FTA 与事件树 · 情景应用 | Fault Tree & Event Tree · Scenario in Action

本课目标 | Learning objectives

1. 按三步走完一个场景，并说出每一步的依据
2. 区分「更有效」与「更先做」两类答案
3. 把结论写回自己的术语表

上传个人图片（可选）/ Add a photo (optional) 清除已上传图片 / Remove photo

图片经过压缩后保存在当前浏览器。导出失败时，可在下方预览图片上长按保存。/ The photo is compressed and stored in this browser. If download fails, long-press the preview below to save it.

场景走一遍 | Walk the scenario

你负责分析「储罐区泄漏起火」。团队已列出的直接原因是：密封失效（0.01/年）、静电积聚（0.02/年）、雷击（0.005/年）、外力撞击（0.002/年）。有人主张把四个原因挂在顶事件下一个 AND 门下；另一人主张全部相加得 0.037/年。你还注意到静电积聚与雷击共用同一套接地系统。

You analyse tank-farm leak and fire. Direct causes on the table: seal failure 0.01 per year, static build-up 0.02, lightning 0.005, impact 0.002. One colleague wants all four under an AND gate; another wants to add them to 0.037 per year. You also note static build-up and lightning share the same earthing system.

1. 第一步：纠正门逻辑——四个原因是「任一即可」关系，应挂 OR 门（AND 门意味着四者必须同年同时发生，概率被缩小到 10⁻⁹ 量级，明显荒谬）；但也不能直接相加：静电与雷击共用接地系统，属共因 — Step 1 — fix the gate logic: any one of the four suffices, so they sit under an OR gate; an AND gate would mean all four in the same year, an absurd 10⁻⁹-scale number. But do not simply add either: static and lightning share the earthing system, a common cause
2. 第二步：共因处理——把「接地系统失效」作为独立事件画出，挂在静电与雷击两条支路的共同上游；静电 0.02 与雷击 0.005 中已包含接地良好的前提，故近似相加时对这两条支路加上共因修正（或单独评接地失效频率并重建支路）。修正后顶事件 ≈ 0.01+0.02+0.005+0.002 共因上浮，约 0.04–0.05/年 — Step 2 — handle the common cause: draw earthing-system failure as its own event upstream of both the static and lightning branches; the 0.02 and 0.005 already assume good earthing, so add a correction or rebuild those branches on the earthing failure frequency. Corrected top event lands around 0.04 to 0.05 per year
3. 第三步：接事件树与行动——顶事件后接屏障：可燃气体探测（PFD 0.1）→ 紧急切断（PFD 0.05）→ 围堰+泡沫（PFD 0.1）；最坏可信路径=三道全失效，频率 ≈ 0.04×0.1×0.05×0.1 = 2×10⁻⁵/年。行动优先级：先查接地系统实测电阻并纳入季度检测（降共因），再给切断阀加独立回路 — Step 3 — feed the event tree and act: after the top event, barriers are gas detection (PFD 0.1), emergency isolation (0.05), bund plus foam (0.1); the worst credible path of all three failing is about 0.04 times 0.1 times 0.05 times 0.1, or 2×10⁻⁵ per year. Priority: measure and quarterly-test the earthing resistance to attack the common cause, then give the isolation valve an independent loop

走完这三步再往下答题；答案不是背出来的，是按步骤推出来的。/ Work the three steps before answering — the answer is derived, not recalled.

情景自测 | Scenario check

考点应用Exam-point application

这道题考什么：考门逻辑判定与共因修正。
Tests gate choice and common-cause correction.

四个泄漏起火原因（密封、静电、雷击、撞击）该用什么门连接？

How should seal failure, static, lightning and impact connect to the top event?

自编练习题，不是 BCSP 官方真题，也不能用来预测分数。 / Original practice item, not an official BCSP exam question.

动手练 | Practice

1. 把本情景完整画成一页树图（故障树+事件树各半页）。
Draw the whole case on one page: half fault tree, half event tree.

学习打卡与笔记 | Progress & notes

已完成 0/4 项 / 0/4 tasks complete

进度保存在当前浏览器，不会自动跨设备同步。/ Progress is stored in this browser only.

可靠来源 | Official references

BCSP — CSP Examination Blueprint (CSP11)

BCSP — Official Self-Assessments

BCSP — Certified Safety Professional (CSP)

Pearson VUE — CSP 考试预约 / Scheduling

本课为一般性学习资料，不替代现场专业评估、法规要求或组织程序。/ Educational content only.