General 大纲

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7.1 General 大纲

按照API570要求制定与执行管道系统范检查计划 An inspection plan should contain the inspection tasks, scope of inspection, and schedule required to monitor damage mechanisms and assure the mechanical integrity of the piping components in the system.

检查计划应包含 (1) 检查任务 (2) 检查范围和 (3)检验计划时间 - 来监控损坏机理从而并保证系 统中的管道元件的机械完整性

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该计划将通常: a) 定义检查需要 (外表,内部, CUI等等) b) 确定下次检查的时间间隔和日期 c) 描述的检查和无损检测技术; d) 描述位置的检查的程度和无损检测; e) 描述任何表面清洗需求 f) 描述所需的任何压力或气密性试验的要求描述任何 必要的维修.

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其他常见的细节: 1. 描述预期的损伤机理或经历, 2. 损害位置, 3. 任何特殊的检验空间要求. 数据应当文档保存: 硬拷贝文件或专用检查软件数据库

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7.2 Developing an Inspection Plan 制定检验计划

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7.2 Developing an Inspection Plan 制定检验计划 检验计划工作往往通过以下人员合作开发 (1) 授权检验员, (2) 管道工程师 (3) 腐蚀专家和 (4) 操作人员 应该考虑信息有:

 Operating temperature ranges,工作温度范围  operating pressure ranges, 工作压力范围  process fluid corrosive contaminant levels, 工艺流体腐蚀性的污染物水平  piping material of construction,管道施工材料  piping system configuration,管道系统配置  process stream mixing and 工艺混合流  inspection/maintenance history.检查/维护历史 以上的信息帮助定义损坏机理的类型与发生位置.

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对无损探伤认识包括的能力和局限性能更加的正确选择合 适的探伤方法. 别外, 参考API 与 NACE 出版物以取相似的系统得行业的 经验有助于制定检验计划. 持续与操作员对话关于工艺过程中的变化或混乱可能会影 响损伤机理和蚀率是至关重要的, 这信息以确保查计划正确 的及时更新

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检查计划应包含以下项目(1)：:       

对具体的损害机理;状态监测点CML 管道支撑管道的接触点 焊管支持 保温层下腐蚀(CUI); 注入点 混合点 土壤空气界面

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检查计划应包含以下项目 (2)：:         

盲管 (Dead Legs) 材料识别 (PMI); 辅助管路 关键公用工程管道 排空或下水管道 螺纹管接头 内部衬管道 关键阀门 伸缩接头

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检查计划可能会根据不同的标准, 但应包括 1.

2.

RBI580风险评估或 API570定义固定的时间间隔

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7.2.1 Risk-Based Inspection (RBI) Plans 基于风险分析计划

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Inspection plans based upon an assessment of the likelihood of failure and the consequence of failure of a piping system or circuit is RBI. RBI may be used to determine inspection intervals and the type and extent of future inspection/examinations. API 580 details the systematic evaluation of both the likelihood of failure and consequence of failure for establishing RBI plans.

API 581 details an RBI methodology that has all of the key elements defined in API 580.

API 580/581 RBI - 根据评估(1)失效的可能性和(2)失败的后 果的评估 RBI 可以用来确定检查的(1) 时间间隔和对未来的(2) 检验类 型和 (3) 程度

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7.2.1.2

估管道发生故障的可能性的重要步骤.

• • • •

识别和评 价潜在的损伤机理 目前的管道情况 过去的检查评的成效评估估

是评估管道发生故障的可能性的重要步骤。 API571 描述了常见的损坏机理的细节.

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7.2.1.3

评估配管故障的相关的后果的重要细节

(1) 工艺流体(媒介), (2) 潜在的伤害, (3) 环境破坏, (4) 管道单元和设备损坏和 (5) 单元的生产损失 7.2.1.4 按照API

580进行彻底的记录.

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7.2.1.5 RBI 评估结果可用于建立检查计划和更好的定义下面的:

• • • • •

最适当的检查和无损检测方法,工具和技术; 无损检测的程度 内部,外部和在职检查的时间间隔 压力测试的需要 预防和缓解措施,以减少管道发生故障的概率和后果

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7.2.2 Interval-based Inspection Plans 基于时间间隔检验计划

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Inspection plans which are based upon the specific inspection intervals for the various types of piping inspection and of specific types of damage are considered interval based. The types of inspection where maximum intervals are defined in API 570 include: external visual, CUI, thickness measurement, injection point, S/A interface, SBP, auxiliary piping and threaded connections. The interval for inspections is based upon a number of factors, including the corrosion rate and remaining life calculations, piping service classification, applicable jurisdictional requirements and the judgment of the inspector, the piping engineer, or a corrosion specialist. The governing factor in the inspection plan for many piping circuits is the piping service classification.

时间间隔检查计划的主导因素是

管道服务分类 (API570 获取更多管道分类详细信息)

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API570定义固定的时间间隔

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API570- CUI Inspection -API570定义固定的时间间隔

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7.2.3 Classifying Piping Service 根据API 570, 所有的工艺管道应根据失败的后果分类. 管道类从1级高的后果 ~ 3级低的后果 Factors to consider when classifying piping are: 分类管道时要考虑的因素有： • • • • • •

Toxicity,毒性 Volatility 蒸发性 Combustibility 可燃性 location of the piping w.r.t to personnel / equipment 管道和人员和其他设备相对位置 experience and history 经验和历史

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Class?

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Class?

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Class?

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API 570Classification of piping for inspection

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API 570- 6.3.4.2 Class 1 Services with the highest potential of resulting in an immediate emergency if a leak were to occur are in Class 1. Such an emergency may be safety or environmental in nature. Examples of Class 1 piping include, but are not necessarily limited to those containing the following.

• •

• • • •

•

Flammable services that can auto-refrigerate and lead to brittle fracture.

Pressurized services that can rapidly vaporize during release, creating vapors that can collect and form an explosive mixture, such as C2, C3, and C4 streams. Fluids that can rapidly vaporize are those with atmospheric boiling temperatures below 50 °F (10 °C) or where the atmospheric boiling point is below the operating temperature (typically a concern with high-temperature services).

Hydrogen sulfide (greater than 3 % weight) in a gaseous stream.

Anhydrous hydrogen chloride.

Hydrofluoric acid.

Piping over or adjacent to water and piping over public throughways (refer to Department of Transportation and U.S. Coast Guard regulations for inspection of over water piping).

Flammable services operating above their auto-ignition temperature.

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API 570- 6.3.4.3 Class 2 Services not included in other classes are in Class 2. This classification includes the majority of unit process piping and selected off-site piping.

Typical examples of these services include but are not necessarily limited to those containing the following: • • •

on-site hydrocarbons that will slowly vaporize during release such as those operating below the flash point, hydrogen, fuel gas, and natural gas, on-site strong acids and caustics.

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API 570- 6.3.4.4 Class 3 Services that are flammable but do not significantly vaporize when they leak and are not located in high-activity areas are in Class 3.

Services that are potentially harmful to human tissue but are located in remote areas may be included in this class. Examples of Class 3 service include but are not necessarily limited to those containing the following: • • • •

on-site hydrocarbons that will not significantly vaporize during release such as those operating below the flash point; distillate and product lines to and from storage and loading; tank farm piping; off-site acids and caustics.

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API 570- 6.3.4.5 Class 4 Services that are essentially nonflammable and nontoxic are in Class 4, as are most utility services. Inspection of Class 4 piping is optional and usually based on reliability needs and business impacts as opposed to safety or environmental impact. Examples of Class 4 service include, but are not necessarily limited to those containing the following: • • • • • • •

steam and steam condensate; air; nitrogen; water, including boiler feed water, stripped sour water; lube oil, seal oil; ASME B31.3, Category D services; plumbing and sewers.

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Some NDT methods used (information)

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Profile Radiography 轮廓射线技术

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Profile Radiography 轮廓射线技术

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LT 泄露

最适当的检查和无损检测方法,工具和技术 Fion Zhang/ Charlie Chong 574-7

UT 超声探伤

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UT 超声探伤

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UT A-Scan 超声探伤

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UT B-Scan 超声探伤

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UT B-Scan 超声探伤

B-Scan of Notched Steel Sheet

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UT C-Scan 超声探伤

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TOFD 超声探伤

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VI 目视

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TOFD

http://www.sonotronndt.com/vidGallery.htm

衍射超声急速

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ACFM 交流感应测量

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ACFM 交流感应测量

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Thermography 红外摄像

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Thermography 红外摄像

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Thickness Gauging 厚度测量

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Smart Pigging 智能通管器

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Smart Pigging 智能通管器

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Thickness Gauging 侧厚

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Thickness Gauging 侧厚

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7.3 Monitoring Process Piping 工艺管道监控

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7.3 Monitoring Process Piping 工艺管道监控 7.3.1 General 大纲 导致管道更换最频繁的损伤机理是腐蚀, 一个有效的过程管道检查计划应当包括管 道厚度检测从而确定; (1) 监测管道腐蚀速率 (2) 剩余寿命 (3) 下次检查日期 (4) 预计管道退休日期 A key to the effective monitoring of piping corrosion is identifying and establishing CMLs. CMLs are designated areas in the piping system where measurements are periodically taken. Ultrasonic (UT) thickness measurements are obtained within examination points on the pipe. Thickness measurements may be averaged within the examination point. By taking repeated measurements and recording data from the same points over extended periods, damage rates can more accurately be calculated or assessed.

