1.1 本规程涵盖了用于储存液体的新型和在用地上储罐的声发射（AE）检查指南。 1.2 本规程将检测在检查过程中受到压力的传感器覆盖区域内的声发射。对于平底储罐，这些区域通常包括侧壁（如果压力施加在液位以上，则包括顶部）。除非传感器位于底部，否则检查可能无法检测到平底储罐底部的缺陷。 1.3 这种做法可能要求储罐承受的负荷大于正常使用中遇到的负荷。储罐的正常内容物通常可用于施加该荷载。 1.4 这种做法不适用于将在高于检查压力的压力下运行的储罐。 1.5 在进行此检查之前，无需排空或清洁油箱。 1.6 本规程适用于碳钢、不锈钢、铝和其他金属制成的储罐。 1.7 这种做法还可以检测储罐衬里中的缺陷（例如，高体积、酚醛树脂和其他脆性材料）。 1.8 声发射测量用于检测和定位发射源。可使用其他无损检测方法确认声发射指示的性质和重要性。其他无损检测技术的程序不在本规程范围内。 1.9 检查液体必须高于其冻结温度，低于其沸腾温度。 1.10 叠加的内部或外部压力不得超过设计压力。 1.11 在检查过程中可能会发现泄漏，但检测泄漏并非本规程的目的。 1.12 单位- 以国际单位制或英寸-磅单位表示的数值应视为标准值。每个系统中规定的值可能不是精确的等效值；因此，每个系统应相互独立使用。将两个系统的值合并可能会导致不符合标准。 1.13 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全和健康实践，并确定监管限制的适用性。 第节给出了具体的预防说明 8. . 1.14 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 概述- 本程序用于评估常压储罐的结构完整性。声发射方法可以检测加压过程中应力位置的缺陷。这些位置包括罐壁、将衬垫连接到罐的焊缝、喷嘴附件以及将周向加劲肋连接到罐的焊缝。 声发射的潜在来源包括: 5.1.1 在母材和焊接相关区域: 5.1.1.1 裂缝， 5.1.1.2 腐蚀的影响，包括腐蚀产物开裂或局部屈服， 5.1.1.3 应力腐蚀开裂， 5.1.1.4 某些物理变化，包括屈服和错位， 5.1.1.5 脆化，以及 5.1.1.6 凹坑和凿槽。 5.1.2 在焊接相关区域: 5.1.2.1 未完全融合， 5.1.2.2 缺乏渗透， 5.1.2.3 咬边，以及 5.1.2.4 孔隙和孔隙度。 5.1.2.5 内含物: 5.1.2.6 污染 5.1.3 在母材中: 5.1.3.1 层压。 5.1.4 在脆性衬里中: 5.1.4.1 裂缝， 5.1.4.2 芯片，以及 5.1.4.3 夹杂物。 注1: 并非所有这些来源通常都在现场检查中遇到，有些是在实验室条件下检测到的。 5.2 本实践结果的准确性可能会受到与仪器设置和校准、背景噪声、材料特性和受检结构特征相关的因素的影响。 5.3 本实践的结果是确定储罐是否适合使用，或者在确定之前是否需要进行后续无损检测。 5.4 无应力区域- 非应力区域的缺陷和被动缺陷（在施加荷载下结构不重要的缺陷）不会产生声发射。这些位置可以包括屋顶和与平台、梯子和楼梯相关的某些焊缝。 5.5 被动缺陷（应力区）- 应力区域中的某些缺陷在应力期间可能不会产生声发射。 这通常意味着缺陷的应力容限高于检查应力。 5.6 填充- 填充速度应使流体流动引起的声发射活动最小化，并使血管变形与施加的载荷保持平衡。在整个填充计划中使用保持期来评估在没有填充噪声的情况下由加载结构产生的声发射活动。 5.7 跟进- 应使用其他无损检测方法检查声发射检测到的声源。 5.8 背景噪声- 过量的背景噪声可能会扭曲声发射数据或使其无用。用户必须了解常见的背景噪声源:高填充率（可测量的流动噪声）、物体与储罐的机械接触（冲击、摩擦、微动）、电磁干扰（EMI）（电机、焊工、桥式起重机）和射频干扰（RFI）（广播设施、对讲机）、管道或软管连接处的泄漏、储罐底部或墙壁的泄漏，气载颗粒物、昆虫或雨滴、加热器、喷雾器、搅拌器、液位检测器和储罐内的其他部件、储罐内发生的化学反应以及气泡的流体动力运动。 如果无法消除或控制背景噪声，则不应使用此做法。

1.1 This practice covers guidelines for acoustic emission (AE) examinations of new and in-service aboveground storage tanks of the type used for storage of liquids. 1.2 This practice will detect acoustic emission in areas of sensor coverage that are stressed during the course of the examination. For flat-bottom tanks these areas will generally include the sidewalls (and roof if pressure is applied above the liquid level). The examination may not detect flaws on the bottom of flat-bottom tanks unless sensors are located on the bottom. 1.3 This practice may require that the tank experience a load that is greater than that encountered in normal use. The normal contents of the tank can usually be used for applying this load. 1.4 This practice is not valid for tanks that will be operated at a pressure greater than the examination pressure. 1.5 It is not necessary to drain or clean the tank before performing this examination. 1.6 This practice applies to tanks made of carbon steel, stainless steel, aluminum and other metals. 1.7 This practice may also detect defects in tank linings (for example, high-bulk, phenolics and other brittle materials). 1.8 AE measurements are used to detect and localize emission sources. Other NDT methods may be used to confirm the nature and significance of the AE indications (s). Procedures for other NDT techniques are beyond the scope of this practice. 1.9 Examination liquid must be above its freezing temperature and below its boiling temperature. 1.10 Superimposed internal or external pressures must not exceed design pressure. 1.11 Leaks may be found during the course of this examination but their detection is not the intention of this practice. 