常常经常，绝缘下的腐蚀（Cui）是一个看不见的看法，在表面下方潜伏的问题。也就是说，直到你终于发现泄漏扰乱你的系统，可能导致安全事件或在领域的小姐附近。

崔的斗争是普遍存在的,如果你不’t yet have a history of CUI leaks, it’s only a matter of time until you encounter your first. So, why is CUI such a common problem and is there anything you can do to stop it? Should you be concerned about CUI at your operations?

Our highly experienced team of API-certified technicians in the Braun IntertecNondestructive Examination（NDE）组可以阐明崔为系统运营商的广泛问题。

What is CUI and what causes it?

根据API 583中的定义，CUI损坏的特征在于由于局部的被动击穿而普通金属浪费或蚀。更简单地，它是一种氧气腐蚀的形式，在暴露于水分和氧气时发生在碳和低合金钢上。

This corrosive damage occurs when water is absorbed by insulation or collects beneath it. Water is absorbed due to breaks in the insulation or pipe jacketing and cannot dissipate from the system. Sources of moisture range from rainwater, spillage from process operations or even condensation on a metal surface in a humid environment.

When considering your own system’s vulnerability to CUI, strictly speaking, the API 583 standard lists a temperature range of 32 F to 212 F when looking for moisture in a system. However, this range should be extended to 10 F to 350 F to account for fluctuations in the system’s operating temperature, ineffective insulation maintenance, temperature gradients within the equipment considered and various operating modes.

We find that this prescribed temperature range can be a tricky factor in gauging the risk and severity of CUI damage because of how users tend to report temperatures and whether they’re reporting the metal or process temperatures. But, generally speaking, the more severe damage takes place at higher temperature ranges between 170 F and 230 F.

涉及崔风险的其他因素是绝缘中的污染物。氯化物和硫化物等化学物质有时存在并且可以有助于腐蚀性环境。

为什么CUI检查和维护计划重要，谁应该关注？

Effective CUI programs matter for all systems. However, these programs are especially important for older systems with aging piping or where insulation has not been well maintained. Where corrosion is present, it’s common to see anywhere from 5-15 millimeters of corrosion every year—but in the most extreme situations this rate of corrosion can be much more severe. The issue of unaddressed corrosion within your system isn’t merely a question of reliability. This yearly rate of corrosion represents a major safety risk for your personnel that should not go ignored.

Quite simply, every system operator should be concerned about CUI. Expectedly, systems in high humidity, high precipitation regions are prone to having the worst CUI issues. However, even in a dry climate moisture collecting under insulation is still possible due to nearby cooling tower plumes and steam tracing leaks.

同样，所有操作条件，无论是在主动操作中还是不应该具有CUI程序。事实上，在再生循环期间或经常在环境条件下经常在崔温度范围内进行循环和退出的系统，即使系统的正常运行在CUI温度范围内，也可以体验最具破坏性的腐蚀损坏。

什么标准通知CUI计划？

API标准570,571,574和583所有覆盖Cui的损坏机构，易腐蚀的区域以及管道的设计，维护和检查实践。API 570在寻找最常见于CUI的区域时最有用。API 583是用于检查和预防技术的主要资源。

The National Association of Corrosion Engineers (NACE) also publishes a useful资源论CUI指南的主题。

有更多关于Cui的问题吗？通过点击下面的按钮并填写联系我们的表格来联系我们的一个非破坏性检查专家。