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7.3.2 Piping Circuits 管路 7.3.2.1 有许多因素可影响管道内壁的腐蚀速度和性质。它们包括但不限于

1. piping metallurgy;管道冶金 2. process fluid and its phase (e.g. gas, liquid, two phase, solid); 工艺流体.其相 3. flow velocity;流速 4. temperature;温度 5. pressure;压力 6. changes in temperature, velocity, pressure, direction, phase, metallurgy, or pipe cross section; 在温度变化时,速度,压力,方向,相位,冶金,或管道的横截面 7. injection of water or chemicals; 注入的水或化学品 8. process fluid contaminants; 工艺流体污染物 9. mixing of two or more streams; 两个或两个以上的媒介的混合 10. piping external conditions, including coating/painting, insulation, and soil conditions, as applicable;管道外部条件 11. stagnant flow areas (e.g. dead-legs).媒介流动停滞区 Fion Zhang/ Charlie Chong 574-7

7.3.2.2 管路的分类. 特别实在复杂的系统, 管路分类成为可管理的下单元, 更加有效的管理必 要的检查安排, 计算和记录管理. 当使用统计方法来评估腐蚀速率和剩余寿命, 正确选择设备元件, CML数量, 是特别重要的.

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7.3.3 Identifying Locations Susceptible to Accelerated Corrosion 确定容易加速腐蚀位置 通常下腐蚀加速的推动: 增加的速度和/或湍流 (弯头,异径管,三通混合,控制阀和孔口) 这些位置一般上需要较多的 CML. 在检查发现或预计开裂情况 需要暂时建立CML 监测开裂率

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7.3.4 Accessibility of CMLs 空间限制 在一些管路系统，监控积极损伤机制的性质将需要特别的空间工具来实现检测工作. 这些工具有; 梯子, 载人机动升降机, 脚手架, 有限空间安全措施和设备等等.

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Confined space entry 进入密闭空间

-只允许有受过正式培训认证人 员才允许执行此类活动. (编辑者忠告)

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7.4 Inspection for Specific Damage Mechanisms 具体的损伤机理检测

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7.4 Inspection for Specific Damage Mechanisms 以下具体类型和恶化的位置需要作为关注点: • • • • • • • • • • • • • • •

injection points, 注入点 process mix points, 工艺管媒介组合点 dead-legs,死角 CUI, 保温层下腐蚀 S/A interfaces, 土壤空气接触面 service specific and localized corrosion,特定服务流程工艺具体和局部腐蚀 erosion and erosion-corrosion,侵蚀和冲刷腐蚀 environmental cracking,环境开裂 corrosion beneath linings and deposits, 管内衬垫和堆积物的腐蚀 fatigue cracking,疲劳裂纹 creep cracking,蠕变开裂 brittle fracture,脆性断裂 freeze damage,冻 害 contact point corrosion,接触点腐蚀 dew-point corrosion.露点腐蚀

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7.4.1 Injection Points 注射点 在正常或不正常情况下,注射点会受到局部或加速腐蚀.注入点可能被视为单独的检验 管路和定期彻底检查. 注射点监测范围为: 上方12”或3D 以大为准 下方 第二改变方向点或 25” 以小为准

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特别关注点: More extensive inspection should be applied to the injection point circuit in an area beginning 12 in.

(300 mm) upstream of the injection nozzle and continuing for at least 10 pipe diameters downstream of the injection point

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7.4.2 Process Mix Points 流程混合点 流程混合点是; 管道元件流程中, 两个不同的成分,温度或其他 参数的过程流组合 NACE Publication 34101 有更加多的描述. 授权管道检验员, 管道工艺师, 腐蚀专家会参与工艺流程审核来 识别可能出现的损坏机理和混合点的范围

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7.4.3 Dead-legs 死角 死角的腐蚀率可能明显有差与活跃的工艺管道. 检查员应监测 壁厚选定的死角, 包括在系统停滞端和活跃线的连接。 In hot piping systems, the high point area can corrode due to convective currents set up in the dead-leg. Additionally, water can collect in dead-legs that can freeze in colder environments resulting in pipe rupture. 在热管道系统, 收到高点死角的媒介对流影响, 高点区域可能 收到异常的腐蚀. 此外，水可以收集死角,在在寒冷的环境中冻结,导致管道破裂.

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7.4.4 CUI 保温层下腐蚀 / 外部检查应包括保温系统系统的完整性审查

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7.4.4.1 Insulated Piping Systems Susceptible to CUI 易受影响管道系统 以下为易受保温层腐蚀的管道系统:

1. those exposed to mist over-spray from cooling water towers; 那些接触过喷雾冷却水塔 2. those exposed to steam vents;那些暴露在蒸汽喷口 3. those exposed to deluge systems;那些暴露在雨淋系统 4. those subject to process spills or ingress of moisture or acid vapors; 工艺流程易被泄漏或水分渗入 5. carbon steel piping systems, including ones insulated for personnel protection, operating between 10o F (–12oC) and 350oF (175oC); CUI is particularly aggressive where operating temperatures cause frequent or continuous condensation and re-evaporation of atmospheric moisture; 工作温度波动易引起连续凝结和蒸发大气中的水分的工艺管路

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6. carbon steel piping systems which normally operate in service above 350oF (175oC), but are in intermittent service; 在高温工作的但间歇服务(这会引起重复的凝结与蒸发-导致一般腐蚀 与环境开裂) 7. dead-legs and attachments that protrude from insulated piping and operate at a different temperature than the operating temperature of the active line; 死角和附件绝缘管道伸出，并在不同的温度下运作 8. austenitic stainless steel piping systems operating between 120oF (60oC) and 400oF (205oC) (susceptible to chloride SCC); 奥氏体不锈钢管道系统在以上温度波动工作,引起重复的凝结与蒸发导致环境开裂

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9. vibrating piping systems that have a tendency to inflict damage to insulation jacketing providing a path for water ingress; 震动管道(引起 保温层破坏) 10. steam traced piping systems that can experience tracing leaks, especially at tubing fittings beneath the insulation; 带蒸汽伴管管道可能泄露导致保温层潮湿 11.piping systems with deteriorated insulation, coatings, and/or wrappings; bulges or staining of the insulation or jacketing system or missing bands (bulges can indicate corrosion product buildup);管道 系统的涂层,保温层,缠绕带劣化的管道

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7.4.4.2 Typical Locations on Piping Circuits Susceptible to CUI CUI 典型位置

穿透绝缘护套系统的死角, 配件,法兰,注入点等等, 在绝缘法兰与其他管道组件终止点(高/低). 绝缘护套损坏或丢失. 水平管道位于顶部上的护套接缝. 高合金管道系保温层下的, 统碳钢或低合金钢法兰,螺栓和 其他组件.

6. 保温层被切割作为CML/TML 检验点.

1.

2.

3.

4.

5.

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7.4.5 Soil-to-air (S/A) Interface 埋地管土壤/空气界面

If the buried piping has satisfactory cathodic protection as determined by monitoring in accordance with API 570, excavation is required only if there is evidence of coating or wrapping damage. If the buried piping is uncoated at grade, consideration should be given to excavating 6 in. (150 mm) to 12 in. (300 mm) deep to assess the potential for hidden damage. Alternately, specialized UT techniques such as guided wave can be used to screen areas for more detailed evaluation. 如果埋地管道具有良好的阴极保护监测由符合API 570, 仅当有损坏的证据时 才有必要开挖检验. 如界面发现管道涂层有劣化现象, 执行开挖时应当考虑 挖掘 6英寸到12英寸 深, 以评估潜在隐藏的损坏 API570 9.3.1 也要求每六个月进行埋地管道, 地面巡查任何可能因管道泄漏 引起的异象 Fion Zhang/ Charlie Chong 574-7

没有良好的阴极保护监测时, 埋地管按照API570 的检验要求如下 API570, 9.3.6 External and Internal Inspection Intervals

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26) At concrete-to-air and asphalt-to-air interfaces of buried piping without cathodic protection, the inspector look for evidence that the caulking or seal at the interface has deteriorated and allowed moisture ingress. If such a condition exists on piping systems over ______ years old, it may be necessary to inspect for corrosion beneath the surface before resealing the joint. (API574-7.4.5) a) b) c) d)