1.12 Units— The values stated in either SI units or inch-pound units are to be regarded as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standards. 1.13 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 8 . 1.14 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 General— This procedure is used for evaluation of the structural integrity of atmospheric storage tanks. The AE method can detect flaws which are in locations that are stressed during pressurization. Such locations include the tank wall, welds attaching pads to the tank, nozzle attachments, and welds attaching circumferential stiffeners to the tank. Among the potential sources of acoustic emission are: 5.1.1 In both parent metal and weld associated regions: 5.1.1.1 Cracks, 5.1.1.2 The effect of corrosion, including cracking of corrosion products or local yielding, 5.1.1.3 Stress corrosion cracking, 5.1.1.4 Certain physical changes, including yielding and dislocations, 5.1.1.5 Embrittlement, and 5.1.1.6 Pits and gouges. 5.1.2 In weld associated regions: 5.1.2.1 Incomplete fusion, 5.1.2.2 Lack of penetration, 5.1.2.3 Undercuts, and 5.1.2.4 Voids and porosity. 5.1.2.5 Inclusions: 5.1.2.6 Contamination. 5.1.3 In parent metal: 5.1.3.1 Laminations. 5.1.4 In brittle linings: 5.1.4.1 Cracks, 5.1.4.2 Chips, and 5.1.4.3 Inclusions. Note 1: Not all of these sources are typically encountered in field examination, some are detected under laboratory conditions. 5.2 Accuracy of the results from this practice can be influenced by factors related to setup and calibration of instrumentation, background noise, material properties and characteristics of an examined structure. 5.3 The outcome of this practice is to determine if the tank is suitable for service or if follow-up NDT is needed before that determination can be made. 5.4 Unstressed Areas— Flaws in unstressed areas and passive flaws (those that are structurally insignificant under the applied load) will not generate AE. Such locations can include the roof and certain welds associated with platforms, ladders, and stairways. 5.5 Passive Flaws (in Stressed Areas)— Some flaws in stressed areas might not generate acoustic emission during stressing. This usually means that the flaw has a higher stress tolerance than the examination stress. 5.6 Filling— Filling proceeds at rates which minimize AE activity caused by fluid flow and which allow vessel deformation to be in equilibrium with applied load. Hold periods are used throughout the filling schedule to evaluate AE activity produced by the loaded structure in the absence of fill noise. 5.7 Follow-up— Sources detected by AE should be examined using other NDT methods. 5.8 Background Noise— Excess background noise may distort AE data or render them useless. Users must be aware of common sources of background noise: high fill rate (measurable flow noise), mechanical contact (impact, friction, fretting) with the tank by objects, electromagnetic interference (EMI) (motors, welders, overhead cranes) and radio frequency interference (RFI) (broadcasting facilities, walkie talkies), leaks at pipe or hose connections, leaks in the tank bottom or walls, airborne particles, insects, or rain drops, heaters, spargers, agitators, level detectors and other components inside the tank, chemical reactions occurring inside the tank, and hydrodynamic movement of gas bubbles. This practice should not be used if background noise cannot be eliminated or controlled.