8 5 15 10

25) Soil-to-air (S/A) interfaces for buried piping are a location where localised corrosion may take place. If the buried part is excavated for inspection, how deep should the excavation be to determine if there is hidden damage? (API574-7.4.5) a) b) c) d) 574-7

12 to 18 inches 6 to 12 inches 12 to 24 inches 6 to 18 inches Fion Zhang/ Charlie Chong

7.4.6 Service-specific and Localized Corrosion 特定工艺服务和局部腐蚀 7.4.6.1 一个有效的检查程序包括以下四个要素以便帮助识别潜在的因特定工艺 服务引起的腐蚀和局部腐蚀并选择适当 CML • • • •

授权检验员对特定工艺服务和局部腐蚀的认识 广泛的运用有效的无损探伤 操作人员沟通关于管道腐蚀的信息 在管路腐蚀分区可能会错过关注异常管道

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7.4.6.2 特定流程服务引起的腐蚀机理的腐蚀类型通常是局部的,可以预料这 种类型的腐蚀的例子包括 a. downstream of injection points and upstream of product separators (e.g. hydroprocessor reactor effluent lines); 注入点的下游和产品分离器上游 b. dew-point corrosion in condensing streams, (e.g. overhead fractionation); 冷凝流-露点腐蚀 c. unanticipated acid or caustic carryover from processes into non-alloyed piping systems or in the case of caustic, into non-post-weld heat treated (PWHTed) steel piping systems; 高合金钢媒介酸或碱流入到非合金管道

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d. where condensation or boiling of acids (organic and inorganic) or water is likely to occur; 管道媒介为凝结或沸腾的酸或水 e. where naphthenic or other organic acids can be present in the process stream. 管道媒介为环烷或其他有机酸 f. where high-temperature hydrogen attack can occur (see API 941); 高温氢攻击可能发生的管路

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g. ammonium salt condensation locations in hydro-processing streams (see API 932-B);铵盐缩合位置 h. mixed-phase flow and turbulent areas in acidic systems, also hydrogen grooving areas;在酸性系统的混相流和湍流区 i. where high-sulfur streams at moderate-to-high temperatures exist; 高含硫流存在中度至高温运作的管道 j. mixed grades of carbon steel piping in hot corrosive oil service [450 °F (232 °C)] or higher temperature and sulfur content in the oil greater than 0.5 % by weight);混合等级的碳钢管道在热腐蚀性石油服务 /油中的 硫含量超过 0.5% wt 的热油管道 NOTE Non-silicon-killed steel pipe (e.g. ASTM A53 and API 5L) can corrode at higher rates than silicon-killed steel pipe (e.g. ASTM A106) in high-temperature sulfidation environments. 非硅镇静钢管 (e.g. ASTM A53 and API 5L)比硅镇静钢管腐蚀 (e.g. ASTM A106)腐 蚀率较高 http://richmond.chevron.com/Files/richmond/pdf/IndustryAlertvFinal2.pdf

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k. under deposit corrosion in slurries, crystallizing solutions, or cokeproducing fluids;泥浆/焦煤中的腐蚀 l. chloride carryover in catalytic reformer units, particularly where it mixes with other wet streams;氯携带 m. welded areas subject to preferential attack;焊接区块择优侵蚀 n. “hot spot” corrosion on piping with external heat tracing; note 1 外部热加温带引起的热点区域 o. steam systems subject to “wire cutting,” graphitization, or where condensation occurs. 蒸汽系统局部高温影响区域-石墨化/墨球化

NOTE 1: In services which become much more corrosive to the piping with increased temperature (e.g. sour water, caustic in carbon steel), corrosion or SCC can develop at hot spots that develop under low flow conditions. 在高温系统里, 低流量或死角区域, 这热点位置可能产生环境开裂.

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27) An example of service-specific and localised corrosion is- API574, 7.4.6) a) Corrosion under insulation in areas exposed to steam vents b) Unanticipated acid or caustic carryover from processes into non-alloyed piping c) Corrosion in deadlegs d) Corrosion of underground piping at soil-to-air interface where it ingresses or egresses.

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7.4.6.3 临时管道 因调试或大修期间系统里的临时非主要工艺管道, 如果没被拆除应当从 系统隔离或应当确保这临时管道,管线工艺与结构承载能力达到系统流 程的要求(包括潜在的无流量,高温硫化或其他损坏机制条件等等). 如果临时管道会在主管路上放置的时间很长, 在临时管道执行 lockout/tag-out 方法可以防止不适当的和无意的将临时管道投入主工艺流 程服务

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7.4.7 Erosion and Erosion-corrosion 冲蚀和冲蚀腐蚀 Erosion can be defined as the removal of surface material by the action of numerous individual impacts of solid or liquid particles, or cavitation. It can be characterized by grooves, rounded holes, waves, and valleys in a directional pattern. Erosion is usually in areas of turbulent flow such as at changes of direction in a piping system or down stream of control valves where vaporization can take place. 冲蚀可以被定义为由许多个别的固体或液体颗粒机械冲刷的作用除去表面 材料，或气蚀. 通常是在管道系统中: (1) 改变方向 / (2) 紊流 区域中发生. 当冲蚀和腐蚀共同的发生时, “冲蚀腐蚀” 会比个别的”冲蚀现象” 或 单纯材” 料腐蚀” 所造成的损坏累计量还大.

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This type of corrosion occurs at high-velocity and high-turbulence areas.

Examples of places to inspect include:

1. downstream of control valves, especially where flashing or cavitation is occurring; 控制阀的下游 2. downstream of orifices;节流孔下流 3. downstream of pump discharges; 4. at any point of flow direction change, such as the outside radii of elbows; 在任何点的流动方向改变如弯头的外半径 5. downstream of piping configurations (welds, thermowells, flanges, etc.) that produce turbulence particularly in velocity sensitive systems, such as ammonium hydrosulfide and sulfuric acid systems. 管道配置产生湍流的部分(焊缝, 热电偶套管,法兰等) 特别是在速度敏 感的系统中, 如铵的硫氢化物和硫酸系统. 被怀疑有局部的冲刷腐蚀的区域, 牵涉较大面积, 使用适当的无损检测 方法有 UT扫描 (网格扫描)和轮廓RT来测量厚度数据 Fion Zhang/ Charlie Chong 574-7

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28) Erosion can be defined as:(API574, 7.4.8) a) Galvanic corrosion of a material where uniform losses occur b) Removal of surface material by action of numerous impacts of solid or liquid particles c) Gradual loss of material by a corrosive medium acting uniformly on the material surface d) Pitting on the surface of a material to the extent that a rough uniform loss occurs 29) A combination of corrosion and erosion results in significantly greater metal loss that can be expected from corrosion or erosion alone. This type of loss occurs at: a) High-velocity and high-turbulence areas b) Areas where condensation or exposure to wet hydrogen sulphide or carbonates occur c) Surface-to-air interfaces f buried piping d) Areas where gradual loss of material occurs because of a corrosive medium

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7.4.8 Environmental Cracking 环境开裂 7.4.8.1 管道建造材料的选择通常是对SCC 环境开裂具备耐性.

Some piping systems can be susceptible to environmental cracking due to: 在管路有的管道受到环境开裂的损坏是因为: • • • •

upset process conditions 不安的工艺条件 CUI, 保温层腐蚀 unanticipated condensation 意料之外的凝结 exposure to wet hydrogen sulfide or carbonates. 暴露于湿硫化氢或碳酸盐

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Examples of this include the following.

1. Chloride SCC of austenitic stainless steels resulting from moisture and chlorides under insulation, under deposits, under gaskets, or in crevices.

2. Polythionic acid SCC of sensitized austenitic alloy steels resulting from exposure to sulfide/moisture condensation/oxygen.

3. Caustic SCC (sometimes known as caustic embrittlement).

4. Amine SCC in nonstress-relieved piping systems.

5. Carbonate SCC in alkaline systems.

6. Wet hydrogen sulfide stress cracking and hydrogen blistering in systems containing sour water.

7. Hydrogen blistering and hydrogen induced cracking (HIC) damage. This has not been as serious of a problem for piping as it has been for pressure vessels.

It is listed here because it is considered to be environmental cracking and can occur in piping although it has not been extensive. One exception where this type of damage has been a problem is longitudinally-welded pipe fabricated from plate materials.

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这方面的例子包括下面;

1. 奥氏体不锈钢-氯化物环境开裂- 保温层, 间隙,法兰面,堆积物下 造成氯化物的浓缩超过临界浓度.

2. 奥氏体不锈钢-碱性环境连多硫酸环境开裂 3. 碱性环境开裂 4. 胺类环境开裂-非应力解除热处理管道.

5. 碱性体系碳酸盐环境开裂 6. 湿硫化氢应力开裂和氢鼓泡(含有酸性水系统) 7. 氢鼓泡和氢致开裂(不常见的环境开裂,除板材制造纵向焊管

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7.4.8.2

当检验员怀疑或被告知某些管路受到环境开裂的影响时, 正切的对策是 “应 安排补充检查” When the inspector suspects or is advised that specific circuits may be susceptible to environmental cracking, he/she should schedule supplemental inspections.

合适的无损探伤方法有: 关注表面探伤方法(PT, MT, WFMT), LRUT, UT, RT) 在可用的情况下受影响的管道可以从管道系统中删除，纵向的把管道破开进 行内表面检查.

Such inspections can take the form of surface NDE [liquid penetrant examination technique (PT) or wet fluorescent magnetic particle examination technique (WFMT)], UT, or eddy current examination technique (ET). Where available, suspect spools may be removed from the piping system and split open for internal surface examination.

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7.4.8.3

如果环境开裂在容器上发现或管路被怀疑时,应当采取步骤.

If environmental cracking is detected during internal inspection of pressure vessels, and the piping is considered equally susceptible, the inspector should designate appropriate piping spools, upstream and downstream of the pressure vessel, for environmental cracking inspection. When the potential for environmental cracking is suspected in piping circuits, inspection of selected spools should be scheduled before an upcoming turnaround. Such inspection should provide information useful in forecasting turnaround maintenance.

如在系统里的容器发现环境开裂现象, 连接管路也应当被认为可能同样 的被损坏, 检验员应当在容器的上游,下游(适合的覆盖)执行环境开裂检测. 当管路被怀疑受到环境开裂影响, 相关管路应安排在”即将到来的周期检 验之前执行环境开裂检验”, 这有助于预测未来周期检验的范围与覆盖率.

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30) Environmental cracking of austenite stainless steels is caused many times by:- (API574-7.4.8) a) b) c) d)

Exposing areas to high-velocity and high-turbulence streams Excessive cyclic stresses that are often very low Exposure to chlorides from salt water, wash-up water, etc.

Creep of the material by long time exposure to high temperature and stress

Q- When the potential for environmental cracking is suspected in piping circuits, inspection of selected spools should be scheduled; (2013/June) a) b) c) d)

Within 6 months.

5 years 10 years Before an upcoming turnaround.

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32) If environmental cracking is detected during internal inspection of pressure vessels, what should the inspector do? (API574-7.4.8 / 2013 June) a) The inspector should designate appropriate piping spools upstream and downstream of the vessel to be inspected if piping is susceptible to environmental cracking. b) The inspector should consult with a metallurgical engineer to determine extent of the problems c) The inspector should review history of adjacent piping to determine if it has ever been affected. d) The inspector should consult with a piping engineer to determine the extent of the problems.

31) When the inspector suspects or is advised that specific piping circuits may be susceptible to environmental cracking, the inspector should: (API5747.4.8) a) b) c) d) 574-7

Call in a piping engineer for consultation.

Investigate the history of the piping circuit.

Obtain advice from a Metallurgical Engineer.

Schedule supplemental inspections.

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7.4.9 Corrosion Beneath Linings and Deposits 内衬下方和堆 积物,的腐蚀.

7.4.9.1 If external or internal coatings, refractory linings, and corrosion-resistant linings are in good condition and there is no reason to suspect a deteriorated condition behind them, it is usually not necessary to remove them for inspection of the piping system. 如果外部或内部的涂料, 耐火内衬, 耐腐蚀内衬 都处于良好状 态, 没有任何理由怀疑内衬里有任何损坏/恶化的状况. 这通常 是没有必要移除内衬做任何检验.

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7.4.9.2 如内衬发现有损坏

如管道内衬发现 (不是怀疑) 有损坏时, 内衬可能有必要移除观察管道内壁情 况.或者，可以从外表面的超声波探伤用于测量管道金属的厚度. 在完全粘合 的耐腐蚀内衬如焊接内衬, 爆炸复合内衬,超声探伤也可以用来探测复合界面 缺陷.

The effectiveness of corrosion-resistant linings is greatly reduced due to breaks or holes in the lining. The linings should be visually inspected for separation, breaks, holes, and blisters. If any of these conditions are noted, it may be necessary to remove portions of the internal lining to investigate the effectiveness of the lining and the condition of the metal piping beneath the lining. Alternatively, ultrasonic inspection from the external surface can be used to measure the base metal thickness. When the lining is metallic and is designed to be fully bonded, external ultrasonic examination can also be used to detect separation, holes and blisters.

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7.4.9.3 耐火内衬温度检测 Refractory linings used to insulate the pipe wall can spall or crack in service, causing hot spots that expose the metal to oxidation and creep cracking. Periodic temperature monitoring via visual, infrared, temperature indicating paints should be undertaken on these types of lines to confirm the integrity of the lining.

Corrosion beneath refractory linings can result in separation and bulging of the refractory. Microwave examination technique (MW) can examine the refractory for volumetric flaws and for separation from the shell surface. If bulging or separation of the refractory lining is detected, portions of the refractory may be removed to permit inspection of the piping beneath the refractory. Otherwise, thickness measurements utilizing UT or profile RT may be obtained from the external metal surface. 应当对这些类型的线, 通过视觉/红外/温度指示漆周期温度监测以确认内衬材料的完 整性.如果耐火衬里的隆起或分离被检测到, 部分耐火材料可以会被删除,以允许检查 管道耐火材料下方的情况.

MW/UT/RT 也能用来探测厚度与体积缺陷.

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7.4.9.4 堆积物腐蚀 Where operating deposits, such as coke are present on the internal pipe surface, NDE techniques employed from the outside of the pipe such as profile radiography , UT, and/or ET should be used to determine whether such deposits have active corrosion beneath them. 堆积物如焦炭管道内部表面上存在时, 轮廓造影(射线), UT, ET应使用, 以确定 是否这些堆积物下是否有活性腐蚀.

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32) If environmental cracking is detected during internal inspection of pressure vessels, what should the inspector do? (API574-7.4.9/2013 June) a) The inspector should designate appropriate piping spools upstream and downstream of the vessel to be inspected if piping is susceptible to environmental cracking. b) The inspector should consult with a metallurgical engineer to determine extent of the problems c) The inspector should review history of adjacent piping to determine if it has ever been affected. d) The inspector should consult with a piping engineer to determine the extent of the problems.

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33) If external or internal coatings or refractory liners on a piping circuit are in good condition, what should an inspector do? (API574-7.4.9/2013 June) a) b) c) d)

After inspection, select a portion of the liner for removal The entire liner should be removed for inspection Selected portions of the liner should be removed for inspection After inspection, if any separation, breaks, holes or blisters are found, it may be necessary to remove portions of the lining to determine the condition under it.

Q- Refractory linings used to insulate the pipe wall can spall or crack in service, causing hot spots that expose the metal to oxidation and creep cracking. NDT method undertaken on these types of lines to confirm the integrity of the lining is; (2013 June) a) b) c) d)

Infrared thermography High temperature UT WFMT PT Fion Zhang/ Charlie Chong

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34) What course of action should be followed it a coating of coke is found on the interior of a large pipe of a reactor on a Fluid Catalytic Cracking Unit? (API574-7.4.9/ 2013June) a) Determine whether such deposits have active corrosion beneath them.

If corrosion is present, thorough inspection in selected areas may be required. b) The coke deposits should be removed from the area for inspection. c) The coke deposits may be ignored – the deposits will probably protect the line from corrosion. d) Consult with a Process Engineer and a Metallurgist on the necessity of removing the coke deposits.

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7.4.10 Fatigue Cracking 疲劳裂纹 7.4.10.1 Fatigue cracking of piping systems can result from excessive cyclic stresses that are often well below the static yield strength of the material.

疲劳裂纹因循环应力导致的开裂现象, 这循环应力往往远低于静态的材 料的屈服强度. 循环应力的产生可能由于(1) 压力变化 (2) 机械(如振动) (3) 温度变化. 两种疲劳裂纹- 低周期或高周疲劳

The onset of low-cycle fatigue cracking is often directly related to the number of heat-up/cool-down cycles experienced. For example, trunnions or other attachments that extend beyond the pipe insulation can act as a cooling fin that sets up a situation favorable to thermal fatigue cracking on the hot pipe.

Thermal fatigue can also occur at mix points when process streams at different operating temperatures combine. Excessive piping system vibration (e.g. machine or flow induced) can also cause high-cycle fatigue damage.

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7.4.10.2 Fatigue cracking can typically be first detected at points of high stress intensification such as branch connections. Locations where metals having different coefficients of thermal expansion are joined by welding can be susceptible to thermal fatigue. Preferred NDE methods of detecting fatigue cracking include PT, magnetic particle examination technique (MT), and angle beam UT when inspecting from the OD for ID cracking. Suggested locations for UT on elbows would include the 3 and 9 o’clock positions. Acoustic emission examination technique (AE) also may be used to detect the presence of cracks that are activated by test pressures or stresses generated during the test. 疲劳开裂通常可以先在 ”高应力增强点” 如分支连接点检测 无损探伤方法有 MT/PT/UT或 AE AE-管道在做水压实验或受应力产生的音射探伤方法 特别关注点:建议位置 管道弯头做UT检测时应包括3点钟和9点钟位置

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7.4.10.3 It is important for the owner/user and the inspector to understand that fatigue cracking is likely to cause piping failure before detection with any NDE methods. Of the fatigue cycles required to produce failure, the vast majority are required to initiate cracking and relatively few cycles are required to propagate the crack to failure. As such, proper design and installation to prevent fatigue cracking are important. 引起“原始开裂的疲劳周期” 和 “开裂伸长导致失效的周期” 的差别特别大, 大多数 的疲劳周期是在引起原始开裂, 当原始开裂形成后, 很短的周期将导致管道失效. 上述的疲劳开裂特征给予疲劳开裂的前期发现带来很多难题, 甚至很多无损探伤 的运用也不能预防疲劳开裂带来的突发失效.

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引起“原始开裂的疲劳周期” 和 “开裂伸长导致失效的周期” 的周 期差别在低应力情况下特别的显著(红线)

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引起“原始开裂的疲劳周期” 和 “开裂伸长导致失效的周期” 的周 期差别在低应力情况下特别的显著(红线)

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Beach marks - Macro

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Striation marks

Striation marks Fion Zhang/ Charlie Chong 574-7

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Corrosion Fatigue

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http://www.me.metu.edu.tr/courses/me307/useful_info.htm Fion Zhang/ Charlie Chong 574-7

http://www.fgg.uni-lj.si/kmk/esdep/master/wg12/l0200.htm Fion Zhang/ Charlie Chong 574-7

35) Fatigue cracking of piping systems may result from a) Embrittlement of the metal due to it operating below its transition temperature b) Erosion or corrosion / erosion that thin the piping where it cracks c) Excessive cyclic stresses that are often well below the static yield strength of the material d) Environmental cracking caused by stress corrosion due to the presence of caustic, amine, or other substance.

36) Where can fatigue cracking typically be first detected? a) b) c) d)

At points of low-stress intensification such as reinforced nozzles At points of high-stress intensification such as branch connections At points where cyclic stresses are very low At points where there are only bending or compressive stresses.

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37) What are the preferred NDE methods for detecting fatigue cracking?

(API574-7.4.10/ 2013 June) a) Eddy current testing ultrasonic A-scan testing, and / or possibly hammer testing b) Liquid penetrant testing, magnetic particle testing and / or possibly acoustic emission testing. c) Visual testing, eddy current testing and / or possibly ultrasonic testing d) Acoustic emission testing, hydro-testing, and / or possibly ultrasonic testing.

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2013 June Paper – “Beach Mark” -the characteristic fracture surface marks on fatigue fracture.

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7.4.11 Creep Cracking 蠕变开裂

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7.4.11 Creep Cracking 蠕变开裂 7.4.11.1 Creep is dependent on time, temperature, and stress. Creep cracking can eventually occur at design conditions since some piping code allowable stresses are in the creep range. Cracking is accelerated by creep/ fatigue interaction when operating conditions in the creep range are cyclic.

Particular attention should be given to areas of high stress concentration. If excessive temperatures are encountered, mechanical property and microstructural changes in metals can also take place, which can permanently weaken equipment. An example of where creep cracking has been experienced in the industry is in 1 1/4 Cr steels above 900oF (482oC). 蠕变是依赖于时间, 温度和应力. 在设计条件下蠕变是可能的因为一些 管道规范允许设计应力在蠕变范围中. 在高温循环应力的工作管道, 蠕 变疲劳交互作用下开裂会加速. 1 1/4 Cr steels工作温度 >900 Deg F (482 Deg C).是个很好的例子

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Damage mechanism in weldment of 2.25Cr–1Mo steel under creep–fatigue loading Fion Zhang/ Charlie Chong 574-7

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http://www.nationalboard.org/Index.aspx?pageID=181

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7.4.11.2 NDE methods of detecting creep cracking include PT, MT, UT, RT, ET and alternating current field measurement (ACFM), in-situ metallography and dimensional verification (i.e. strapping pipe diameter) are other common practices for detection. NDE volumetric examination methods, including profile RT and UT, can be used for detection of creep cracking.

AE can be utilized to identify active creep cracking. The examination can be conducted whilst piping is in or out of operation. When the examination is conducted, the probability of detecting creep cracks can be a function of crack orientation. Any piping examined out of operation requires a pressure stimulus to activate any damage present. 蠕变裂纹检测的无损检测方法包括PT,MT, UT, RT, ET和交变磁场测量( ACFM). 原位金相和尺寸验证(即捆扎管径) 是其他常见进行检测的做法. RT和UT可以用来 发现蠕变开裂.

AE也能有来作为在职或非运转管道探测方法. 非运转管道必须受外来压力刺激, 任何存在的开裂延伸会相应的产生音射. 评估这音射是AE 探伤方法的基本原理.

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38) Creep is dependent on: a) b) c) d)

Time, temperature, and stress Material, product contained, and stress Temperature, corrosive medium, and load Time, product contained and load

39) An example of where creep cracking has been experienced in the industry is in the problems experienced with cracking of 1.25 % Chrome steels operating at temperatures above ______째F. a) b) c) d)

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500 900 1000 1200

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7.4.12 Brittle Fracture 脆性破裂

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7.4.12 Brittle Fracture 脆性破裂 7.4.12.1 Carbon, low-alloy, and other ferritic steels can be susceptible to brittle failure at or below ambient temperatures. In some cases, the refrigerating effect of vaporizing liquids such as ammonia or C2 or C3 hydrocarbons can chill the piping and promote brittle fracture in material that may not otherwise fail. Brittle fracture usually is not a concern with relatively thin wall piping. Most brittle fractures have occurred on the first application of a particular stress level (that is, the first hydrotest or overload) unless critical defects are introduced in service. The potential for a brittle failure should be considered when pressure testing or more carefully evaluated when pressure testing equipment pneumatically or when adding any other additional loads.

Special attention should be given to low-alloy steels (especially 2 1/4 Cr-1 Mo material), because they can be prone to temper embrittlement, and to ferritic stainless steels.

碳钢, 低合金等铁素体钢, 很容易在环境温度或低于在环境温度下受到脆 性破坏. 气化的液体, 如氨或C2或C3烃的制冷效果导致冷却管道从而促 进管道脆性断裂. 脆性断裂的注意事项: 2 1/4 Cr-1 Mo 材料(容易回火脆化) 和铁素体不锈钢.

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7.4.12 Brittle Fracture 脆性破裂 7.4.12.1  碳钢, 低合金等铁素体钢, 很容易在环境温度或低于在环境温度下受 到脆性破坏.  气化的液体, 如氨或C2或C3烃的制冷效果导致冷却管道从而促进管道 脆性断裂.  脆性破裂通常在第一关键超压突然发生(如水压或过载)  脆性断裂通常在薄壁管道不常见.  脆性断裂的注意事项: 2 1/4 Cr-1 Mo 材料(容易回火脆化) 和铁素体不 锈钢.

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(API570) 一些脆性断裂发生在25%水压试验压力或8KSI压力 (以较低者为准) 为了预防脆性断裂在管道试压时发生; 水压实验时,管道金属的温度应保持在至少：但不需要高于 50 Deg C >2 in. (5 cm) thick： MDMT + 30oF / 17oC <2 in. (5 cm) thick： MDMT + 10oF / 6oC

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7.4.12.2 A through-wall crack resulting from brittle fracture and causing a leak can be detected with helium leak detection. Alternatively, active cracking in embrittled material can be detected and possibly located with AE. 通壁开裂能用氦检漏探测方法, 活性裂解用 AE探伤方法检测

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活性裂解用 AE探伤方法

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40) Brittle fracture can occur in carbon, low-alloy and other ferritic steels at or below __________. a) b) c) d)

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140 degree Ambient 100 degree 30 degree

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7.4.13 Freeze Damage 冻害

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7.4.13 Freeze Damage 冻害 7.4.13.1 At subfreezing temperatures, water and aqueous solutions handled in piping systems can freeze and cause failure because of the expansion of these materials. After unexpectedly severe freezing weather, it is important to visually check for freeze damage to exposed piping components before the system thaws. If rupture has occurred, leakage can be temporarily prevented by the frozen fluid. Low points, drip-legs, and dead-legs of piping systems containing water should be carefully examined for damage. 在低于冰点的温度, 水和管道系统中处理的水溶液可以冻结而膨胀, 并导致 开裂失效. 通常这开裂因冻结固体的堵塞而起暂时防止泄漏作用, 在解冻之 前管道检验确保管道完好是必要的.

•易受影响的含水管路: •管道系统的最低点, 滴腿, 死角 http://www.vannella.com/lesson-learnt-from-valeros-mckee-refinery-explosion

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/

41) Water and aqueous solutions in piping systems may freeze and cause failure because of the a) b) c) d)

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Expansion of these materials Contraction of these materials Construction of these materials Decrease of these materials

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7.4.13.2 To prevent freeze damage, precautions need to be taken to drain, purge, or heat trace systems where moisture could collect and unexpectedly freeze during severe or sudden subfreezing temperature excursions. One of the most critical locations for these precautions is the top of the seat of relief valves and pilot-operated relief valves, when moisture could be present. Tail pipes on relief valves that discharge to the atmosphere should always have adequate drainage or heat tracing. 需要采取预防措施有: 排放,吹扫,或 伴热系统. 特别注意设备:泄压阀的座位顶部, 泄压阀尾管.

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http://www.csb.gov/csb-determines-massive-propane-fireat-valero-refinery-in-sunray-texas-resulted-from-waterfreezing-and-cracking-idle-section-of-process-piping-newsafety-video-released/

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7.4.14 Contact Point Corrosion 接触点腐蚀

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7.4.14 Contact Point Corrosion 接触点腐蚀 接触点腐蚀是因隙间中含有腐蚀性物种, 水和氧产生腐蚀现象. 潮湿的气候, 海洋 气候, 较大的接触面积将加速腐蚀,最后导致管道泄漏

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7.4.15 Nonmetallic Damage Mechanisms 非金属损伤机理

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7.5 Integrity Operating Envelopes 作业参数控制

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7.5 Integrity Operating Envelopes 作业参数控制 The use of integrity operating envelopes (or integrity operating windows) for key process parameters (both physical and chemical) that could impact piping integrity if not properly controlled reinforces inspection plans. Examples of the process parameters include temperatures, pressures, fluid velocities, pH, flow rates, chemical or water injection rates, levels of corrosive constituents, chemical composition, etc. Key process parameters for integrity operating envelopes containing upper and lower limits can be established, as needed, and deviations from these limits brought to the attention of inspection / engineering personnel.

Particular attention to monitoring integrity operating envelopes should also be provided during start-ups, shutdowns and significant process upsets.

初创, 正常运转, 停机, 显著的工艺流程不安状况下, 都应当确保作业参数在预 先设定的范围 (上线,下线). 关键作业参数有: 温度, 压力, 流体速度, pH值, 流速, 化学或注水率, 腐蚀性成分, 化学成分等 Fion Zhang/ Charlie Chong 574-7

Q- Which of the following is true of â&#x20AC;&#x153;deadlegsâ&#x20AC;? in a piping system?

(API574-7.4.3) a) b) c) d)

NDT cannot be done on deadlegs A portion of the piping which has fallen out of the test system The corrosion rate can very significantly from adjacent piping None of the above

9. If external or internal coatings or refractory liners on a piping circuit are in good condition, what should an inspector do? (API574, 7.4.9.1 / 2013 June) a) b) c) d)

After inspection, remove the liner for UT check The entire liner should be removed for inspection Selected portions of the liner should be removed for inspection Liner need not be removed if it is found to be in sound condition

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10. Where can fatigue cracking typically be first detected? a) b) c) d)

At points of low-stress intensification such as reinforced nozzles At points of high-stress intensification such as branch connections At points where cyclic stresses are very low At points where there are only bending or compressive stresses

16. Fatigue cracking of piping systems may result from a) Embrittlement of the metal due to it operating below its transition temperature b) Erosion or corrosion / erosion that thin the piping where it cracks c) Excessive cyclic stresses that are often well below the static yield strength of the material d) Environmental cracking caused by stress corrosion due to the presence of caustic, amine, or other substance.

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17. What are the preferred NDE methods for detecting fatigue cracking? a) Eddy current testing ultrasonic A-scan testing, and / or possibly hammer testing b) Liquid penetrant testing, magnetic particle testing c) Visual testing, eddy current testing and / or possibly ultrasonic testing d) Acoustic emission testing, hydro-testing, and / or possibly ultrasonic testing

18. Water and aqueous solutions in piping systems may freeze and cause failure because of the a. b. c. d.

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Expansion of these materials; Contraction of these materials Construction of these materials Decrease of these materials

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20. Why should deadlegs in piping be inspected? a. API 570 mandates the inspection of deadlegs. b. Acid products and debris build up in deadlegs. c. The corrosion rate in deadlegs can vary significantly from adjacent active piping. d. Caustic products and debris build up in deadlegs.

18- Why should deadlegs in piping be inspected? (API574-7.4.3) a) API 510 mandates the inspection of deadlegs b) Acid products and debris build up in deadlegs c) The corrosion rate in deadlegs can vary significantly from adjacent active piping. d) Caustic products and debris build up in deadlegs.

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19) Both the stagnant end and the connection to an active line of a deadleg should be monitored. In a hot piping system, why does the high point of a deadleg corrode and need to be inspected? (API574-7.4.3) a) b) c) d)

Corrosion occurs due to directed currents set up in the deadleg Erosion occurs due to convective currents set up in the deadleg.

Corrosion occurs due to convective currents set up in the deadleg Erosion occurs due to directed currents et up in the deadleg

20) What is the best thing to do with deadlegs that are no longer in service?

(API574-7.4.3) a) b) c) d)

Ultrasonically inspect often Radiograph often Inspect often Remove them

API 570-1 Fion Zhang/ Charlie Chong

8 Frequency and Extent of Inspection 8.1 General 8.2 Online Inspection 8.3 Offline Inspection 8.4 Inspection Scope.

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8.1 General 大纲 8.1.1管道检查的频率和彻底性应当由以下条件确定： a) b) c) d) e)

consequence of a failure (piping classification), 故障的后果 degree of risk (likelihood and consequence of a failure),风险程度 amount of corrosion allowance remaining,剩余腐蚀余量 available historical data,可用的历史数据 regulatory requirements.法定监管要求

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8.1.2 API 570 requires classifying piping systems according to the consequences of failure. Each refinery or process plant should review their own piping systems and develop a classification system using the information provided in API 570.

This system helps to establish minimum inspection frequencies for each piping classification.

API 570要求的管道系统根据(1) 失效的后果作为分类的依据.

API580 是以评估(1) 失效的概率与 (2) 失效的后果来确定检验 的频率与覆盖率.

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8.1.3 检验时间 Some inspections can and should be made while the piping is operating.

Inspections that cannot be made during operation should be made while the piping is not in service. Elevated operating temperature can limit the inspections techniques that can be effectively used during operation.

管道检验按照需要会在, 在职, 不在职, 在线,离线等状况下执行. 值得注意的 有,高温管道检测会给无损探伤方法带来限制与特别的要求.

http://www.twi.co.uk/news-events/casestudies/high-temperature-ultrasonicweld-inspection-083/

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8.2 Online Inspection 在职检验 8.2.1 Technical Reasons for Inspecting Online 在线检查的 “技术原因” 8.2.1.1 Certain kinds of external inspections must be done while piping is operating. Vibration and swaying is evident with process flow through the pipe.

Proper position and function of supports, hangers, and anchors is most apparent while piping is in operation at temperature. The inspector should look for distortion, settlement or foundation movement which could indicate improper design or fabrication. Pipe rollers and slide plates should be checked to ensure that they operate freely. 机械因素: 管道的振动和摇摆不定, 地基沉降, 管座, 管道悬挂,管辊

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8.2.1.2 Leakage is often more obvious during operation. Inspectors should look for signs of leakage both coming from each pipe and onto each pipe. The leakage from a pipe can indicate a hole in the pipe, and leakage onto a pipe can indicate a leak from an unobserved source (e.g. beneath insulation).

泄漏是在操作过程中往往更明显

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8.2.1.3 Thermal imaging inspections may be performed for various reasons but must be done under operating conditions. Thermal images can show pluggage and/or mal-distribution of flow that can affect corrosion mechanisms. Thermal imaging can also show wet insulation that can lead to CUI. Thermal imaging can show breakdown of internal insulating refractory which can lead to hightemperature corrosion of the pipe wall. Thermal imaging may show malfunctions of heat tracing which could allow unexpected damage mechanisms to operate.

For instance, tracing that is too hot may cause caustic SCC of carbon steel carrying caustic solutions, and tracing that is too cold may allow dew-point corrosion.

热成像检查必须在在职管道上执行: 热成像检测能提供以下信息: (1)堵塞, (2)潮湿保温层, (3) 耐热内衬状况, (4) 伴热带状况,等

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8.2.1.4 Radiography can be as effective during operation as when the piping is offline. Online radiography could detect fouling that might be washed out of piping during unit entry preparation.

在职管线轮廓射线探伤能有效的显示管内堆积物的状况

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http://www.ndt.net/article/ecndt02/414/414.htm

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8.2.2 Practical Reasons for Inspecting Online 在线检查的现实原因 8.2.2.1 On-stream inspection can increase unit run lengths by giving assurance that piping is fit for continued service.

8.2.2.2 When piping must be replaced, on-stream inspection allows an inspector to define the extent of replacement necessary and have replacement piping fabricated before the shutdown.

8.2.2.3 Units are often crowded during a shutdown, and on-stream piping inspection can increase the safety and efficiency of shutdown operations by reducing the number of people who need to be in the unit during that time.

8.2.2.4 On-stream inspection can reduce surges in work load and thus stabilize personnel requirements.

实际原因: • 在职检验你呢个及时提供管道现况, 这有助于提高管道的安全性.

• 部分的在线管道提前检验有助于减少减轻预定的大修检验工作量.

• 检验工作量合理的分摊有助于确保质量与人员安全.

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8.3 Offline Inspection 离线检测 8.3.1 A common limitation to online inspection is temperature. The equipment used in some kinds of techniques cannot operate at temperatures much above ambient. In addition, the radiant heat from some piping can be too great for technicians to make measurements safely. In both of these instances, piping inspection may need to be done when the piping is not in operation. 常见的在线检验限制是 “温度” , 高温在职管道对探伤方法, 人员操作安全, 带来很 大的限制. 有的时候管道只能在非在线下执行.

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8.3.2 Signs of wet insulation should be noted when piping is offline. Water dripping onto insulation may not show dampness during operation because heat from the pipe causes surface water to evaporate, but water deeper in the insulation can still cause CUI. If dampness is noted during a shutdown, the damp piping should be considered for CUI inspection.

8.3.3 When piping is opened for any reason, it should be inspected internally as far as accessibility permits. Some piping is large enough for internal inspection which can only occur while the piping is offline.

8.3.4 Adequate follow-up inspections should be conducted to determine the causes of defects, such as leaks, misalignment, vibration, and swaying, which were detected while the unit was operating.

其他原因: • 泄漏导致的保温层潮湿只能在低温非在职管道下检测到.

• 当管道需要执行内则检验 • 当在线管道检验的检验发现需要离线随访检验/跟踪.

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8.4 Inspection Scope 检验范围 8.4.1 Piping inspection should be frequent enough to assure that all piping has sufficient thickness to provide both pressure containment and mechanical support. For pipes undergoing uniform corrosion, calculating the corrosion rate and remaining life at each CML and setting the inspection interval at the halflife had traditionally given that assurance. The inspector, often in consultation with corrosion specialists and piping engineers, has decided the number and locations of CMLs (see API 570). RBI may be used to determine interval and extent. 管道检查应该是足够频繁,以确保所有的管道有足够的厚度提供压力要求和机械 支撑. 其他考虑因素有: 1. 对均匀腐蚀的管道, API570 半衰期壁厚计算,传统上能保证管道的安全操作.

2. 授权检验员, 管道工程师, 腐蚀专家 一起探讨 CML的 位置与数量 3. RBI可被用来确定检验时间间隔和检验程度

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8.4.2 For degradation mechanisms other than uniform corrosion, the inspector should determine the type of inspection, the frequency, the extent, and the locations of CMLs. Corrosion and pressure equipment engineers have typically helped in this process. 对非均匀腐蚀的管道, 同样的应确定检查的类型, 频率, 程度和CML位置. 质询腐蚀工程师,压力设备工程师有助于上诉工作.

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48) Qualified operating or maintenance personnel also may conduct external visual inspections when: a) b) c) d)

Satisfactory to the owner-user Acceptable to the inspector Agreeable to the maintenance supervisor Permissible to the operation supervisor

49) Who would normally report vibrating or swaying piping to engineering or inspection personnel? a) Operating personnel b) Maintenance personnel c) Jurisdictional personnel d) OSHA personnel

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9 Safety Precautions and Preparatory Work 安全注意事项和筹备工作 9.1 Safety Precautions 9.2 Preparatory Work 9.3 Investigation of Leaks.

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9.1 Safety Precautions 安全预防 •

描述了一般石油行业安全要求

在检查在职管道时, 如有通壁泄漏的风险时, 以下措施应考虑作为减轻通壁事件的 风险

1. Use of profile RT or UT NDE to inspect under deposits and determine the amount of corrosion damage, before disturbing the deposits. 还没扰乱管道外表堆积物前应用轮廓射线或其他方法检测实际状况.

2. Develop an emergency response plan in the event that a through-wall leak develops. This plan should include provisions to isolate the affected area, temporary repair provisions, and any additional PPE requirements. 制定应急方案: 设定隔离区, 临时修理方法, 以及任何额外PPT要求.

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9.2 Preparatory Work 准备工作 9.2.1 All possible preparatory work should be done before the scheduled start of inspection. Scaffolds should be erected, insulation removed and surface preparation completed where required. Buried piping should be excavated at the points to be inspected. Equipment required for personal safety should be checked to determine its availability and condition. Any necessary warning signs should be obtained in advance, and barricades should be erected around all excavations. The appropriate signs and barricades as required by the site and jurisdiction must be in place before radiography is performed. 检查前应做所有的筹备工作应当完善 (安全, 空间要求等) 9.2.2 The tools needed for inspection should be checked for availability, proper working condition, calibration and accuracy. The following tools and instruments are often used in inspection of piping: 确保检验工具在完好校准和规定精确度状态.

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推荐的检验工具有:

ACFM crack detection equipment; / alloy analyzer (nuclear source for material identification); / borescope and/or fiber-optic; / camera; / crayon or marker; / direct-reading calipers with specially-shaped legs; / eddy current equipment; / flashlight and additional portable lighting; / hammer; / ID and OD transfer calipers; / infrared pyrometer and camera; / knife; / leak detector (sonic, gas test, or soap solution); / liquid penetrant equipment; / magnet; / magnetic particle equipment; / magnifying glass; / material identification kit; / microwave inspection equipment; / mirror; / notebook or sketches; / paint; / pit-depth gauge; / portable hardness tester; / radiographic equipment; / remote television camera (for internal inspection); / scraper; / steel rule; / thickness or hook gauge; / ultrasonic equipment; / wire brush.

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9.2.3 In addition to the list above, grit blasting or comparable equipment may be required to remove paint and other protective coatings, dirt, or corrosion products so that the surface is properly prepared for the inspection technique e.g. inspection for cracks with MT. 值得留意的是,在执行检验时有的时候有必要把管道表面清理, 清理的方法包 括冲砂能把表面的腐蚀物, 涂层等清除.

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9.3 Investigation of Leaks 泄漏调查 On-stream piping leaks in process units can occur for various reasons.

Those who investigate the leak may be particularly at risk to the consequence associated with release of the process fluid. A site may want to create a general safety procedure to be followed during a piping leak investigation. A further precaution is to hold a safety review before any leak investigation. The review would consider the state of a piping system in terms of pressure, temperature, remaining inventory of process fluids, potential damage mechanisms and similar factors. 泄漏调查安全事项有 (1) :遵守安全遵循的程序 (2) 开发具针对性的安全评审 (应考虑压力,.温度,剩余流体, 潜在的破坏机理和类似的因素) 按照上述文件执行工作.

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特定安全评审应定义: •

•

a “hot zone” around the leak site, and establish PPE and additional firefighting equipment requirements to perform work inside this zone; 设定热点区域, 作为特殊安全要求区 decontamination requirements upon exit from the hot zone and other requirements necessary to protect personnel and the environment. 人员安全, 环境保护和离开污染区去污要求等

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10 Inspection Procedures & Practices 检查程序及实践 10.1 External Visual Inspection 10.2 Thickness Measurements 10.3 Internal Visual Inspection 10.4 Nonmetallic Piping 10.5 Pressure Tests 10.6 Hammer Testing 10.7 Tell-tale Hole Drilling 10.8 Inspection of Piping Welds 10.9 Other Inspection Methods 10.10 Inspection of Underground Piping 10.11 Inspection of New Fabrication, Repairs and Alterations.

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10.1 External Visual Inspection 外部目视检查

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10.2 Thickness Measurements 厚度测量

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10.3 Internal Visual Inspection 内部目视检查

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10.4 Nonmetallic Piping 非金属管道

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10.5 Pressure Tests

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10.6 Hammer Testing

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10.7 Tell-tale Hole Drilling

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10.8 Inspection of Piping Welds .

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10.9 Other Inspection Methods

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10.10 Inspection of Underground Piping

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10.11 Inspection of New Fabrication, Repairs and Alterations

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Q.1 A typical soil corrosion is aggravated under which of the following conditions a) b) c) d)

Hgh moisture content and high resistivity of soil.

Hgh moisture content and low resistivity of soil.

Low moisture content and high resistivity of soil.

Low moisture content and low resistivity of soil.

Q.2 Typical â&#x20AC;&#x153;high cycle fatigue is: a) b) c) d)

Thermal fatigue.

Mechanical fatigue.

Vibration fatigue.

Both a and b.

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API571, 4.2.16 Mechanical Fatigue 4.2.16.1 Description of Damage a) Fatigue cracking is a mechanical form of degradation that occurs when a component is exposed to cyclical stresses for an extended period, often resulting in sudden, unexpected failure. b) These stresses can arise from either mechanical loading or thermal cycling and are typically well below the yield strength of the material. 这里所说的是机械非连贯造成的易受疲劳损坏机理影响的现象. 不是常规的”机械疲劳” 如震动管道产生的疲劳损坏等. 每个行业学会对技术单词有不同的定义.

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11 Determination of Minimum Required Thickness 所需的最小厚度

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11.1 Piping 管道 11.1.1 General 大纲 11.1.1.1 In specifying piping for original installation, ASME B31.3 requires that the following be taken into account when pipe thickness is determined: 管道设置时ASME B31.3 需要采取以下考虑:

1. corrosion allowance;腐蚀余度 2. threads and other mechanical allowances (consideration should be given to crevice corrosion and loss of thickness due to cutting the threads);线程和其他机械余度 3. stresses caused by mechanical loading, hydraulic surge pressure, thermal expansion, and other conditions; 机械负荷, 液 压冲击压力, 热膨胀性, 和其它条件引起的应力 4. reinforcement of openings; 开口加强 5. other allowances. 其他余度

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Additional thickness is nearly always required when Item a) through Item e) are considered. Normally, the engineer will select the pipe schedule that accommodates the required thickness plus the manufacturing tolerance permitted by the pipe material specification. 一般上当考虑 (a) 至 (e) 时几乎总是需要额外的厚度.

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11.1.1.2 Additional thickness is often needed near branch connections.

This additional thickness is usually provided by one of the following: 分支连接 额外的厚度通常由 • a welding tee,焊接三通 • a saddle,马鞍; • an integrally reinforced branch outlet (e.g. a weldolet), 整 体增强的分支 • the header and/or run pipe thickness is greater than required by design conditions.大于设计要求的配件 These calculations should be performed by a piping engineer 计算应由管道工程师进行 Fion Zhang/ Charlie Chong 574-11

11.1.1.3 For in-service piping subject to localized damage (e.g. pitting, cracking, blistering, gouging), as well as weld misalignment and distortion, the inspector may choose to evaluate the piping strength and suitability for continued service utilizing the approach discussed in API 579. Such an analysis should be performed by, or under the direction of, a piping engineer.

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11.1.2 Pressure Design Thickness The Barlow formula gives results that are practically equivalent to those obtained by the more elaborate ASME B31.3 formula except in cases involving high pressures where thick-walled tubing is required. Metallic pipe for which t > d /6 or P/SE > 0.385 requires special consideration.

API570公式实际上是等效的更加详细ASME B31.3的简化公 式

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11.1.3 Structural Minimum Thickness 结构最小厚度 除了压力设计厚度, 用户应指定如何确定在他们的设施结构最小厚度或运用 以下的数据

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在设计结构最低厚度时, 其他考虑因素有; 1. screwed piping and fittings; 螺纹管道及配件 2. piping diameters greater than 24 in. (610 mm); 管道的直径大于24英寸 3. temperatures exceeding 400 Deg F (205D Deg C) for carbon and lowalloy steel; 温度超过400 Deg F 4. higher alloys (other than carbon steel and Cr-Mo); 更高的合金 5. spans in excess of 20 ft (6 m); 跨度超过20英尺 6. high external loads (e.g. refractory lined, pipe that is also used to support other pipe, rigging loads, and personnel support loading);高外 部负载 7. excessive vibration.过度的振动

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Engineering calculations, typically using a computerized piping stress analysis program 工程计算, 通常使用一个计算机化的管道应力分析程序, 以确定结构的最 小厚度 Austenitic stainless steel piping often have lower minimum structural thickness requirements based upon their typically higher strength, higher toughness and thinner initial thicknesses of piping components. Separate tables are often created for stainless steel piping. 奥氏体不锈钢管道根据他们通常较高 的强度的往往具有较低的最小结构厚 度要求

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11.1.4 Minimum Required Thickness 所需的最小厚度 1. STEP 1 Calculate pressure design thickness per rating code. 计算压力设计厚 2. STEP 2 Determine structural minimum thickness per owner/user table or engineering calculations. 业主/用户表或工程计算确定结构的最小厚度 3. STEP 3 Select minimum required thickness. This is the larger of the pressure design thickness or structural minimum thickness determined in Step 1 and Step 2. 在步骤1和步骤2中确定的较大值 对于服务具有高潜在失败后果, 管道工程师应考虑增加所允许的 最小厚度

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11.1.5 Minimum Alert Thickness 最小警报厚度 The alert thickness signals the inspector that it is timely for a remaining life assessment 最小警报厚度提醒及时的剩余寿命 评估

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11.2 Valves and Flanged Fittings 阀门和法兰配件 The formula for calculating the minimum required thickness of pipe can be adapted for valves and flanged fittings by using the factor of 1.5 and the allowable stress for the material specified in ASME B31.3. 算所需的最小厚度的公式计

The calculations described above do not apply to welded fittings. The calculations for pipe can be applied to welded fittings using appropriate corrections for shape, if necessary.管 的计算可以适用于焊接接头, 如有必要乘于适当的形状修正系数.

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12 Records 记录

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12.1 General 保持一个详细完整的记录是授权检验员的一项重要职责, 以及许多法规的要求 (e.g. OSHA 29 CFR 1910.119).

Inspection records should contain: a) b) c) d) e) f) g) h) i) j)

original date of installation;原安装日期 specifications of the materials used;所使用的材料规格 original thickness measurements;原始厚度的测量 locations and dates of all subsequent thickness measurements;所有后 续厚度测量的地点和日期 calculated retirement thickness;计算的退休厚度 repairs and replacements;维修及更换 temporary repairs;应急修理 pertinent operational changes i.e. change in service;相关的操作的变化 Fitness-For-Service assessments;适用性评价 RBI assessments. 风险分析检验评估

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12.2 Sketches 草图 1. Sketches have the following functions.草图具有以下功能 2. Identify particular piping systems and circuits in terms of location, size, material specification, general process flow, and service conditions.识 别识别管道系统和管路的位置,大小,材料的规格,一般工艺流程,服务 条件b) Show points to be opened for visual inspection and parts that require replacement or repair.需要维修或更换的部件 3. Serve as field datasheets on which can be recorded the locations of thickness measurements, corrosion findings, and sections requiring replacement. These data can be transferred to continuous records at a later date.作为现场数据表 4. Assist at future inspections in determining locations that require examination 协助确定今后的检查需要检查的位置

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12.3 Numbering Systems 编数系统 Typically, a coding system is used to uniquely identify the process unit, the piping system, the circuit, and the CMLs. 12.4 Thickness Data 厚度数据 A record of thickness data obtained during periodic or scheduled inspections provides a means of arriving at corrosion or erosion rates and expected material life. Some companies use computerized record systems for this purpose. The data can be shown on sketches or presented as tabulated information attached to the sketches. Figure 34 shows one method of tabulating thickness readings and other information.

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12.5 Review of Records 记录复审 Records of previous inspections and of inspections conducted during the current operating period should be reviewed soon after the inspections are conducted to schedule the next inspection date. This review should provide lists of areas that are approaching retirement thickness, areas that have previously shown high corrosion rates, and areas in which current inspection has indicated a need for further investigation. From these lists, a work schedule should be prepared for additional on-stream inspection, if possible, and for inspections to be conducted during the next shutdown period. Such a schedule will assist in determining the number of inspectors to be assigned to the work. In addition, from the review of the records of previous inspections, a list should be made of all expected repairs and replacements. This list should be submitted to the maintenance department far enough in advance of the shutdown to permit any required material to be obtained or, if necessary, fabricated.

This list will also assist the maintenance personnel in determining the number of personnel required during the shutdown period.

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12.6 Record Updates 记录更新 Records should be updated following inspection activities within a reasonable amount of time affording the inspector enough time to properly gather, analyze and record data. Many sites have internal requirements indicating a maximum duration between obtaining data and updating records. These requirements generally allow records be updated within a few weeks of completing the inspection activities. Establishing a time frame for record updates helps assure data and information are accurately recorded and do not become lost and details forgotten.

12.7 Audit of Records 审计记录 Inspection records should be regularly audited against code requirements, site’s quality assurance inspection manual and site procedures. The audit should assess whether the records meet requirements and whether the records are of appropriate quality/accuracy. Regular audits provide a means to identify gaps and deficiencies in existing inspection programs and define corrective actions, such as focused training.

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